[Federal Register Volume 68, Number 250 (Wednesday, December 31, 2003)]
[Notices]
[Pages 75531-75552]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-32217]
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ENVIRONMENTAL PROTECTION AGENCY
[FRL-7605-8]
Standards for the Use or Disposal of Sewage Sludge; Final Agency
Response to the National Research Council Report on Biosolids Applied
to Land and the Results of EPA's Review of Existing Sewage Sludge
Regulations
AGENCY: Environmental Protection Agency.
ACTION: Notice.
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SUMMARY: The U.S. Environmental Protection Agency (EPA) is publishing
the results of its review of regulations under the Clean Water Act
(CWA) governing the use and disposal of sewage sludge. The Clean Water
Act requires that EPA review the sewage sludge regulations for the
purpose of identifying additional toxic pollutants and promulgating
regulations for such pollutants consistent with the requirements. As
part of this review, EPA commissioned the National Research Council
(NRC) of the National Academy of Sciences to independently review the
technical basis of the chemical and microbial regulations applicable to
sewage sludge that is applied to land. In July 2002, the NRC published
a report entitled ``Biosolids Applied to Land: Advancing Standards and
Practices'' in response to the EPA's request.
In April 2003 EPA announced and requested public comments on a
preliminary strategy explaining how EPA planned to respond to the NRC
report recommendations. Today, the Agency is announcing its final
response, also known as the final action plan, to the NRC report. EPA
is also presenting the results of its review of existing sewage sludge
regulations to identify additional toxic pollutants in sewage sludge
for potential future regulations. Based on a screening assessment of
chemical pollutants for which EPA had adequate data (e.g., human health
benchmark values, and information on fate and transport in the
environment), as well as concentration data in sewage sludge for those
pollutants, EPA has identified 15 pollutants for possible regulation.
This list constitutes the final results of EPA's current review of
existing sewage sludge regulations as required by the CWA. These
pollutants will undergo a more refined risk assessment and risk
characterization which may lead to a notice of proposed rulemaking
under the Clean Water Act. In this notice, the term ``biosolids'' is
used interchangeably with ``sewage sludge,'' which is defined in the
regulations and used in the statute.
ADDRESSES: The public record for this action has been established under
Docket ID No. OW-2003-0006. Materials are available for public viewing
at the Water Docket in the EPA Docket Center, EPA West, Room B102, 1301
Constitution Ave., NW., Washington, DC. The EPA Docket Center Public
Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through
Friday, excluding legal holidays. The telephone number for the Public
Reading Room is (202) 566-1744, and the telephone number for the Water
Docket is (202) 566-2426.
FOR FURTHER INFORMATION CONTACT: Rick Stevens, U.S. Environmental
Protection
[[Page 75532]]
Agency, Office of Water, Health and Ecological Criteria Division
(4304T), 1200 Pennsylvania Avenue, NW., Washington, DC 20460. (202)
566-1135. [email protected].
SUPPLEMENTARY INFORMATION:
General Information
A. Interested Entities
Entities potentially interested in this notice are those who
prepare sewage sludge, apply sewage sludge to land, dispose of sewage
sludge in a surface disposal unit, or incinerate sewage sludge in a
sewage sludge incinerator. Categories and entities include:
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Category Examples of interested entities
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State/Local/Tribal Government.......... Publicly owned treatment works
and other treatment works that
treat domestic sewage, prepare
sewage sludge and/or apply
sewage sludge to the land,
place sewage sludge in a
surface disposal unit, or
incinerate sewage sludge.
Federal Government..................... Federal Agencies with treatment
works that treat domestic
sewage, prepare sewage sludge
and/or apply sewage sludge to
the land, place sewage sludge
in a surface disposal unit, or
incinerate sewage sludge.
Farmers, Ranchers and Home Gardeners... Individuals who apply sewage
sludge to land.
Industry............................... Privately-owned treatment works
that treat domestic sewage, as
well as persons who receive
sewage sludge and change the
quality of the sewage sludge
before it is applied to the
land, place sewage sludge in a
surface disposal unit, or
incinerate sewage sludge.
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This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be interested in this
action. This table lists the types of entities that EPA is now aware
could potentially be interested in this action. Other types of entities
not listed in the table could also be interested. To determine whether
your facility is affected by this action, you should carefully examine
today's notice. If you have questions regarding the applicability of
this action to a particular entity, consult the person listed in the
preceding FOR FURTHER INFORMATION CONTACT section.
B. How Can I Get Copies of This Document and Other Related Information?
1. Docket. EPA has established an official public docket for this
action under Docket ID No. OW-2003-0006. The official public docket
consists of the documents specifically referenced in this action, any
public comments received, and other information related to this action.
Although a part of the official docket, the public docket does not
include Confidential Business Information (CBI) or other information
whose disclosure is restricted by statute. The official public docket
is the collection of materials that is available for public viewing at
the Water Docket in the EPA Docket Center, EPA West, Room B102, 1301
Constitution Ave., NW., Washington, DC. The EPA Docket Center Public
Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through
Friday, excluding legal holidays. The telephone number for the Public
Reading Room is (202) 566-1744, and the telephone number for the Water
Docket is (202) 566-2426.
2. Electronic Access. You may access this Federal Register document
electronically through the EPA Internet under the Federal Register
listings at http://www.epa.gov/fedrgstr/.
An electronic version of the public docket is available through
EPA's electronic public docket and comment system, EPA Dockets. You may
use EPA Dockets at http://www.epa.gov/edocket/ to view public comments,
access the index listing of the contents of the official public docket,
and to access those documents in the public docket that are available
electronically. Although not all docket materials may be available
electronically, you may still access any of the publicly available
docket materials through the docket facility identified in section B.1.
Once in the system, select ``search,'' then key in the appropriate
docket identification number.
C. Abbreviations and Acronyms Used
AMSA--Association of Metropolitan Sewerage Agencies
ASTM--American Society for Testing and Materials
CDC--Centers for Disease Control and Prevention
CFR--Code of Federal Regulations
CPE--Cytopathic Effects
CWA--Clean Water Act
EMS--Environmental Management System
EPA--U.S. Environmental Protection Agency
FQPA--Food Quality Protection Act
HQ--Hazard Quotient
ICC-PCR--Integrated cell culture--polymerase chain reaction
ICMA--International City/County Management Association
IRED--Interim Reregistration Eligibility Decision
IRIS--Integrated Risk Information System
ISG--Information Sharing Group
LGEAN--Local Government Environmental Assistance Network
NBP--National Biosolids Partnership
NPDES--National Pollutant Discharge Elimination System
NODA--Notice of Data Availability
NRC--National Research Council
NSSS--National Sewage Sludge Survey
OPP--Office of Pesticide Programs
OW--Office of Water
PCBs--Polychlorinated biphenyls
PCDDs/Fs--Polychlorinated dibenzo-p-dioxins/dibenzofurans
PCR--polymerase chain reaction
PCS--Permit Compliance System
PEC--Pathogen Equivalency Committee
PFRP--Process to Further Reduce Pathogens
POTW--Publicly Owned Treatment Works
PPCPs--Pharmaceutical and Personal Care Products
PSRP--Processes to Significantly Reduce Pathogens
QA/QC--Quality Assurance/Quality Control
QMRA--Quantitative Microbial Risk Assessment
RED--Reregistration Eligibility Decision
RME--Reasonable Maximum Exposure
SOP--Standard Operating Procedure
SSI--Sewage Sludge Incinerator
TBD--Technical Background Document
UA--University of Arizona
USDA--United States Department of Agriculture
VOC--volatile organic compounds
WEF--Water Environment Federation
WERF--Water Environment Research Foundation
Table of Contents
I. What is the Legal History of the Standards for the Use or
Disposal of Sewage Sludge?
II. What Requirements are Included in the Standards for the Use or
Disposal of Sewage Sludge (40 CFR Part 503)?
III. What Is the Purpose of Today's Notice?
IV. What Was EPA's Charge to the National Research Council?
[[Page 75533]]
V. What Were the National Research Council's Major Findings and
Recommendations Concerning Land Application of Sewage Sludge?
VI. What Process did EPA Use to Address the NRC Recommendations?
VII. EPA's Final Action Plan to Address NRC Recommendations
VIII.Process to Review Part 503 Regulations under the CWA Section
405(d)(2)(C)
IX. Hazard-Based Screening Assessment
X. Results of the Review of the Part 503 Regulations under CWA
Section 405(d)(2)(C)
XI. References
I. What Is the Legal History of the Standards for the Use or Disposal
of Sewage Sludge?
In section 405 of the CWA, Congress, for the first time, set forth
a comprehensive program designed to reduce potential health and
environmental risks and maximize the beneficial use of sewage sludge.
As amended, section 405(d) of the CWA requires EPA to establish
numerical limits and management practices that protect public health
and the environment from the reasonably anticipated adverse effects of
chemical and microbial pollutants in sewage sludge. Section 405(e)
prohibits any person from disposing of sewage sludge from publicly
owned treatment works (POTWs) or other treatment works treating
domestic sewage except in compliance with regulations promulgated under
section 405.
Section 405(d) calls for two rounds of sewage sludge regulations
and sets deadlines for promulgation. In the first round, EPA was
required to establish numerical limits and management practices for
those toxic pollutants that, based on ``available information on their
toxicity, persistence, concentration, mobility, or potential for
exposure, may be present in sewage sludge in concentrations that may
adversely affect public health or the environment.'' See CWA section
405(d)(2)(A). EPA was then required to undertake a second round of
rulemaking, to address toxic pollutants not regulated in the first
round ``which may adversely affect public health or the environment.''
See CWA section 405(d)(2)(B).
EPA did not meet the section 405(d) timetable for promulgating the
first round of regulations, and a citizen's suit was filed to require
EPA to fulfill this mandate. See Gearhart v. Reilly, Civ. No. 89-6266-
HO (D. Ore.). A consent decree was entered by the court in this case,
establishing schedules for both rounds of sewage sludge rules. EPA
promulgated the first rule (``Round One'') on February 19, 1993 (40 CFR
part 503, 58 FR 9248). The consent decree required the Administrator to
sign a notice proposing Round Two regulations no later than December
15, 1999, and to sign a notice taking final action on the proposal no
later than December 15, 2001.
For the second round (``Round Two''), EPA identified 31 pollutants
and pollutant categories not regulated in Round One that EPA was
considering for regulation. In November 1995, EPA narrowed the original
list of 31 pollutants to two pollutant groups for the second round
rulemaking: polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDDs/Fs)
and dioxin-like coplanar polychlorinated biphenyls (PCBs) (USEPA,
1996).
On December 15, 1999, the Administrator signed a proposal to
establish numerical limits for chlorinated dibenzo-p-dioxin,
chlorinated dibenzofurans, and co-planar PCBs (``dioxins'') in sewage
sludge that is applied to the land and proposed not to regulate dioxins
in sewage sludge that is disposed of in a surface disposal unit or
fired in a sewage sludge incinerator. 64 FR 72045 (December 23, 1999).
On December 21, 2001, the Administrator gave final notice of EPA's
determination that numerical standards or management practices are not
warranted for dioxins in sewage sludge that is disposed of at a surface
disposal unit or a sewage sludge incinerator. 66 FR 66228 (December 21,
2001). The consent decree in Gearhart v. Whitman was amended to extend
the deadline for final action on the land application Round Two
rulemaking from the original date of December 15, 2001, to a new date
of October 17, 2003.
On June 12, 2002, EPA published a Notice of Data Availability
(NODA) containing new information relating to dioxins in land-applied
sewage sludge and requested public comments. 67 FR 40554. On October
17, 2003, the Administrator signed a notice for publication in the
Federal Register announcing EPA's decision that regulation of
``dioxins'' in land-applied sewage sludge was not needed to adequately
protect human health and the environment. 68 FR 61084 (October 24,
2003).
Section 405(d)(2)(C) requires EPA to biennially review existing
sewage sludge regulations for the purpose of identifying and regulating
additional toxic pollutants in sewage sludge to adequately protect
human health and the environment from the reasonably anticipated
effects of such pollutants. The Agency commissioned the NRC to
independently review the technical basis of the chemical and microbial
regulations governing land application to help address the human health
concerns raised by the public and to fulfill the requirement for
periodic reassessment of the Standards for Use or Disposal of Sewage
Sludge. The NRC study took place between January 2001 and June 2002. In
July 2002, the NRC published a report entitled, ``Biosolids Applied to
Land: Advancing Standards and Practices'' in response to EPA's request.
The NRC identified a need to update the scientific basis of part 503
and provided approximately 60 recommendations.
EPA entered into an agreement with the parties in Gearhart v.
Whitman, to publish a notice in the Federal Register describing how the
Agency intends to respond to the NRC report recommendations and to seek
public comment on its planned response. EPA also agreed to review
publicly available information to identify additional toxic pollutants
in sewage sludge and to publish a notice and seek public comment on the
results of the review. Fulfilling these commitments, EPA published a
notice in the Federal Register on April 9, 2003 (68 FR 17379). EPA also
agreed to publish its final response to the NRC recommendations and the
final results of its review under section 405(d)(2)(C). Today's Notice
fulfills this agreement.
II. What Requirements Are Included in the Standards for the Use or
Disposal of Sewage Sludge (40 CFR Part 503)?
CWA section 405(d)(2)(A) required the first round of regulation to
be based on ``available information on [the] toxicity, persistence,
concentration, mobility, or potential for exposure'' of toxic
pollutants in sewage sludge. EPA published the Round One standards (40
CFR part 503) on February 19, 1993, establishing requirements for the
final use or disposal of sewage sludge when it is: (1) Applied to the
land for a beneficial purpose, including in home gardens, (2) placed in
a surface disposal site, including sewage sludge-only landfills, or (3)
incinerated.
