Federal Register: December 31, 2003 (Volume 68, Number 250)
DOCID: FR Doc 03-32217
ENVIRONMENTAL PROTECTION AGENCY
Environmental Protection Agency
FRL ID: [FRL-7605-8]
NOTICE: NOTICES
ACTION: Water pollution control:
DOCUMENT ACTION: Notice.
SUBJECT CATEGORY:
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
DOCUMENT 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.
SUMMARY:
Sewage sludge; use or disposal standards; regulatory review,
SUPPLEMENTAL 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:
Category Examples of interested entities
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............................... Privatelyowned 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.
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. OW20030006. 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) 5661744, and the telephone number for the Water Docket is (202) 5662426.
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
AMSAAssociation of Metropolitan Sewerage Agencies
ASTMAmerican Society for Testing and Materials
CDCCenters for Disease Control and Prevention
CFRCode of Federal Regulations
CPECytopathic Effects
CWAClean Water Act
EMSEnvironmental Management System
EPAU.S. Environmental Protection Agency
FQPAFood Quality Protection Act
HQHazard Quotient
ICCPCRIntegrated cell culturepolymerase chain reaction
ICMAInternational City/County Management Association
IREDInterim Reregistration Eligibility Decision
IRISIntegrated Risk Information System
ISGInformation Sharing Group
LGEANLocal Government Environmental Assistance Network
NBPNational Biosolids Partnership
NPDESNational Pollutant Discharge Elimination System
NODANotice of Data Availability
NRCNational Research Council
NSSSNational Sewage Sludge Survey
OPPOffice of Pesticide Programs
OWOffice of Water
PCBsPolychlorinated biphenyls
PCDDs/FsPolychlorinated dibenzopdioxins/dibenzofurans
PCRpolymerase chain reaction
PCSPermit Compliance System
PECPathogen Equivalency Committee
PFRPProcess to Further Reduce Pathogens
POTWPublicly Owned Treatment Works
PPCPsPharmaceutical and Personal Care Products
PSRPProcesses to Significantly Reduce Pathogens
QA/QCQuality Assurance/Quality Control
QMRAQuantitative Microbial Risk Assessment
REDReregistration Eligibility Decision
RMEReasonable Maximum Exposure
SOPStandard Operating Procedure
SSISewage Sludge Incinerator
TBDTechnical Background Document
UAUniversity of Arizona
USDAUnited States Department of Agriculture
VOCvolatile organic compounds
WEFWater Environment Federation
WERFWater 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. HazardBased 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. 896266 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 dibenzopdioxins/dibenzofurans (PCDDs/Fs) and dioxinlike coplanar polychlorinated biphenyls (PCBs) (USEPA, 1996).
On December 15, 1999, the Administrator signed a proposal to establish numerical limits for chlorinated dibenzopdioxin, chlorinated dibenzofurans, and coplanar 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 landapplied 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 landapplied 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 sludgeonly 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 sludgeonly 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 privatelyowned 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 landapplied 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 landapplied 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 technologybased 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 landapplied 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 landapplied. 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 landapplied 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 selfimplementing. 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 landapplied. 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 26 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 1738417393.
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 EPAspecific 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), reevaluation 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. NearTerm 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 nonregulatory 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 longterm 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 hazardbased 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 landapplied 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 peerreviewed 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 19952002, 119 administrative penalty orders for FY 19952002, and one civil judicial action in FY 1997. The PCS database documents 382 regional and state biosolids inspections for FY 20002002.
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 CDROM, 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 landapplied (40 CFR part 503, subpart D). The regulations require that landapplied 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 longterm 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 pathogenrelated comments were directed to the issue of EPA's response regarding risk assessment, treatment efficacy, and sitespecific 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 multilaboratory 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
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viruses when monitoring is required, according to this publication, is
the American Society of Testing and Materials (ASTM) Method D499489.
Although Method D499489 was validated in a multilaboratory 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 D499489 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 D499489. However, limited data are available to evaluate these methods. EPA supports the concept of performancebased methods, and the PEC would accept data from simpler methods, if shown to be at least as effective as Method D499489. 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 D499489. 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 D499489. This quantitative assay relies upon the development of virusinduced 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 2to 100fold lower concentrations than plaque assays, with the higher sensitivities observed for environmental water samples.
The plaque assay and the MPNbased 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 culturePCR (ICCPCR) assay to determine whether previously undetectable human enteric viral pathogens are present in sewage sludge.
Method validation will be accomplished by comparing Method D499489 using plaque, MPN, and ICCPCR 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 fullscale 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 MultipleTube 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
fullscale 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 RappaportVassiliadis (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 1738517386, 1738817390), 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 soilbound
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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 198889 National Sewage Sludge Survey (NSSS) (68 FR 17385). Some commenters liked the targeted survey approach, but most commenters requested that EPA consider another national fullscale 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 multistakeholder 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 exposurerelated 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 technologybased 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 landapplied 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 p
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)
5661135. stevens.rick@epa.gov.