For land application, EPA set numerical limits for nine metals in
sewage sludge, established operational standards (described later in
this notice) to reduce or eliminate pathogens in sewage sludge and to
reduce vector attraction, and required management practices to restrict
the application rate and placement of sewage sludge on the land. For
surface disposal in sewage sludge-only units, part 503 includes
numerical limits for three metals in sewage sludge, requirements for
the placement and management of a surface disposal site, and
operational standards
[[Page 75534]]
to reduce or eliminate pathogens in sewage sludge and to reduce vector
attraction. For incineration in a sewage sludge incinerator (SSI), EPA
establishes limits for five metal pollutants in sewage sludge fired in
a SSI and adopted standards under the Clean Air Act for two additional
metal pollutants. The Agency has also established performance standards
for SSIs through an operational standard for total hydrocarbons or
carbon monoxide emissions that controls numerous organic compounds
found in the emissions of sewage sludge incinerators. Part 503 also
allows disposal of sewage sludge in a municipal solid waste landfill
that meets the requirements of 40 CFR part 258. In addition, the final
rule requires monitoring, record keeping, and reporting. Standards
apply to publicly and privately-owned treatment works that generate or
treat domestic sewage sludge and to anyone who uses or disposes of
sewage sludge.
The Part 503 Standards consist of seven elements designed to work
together to protect human health and the environment. These elements
are:
(1) General requirements,
(2) Numerical limits for certain pollutants,
(3) Management practices,
(4) Operational standards,
(5) Monitoring,
(6) Recordkeeping, and
(7) Reporting.
An example of a general requirement in the standards is the
provision, applicable to all land-applied sewage sludge, for sewage
sludge preparers to obtain information on the nutrient content of the
sewage sludge and pass this information to land appliers so that the
land appliers can comply with the requirement to apply the sewage
sludge at a suitable agronomic rate. Numerical pollutant limitations
for certain pollutants in land-applied sewage sludge are expressed as
pollutant concentrations in sewage sludge or as cumulative or annual
loading rates of pollutants applied on receiving soils. Management
practices prescribe how the sewage sludge is to be placed on the land
or otherwise managed in the environment. For example, one management
practice prohibits the application of sewage sludge to land closer than
10 meters from waters of the United States. Operational standards are
technology requirements such as process descriptions and performance
requirements to reduce or eliminate pathogens from sewage sludge and to
reduce vector attraction. These technology-based requirements, together
with required crop harvesting restrictions and site controls,
constitute the approach for the control of pathogens in sewage sludge.
Under part 503, monitoring of chemical and microbial pollutants in
sewage sludge and certification of certain actions by the preparer or
land applier must be performed at a frequency commensurate with the
annual amount of land-applied sewage sludge. Sewage sludge preparers
and land appliers must keep records of these monitoring and
certification activities. Finally, sewage sludge preparers and land
appliers must report this information to the permitting authority (EPA
or States authorized to administer the program) at least annually.
EPA has amended part 503 several times since its initial
publication in February 1993. Following promulgation of the Round One
rule, several petitions were filed that challenged various aspects of
the rule. In one petition, mining and chemical concerns successfully
challenged the land application molybdenum limits. EPA amended the
numerical standards for molybdenum to delete the cumulative loading
rate, annual loading rate, and the pollutant concentration in sewage
sludge to be land-applied. 59 FR 9095 (February 25, 1994). The Agency
retained the ceiling concentration value for molybdenum. Also, in the
same Federal Register notice, EPA added to the sewage sludge
incinerator requirements continuous monitoring of carbon monoxide as an
alternative to continuous monitoring of total hydrocarbons. In
addition, the court remanded several of the land application
requirements as a result of petitions for review challenging various
other land application standards (Leather Industries of America v. EPA,
40 F.3d 392 (D.C. Cir. 1994)). EPA deleted all numerical standards for
chromium in sewage sludge to be land-applied and adjusted the limit for
selenium as a result of that decision. 60 FR 54764 (October 25, 1995).
In August 1999, EPA amended part 503 to make a number of technical
amendments, provide regulatory flexibility, and make the sewage sludge
incinerator standards self-implementing. 64 FR 42552 (August 4, 1999).
For a detailed discussion of the part 503 rule, see A Plain English
Guide to the EPA Part 503 Biosolids Rule (1994). A copy of the Plain
English Guide is available at the EPA Web site at http://www.epa.gov/owm/mtb/biosolids/503pe/index.htm.
III. What Is the Purpose of Today's Notice?
In today's Federal Register notice, the Agency describes its final
action plan to address the NRC recommendations. In addition, EPA is
stating the final results of its review under section 405(d)(2)(C) of
the CWA and is identifying 15 additional toxic pollutants in sewage
sludge that will be further evaluated for potential regulation. As
described later, EPA has considered public comments and other factors
in developing its action plan and in identifying additional toxic
pollutants in its review of existing regulations under section
405(d)(2)(C).
IV. What Was EPA's Charge to the National Research Council?
EPA asked the NRC to evaluate the scientific basis of EPA's current
regulations and standards for chemical pollutants and microbial
pollutants (pathogens) in sewage sludge that is land-applied.
Specifically, EPA asked the NRC to focus on the adequacy and
appropriateness of the risk assessment methods and data that the Agency
used in setting regulatory requirements to protect human health. The
NRC convened the Committee on Toxicants and Pathogens in Biosolids
Applied to Land (``the Committee''), which conducted the evaluation and
prepared a final report. The Statement of Tasks included the following:
1. Review the risk assessment methods and data used to establish
concentration limits for chemical pollutants in biosolids to determine
whether they are the most appropriate approaches.
2. Review the current standards for pathogen reduction or
elimination in biosolids and their adequacy for protecting public
health.
3. Explore whether approaches for conducting pathogen risk
assessment can be integrated with those for chemical risk assessment.
The April 9, 2003, notice (68 FR 17379) contains additional details
regarding EPA's charge to the NRC.
V. What Were the National Research Council's Major Findings and
Recommendations Concerning Land Application of Sewage Sludge?
The NRC Committee concluded that ``There is no documented
scientific evidence that the part 503 rule has failed to protect human
health. However, additional scientific work is needed to reduce
persistent uncertainty about the potential for adverse human health
effects from exposure to [sewage sludge].'' The Committee recognized
that land application of sewage sludge is a widely used, practical
option for managing the large volume of sewage sludge generated at
waste water treatment plants that otherwise would
[[Page 75535]]
be disposed of at landfills or by incineration. The Committee also
identified a need to update the scientific basis of part 503 to ensure
that the current chemical and microbial standards are supported by
current scientific data and risk assessment methods. They also
recommended that the EPA demonstrate effective enforcement of part 503
and validate the effectiveness of sewage sludge management practices.
The NRC report contains four overarching recommendations: (1) Use
improved risk assessment methods to better establish standards for
chemicals and pathogens, (2) conduct a new national survey of chemicals
and pathogens in biosolids, (3) establish an approach to human health
investigations, and (4) increase the resources devoted to EPA's
biosolids program. These four overarching recommendations are discussed
in detail and supplemented by around 56 individual recommendations
contained in Chapters 2-6 of the NRC report. The April 9, 2003 notice
(68 FR 17379) contains additional details regarding these findings.
VI. What Process Did EPA Use To Address the NRC Recommendations?
The April 9, 2003, Federal Register notice (68 FR 17379) contains
details concerning this process. To summarize, upon release of the NRC
report, EPA established a committee to respond to the recommendations
in the report. The committee includes EPA representatives from a cross-
section of offices that are involved or interested in the sewage sludge
program. The committee identified and prioritized each NRC
recommendation, and developed a preliminary strategy to carry out the
activities identified in response to the NRC recommendations. In
section VII of the April 9, 2003, Federal Register notice (68 FR
17384), EPA presented its preliminary strategy for responding to the
NRC recommendations. The section presented three main objectives for
attaining a better understanding of sewage sludge and reducing the
potential for, or reducing the uncertainty related to, human health
impact: (1) Update the scientific basis of part 503 by conducting
research in priority areas, (2) strengthen the biosolids program by
evaluating results of completed, ongoing, or planned studies both
within and outside EPA, and (3) continue ongoing activities for
enhancing communications with outside associations and with the public.
EPA then presented responses to the NRC recommendations and a
planned strategy by specific categories: (1) Survey; (2) exposure; (3)
risk assessment; (4) methods development; (5) pathogens; (6) human
health studies; (7) regulatory activities; and (8) biosolids management
See section VIII of the April 9 notice, 68 FR 17384-17393.
The format of today's notice differs from the April 9, 2003,
notice. In today's notice, EPA is presenting a final action plan that
includes specific projects that are an outgrowth of the categories
presented in the April 9, 2003, notice, in response to many comments
that the Agency was too vague in its presentation of preliminary
strategies. EPA weighed several factors in determining its final action
plan: (1) Major concerns presented in public comments received on the
April 9, 2003, notice; (2) the findings of the Water Environment
Research Foundation (WERF) Research Summit in July 2003; (3) EPA's
existing research commitments in response to areas in the NRC report;
and (4) feasibility of responding to specific areas given available
resources.
VII. EPA's Final Action Plan To Address NRC Recommendations
A. Background
On April 9, 2003, EPA published a preliminary strategy in the
Federal Register (68 FR 17379) to prioritize projects to respond to the
NRC recommendations and to add value to the Agency's sewage sludge
program. The notice summarized the NRC recommendations by category and
presented EPA's evaluation of the recommendations and planned
responses, and requested public comments. EPA received nearly 100
comments from States, citizens, the sewage treatment and land
application industries, environmental groups, and academia. Comments
ranged from support for Agency commitments and its preliminary response
strategy to seeking a complete overhaul of EPA's sewage sludge program
as well as for EPA to implement all of the NRC's recommendations. All
comments and the Agency responses are included in the docket in a
separate Response to Public Comments Document (USEPA, 2003d).
In the time since the NRC issued its report in 2002, EPA has taken
steps to enhance its research program to improve the sewage sludge
program and to begin implementing recommendations by the NRC. Much of
EPA's research complements work being done by others outside the
Agency, such as the research projects and the research issues
identified at the July 2003 Biosolids Research Summit sponsored by the
Water Environment Research Foundation (WERF). EPA plans to participate
in and/or use, as appropriate, outside research, in conjunction with
EPA-specific research, in order to make the most of the Agency's
limited resources and to enhance the part 503 program. EPA's research
program includes projects that will be initiated or completed in the
near term (i.e., through 2005).
The Agency does not have sufficient resources to implement all of
the NRC recommendations, but we do agree that certain projects can help
reduce the persistent uncertainty related to exposure to sewage sludge.
EPA plans to review and evaluate completed research projects, both
inside and outside EPA, as well as complete or begin other projects, to
improve the basis for conducting risk assessments and upgrading the
basis for the part 503 regulations or improving management practices.
Therefore, EPA has developed this final action plan in response to the
NRC recommendations with consideration of public comments on the April
9, 2003, preliminary strategy, information gathered from broad
stakeholder input received through the WERF Research Summit, and Agency
priorities and resource availability. This final action plan is based
on fiscal year (FY) 2004 estimated resources. For planning purposes,
the Agency has assumed the same level of funding (i.e., at the
estimated FY 2004 level) for future years; however, EPA recognizes that
funding for FY 2005 and thereafter is subject to final appropriations.
There are two projects in the Agency's preliminary strategy (68 FR
17379), re-evaluation of the risk assessment used for pollutants
regulated or evaluated in Round One and a molecular pathogen tracking
exposure study, that EPA has decided not to do given all ongoing
studies presented in this action plan, changing priorities, and limited
resources. In addition, the latter project was intended to focus on
individuals who have received medical attention and who suspect that
they have been affected by sewage sludge application practices to
potentially isolate causative agents. The Agency believes that such a
study may still have merit, but in order to respond to reported
incidences of human illnesses and adverse health effects alleged to
have been caused by land application of sewage sludge, EPA believes
that it should include various stakeholders who have had experiences
with incidences related to sewage sludge, stakeholders who may be
interested in participating, and those
[[Page 75536]]
who have the expertise and should take part in helping to develop such
a program. For this reason, EPA will participate in an incident
tracking workshop to bring these stakeholders together and determine
the next steps. See Project 6 later in this notice.
B. Near-Term Projects (FY 2004 through FY 2005)
The Agency expects to complete or begin the following activities,
presented in this notice as ``projects,'' within the next two to three
years, with the goal of strengthening the sewage sludge use and
disposal program. The sewage sludge program encompasses regulatory and
non-regulatory components, as described in these projects.
Project 1: Biennial Review Under CWA Section 405(d)(2)(C)
As described above, the CWA requires EPA to review existing sewage
sludge regulations at least every two years for the purpose of
identifying additional pollutants for possible regulation under the CWA
section 405(d)(2)(C).
This project relates to Category G, Regulatory Activities, in the
April 9, 2003, notice. See 68 FR 17390. It also relates to major short-
term and major long-term goals of continuing program implementation
outlined in that notice. For the current biennial review, EPA has
assessed available data on chemical pollutants that have been detected
in sewage sludge and that have not been regulated or previously
assessed in Rounds One and Two. EPA collected and conducted a
preliminary review of publicly available information on chemical
toxicity, environmental properties (e.g., mobility and persistence),
and concentration; identified chemical pollutants for which appropriate
analytical methods and human health benchmarks are available; made
preliminary determinations regarding sufficiency of information; and
conducted an exposure and hazard-based screening assessment. Details
are presented in Sections VIII through X of this notice.
In addition to any regulatory amendments that EPA may propose as a
result of the current review, EPA is planning to assess the need and
appropriate levels for new numerical limitations for molybdenum in
land-applied sewage sludge. See Project 13 later in this notice.
Subsequent reviews will be conducted every two years as required by
the CWA. EPA will review any new peer-reviewed research and other
relevant information to determine whether to identify any additional
toxic pollutants for regulatory consideration. This biennial review
process may also be useful for identifying toxic pollutants that may
warrant further research.
Project 2: Compliance Assistance and Enforcement Actions
As indicated in the Agency's preliminary strategy of April 9, 2003
(see 69 FR 17391), and this final action plan, EPA will continue to
provide compliance assistance to individuals, municipalities, or other
entities on matters pertaining to sewage sludge use and disposal and
will take enforcement actions, as appropriate. This project relates to
Category H, Biosolids Management Activities, in the April 9, 2003,
notice. See 68 FR 17391.
EPA has maintained an active presence in biosolids compliance and
enforcement activities. EPA's enforcement and compliance activities are
tracked in the Integrated Compliance Information System (ICIS) and
Permit Compliance System (PCS) databases. Specifically, the ICIS
database documents the following Federal enforcement actions taken to
address biosolids: 391 administrative orders for FY 1995-2002, 119
administrative penalty orders for FY 1995-2002, and one civil judicial
action in FY 1997. The PCS database documents 382 regional and state
biosolids inspections for FY 2000-2002.
Furthermore, EPA Regions and States have the responsibility to
address situations where compliance assistance and enforcement actions
to address biosolids are appropriate and necessary. Regional
responsibilities for the biosolids program include actively following
up on phone calls and complaints received from the public, and, where
appropriate as demonstrated by the data, initiating Agency enforcement
actions. EPA has taken enforcement actions and/or appropriate
administrative remedies to address biosolids violations of 40 CFR part
503 and will continue to take such actions, including instances where
biosolids pose an imminent and substantial endangerment to human health
or the environment.
To assist the States and Regions in their oversight of the
biosolids program, EPA has, either in place or in development, tools to
assist and promote compliance with biosolids regulatory requirements.
The National Pollutant Discharge Elimination System (NPDES) Compliance
Inspection Manual, which is used by EPA and State inspectors to perform
inspections in the field, includes a ``Sludge (Biosolids)'' chapter.
EPA is currently revising and updating the manual, which is expected to
be complete in 2004. The Clean Water Act/NPDES Computer Based Inspector
Training CD-ROM, including a module specific to biosolids inspections,
was finalized in August 2003. EPA plans to make both of these tools
available on the EPA Web site.
Additionally, there are two compliance assistance Web sites, which
are available for biosolids compliance studies, information and tools,
and for links to other sites with pertinent biosolids compliance
information. One is the National Environmental Compliance Assistance
Clearinghouse at: http://cfpub.epa.gov/clearinghouse/. This site is a
searchable clearinghouse of compliance assistance materials. The second
Web site is the Local Government Environmental Assistance Network
(LGEAN) at http://www.lgean.net. This online compliance assistance
center, which focuses on local government environmental requirements,
is operated by the International City/County Management Association
(ICMA), and has six other partners representing local government.
EPA is also working to improve its data reporting and management
system that supports compliance oversight. EPA is continuing to work
with States as it modernizes the Permit Compliance System (PCS) to
allow for more effective program oversight. As part of the PCS
modernization, a separate workgroup (including States and EPA) was
devoted to the data needed to manage the biosolids program. Based upon
the recommendations of this workgroup, the PCS Executive Council
decided to add data elements to PCS to improve tracking and oversight
of the biosolids program, and the draft detailed design was distributed
for review. The detailed design document was finalized in September
2003, which served as the basis for the software development. The
anticipated implementation date for the modernized PCS is December
2005, provided adequate funding is committed to this project.
The land application of sewage sludge in compliance with EPA's
regulations is an appropriate choice for communities. The NRC concluded
that ``There is no documented scientific evidence that the part 503
rule has failed to protect human health. However, additional scientific
work is needed to reduce persistent uncertainty about the potential for
adverse human health effects from exposure to biosolids.'' Thus, EPA
has directed its water enforcement and compliance resources to focus on
risks posed by wet weather issues and untreated pollutants, including
raw sewage and wastes associated with storm water, sanitary sewer
overflows, combined sewer
[[Page 75537]]
overflows, and concentrated animal feeding operations. Both agriculture
and urban runoff/storm sewers are listed in the top four sources of
impaired river miles in the 2000 National Water Quality Inventory
Report to Congress (section 305(b) report). Given the complexity and
magnitude of addressing potential human exposures to pathogens and
chemicals from untreated human and animal wastes from wet weather and
the present scientific knowledge of the relative risks associated with
biosolids, there is an appropriate level of resources allocated to
biosolids compliance and enforcement activities.
Project 3: Methods Development, Optimization, and Validation for
Microbial Pollutants in Sewage Sludge
EPA's sewage sludge regulations are designed to protect human
health and the environment by requiring treatment of sewage sludge to
reduce or eliminate pathogens (also referred to as microbial
pollutants) when land-applied (40 CFR part 503, subpart D). The
regulations require that land-applied sewage sludge meet either Class A
or Class B requirements to treat sewage sludge using one of various
treatment processes. There are six alternative methods, one of which
must be met to be classified as Class A sewage sludge. In addition, in
order to be classified as Class A sewage sludge, the pathogen reduction
treatment must occur prior to or in conjunction with vector attraction
reduction measures, except for vector attraction reduction by alkali
addition or drying. To be classified as Class B sewage sludge, one of
three alternative treatment methods must be met. Because these three
Class B treatment methods do not reduce pathogens to the same extent as
the Class A methods, Class B sewage sludge is also subject to site
restrictions, such as restrictions on crop harvesting, animal grazing
and public access.
EPA recently published a document entitled Environmental
Regulations and Technology: Control of Pathogens and Vector Attraction
in Sewage Sludge (USEPA, 2003e). This document provides information
concerning federal requirements under subpart D of part 503, a
description of different treatment processes, vector attraction
reduction issues, sampling and analysis protocols for pathogens, the
process for applying for equivalency, and the kind of support EPA's
Pathogen Equivalency Committee (PEC) can provide to permitting
authorities. This publication not only serves to assist the user
community and to link researchers with their clients, but also has been
produced as part of the Agency's strategic long-term research plan for
preventing and reducing risks from pollution that threaten human health
and the environment.
The NRC recommended that EPA undertake a new national sewage sludge
survey to look for pathogens in sewage sludge. In addition, the NRC
report identified standardization and validation of methods for
detection and enumeration of indicator organisms and specific pathogens
as essential for oversight and compliance testing. Raw sewage,
anaerobically and aerobically digested sewage sludge, and wastewater
are known to contain numerous residual microorganisms that can cause
disease in humans and animals. These include viruses, bacteria,
protozoans and helminth ova. As described in the April 9, 2003, notice,
EPA agrees that pathogens deserve further attention, and the Agency had
sponsored a workshop in 2001 and initiated a number of studies (see
Project 11). Pathogen projects relate back to Category D, Methods
Development, and Category E, Pathogens, in the April 9, 2003, FR
notice. See 68 FR 17388.
Several commenters stated that there is an urgent need for EPA to
develop and validate methods for detection and enumeration of bacteria
and viruses in sewage sludge, soil, water and air. EPA agrees and
recognizes that reliable analytical methods are critical to measuring
pathogens in sewage sludge, whether ``raw'' or ``finished.'' Therefore,
one of the Agency's priority microbial agent research areas is the
development or improvement of analytical methodology. The following
sections describe the available methods for helminth ova, viruses, and
bacteria, each of which are in need of improvement to increase
analytical specificity, sensitivity, and accuracy.
It was also suggested that EPA propose a vigorous study program to
determine whether or not Class B sludge site restrictions are
protective against infectious diseases. The greatest number of
pathogen-related comments were directed to the issue of EPA's response
regarding risk assessment, treatment efficacy, and site-specific
restrictions for both Class A and B Sewage sludge. Some recommended the
sewage sludge industry be involved in study efforts because of their
experience in the area, while others recommended against industry
involvement because of their potential bias. EPA plans to improve the
methods and procedures for determining the effectiveness of these
pathogen reduction or elimination treatment processes.
In addition to developing and improving the microbial analytical
methods described below, WERF and EPA are funding research termed
quantitative microbial risk assessment (QMRA), as described in ``A
Dynamic Model to Assess Microbial Health Risks Associated with
Beneficial Uses of Biosolids' (WERF, 2003). See Project 8 later in this
notice for a description of the QMRA project.
Project 3a: Optimization of the Method for Detecting, Enumerating, and
Determining the Viability of Ascaris Ova in Sewage Sludge
The goal of this project is to optimize the helminth ova method for
the detection in the various sewage sludge matrices in order to assess
the effectiveness of treatment practices meant to inactivate ova. The
helminth (Ascaris) ova assay described in Environmental Regulations and
Technology: Control of Pathogens and Vector Attraction in Sewage Sludge
(USEPA, 2003e) has been used a number of times, it is time consuming,
and it has never been fully optimized and validated for the various
sewage sludge matrices.
The first stage will optimize the assay for various sewage sludge
matrices. The next stage will be a single laboratory validation
followed by multi-laboratory validation of the assay. We anticipate
that this research will be conducted over the next three years.
Products include publication of one or more scientific papers
characterizing the Ascaris ova assay for the various sewage sludge
matrices and a standard operating procedure (SOP) detailing the optimal
method for laboratory validation studies by 2007.
Project 3b: Improved Methods for Detecting Viruses in Sewage Sludge
EPA will develop improved virus detection methods for evaluating
treatment technology efficacy. Some members of EPA's PEC, an ongoing
committee charged with making recommendations on the adequacy of new
sewage sludge treatment processes, and the NRC have questioned the
reliability of existing virus methods for analysis of sewage sludge
matrices. The PEC has recommended research that would improve the
reliability of available analytical methods.
40 CFR 503.8(b) specifies methods that must be used when analyzing
for various pathogens. The publication Environmental Regulations and
Technology: Control of Pathogens and Vector Attraction in Sewage Sludge
(USEPA, 2003e) lists the required pathogen methods, along with complete
references for these methods. The appropriate method to test for
enteric
[[Page 75538]]
viruses when monitoring is required, according to this publication, is
the American Society of Testing and Materials (ASTM) Method D4994-89.
Although Method D4994-89 was validated in a multi-laboratory study, the
Method achieves only partial recovery of virus from sewage sludge and
laboratories are sometimes allowed to use their own standard virus
plaque assays. This results in wide variations in virus levels and
types recovered from various sewage sludge samples, calling into
question the utility of the method. Furthermore, Method D4994-89 is
labor intensive, making it difficult for many laboratories to
undertake.
Several groups have proposed simpler methods which may yield higher
virus recoveries than Method D4994-89. However, limited data are
available to evaluate these methods. EPA supports the concept of
performance-based methods, and the PEC would accept data from simpler
methods, if shown to be at least as effective as Method D4994-89.
Therefore, the Agency has developed a research plan to improve
analytical methods for viruses and anticipates this work to be
completed in 2005. The goal is to have improved methods with higher
sensitivity, specificity, and accuracy for detecting viruses in sewage
sludge. One objective in this plan is to demonstrate whether other
methods are comparable to Method D4994-89. Methods will be compared for
their ability to recover viruses that are naturally present in sewage
sludge in addition to their ability to recover seeded viruses.
The plaque assay was used for virus detection in the initial round-
robin testing of Method D4994-89. This quantitative assay relies upon
the development of virus-induced plaques within cell culture
monolayers. A most probable number (MPN)-based method for measuring
cytopathic effect (CPE) in cell cultures may prove a more useful assay
as this is reported capable of detecting viruses at 2-to 100-fold lower
concentrations than plaque assays, with the higher sensitivities
observed for environmental water samples.
The plaque assay and the MPN-based CPE assays are limited because
it fails to detect many of the most important human enteric viral
pathogens. Thus, they may provide limited data on whether viral
pathogens are inactivated by sewage sludge treatment processes. A new
assay has been developed that combines the advantages of cell culture
(e.g., detection of infectious particles only) and polymerase chain
reaction (PCR) techniques for rapid detection of important human viral
pathogens. The Agency will evaluate this integrated cell culture--PCR
(ICC-PCR) assay to determine whether previously undetectable human
enteric viral pathogens are present in sewage sludge.
Method validation will be accomplished by comparing Method D4994-89
using plaque, MPN, and ICC-PCR assays for seeded and unseeded sewage
sludge types. EPA will develop standard operating procedures (SOP) to
be further tested on a wide variety of sewage sludge types.
The final objective will be to determine the appropriate virus type
to use in seeding viruses in sewage sludge. Utilizing the method
described in the SOP, virus recoveries will be compared using a range
of virus types, including poliovirus, coxsackievirus, echovirus, and
others to be determined. If possible, the Agency will determine
recoveries before and after a sewage sludge treatment process. It is
estimated that this project will take two years. Products include
publication of scientific papers describing the method comparisons and
a SOP detailing the optimal method for validation studies.
Project 3c: Development and Validation of Analytical Methods for Fecal
Coliform in Sewage Sludge
Fecal coliform bacteria are used as indicators of treatment process
effectiveness in the production of Class A and Class B sewage sludge.
This ongoing project identifies available methods for enumerating fecal
coliforms in sewage sludge, selects the most appropriate methods,
determines minimum performance characteristics that must be met, and
evaluates these methods in quantifying such organisms using multiple
laboratories.
EPA will use multiple laboratories to update and evaluate protocols
for assaying fecal coliforms in sewage sludge using multiple tube
fermentation techniques and test the method on treated sewage sludge
samples using independent laboratories. Samples of Class A and B sewage
sludge from full-scale wastewater treatment facilities will be assayed
with and without known amounts of Escherichia coli, a species of fecal
coliform. The Agency will compare the relative performance of
individual laboratories performing such tests and develop acceptable
standards. The final product, anticipated to be completed in 2005, will
be a draft EPA Method 1680 entitled ``Fecal Coliforms in Treated Sewage
Sludge by Multiple-Tube Fermentation Procedures.''
Project 3d: Development and Validation of Analytical Methods for
Salmonella in Sewage Sludge
Many serovars of Salmonellae can cause gastroenteritis and typhoid
fever. S. enterica serovar Typhi is the causative agent for typhoid
fever. These bacteria may be used to demonstrate treatment
effectiveness of Class A sewage sludge. This project will identify
available methods for enumerating Salmonella in treated sewage sludge,
select the most appropriate methods, evaluate minimal performance
characteristics that must be met, and evaluate these methods in
quantifying such organisms using multiple laboratories. EPA will
develop and test the method on treated sewage sludge samples.
The Agency will update and evaluate protocols for assaying
Salmonella in sewage sludge using multiple tube fermentation techniques
among multiple laboratories. Samples of Class A sewage sludge from
full-scale wastewater treatment facilities will be assayed with and
without known amounts of Salmonella. EPA will compare the relative
performance of individual laboratories performing such tests and
develop acceptable standards. The final product, to be completed in
late FY 2004, will be a draft EPA Method 1682 titled ``Salmonella in
Sewage Sludge by Modified Semisolid Rappaport-Vassiliadis (MSRV)
Medium.''
Project 4: Field Studies of Application of Treated Sewage Sludge
EPA will initiate field studies to evaluate management techniques
for treated sewage sludge in order to determine whether the pathogen
and chemical requirements of part 503 are being met. These studies,
that relate to certain categories discussed in the Agency's preliminary
strategy of April 9, 2003, notice (68 FR 17385-17386, 17388-17390),
will measure selected indicators of microbial, chemical, and
particulate emissions from sewage sludge land application sites and
will study the fate of contaminants in the soil to which biosolids are
applied. Data resulting from these studies may also be appropriate for
inclusion in future risk assessments of biosolids application
scenarios.
EPA plans to work with State, Regional, USDA, and other partners to
conduct field studies of land application practices at up to five
sewage sludge land application sites. Field sampling at actual
application sites will involve a variety of media and methods to
characterize airborne and soil-bound
[[Page 75539]]
contaminants resulting from land application of sewage sludge.
Depending on resources, items that will be investigated include, but
are not limited to: (1) Quantification of aerosol components such as
pathogens, endotoxins, particulate matter, odor compounds, and volatile
organic compounds (VOCs); (2) quantification of sewage sludge
components such as pathogens and metals, and (3) effects of these
components on the soil to which the sewage sludge is applied. Quality
Assurance (QA) and specific research plans are being developed. EPA
plans to initiate peer review on this research plan in 2004 and field
work will not begin until the plan has been peer reviewed. The Agency
plans to complete the study and draft a report two years after the QA
plan has been approved.
Project 5: Targeted National Survey of Pollutants in Sewage Sludge
As EPA described in the April 9, 2003, Federal Register notice, EPA
has concluded that undertaking a targeted survey is at present more
useful than conducting a comprehensive survey modeled on the 1988-89
National Sewage Sludge Survey (NSSS) (68 FR 17385). Some commenters
liked the targeted survey approach, but most commenters requested that
EPA consider another national full-scale survey and made suggestions as
to which pollutants should be included, or excluded, from such a
survey.
Pending results of ongoing research projects and regulatory review,
EPA will design and conduct a targeted survey of select chemical
pollutants. Microbial pollutants (pathogens) in sewage sludge may also
be included, depending on availability of resources and adequacy of
methods. A survey may provide feedback for updating the science and
technology of sewage sludge applied to land, disposed of in a surface
disposal unit, or incinerated. The new concentration data would be used
to assess human and ecological risk of identified, unregulated
pollutants found in sewage sludge and identify pollutants for potential
regulation.
EPA is committed in FY 2005 to starting a limited analytical survey
of chemical pollutants found in sewage sludge. EPA expects this survey
to address the pollutants identified by the exposure and hazard
screening assessment as presenting a potential hazard, as identified in
the current section 405(d)(2)(C) biennial review. The Agency will
evaluate the extent to which methodology will allow expansion of the
survey scope within available resources to include additional
pollutants (e.g., the survey may also include metals regulated in Round
One using improved methods while surveying for new metals identified as
presenting a potential hazard in the current review). See section X of
this notice for a list of these pollutants.
Furthermore, the results of current research projects may help
determine the scope of a survey. The survey design and pollutants to be
included in the survey may be influenced based on factors that include:
[sbull] Whether to survey pollutants that were not previously
detected in sewage sludge, but where new or improved methods are
available and other data may indicate a potential for hazard,
[sbull] Whether to survey pollutants with reported occurrences in
sewage sludge from other countries only (i.e., not studied in U.S.
sewage sludge),
[sbull] Whether to include pathogens, and
[sbull] Whether to include pollutants with a high indication of
potential hazard when the scientific basis of the human health
benchmarks in IRIS or OPP databases for these pollutants is in the
process of reassessment.
EPA will design the survey starting in FY 2005. The Agency will
seek stakeholder involvement in the design and implementation of the
survey.
Project 6: Participate in an Incident Tracking Workshop
One of the highest research priorities identified by the NRC and
participants at the July 2003 WERF Biosolids Research Summit is the
need for rapid response investigations of reported health effects
potentially resulting from land application practices. EPA also
received many public comments urging development of an incident
tracking and response process. The Agency agrees that developing an
incident tracking program is important. However, the Agency believes
that it should not develop an incident monitoring program on its own,
but should include various stakeholders who have had experiences with
incidents related to sewage sludge, stakeholders who may be interested
in participating, and those who have the expertise and should take part
in helping to develop such a program.
As stated above, stakeholders who have had experiences with
reported incidents related to land application of sewage sludge should
be consulted. A program of incident monitoring and investigation could
be modeled after an existing program. Once such organization that has
experience with such incidents is the State of North Carolina (NC). The
North Carolina Department of Environment and Natural Resources is
responsible for environmental programs in the state, including
biosolids and residuals management. One purpose of the program is to
assure timely and meaningful response to perceived and actual
environmental incidents. The experiences of NC and others could be
helpful in developing such a program and determining the next steps.
In order to respond to reported incidents of human illnesses and
adverse health effects alleged to have been caused by land application
of sewage sludge, and to determine the appropriate next steps in the
process, EPA believes that local and State health agencies, in addition
to other Federal health agencies, such as the Center for Disease
Control and Prevention (CDC), are positioned best and have the
necessary expertise to respond to allegations of adverse health effects
following use or disposal of sewage sludge. However, EPA is committed
to participating in activities related to this issue and plans to
participate in the incident tracking workshop with WERF and other
stakeholders in developing the research concepts and methods, and in
interpreting and summarizing results.
The first step in the process will take place when WERF assembles
stakeholders in a workshop to be held in 2004. EPA will participate in
the workshop, which will begin evaluating the next steps for
investigating adverse human health allegations following land
application of sewage sludge. Ultimately, the objective is to determine
whether such reported symptoms of illness can be attributed to the land
application of sewage sludge.
The Cornell Waste Management Institute (CWMI) has collected over
300 incidents over the past several years in which residents living
near sites where sewage sludge has been applied have reported illness
(Cornell Waste Management Institute, 2003; Harrison and Oakes, 2002).
However, the CWMI states that it has not been confirmed by scientific
investigation that illnesses have resulted from land application of
sewage sludge. The information provided by the CWMI may be useful as
stakeholders begin to plan for a workshop to address such incidents.
This process, starting with the multi-stakeholder workshop, will
take place at least through FY 2005. Additional activities beyond that
time frame will depend on the outcome of the workshop, work with local,
State and Federal agencies, as well as other stakeholders and
availability of resources. Additional activities may include
participating in subsequent stakeholder meetings or workshops and
[[Page 75540]]
deciding on additional activities and next steps.
Project 7: Conduct Exposure Measurement Workshop
The purpose of this workshop is to identify exposure-related
research priorities. This workshop is meant to compliment the
objectives of the WERF workshop (see Project 6) or be a related follow-
up activity that is structured around issues and ideas identified in
the WERF workshop. Workshop discussions will focus on exposure
measurement tools that researchers or health agencies can use to
investigate reports of adverse human health effects from land
application of sewage sludge. The discussions and tools will focus on
scientific uncertainties related to: (1) Which particular sewage sludge
contaminants or combinations of contaminants may be potentially
responsible for disease outbreaks; (2) how affected individuals are
exposed to these contaminants; (3) how sewage sludge treatment and
management practices can reduce potential risks; and (4) how good
analytical methods and monitoring have to be to obtain satisfactory
answers. The workshop will explore such topic areas for identifying
research priorities as methods development, ambient measurements
(including spatial and temporal monitoring requirements), fate and
transport modeling, and exposure measurements, including identifying
the specific exposure routes (e.g., oral and inhalation), exposure
pathways (e.g., eating food, drinking water), and contaminants.
Workshop participants would include representatives from EPA; other
Federal, State and local agencies; academia; wastewater utilities;
environmental groups; industry; and citizen groups. Participants would
identify and possibly prioritize what, when, and where measurements
should be taken, and how they should be taken during rapid response
investigations. EPA will develop a report to summarize discussions and
identify the exposure research tools needed to investigate reported
incidents of exposure. Pending the results from a similar effort being
sponsored by WERF and in which EPA will participate (Project 6), we
expect to hold this workshop in 2004.
Project 8: Assess the Quality and Utility of Data, Tools and
Methodologies to Conduct Microbial Risk Assessments on Pathogens
The NRC recommended that EPA develop risk assessment methods to
apply to pathogenic risks from land application of sewage sludge. While
numerical limits for chemical pollutants in sewage sludge are based on
assessment of risk, EPA currently regulates pathogens in sewage sludge
through technology-based operational standards. In issuing part 503 in
1993, the Agency acknowledged that it lacked essential tools and data
to conduct microbial risk assessments on sewage sludge. As the NRC
noted, while methods for assessing risks from pathogens have advanced
since 1993, there are still obstacles with respect to available data,
analytical methods, and exposure and risk assessment modeling.
EPA is working on a number of areas related to risk assessments of
pathogens. There are two examples of projects that are ongoing and that
will be assessed as part of this broader effort. One is a conceptual
framework for assessing the risks of human disease following exposure
to waterborne pathogens, as described in ``Revised Framework for
Microbial Risk Assessment'' (International Life Sciences Institute,
2000). The second is a quantitative microbial risk assessment (QMRA),
as described in ``A Dynamic Model to Assess Microbial Health Risks
Associated with Beneficial Uses of Biosolids'' (WERF, 2003).
In the first example, the International Life Sciences Institute
(ILSI), in cooperation with EPA, developed a framework that provides a
useful and proven tool for conducting microbial risk assessments. The
framework emphasizes the dynamic and iterative nature of the risk
assessment process, and that future efforts need to be directed toward
the examination of methods for estimating risk and ways to improve the
estimates. Areas for further evaluating the assumptions in the
framework model, described in the ILSI framework, include understanding
the relationship between infection and subsequent illness, impact of
critical susceptibility factors such as age and immune status,
secondary transmission of diseases, and heterogeneous distributions of
microorganisms and the potential changes in concentration of
microorganisms in the environment.
In the second example, WERF and EPA are funding Quantitative
Microbial Risk Assessment (QMRA) research. In addition to WERF and EPA,
other organizations involved in this research include the University of
California at Berkeley and Eisenberg, Olevieri and Associates. The
document describing this research also presents a methodology for
assessing exposure and risks to human health from pathogens in
biosolids. The present methodology provides initial screening for a
given scenario, identifies broad conditions for high and low risk
situations, and estimates where more data are needed. Future work
(beyond 2004) may focus on applying this methodology to more refined
scenarios. Such validation activities will assist EPA in ultimately
developing microbial risk assessment guidelines.
EPA will inventory and assess data, methods, and tools for risk
assessment on pathogens in sewage sludge (such as the two examples
discussed above as well as others) to better inform research activities
in sewage sludge and microbial risk assessment. In conducting this
assessment, EPA will review information gathered from others doing
research on this issue, some of which was described in the April 2003
draft response (68 FR 17379). This project will start with a problem
formulation step to identify the key elements in assessing pathogen
risks in land-applied sewage sludge. During the second phase, EPA will
develop a plan to identify the available and appropriate methods and
data to perform the risk assessment defined in problem formulation. An
expert panel will review the material and EPA will address panel
comments in the final document. This project will serve as a vehicle to
better define the deficiencies in microbial risk assessment and better
identify research needs for microbial risk assessment in sewage sludge
matrices. The final product in FY 2005 will be a peer-reviewed plan for
future analysis.
Project 9: Support Pathogen Equivalency Committee
In its April 9, 2003, notice, EPA described the work of the
Pathogen Equivalency Committee (PEC), which has been operating since
1985. Public comments mentioned the PEC Committee a number of times,
and there was a generally favorable opinion of the Committee. Most
commenters recommended that the PEC be fully recognized and authorized
by EPA to approve new part 503 processes. Supporting comments by some
agreed with both the Haas report (Haas, 2001) and the NRC conclusions
that the PEC has an important mission. A few comments indicated that,
if the PEC were further legitimized, it should be expanded to include
industry and academic experts outside of the EPA.
EPA plans additional support for the PEC, including resources to
help address the increasing number and complexity of requests for
guidance regarding the regulatory requirements for reducing pathogens,
as well as development of alternative treatment technologies. The NRC
report affirmed
[[Page 75541]]
the importance of the Committee's mission to regulators and the
regulated community. The states and the Office of the Inspector General
have also identified the Committee's work as a high priority. Public
comments also reflected a desire to see the PEC adequately supported by
EPA. All stressed the need for the PEC to have the resources it needs
to fulfill its mission.
EPA created the PEC in 1985 to make recommendations to EPA
management on applications for Processes to Significantly Reduce
Pathogens (PSRP) and Processes to Further Reduce Pathogens (PFRP)
equivalency under part 257 and later part 503. The PEC also provides
guidance to applicants on the data necessary to determine equivalency,
and to permitting authorities and members of the regulated community on
issues (e.g., sampling and analysis) related to meeting subpart D
(pathogen and vector attraction reduction) requirements of part 503. If
the PEC recommends that a process is equivalent to PSRP or PFRP, the
operating parameters and any other conditions critical to adequate
pathogen reduction are specified. The PEC consists of members with
expertise in bacteriology, virology, parasitology, environmental
engineering, medical and veterinary sciences, statistics, and sewage
sludge regulations. It includes representatives from EPA's Offices of
Research and Development, Office of Water, and Regional Offices, and
the Centers for Disease Control and Prevention.
Project 10: Development and Application of Analytical Methods for
Detecting Pharmaceutical and Personal Care Products in Sewage Sludge
The purpose of this project is to develop and apply analytical
methodologies for detecting pharmaceutical and personal care products
(PPCPs) in sewage sludge. The NRC Report specifically identified PPCPs
as one category of diverse compounds that has not been studied in
sewage sludge and that is especially likely to be present in domestic
sewage sludge. The NRC report indicated that there is a need for a new
hazard assessment of sewage sludge to expand the suite of chemicals
evaluated.
EPA's preliminary strategy in the April 9, 2003, notice indicated
that while study emphasis is being placed on pathogens to address areas
of uncertainty and public interest, selected chemicals are also being
addressed to help determine significant issues and identify information
gaps that remain to be addressed in these areas. See 68 FR 17385.
Chemical pollutants in pharmaceutical and personal care products are
among those that EPA intends to study.
In FY 2004 through FY 2005, chemical analysis methods developed in-
house previously for PPCPs (e.g., antibiotics and musks) would be
adapted for sewage sludge. In FY 2006, EPA may finish methods
development, convert them to 40 CFR part 136 methodology, and publish
methodologies. Subsequently, the methods may be applied to a limited
number of real-world samples for a pilot-scale survey of PPCPs in
sewage sludge.
Project 11: Publish the Proceedings of USEPA-USDA Workshop on Emerging
Infectious Disease Agents and Issues Associated with Animal Manures,
Biosolids, and Other Similar By-Products
As mentioned in connection with Project 3 (Methods for Microbial
Pollutants), the NRC Report called for more information on the risks of
disease associated with pathogens and how to analyze for them. It also
called for more information on how to better disinfect sewage sludge.
In June 2001, EPA and USDA sponsored a workshop on ``Emerging
Pathogen Issues in Biosolids, Animal Manures, and Other Similar By-
Products'' (USEPA in press). The workshop brought together experts in
sewage sludge management and animal wastes to review the state of the
science, exchange ideas on how to deal with unresolved issues and
suggest areas where the scientific community should focus its efforts.
Participants discussed:
[sbull] Viruses, bacteria, protozoa, prions, fungi, and helminth
ova;
[sbull] Migration of pathogens to groundwater and air from
recycling and treatment operations;
[sbull] Qualitative identification and detection methods for
pathogens; the fate of antibiotics in animal and human wastes;
[sbull] Pathogen resistance to antibiotics; and
[sbull] Susceptibility of people with immuno-suppressed conditions
to pathogens.
As stated in Category E (Pathogens) of the preliminary strategy
dated April 9, 2003 (68 FR 17389), EPA will make available the
information produced at this workshop on pathogens in sewage sludge and
animal wastes by publishing the proceedings of the workshop. The
proceedings from the workshop have been peer reviewed by national and
international experts, and the report will be published in early 2004.
Project 12: Support ``Sustainable Land Application Conference''
The purpose of this conference will be to address soil reactions of
constituents in treated sewage sludge, manures, and other non-hazardous
wastes, and to further environmentally friendly management of wastes in
a sustainable manner. This January 2004 conference in Lake Buena Vista,
Florida will address soil constituents (chemicals and microorganisms)
reactions with constituents in treated sewage sludge, wastewater
treatment plant effluents, manures, and other non-hazardous wastes.
Further, this international conference is expected to have about 300
participants discussing metals, pathogens, organics, nutrients, and the
interface between science and real-world applications by:
[sbull] Reviewing fundamental and specific soil reactions of non-
hazardous waste constituents (nutrients, organics, metals and
pathogens);
[sbull] Improving our understanding of contaminant reactions in
soils, emphasizing the commonalities of soil reactions among wastes;
[sbull] Synthesizing multi-disciplinary information and
characterizing the state-of-the-science for land application (``what do
we know?'');
[sbull] Identifying high-priority and critical research needs
(``what do we need to know?''); and
[sbull] Promoting intra- and inter-disciplinary approaches to
solving problems of sustainable waste disposal and utilization.
Papers and presentations will be both invited and volunteered. All
papers will be refereed and EPA will use conference findings, as
appropriate, in future refinements of part 503.
Project 13: Review Criteria for Molybdenum in Land-applied Treated
Sewage Sludge
One of the NRC's recommendations was that EPA should propose
molybdenum standards to replace those that EPA rescinded following a
legal challenge to numerical limitations promulgated in the Round One
rule. Also, some commenters believe that EPA should reassess the
molybdenum standard. The preliminary strategy in the April 9, 2003,
notice indicated that EPA would determine the applicability of new
information as the basis for re-proposing molybdenum standards for
land-applied sewage sludge. See 68 FR 17391. This activity is included
in the Agency's final action plan, as stated below.
In 2000, EPA held a workshop to update toxicity and environmental
[[Page 75542]]
properties for molybdenum in sewage sludge. Based on that workshop, EPA
intends to assess the need and appropriate level for a numerical
standard for molybdenum in sewage sludge using a summary of workshop
results and conclusions (O'Connor et al., 2001), supplemented with
additional data developed since 2000. EPA expects to complete this
assessment in 2005.
Project 14: Improve Stakeholder Involvement and Risk Communication
The NRC recommended that stakeholders should be involved in the
risk assessment process and to examine biosolids management practices
to ensure that the underlying risk assessment principles are
effectively translated into practice. As stated in its preliminary
strategy in the April 9, 2003, notice, the Agency's policy is to
involve stakeholders at various stages of policy development. The
Agency intends to consider how consultation with stakeholders should be
included in developing future sewage sludge risk assessments. See 68 FR
17386. EPA received many comments on its preliminary strategy of April
9, 2003, urging the Agency to involve stakeholders more widely in the
many aspects of the sewage sludge program.
EPA is committed to working with stakeholders who are concerned
with the application or disposal of sewage sludge (the general public,
State and local agencies, and private groups). In addition, the Agency
will consider how it can implement the NRC's recommendations to involve
stakeholders in updating and strengthening the scientific credibility
of the sewage sludge regulations.
The Agency's risk communication programs are aimed at improving
public awareness of the issues and achieving pollutant exposure
reductions. Embodied in all of the projects is not only a need to
foster public awareness of the issues surrounding sewage sludge use and
exposure, but also a recognition of the advances in problem-solving
that can be achieved through collaboration and cooperation.
Through the activities and organizations described in this project,
EPA will participate in improving the effectiveness of risk
communication methods at national, regional, and local levels. States
have their own oversight programs, some of which are quite
comprehensive. There is a total of about 150 full time equivalent State
employees assigned to their respective biosolids programs. Five States
have been authorized by EPA to administer the part 503 program, and 15
additional States are at various stages in the authorization process.
National coordination of State, regional and Headquarters biosolids
programs are achieved via an annual State and Regional biosolids
coordinators meeting. EPA plans to continue to work closely with State
and Regional biosolids coordinators and plans to support the annual
workshop for sharing the latest information about biosolids management
and oversight. Other organizations and activities that are designed to
promote stakeholder involvement include the following:
An Information-Sharing Group (ISG) has been established based upon
the concepts developed in WERF studies concerning joint fact-finding
research. The ISG includes concerned citizens, health scientists,
municipal operators, farmer representation, biosolids managers, and
input from State and Federal regulatory agencies. The ISG has been
established to work jointly with about 25 scientific experts in a large
cooperative study of odor, particulates, pathogens, and endotoxins in
the air around biosolids and animal manure land application sites. WERF
has efforts underway to expand the use of such information-sharing in
various research projects.
The National Biosolids Partnership (NBP) is an alliance formed in
1997 with the Association of Metropolitan Sewerage Agencies (AMSA), the
Water Environment Federation (WEF), and EPA. The goal of the NBP is to
advance environmentally sound and accepted sewage sludge management
practices through partnerships with producers, service contractors,
users, regulatory agencies, universities, the farming community, and
environmental organizations.
The NBP is developing a voluntary Environmental Management System
(EMS) for sewage sludge to help wastewater agencies improve their
sewage sludge management programs beyond the regulatory minimums. The
EMS involves environmental improvement, public involvement, and
independent third party review of the facility applying for EMS status.
Fifty-three wastewater agencies in the U.S. are participating in this
voluntary program. Several of these municipalities are ready or will be
ready for third-party audit of their EMS programs in 2004.
Participating municipalities report benefits, such as more efficient
operation, reduced odors in sewage sludge, less intrusive transport of
the sewage sludge to land application sites, better communication, and
meaningful involvement by the public.
In order for a wastewater facility to be admitted and certified to
the Partnership EMS program, it must meet five requirements established
by the NBP:
1. Document responsibility for the Biosolids Value Chain-
pretreatment, treatment, and all biosolids management practices;
2. Commit to 10 principles in the NBP's Code of Good Practice;
3. Meet all NBP requirements;
4. Complete a fully independent third-party audit of its EMS that
has been verified by a NBP's accredited audit company; and
5. Demonstrate their commitment to continual improvements in their
EMS for environmental performance, regulatory compliance, public
participation, and quality biosolids management practices.
Recently, the NBP recognized the Orange County Sanitation District
(OCSD) in Fountain Valley, California, as the first wastewater agency
in the Nation to be admitted to the Partnership EMS for biosolids
programs. The EMS certification signifies that OCSD meets the NBP's
requirements for the EMS program and that it supports excellence in
sewage sludge management practices, exceeds regulatory compliance
obligations, and provides meaningful opportunities for public
participation.
The NBP recognized the City of Los Angeles Department of Public
Works as the second wastewater agency in the Nation to be admitted to
the Partnership EMS for sewage sludge program. A third-party audit of
the City's Biosolids EMS program led to certification on September 4,
2003. EPA continues to support the development of EMS programs for
wastewater agencies and the goals of improved communication and
addressing public concerns in a more timely manner.
The NBP also announced release of its 2003 Environmental Management
System for Biosolids ``Self Help'' Training Program intended to help
wastewater agencies that are interested in starting their own EMS. The
Agency plans to continue supporting NBP activities and to work with
municipalities to expand their use of EMS and other programs in
biosolids management. Two NBP Web sites present relevant sewage sludge
information: http://www.biosolids.org and http://biosolids.policy.net/emsguide/manual/goodpractmanual.vtml.
In conclusion, EPA believes these 14 projects and associated
activities will strengthen the biosolids program by improving our
ability to:
[sbull] Measure pollutants of interest;
[[Page 75543]]
[sbull] Determine the risks posed by contaminants identified as
potentially hazardous;
[sbull] Bring various stakeholder groups together via a workshop to
begin development of a national incidence tracking system to ultimately
determine health effects following land application of sewage sludge;
[sbull] Better understand and characterize the odors, volatile
chemicals, and bioaerosols that may be emitted from land application
sites;
[sbull] Better understand the effectiveness of sewage sludge
processes and management practices to control pathogens;
[sbull] Improve the Agency's inspection and compliance initiatives;
and
[sbull] Improve stakeholders' involvement in EPA's sewage sludge
program.
C. Other Projects
Projects that are longer term in nature are those that EPA
anticipates will be initiated after 2005. Initiation of longer-term
projects will depend on the outcome of the research projects listed in
section B, results of research being conducted by others outside the
Agency, and availability of sufficient resources.
In addition to EPA directed research and activities, there is also
considerable relevant work being conducted by others outside the Agency
in academia, other State and Federal agencies, and trade groups, among
others, that will address issues raised by the NRC recommendations. For
example, WERF's sewage sludge research projects include identifying
emergent trends in pathogen detection, assessing microbial health
risks, identifying and controlling odors, and better understanding the
fate, effects, and bioavailability of metals and certain chemicals in
sewage sludge after land application. Two WERF Web sites that address
relevant sewage sludge information and research are http://www.werf.org/Collection/biosolids_chart.cfm#table1 and http://www.werf.org/press/winter03/default.cfm.
One WERF project involves ``Biosolids Public Perception &
Participation'' (WERF, In Press). The project team included members
from the New England Biosolids and Residuals Association, the Northwest
Biosolids Management Association, the Center for Environmental
Communication, and BioCycle, as well as two review panels consisting of
biosolids stakeholders and academics. The study concludes that positive
public relationships with stakeholders starts by developing public
participation and thus earning public trust. Building success with
stakeholders involves two way communication with the public, not only
through the use of brochures, fact sheets, television spots and radio
talk shows, but also by having a complaint hotline, tours, open houses,
door-to-door contact, and community advisory groups. The final report
from this study should be available by the end of winter 2004.
The University of Arizona (UA), Department of Soil, Water and
Environmental Science, investigates physical, chemical, and microbial
processes that affect the quality of surface and subsurface waters.
Some of the UA's research projects deal with sewage sludge land
application and utilization (e.g., agricultural land application and
mine tailing stabilization), sewage sludge management (e.g., pathogen
reduction in solar drying beds), health protection (e.g., fate and
transport of pathogens within sewage sludge, fate of Staphylococcus
aureus in sewage sludge and evaluation of odors from land-applied
sewage sludge), and rapid response to emerging issues (e.g.,
antibiotic-resistant bacteria and endotoxins in land-applied sewage
sludge, endocrine-related effects, and fate and transport of SARS
virus). In one recent study at the UA, scientists are studying
Staphylococcus aureus in sewage sludge after it had been processed at
full-scale treatment plants (Rusin et al., 2003).
Much of the work being done outside of EPA, including the research
described above, that relates directly to NRC recommendations is being
used to improve the Agency's sewage sludge program. EPA plans to review
and evaluate studies external to EPA to determine if they are useful
for conducting risk assessments and improving the basis for the part
503 regulations or improving management practices. The Agency will
review these studies in accordance with the Information Quality
Guidelines (see ``Guidelines for Ensuring and Maximizing the Quality,
Objectivity, Utility, and Integrity of Information Disseminated by the
Environmental Protection Agency'' USEPA, 2002). These guidelines stress
that information disseminated by EPA should adhere to a basic standard
of quality, including objectivity, utility, and integrity.
VIII. Process To Review Part 503 Regulations Under the CWA Section
405(d)(2)(C)
As previously described, section 405(d)(2)(C) of the CWA requires
that EPA review the sewage sludge regulations for the purpose of
identifying additional toxic pollutants and promulgating regulations
for such pollutants consistent with the requirements of section 405(d).
In 1993, EPA promulgated regulations in 40 CFR part 503 setting
numerical standards for certain toxic pollutants in sludge,
requirements for pathogen and vector attraction reduction, and
operational standards for emissions from sewage sludge incinerators.
As explained in section IV, EPA commissioned the NRC study of
existing sewage sludge land application regulations to strengthen its
scientific review under section 405(d)(2)(C). EPA agreed with the
parties in Gearhart v. Whitman to publish a preliminary notice seeking
public comment and a final notice, stating the results of its section
405(d)(2)(C) review.
In fulfilling this commitment, EPA first collected and conducted a
preliminary review of publicly available information on the occurrence
of chemicals in sewage sludge. This information consists of
concentration data found in national and international literature
sources published between 1990 and 2002 and the 1989 National Sewage
Sludge Survey (NSSS); data on environmental properties such as mobility
and persistence; and available human health benchmarks (HHBs). EPA
compiled a list of 799 chemical pollutants for which such information
was found and described this list of candidate pollutants for ongoing
sewage sludge evaluation in the April 2003 Federal Register notice. EPA
placed the full list of candidate pollutants in the docket for public
review and comment (USEPA, 2003a). EPA made minor corrections to the
list, which resulted in slightly revising the list from 799 candidate
pollutants to 803 candidate pollutants. See Table 1 in Appendix O of
the Technical Background Document (TBD) (USEPA, 2003b).
EPA then used a human health-based data evaluation and pollutant
selection process to determine whether the existing data were
sufficient for each of these 803 pollutants to proceed with an exposure
and hazard screening assessment. This process involved identifying the
pollutants for which EPA peer-reviewed final HHBs are available, and
for which there are data on concentrations in U.S. sewage sludge for
those pollutants with HHBs, either in the NSSS or reported in the
literature.
In summary, a pollutant was selected from the list of 803
pollutants for an exposure and hazard screening assessment if it met
two criteria: (1) It has measured concentrations in U.S. sewage sludge
based on the literature, or it had been measured in the 1989 NSSS;
[[Page 75544]]
and (2) it has a HHB from one of two sources that was not undergoing
reevaluation as of October 1, 2003. The sources for HHBs were EPA's
Integrated Risk Information System (IRIS) health assessments and EPA's
Office of Pesticide Programs (OPP) Reregistration Eligibility Decisions
(REDs) or Interim Reregistration Eligibility Decisions (IREDs). Figure
1 depicts the steps involved in this process.
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Applying this process resulted in a list of 40 pollutants that
merited exposure and hazard screening. These 40 pollutants are listed
in Table 1.
Table 1.--Candidate Pollutants for Exposure and Hazard Screening
------------------------------------------------------------------------
Chemical CASRN
------------------------------------------------------------------------
Acetone.................................................... 67-64-1
Acetophenone............................................... 98-86-2
Anthracene................................................. 120-12-7
Azinphos methyl............................................ 86-50-0
Barium..................................................... 7440-39-3
Benzoic acid............................................... 65-85-0
Beryllium.................................................. 7440-41-7
Biphenyl, 1,1-............................................. 92-52-4
Butyl benzyl phthalate..................................... 85-68-7
Carbon disulfide........................................... 75-15-0
Chloroaniline, 4-.......................................... 106-47-8
Chlorobenzene; Phenyl chloride............................. 108-90-7
[[Page 75545]]
Chlorobenzilate............................................ 510-15-6
Chlorpyrifos............................................... 2921-88-2
Cresol, o-; 2-Methylphenol................................. 95-48-7
Diazinon................................................... 333-41-5
Dichloroethene, 1,2-trans-................................. 156-60-5
Dichloromethane; Methylene chloride........................ 75-09-2
Dioxane, 1,4-.............................................. 123-91-1
Endrin..................................................... 72-20-8
Ethyl p-nitrophenyl phenylphosphorothioate; EPN; Santox.... 2104-64-5
Fluoranthene............................................... 206-44-0
Hexachlorocyclohexane, alpha-.............................. 319-84-6
Hexachlorocyclohexane, beta-............................... 319-85-7
Isobutyl alcohol........................................... 78-83-1
Manganese.................................................. 7439-96-5
Methyl ethyl ketone........................................ 78-93-3
Methyl isobutyl ketone (MIBK); Methyl-2-pentanone, 4-...... 108-10-1
Naled...................................................... 300-76-5
Nitrate.................................................... 14797-55-8
Nitrite.................................................... 14797-65-0
N-Nitrosodiphenylamine..................................... 86-30-6
Phenol..................................................... 108-95-2
Pyrene..................................................... 129-00-0
Silver..................................................... 7440-22-4
Trichlorofluoromethane..................................... 75-69-4
Trichlorophenoxy propionic acid, 2-2,4,5-; Silvex.......... 93-72-1
Trichlorophenoxyacetic acid, 2,4,5-; 2,4,5-T............... 93-76-5
Trifluralin................................................ 1582-09-8
Xylenes (mixture).......................................... 1330-20-7
------------------------------------------------------------------------
Data collection and evaluation, along with the results for
determining sufficiency of data to proceed with an exposure and hazard
screening assessment for a pollutant, are available in detail in
appendix O of the TBD (USEPA, 2003b).
As described by Figure 1, EPA did not include pollutants for which
the scientific basis for the HHBs is currently being reassessed. This
applied to certain chemicals with HHBs in IRIS or OPP's IREDs and REDs.
EPA has not included these chemicals in the list of chemicals to
consider for exposure and hazard screening assessment at this time
because these HHBs are critical to determining whether, and at what
level, pollutants might be of potential hazard in sewage sludge.
Because, under section 405(d)(2)(C), EPA is required to review the
sewage sludge regulations for identification of additional toxic
pollutants every two years, EPA has deferred chemicals with ongoing
health assessments for a future review when the assessment is complete.
EPA believes that the HHB reassessments will provide valuable
information relevant to possible further regulation of sewage sludge
once they are complete and that it would be premature to include these
pollutants in a hazard screening process at this time.
At the same time, EPA recognizes that some of the chemical
pollutants which are undergoing HHB reevaluation may be of concern in
sewage sludge, and that it may be prudent to include such pollutants in
the planned targeted survey (i.e., section VII.B, Project 5) so that
concentration values in sewage sludge may be obtained and used in
future section 405(d)(2)(C) reviews. Therefore, EPA used a simple
estimate of potential hazard to prioritize chemicals with ongoing
health assessments for possible inclusion in the targeted survey.
The simple estimate involved calculating a theoretical hazard
quotient (THQ) for each of the 20 chemicals with ongoing IRIS or OPP
health assessments using existing oral human health benchmarks. The THQ
is the ratio of the theoretical average daily intake (TADI), for a 1-3
year old child, one of the most highly exposed population groups on a
kg body weight basis, to the oral critical dose (OCD), where the OCD
(in milligrams/kilograms/day, or mg/kg/day) is the lowest of the
reference dose, population adjusted dose, or dose for 10-5
cancer risk.\1\ On this basis, a prioritization scale was established
for the 20 chemicals with ongoing IRIS or OPP health assessments, which
have existing oral human health benchmarks. Using this priority scale
and results of the exposure screening assessment, EPA decided which
chemicals to consider high priority for potential health concern and,
subject to the availability of adequate budgetary resources, to include
in the targeted survey to be initiated in FY 2005. These are
benzo[a]pyrene, PCB congeners and Aroclors (excluding coplanar PCB
congeners already included in the 2001 dioxins survey), di(2-
ethylhexyl) phthalate, thallium, antimony, carbon tetrachloride and
fluoride. This prioritization strategy is further described in appendix
O of the Technical Background Document (USEPA, 2003b). These pollutants
are not being identified at this time for purposes of further
regulatory consideration as part of EPA's current review under section
405(d)(2)(C).
---------------------------------------------------------------------------
\1\ The NRC recommended that EPA evaluate risks based on
``reasonable maximum exposure'' (RME). Therefore, in the hazard
screening assessment, EPA uses a risk level of 1E-5 to calculate the
RME to a subpopulation of highly exposed individuals, rather than a
1E-6 risk level to calculate risk to the general population. A risk
level of 1E-5 is consistent with setting such a risk level for, and
being protective of, the RME in the sewage sludge regulations.
Members of the subpopulation defined as subject to RME are farm
families assumed to live on a farm and consume farm-raised foods
where land-applied sewage sludge is used as fertilizer or a soil
amendment and, therefore, are more highly exposed to sewage sludge
than the general population.
---------------------------------------------------------------------------
As mentioned above, the 40 pollutants listed as a result of the
selection process depicted in Figure 1 were next analyzed through an
exposure and hazard screening process. The principal objective was to
evaluate whether the Agency should consider any of these as additional
toxic pollutants for regulation in sewage sludge under section 405(d)
of the CWA. As discussed in section X, the screening assessment
identified 15 pollutants with hazard quotient (HQ) values equal to or
greater than one.
IX. Hazard-Based Screening Assessment
EPA used a probabilistic hazard assessment model with appropriately
conservative assumptions to analyze the 40 pollutants identified as a
result of the data evaluation and pollutant selection process. This
section describes the data and analyses EPA used in this screen for the
40 pollutants listed in Table 1. The two major questions addressed in
this assessment were:
[sbull] Which environmental pathways are of concern?
[sbull] What is the potential hazard associated with each
pollutant?
The Technical Background Document (TBD) (USEPA, 2003b) contains the
rationale behind the relationships addressed and the methods, data
gaps, and uncertainties associated with the data and models. The TBD
also contains details about properties of sewage sludge, regional
climate, soil characteristics, farm size, exposure routes and pathways,
toxicity values, source models and other modeling parameters and
assumptions related to the screening assessment.
A. Sewage Sludge Management Practices Modeled
The exposure and hazard screening assessment evaluated the 40
chemicals for three sewage sludge management practices:
[sbull] Disposal in sewage sludge lagoons (surface disposal units),
[sbull] Application of sewage sludge to pastureland and cropland,
and
[sbull] Sewage sludge fired in a sewage sludge incinerator.
Below is a summary description of the screening scenarios and key
assumptions for the three sewage sludge management practices.
1. Sewage Sludge Lagoon Scenario
The lagoon scenario was the surface disposal unit chosen for the
model
[[Page 75546]]
because sewage sludge disposed in such an impoundment is likely to have
the greatest potential to cause groundwater contamination of the
various surface disposal configurations. For the sewage sludge lagoon
scenario, EPA assumed that sewage sludge is managed in a lagoon or
surface impoundment that holds the sludge for disposal. For this hazard
assessment, the lagoon modeled was a non-aerated surface impoundment.
Exposure to pollutants via sewage sludge in lagoons occurs through the
drinking water and ambient air. We assumed that no food chain exposures
occur from sewage sludge in this surface lagoon scenario because EPA
has no data indicating that food is grown or raised in close proximity
to surface disposal units. The surface impoundment was assumed to
operate for 50 years (i.e., sewage sludge is surface-disposed in the
lagoon over that time period) after which it was closed. Surface
impoundments were modeled based on a nationally representative sample
of non-aerated, non-hazardous waste surface impoundments. See appendix
A of the TBD (USEPA, 2003b).
It was assumed that these impoundments are located in a rural
industrial setting where residents live within a distribution of
distances relatively close to the lagoon, where they might be exposed
to ambient air contaminated by sludge pollutants and where they might
ingest drinking water from residential groundwater wells. These modeled
residents also use their residential wells as a source of drinking
water and for other household uses, such as showering. More details of
the sewage sludge lagoon screening assessment are available in the TBD
(USEPA 2003b).
2. Land Application Scenario
For the agricultural land application scenario, EPA assumed that
sewage sludge is applied to both pastureland and cropland that are used
to raise food for human consumption. The farmer was assumed to apply
sewage sludge to pastureland and cropland at the appropriate agronomic
rates. For this exposure and hazard screening assessment, the following
assumptions were used to reflect a distribution of typical agricultural
practices common throughout the United States:
[sbull] Sewage sludge is applied at a rate of 5 to 10 metric tons
per hectare per application (uniform distribution).
[sbull] Applications occur once every 2 years.
[sbull] Applications are limited to a maximum of 40 years (20
applications).
[sbull] Cropland is tilled to a depth of 20 cm at application and
at two additional times during the year.
[sbull] Pastureland is not tilled, but the sludge is assumed
incorporated to a depth of 2 cm by bioturbidation.
Application to both row crops and pasture includes runoff into two
water-bodies types. The first is an ``index reservoir'' using the
Shipman City Lake in Shipman, Indiana as a model for drinking water
exposures. This reservoir covers 13 acres, is 9 ft deep, and has a
watershed area of 427 acres. The ratio of drainage area to capacity
(volume of water in the lake) is approximately 12 for the index
reservoir in this assessment. These areas remain constant in this
assessment, and the same index reservoir was assumed to occur in each
of the 41 climate regions. Also, in the screening assessment, it was
assumed that the 427-acre watershed area contains other farms that also
apply sewage sludge occupying 10 to 80 percent of the watershed in
aggregate (in addition to the modeled farm).
The second water-body type is a farm pond and was used to evaluate
ecological exposure, and human exposure from fish consumption. It was
assumed that the pond had the farm area as its total drainage basin and
to have a drainage area to capacity ratio of five. The farm pond depth
is assumed to be constant at 9 feet. The area of the pond is
proportional to the area of the farm. EPA also assumed that there is no
buffer between the amended agricultural land and the farm pond; thus,
EPA assumes that the erosion and runoff from the agricultural land go
directly to the farm pond. Additional details of the screening
assessment for the land application scenario are available in the TBD
(USEPA 2003b).
3. Sewage Sludge Incinerator Scenario
For the sewage sludge incinerator scenario, EPA assumed that the
modeled receptor resides and inhales ambient air in the shadow of a
sewage sludge incinerator's emissions plume. To estimate maximum
exposure to ground-level concentrations of pollutants to which the
modeled individual would be exposed, we used the following parameters
in exposure modeling:
[sbull] Sewage sludge feed rate (SF) in the units of dry metric
tons of sewage sludge fed into the incinerator per second.
[sbull] An emission factor (EF) in the units of grams of pollutant
emitted at the incinerator stack per dry metric ton of sewage sludge
fed into the incinerator.
[sbull] A dispersion factor (DF) obtained by air modeling in the
units of micrograms of pollutant per cubic meter of ambient air at
ground level per grams of pollutant emitted at the incinerator stack
per second.
Multiplication of these three factors together yields an estimated
maximum ground level concentration of a pollutant in units of
micrograms of pollutant per cubic meter of ambient air. Additional
details of the screening assessment for the incinerator scenario are
available in the incineration pathway analysis (USEPA 2003c).
B. Receptors
The exposure pathways by which humans and ecological species (i.e.,
those humans and wildlife that are exposed to components in sewage
sludge) for the three sewage sludge management practices are described
in the TBD, section 1.7. In summary, families living near sewage sludge
incinerators and sewage sludge lagoons, as well as farm families
consuming food produced on sewage sludge-amended soil, were considered
the affected populations in this exposure screening assessment.
Ecological receptors were assessed for exposure to contaminated
habitat, food and feed following agricultural land application of
sewage sludge.
For the agricultural land application scenario, human members of
the subpopulation defined as subject to reasonable maximum exposure
(RME) are members of a farm family assumed to live on a farm and
consume farm-raised foods where land-applied sewage sludge is used as
fertilizer or a soil amendment. These individuals are more highly
exposed to sewage sludge than the general population. Much of the
information for the RME for the agricultural land application scenario
comes from the EPA Exposure Factors Handbook, a peer-reviewed source of
data for use in risk assessments (USEPA, 1997). A higher percentage of
the farm family's diet consists of food grown on sewage sludge-amended
soil. EPA assumed that adults and children on the farm consume fish
caught from a nearby waterbody (a pond) and that the farm family also
raised a significant portion of its fruit and vegetable diet on sewage
sludge amended soils. In addition, the farm family is exposed through
drinking water or showering in either untreated surface water from an
index reservoir or groundwater from a residential well.
For the incineration scenario, EPA defined RME as exposure to a
rural family living in proximity to a sewage sludge incinerator. These
individuals were assumed to be exposed by direct inhalation of
emissions from a sewage sludge incinerator.
[[Page 75547]]
For the surface disposal scenario, EPA defined RME as exposure to a
rural family living near a sewage sludge lagoon. EPA assumed these
individuals are exposed to constituents of sewage sludge through
ingestion of groundwater from a nearby residential well and by
inhalation from showering.
Affected wildlife included invertebrate and vertebrate animals that
may be exposed to contaminants through land application of sewage
sludge. It was assumed that the ecological receptors, both aquatic and
terrestrial, are exposed in the crop and pasture and in and around a
farm pond. The representative terrestrial and aquatic wildlife species
were selected based on their living, feeding, and foraging habitat. We
included animals that derive a significant portion of their diet from a
farm, as well as those that live in or feed in and around farm ponds.
The Agency did not assess exposure pathways for wildlife in the
sewage sludge lagoon scenario (as a surface disposal unit) or the
incineration scenario, only the land application scenario. EPA
estimates that less than one percent of the sewage sludge produced
annually in the United States is disposed of in surface disposal units
and approximately 17 percent is disposed of by combustion in sewage
sludge incinerators. Thus, these disposal methods involve a relatively
small proportion of total sewage sludge produced compared to land
application of sewage sludge. In addition, surface disposal sites
generally are areas with poor ecological habitat. Most of the sewage
sludge produced in the U.S. goes to land application to fertilize crop
or as a soil amendment. Therefore, the Agency did not assess aquatic
and terrestrial wildlife exposure associated with surface disposal or
incineration for this screen. We deem the land application scenario,
which includes the treated agricultural crop and pasture land and farm
pond, to be more representative of wildlife habitat, and thus, where
ecological exposures are most likely to happen. Therefore, EPA believes
that the agricultural land application scenario is a good indicator of
ecological hazard.
C. Exposure Assessment Modeling
Human exposures may occur as a result of sewage sludge disposal in
a lagoon or incinerator, or as the result of application of sewage
sludge to agricultural land. The human exposure pathways modeled for
the sewage sludge lagoon scenario are presented in Table 2. It was
assumed that a resident family lives near a facility with a sewage
sludge lagoon and breathes the ambient air at that location. It was
also assumed that the family has a residential well that supplies tap
water to the household for drinking water and showering. Ambient air
exposures and the inhalation of contaminants during showering were
estimated by the average daily air concentrations of vapors to which an
individual might be exposed. Exposure via drinking water was estimated
by multiplying the modeled concentrations of the pollutants in
groundwater by the drinking water consumption rate of the individual.
Table 2.--Human Exposure Pathways for the Sewage Sludge Lagoon Scenario
----------------------------------------------------------------------------------------------------------------
Inhalation of Ingestion of
Inhalation of shower air drinking water
Receptor ambient air (groundwater (groundwater
source) source)
----------------------------------------------------------------------------------------------------------------
Adult Resident............................................... x x x
Child Resident............................................... x x x
----------------------------------------------------------------------------------------------------------------
In the agricultural land application scenario, more exposure routes
are considered in the assessment. The exposure pathways considered for
the farm family are presented in the Table 3.
Table 3.--Human Exposure Pathways for the Agricultural Land Application Scenario
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inhalation of Ingestion of
shower indoor drinking water Ingestion of Ingestion of
Receptor Inhalation of air (groundwater or Ingestion of Ingestion of beef and dairy fish (farm
ambient air (groundwater or index soil produce products pond)
surface water) reservoir)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Adult Farmer..................... x x x x x x x
Child Farm Resident.............. x x x x x x x
--------------------------------------------------------------------------------------------------------------------------------------------------------
Although all of the ingestion pathways (ingestion of food and
water) were aggregated in the exposure model to estimate total
ingestion hazards to humans in this screening assessment, EPA did not
aggregate the ingestion and inhalation pathways. The Agency aggregates
oral and inhalation pathways under certain circumstances (e.g., as
required by the Food Quality Protection Act, OPP adds together the
ingestion and inhalation pathways for pesticides that have similar
toxicological endpoints for both pathways). For purposes of this
screening assessment, a pathway providing exposure approximately three
orders of magnitude lower than the predominating pathway (i.e.,
ingestion, and in particular ingestion of drinking water) need not be
aggregated. In this screening assessment for sewage sludge, exposure to
humans via inhalation for the pollutants that have reference
concentration (RfC) values is negligible, as shown by the results of
the TBD. The inhalation HQs are several orders of magnitude lower than
ingestion HQs; thus, aggregating these two pathways would not add
meaningful results.\2\
---------------------------------------------------------------------------
\2\ There were no ingestion pathways considered for the sewage
sludge incineration scenario.
---------------------------------------------------------------------------
For the ecological screening assessment, exposure concentrations
were calculated for both direct contact and ingestion pathways. The
exposure pathways assessed include direct contact with treated sewage
sludge applied to agricultural land and indirect exposure through
ingestion of contaminated food and soil or ingestion of, or contact
with, surface water that
[[Page 75548]]
receives runoff from a sewage sludge-amended field. Table 4 shows the
affected wildlife and exposure pathways in the ecological screening
assessment. It was assumed that exposure concentrations in sediment and
soil were the maximum annual average modeled concentrations. For
exposure through surface water contact, exposure concentrations were
calculated to match benchmark exposure durations. For example, if the
benchmark for aquatic organisms was derived from a toxicological study
in which fish were exposed to the contaminant for 96 hours, then the 4-
day (96-hour) maximum modeled concentration was selected as the
exposure concentration. For chronic benchmarks intended to reflect
long-term or lifetime exposure, the maximum annual concentration was
used in the assessment.
Table 4.--Exposure Pathways for Wildlife Species
----------------------------------------------------------------------------------------------------------------
Receptor Direct contact Direct contact medium Ingestion
----------------------------------------------------------------------------------------------------------------
Fish......................................... x Surface water (farm pond)...... ...............
Aquatic Invertebrates........................ x Surface water (farm pond)...... ...............
Aquatic Plants............................... x Surface water (farm pond)...... ...............
Amphibians................................... x Surface water (farm pond)...... ...............
Aquatic Community............................ x Surface water (farm pond)...... ...............
Sediment Biota............................... x Sediment (farm pond)........... ...............
Soil Invertebrates........................... x Soil (agricultural field)...... ...............
Mammals...................................... ............... ............................... x
Birds........................................ ............... ............................... x
----------------------------------------------------------------------------------------------------------------
The exposure dose of the ingestion pathway for terrestrial and
aquatic species was calculated as a function of the combination of
concentrations in each receptor's diet items and receptor-specific
ingestion rates, body weight, and bioconcentration factors. The dietary
compositions were based on species-specific data on foraging and
feeding behavior and reflected a year-round adult diet. Diet items were
grouped by category, including different types of vegetation (e.g.,
fruits, forage, grain, roots) and several types of prey (e.g., small
birds, small mammals, invertebrates, fish).
Each species' diet was modeled using the midpoint of dietary
percentages for each diet item, beginning with the item with highest
midpoint value and proceeding through the diet items until a full diet
(100 percent) was accumulated. In this example, a robin's diet would
consist of 50.5 percent soil invertebrates and 49.5 percent fruits.
The species-specific exposure factors (ingestion rates and body
weights) were taken from EPA's Wildlife Exposure Factors Handbook
(USEPA, 1993) and are presented in the Technical Background Document
(USEPA, 2003b).
D. Screening Criteria Development
1. Human Health Benchmarks
As indicated in the data collection and evaluation steps, we used
in the screening assessment human toxicity values (or HHBs) that are
available in EPA's IRIS, RED, or IRED. These toxicity values include
chronic reference doses (RfDs), chronic population adjusted doses,
inhalation reference concentrations (RfCs), oral cancer slope factors,
air unit risk factors, and oral doses and air concentrations at
specified cancer risk levels. The HHBs used in this assessment are
critical doses for ingestion pathways or critical concentrations used
as an air pathway criterion. For air exposures to pollutants, the
critical concentration is the lower value of the RfC or concentrations
in air associated with an excess cancer risk of E-5 (1 in 100,000),
based on the air unit risk factor. For ingestion, the critical dose is
the lower of the RfD, population adjusted dose, or dose for an excess
cancer risk of E-5, based on oral cancer slope factor over a lifetime.
2. Ecological Benchmarks
The benchmarks used for ecological hazard assessment are effects or
toxicity values expressed in terms of media concentration (e.g., mg/l
for surface water or mg/kg for soil) for the direct contact pathway and
in terms of dose (mg/kg-d) for the ingestion pathway. Because there is
no single repository for EPA-approved ecological benchmarks analogous
to EPA's IRIS or OPP RED and IRED documents, ecological benchmarks from
EPA, other government reports, and from toxicological studies in the
published literature were considered for the ecological screening
assessment. General criteria for selecting ecological benchmarks, as
well as a hierarchy of data sources, used in the screening assessment
are included in Appendix P of the TBD (USEPA 2003b).
The ecological hazard screening assessment addresses the potential
for adverse effects to terrestrial and aquatic wildlife, which EPA
believes are the receptors which are anticipated to experience the
highest exposure to pollutants in sewage sludge. The potential for
pollutants to bioaccumulate in wildlife receptors is specifically
addressed through the assessment of the ingestion pathway. The
assessment includes receptors exposed through ingestion of both aquatic
and terrestrial food items and thus addresses the potential for
bioaccumulation of pollutants from soil, surface water, and sediment.
3. Hazard Characterization
The potential hazard to human and ecological receptors is expressed
in terms of hazard quotients (HQs). An HQ equal to or greater than one
indicates a potential for adverse effects to occur and the need to
conduct a more detailed or refined risk assessment and risk
characterization. For chemicals with a human health benchmark (HHB) for
ingestion, the results of the screening assessment are a ratio of the
estimated average daily dose or lifetime average daily dose to a
critical dose for each pollutant. For chemicals with an HHB for
inhalation, the average daily air concentration is compared with the
critical concentration for these pollutants. If either of these ratios
exceeds one at the 95th exposure percentile, the pollutant fails the
screen.
A similar comparison is performed for ecological benchmarks. If the
HQs equal or exceed one for any pollutant, that pollutant also fails
the screen. For the direct exposure pathway, HQs are calculated as the
ratio of the exposure concentration to the relevant toxicity value. For
example, we calculate the HQ for fish as the ratio of the surface water
concentration to the fish 96-hour toxicity value. For the ingestion
pathway, HQs are the ratio of the exposure dose to the relevant
[[Page 75549]]
benchmark. The screening assessment was neither designed nor intended
to provide definitive risk estimates. The assessments simply indicate
the potential for adverse ecological effects to a variety of wildlife
and provide information on the ongoing assessment of ecological risks
associated with the agricultural application of sewage sludge.
Additional details concerning the screening assessment are presented in
sections 2 and 3 of the TBD.
X. Results of the Review of the Part 503 Regulations Under CWA Section
405(d)(2)(C)
Of the 40 pollutants for which EPA conducted its exposure and
hazard screening assessment, 15 have hazard quotients (HQs) \3\ that
either exceed one for human receptors, or equal or exceed one for
ecological receptors. We considered these 15 pollutants to have failed
the screen, and, therefore, constitute the final results of EPA's
current review under section 405(d)(2)(C) of the CWA. The details of
screening results for all pollutants in this screening analysis are
found in the TBD (USEPA, 2003b).
---------------------------------------------------------------------------
\3\ Exposure at or below the HHB values are considered
protective of human health. Hence, the HQ values greater than one
are considered to have failed the human health screen. Exposure at
or above the ecological benchmarks or values are considered to
exceed a level considered to be protective of wildlife species and
the environment. Hence, the HQ values equal to or greater than one
are considered to have failed the ecological screen.
---------------------------------------------------------------------------
The results of the human and ecological exposure and hazard
assessments contained in this section are intended to identify those
pollutants that warrant further consideration for rulemaking. These
results also indicate which exposure pathway or pathways should be the
focus of further consideration with respect to these pollutants.
EPA expects to complete a more refined risk assessment and
characterization for these 15 pollutants for purposes of determining
whether, and if so for which, of these 15 pollutants EPA will propose
rule amendments under section 405(d). Upon completion of additional
assessments, if indicated, EPA will initiate a proposed rulemaking
under section 405(d). Any proposed regulations may take the form of
numerical limits, best management practices, or other controls and
limitations needed to protect the environment and human health. The
results of EPA's review described in today's notice (i.e., the
identified 15 pollutants) do not mean that EPA has concluded that these
pollutants in sewage sludge adversely affect human health or the
environment. Some, or perhaps even all, of these pollutants may not be
present in concentrations that warrant regulation; or a refined risk
assessment may indicate that there is insufficient risk to human health
or the environment to warrant regulation. The results of EPA's review
mean that EPA will obtain updated concentration data for these
pollutants and will conduct a refined risk assessment using the new
concentration data to determine whether to propose amendments to part
503 in order to regulate any of these pollutants under section 405(d)
of the CWA.
A. Results of Human Health Screening Assessment
EPA performed a human health exposure and hazard screening
assessment using both cancer and non-cancer endpoints. None of the
chemicals with cancer end-points had HQs equal to or greater than one,
or were considered to have failed the screen, for either the land
application, surface disposal, or incineration scenarios. Also, no
pollutant with a non-cancer endpoint failed the screen on the basis of
inhalation exposure, either from incineration or indirectly from land
application or surface disposal. Thus, EPA has identified no additional
pollutants to consider for rulemaking for sewage sludge that is
disposed of by incineration in a sewage sludge incinerator. However, as
explained below, some pollutants failed the screen for non-cancer risks
when screened for the land application and surface disposal scenarios.
Table 5 presents the results for the pollutants that had HQs greater
than one for the agricultural land application scenario, and Table 6
presents the results for the pollutants that had HQs greater than one
for the sewage sludge lagoon scenario. Values are presented for
pollutants at the 95th percentile exposure scenario of the HQ
distribution.
Table 5.--Human Hazard Quotient Values Greater Than One by Pathway for the Agricultural Land Application
Scenario at the 95th Percentile of the HQ Distribution
----------------------------------------------------------------------------------------------------------------
CASRN Chemical Pathway receptor HQ
----------------------------------------------------------------------------------------------------------------
14797-65-0............................. Nitrite................... Ingestion of Surface Water: 1.1
Child
.......................... Total Ingestion: Child........ 1.3
7440-22-4.............................. Silver.................... Ingestion of Milk: ...........
Adult....................... 3.8
Child....................... 12.0
.......................... Total Ingestion:
Adult....................... 4.0
Child....................... 12.3
----------------------------------------------------------------------------------------------------------------
Table 6.--Human Hazard Quotient Values Greater Than One by Pathway for the Sewage Sludge Lagoon Scenario at the
95th Percentile of the HQ Distribution
----------------------------------------------------------------------------------------------------------------
CASRN Chemical Pathway receptor HQ
----------------------------------------------------------------------------------------------------------------
7440-39-3.............................. Barium................... Drinking Water from ............
Groundwater:
Adult....................... 1.5
Child....................... 3.5
106-47-8............................... 4-Chloroaniline.......... Drinking Water from ............
Groundwater:
Adult....................... 2.7
Child....................... 6.4
7439-96-5.............................. Manganese................ Drinking Water from ............
Groundwater:
Adult....................... 32
Child....................... 76
[[Page 75550]]
14797-55-8............................. Nitrate.................. Drinking Water from ............
Groundwater:
..............................
Adult....................... 9.2
Child....................... 23
14797-65-0............................. Nitrite.................. Drinking Water from ............
Groundwater:
Adult....................... 14
Child....................... 34
----------------------------------------------------------------------------------------------------------------
Nitrite had HQs greater than one in both the agricultural land
application and sewage sludge lagoon scenarios. Silver had HQs greater
than one for the agricultural land application only. Barium, manganese,
and nitrate had HQs greater than one for the sewage sludge lagoon
scenario only. The only organic chemical that had an HQ greater than
one was 4-chloroaniline, also in the sewage sludge lagoon scenario.
Complete human health screening assessment results are available in
appendix Q of the TBD (USEPA, 2003b).
B. Results of Ecological Screening Assessment
The ecological screen was performed by either comparing
environmental concentrations to which the ecological species are
exposed to comparable ambient media benchmarks for direct contact
(surface water, sediment, or soil) or by comparing exposure via
ingestion (food, forage, water, and incidental ingestion of soil or
sediment) to comparable ingestion benchmarks. The ecological screening
was performed only for the agricultural scenario, since this was
considered the higher exposure scenario. Table 7 shows the pollutants
that had HQs equal to or greater than one for terrestrial wildlife via
the direct contact pathways. There are no ingestion hazards for any
aquatic or terrestrial wildlife species from any of the chemicals,
based on the results presented in the TBD. Because there are many
wildlife receptors, EPA grouped the receptors and listed only the
highest HQ for each receptor group in Table 7. See appendix R of the
TBD for a complete listing of HQs for each receptor group.
Table 7.--Hazard Quotient Values Equal to or Greater Than One for Aquatic and Terrestrial Wildlife via Direct
Contact Pathways for the 95th Percentile of the HQ Distribution
----------------------------------------------------------------------------------------------------------------
CASRN Chemical Receptor \1\ HQ
----------------------------------------------------------------------------------------------------------------
67-64-1.................................. Acetone.................... Sediment Biota............. 356.2
120-12-7................................. Anthracene................. Sediment Biota............. 2.9
7440-39-3................................ Barium..................... Aquatic Community.......... 235.7
7440-41-7................................ Beryllium.................. Aquatic Community.......... 7.8
75-15-0.................................. Carbon disulfide........... Sediment Biota............. 1.9
106-47-8................................. 4-Chloroaniline............ Aquatic Invertebrates...... 1.3
333-41-5................................. Diazinon................... Sediment Biota............. 1.1
206-44-0................................. Fluoranthene............... Aquatic Community.......... 10.7
Sediment Biota............. 4.2
7439-96-5................................ Manganese.................. Aquatic Community.......... 13.9
78-93-3.................................. Methyl Ethyl Ketone........ Sediment Biota............. 5.8
108-95-2................................. Phenol..................... Sediment Biota............. 102.4
129-00-0................................. Pyrene..................... Aquatic Community.......... 41.9
Sediment Biota............. 21.1
Soil Biota................. 4.5
7440-22-4................................ Silver..................... Aquatic Community.......... 246.6
Aquatic Invertebrates...... 28.2
Fish....................... 4.8
----------------------------------------------------------------------------------------------------------------
\1\ Sediment biota organisms include sediment invertebrates; aquatic community organisms include fish, aquatic
invertebrates, aquatic plants, and amphibians; soil biota organisms include soil invertebrates.
Values presented in Table 7 are at the 95th exposure percentile of
the HQ distribution for direct contact. The screening showed that
thirteen pollutants had HQs greater than one via direct contact with
surface water, sediment, or soil. These consisted of four metals and
nine organic pollutants. These results indicate that a more refined
risk assessment and risk characterization are warranted. Full results
for all pollutants and receptors assessed are presented in appendix R
of the TBD (EPA, 2003b).
C. Summary
The results of the hazard screening assessment contained in this
section identify those pollutants which EPA is considering for
rulemaking under section 405(d). These results also indicate which
exposure pathway or pathways should be the focus of further
consideration with respect to these pollutants. EPA has identified 15
pollutants in its review under section 405(d)(2)(C). The results of
EPA's review do not mean that EPA has concluded that these pollutants
in sewage sludge adversely affect human health or the environment. The
magnitude of the hazard indices discussed previously do not indicate
the absolute risk for a pollutant/pathway. The results of EPA's review
mean that EPA will obtain updated concentration data and conduct a
refined risk assessment using the data to determine whether to propose
amendments to part
[[Page 75551]]
503 in order to regulate any of these pollutants under section 405(d)
of the CWA.
In summary, of the 40 pollutants evaluated in the screen, 15
pollutants have HQs that either exceed one for human health or are
equal to or greater than one for wildlife species (see Tables 5 through
8), as summarized in Table 8:
Table 8.--Summary Table of the 15 Pollutants With HQs That Either Exceed One for Human Health or Are Equal to or
Greater Than One for Ecological Receptors
----------------------------------------------------------------------------------------------------------------
Sewage sludge scenario
-------------------------------------------------
Chemical Receptor Agricultural
land Surface Incinerator
application disposal \1\
----------------------------------------------------------------------------------------------------------------
Acetone.............................. Sediment biota......... x ............... ..............
Anthracene........................... Sediment biota......... x ............... ..............
Barium............................... Aquatic community...... x ............... ..............
Adult.................. ............... x ..............
Child.................. ............... x ..............
Beryllium............................ Aquatic community...... x ............... ..............
Carbon disulfide..................... Sediment biota......... x ............... ..............
4-Chloroaniline...................... Aquatic invertebrates.. x ............... ..............
Adult.................. ............... x ..............
Child.................. ............... x ..............
Diazinon............................. Sediment biota......... x ............... ..............
Fluoranthene......................... Aquatic community...... x ............... ..............
Sediment biota......... x ............... ..............
Manganese............................ Aquatic community...... x ............... ..............
Adult.................. ............... x ..............
Child.................. ............... x ..............
Methyl ethyl ketone.................. Sediment biota......... x ............... ..............
Nitrate.............................. Adult.................. ............... x ..............
Child.................. ............... x ..............
Nitrite.............................. Adult.................. ............... x ..............
Child.................. x x ..............
Phenol............................... Sediment biota......... x ............... ..............
Pyrene............................... Aquatic community...... x ............... ..............
Sediment biota......... x ............... ..............
Soil biota............. x ............... ..............
Silver............................... Aquatic community...... x ............... ..............
Aquatic invertebrates.. x ............... ..............
Fish................... x ............... ..............
Adult.................. x ............... ..............
Child.................. x ............... ..............
----------------------------------------------------------------------------------------------------------------
\1\ No chemical with cancer or non-cancer end-points failed the screening assessment from incineration. In
addition, no chemical with cancer end-points failed the screening assessment by either the land application or
the surface disposal scenarios.
EPA will design and conduct a targeted national survey of
pollutants in sewage sludge in 2005 through 2007. The results of the
survey will provide pollutant concentration values that EPA will then
use in a more refined risk assessment and risk characterization. Based
on the results of these refined analyses, EPA will propose as soon as
practicable new regulations under section 405(d) for any pollutants
which it determines may be present in sewage sludge in concentrations
which may adversely affect public health or the environment.
XI. References
Cornell Waste Management Institute. 2003. Clustering of Biosolid
Land-Application Reported Health Incidents by Locality. http://cwmi.css.cornell.edu/sludge/incidents.htm (Revised November 8, 2003).
Haas, C.N. 2001. Assessment of the PEC Process. Drexel University.
January 2, 2001.
Harrison, E.Z. and S.R. Oakes. 2002. Investigation of Alleged
Health Incidents Associated with Land Application of Sewage Sludges.
New Solutions, Vol. 12 (4): 387-408 (2002).
International Life Sciences Institute. 2000. Revised Framework for
Microbial Risk Assessment. An ILSI Risk Science Institute Workshop
Report. Washington, DC.
NRC, 2002. Biosolids Applied to Land; Advancing Standards and
Practices, National Research Council of the National Academies. The
National Academies Press. Available online at http://search.nap.edu/books/0309084865/html.
O'Connor, G.A., R.B. Brobst, R.L. Chaney, et al. 2001. A modified
risk assessment to establish molybdenum standards for land application
of biosolids. J. Environ. Qual. 30:1490-1507.
Rusin, P.A., S.L. Maxwell, J.P. Brooks, et al. 2003. Evidence for
the Absence of Staphylococcus aureus in Land Applied Biosolids,
Environ. Sci. Technol. 2003, Vol. 37, No. 18, 4027-4030.
USEPA, 1994. A Plain English Guide to the EPA Part 503 Biosolids
Rule. 190 pages. Office of Water, Office of Wastewater Management.
Available online at: http://www.epa.gov/owm/mtb/biosolids/503pe/index.htm.
USEPA, 1996. Technical Support Document for the Round Two Sewage
Sludge Pollutants. EPA-822-R-96-003. Office of Water. Washington, DC.
USEPA, 2000. National Water Quality Inventory Report to Congress
(section 305(b) report).
USEPA, 2002. Guidelines for Ensuring and Maximizing the Quality,
Objectivity, Utility, and Integrity of Information Disseminated by the
Environmental Protection Agency. EPA
[[Page 75552]]
260R-02-008. Office of Environmental Information. Washington, DC.
October 2002. Available online at http://www.epa.gov/oei/qualityguidelines.
USEPA, 2003a. Candidate Pollutants for Ongoing Sewage Sludge
Evaluation. 15 pages. Office of Water, Office of Science and
Technology. Washington, DC. (EPA Docket for 68 FR 17379).
USEPA, 2003b. Technical Background Document for the Sewage Sludge
Exposure and Hazard Screening Assessment. Office of Water. RTI Project
No. 08317.001.024.005.
USEPA, 2003c. Methodology and Results of the Screening Analysis for
Pollutants Managed by Incineration. Office of Air. Washington, DC.
USEPA, 2003d. Responses to Public Comments Document. Office of
Water. Office of Science and Technology. Washington, DC.
USEPA, 2003e. Environmental Regulations and Technology: Control of
Pathogens and Vector Attraction in Sewage Sludge. EPA/625/R-92/013-
2003.
WERF, 2003. Dynamic Model to Assess Microbial Health Risks
Associated with Beneficial Uses of Biosolids. Cooperative Agreement No.
CR-825237. Alexandria, VA.
WERF, In Press. Biosolids Public Perception & Participation. Ned
Beecher, New England Biosolids & Residuals Association, Principal
Investigator. Alexandria, VA.
Dated: December 23, 2003.
G. Tracy Mehan III,
Assistant Administrator, Office of Water.
[FR Doc. 03-32217 Filed 12-30-03; 8:45 am]
BILLING CODE 6560-50-P