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Regulatory Alert - RA 02-16 - NATIONAL RESEARCH COUNCIL RELEASES SCIENCE STUDY OF LAND-APPLIED BIOSOLIDS

Member Pipeline - Regulatory - Alert (RA 02-16)

To: Members & Affiliates, Pretreatment & Biosolids Management Committee
From: National Office
Date: July 10, 2002
Subject: NATIONAL RESEARCH COUNCIL RELEASES SCIENCE STUDY OF LAND-APPLIED BIOSOLIDS
Reference: RA 02-16

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On July 2, the National Research Council (NRC), the principal operating arm of the National Academy of Sciences (NAS), released the findings from its review of the science and methodology behind the U.S. Environmental Protection Agency’s (EPA’s) biosolids land application standards (40 CFR Part 503). The report, Biosolids Applied to Land: Advancing Standards and Practices (NRC Report), makes a number of recommendations for updating the scientific underpinnings of the Part 503 standards, but finds no substantive evidence that the existing Part 503 standards are failing to protect public health. The report is available on the internet at http://www.nap.edu. Copies will be available for purchase later this summer from the National Academy Press at 1-800-624-6242.

Background
In February 1993, EPA published Standards for the Use or Disposal of Sewage Sludge (40 CFR Part 503) under Section 405(d) of the Clean Water Act. EPA subsequently funded two NRC reviews of biosolids practices – in 1993 and 1996. On March 22, 2000, EPA's Office of Inspector General released an audit report, "Biosolids Management and Enforcement" (Report Number 2000-P-10). While the audit did not review the science and risk assessments related to Part 503, the Inspector General found that EPA could not "assure the public that current land application practices are protective of public health."

In response to the report, on August 3, 2000, EPA announced that it had requested a NAS review of the science and methodology behind the Agency's biosolids land application standards. At the time, the U.S. Centers for Disease Control and Prevention - National Institute of Occupational Safety and Health (NIOSH) agreed to work with EPA and the NAS on the review. In its proposal to EPA, NAS indicated the study would review the risks and risk assessment methods used by EPA for establishing regulatory standards for chemical pollutants and pathogens in biosolids applied to land as fertilizer. NAS noted that new information relevant to toxicological and pathogenic risks of biosolids following land application had been generated, and that the study would review the data to determine their applicability to the 503 rule.

National Research Council Committee Formed
The NRC formed a sixteen member committee in early 2001 to review the information relevant to EPA’s request. The project was entitled “Risks from Toxicants and Pathogens in Biosolids Applied to Land.” The Committee's charge was to 1) review the risk assessment methods and data used to establish concentration limits for chemical pollutants in sludge to determine whether they are the most appropriate approaches; 2) review the current standards for pathogen elimination in sludge and their adequacy for protecting public health; and 3) explore whether approaches for conducting pathogen risk assessment can be integrated with those for chemical risk assessment. The Committee met five times. The public was given an opportunity to make statements only at the first meeting. Dr. Cecil Lue-Hing, former Director of Research and Development at the Metropolitan Water Reclamation District of Greater Chicago, addressed NRC Committee members on behalf of the wastewater treatment community. For more information on the project scope and the meetings, go to the project website at: http://www4.nas.edu/webcr.nsf/ProjectScopeDisplay/BEST-K-00-02-A?OpenDocument.

The NRC Report
The 270-page report detailing the Committee’s findings is organized into seven chapters. Chapter 1 provides a brief introduction to biosolids, what they are and how they are used, and the current Part 503 standards. It also summarizes the 1996 NRC review and outlines the Committee’s approach to accomplishing its task. Chapter 2 describes the history of the biosolids regulations, treatment processes, use practices, compliance issues, and risk management practices in the United States. It also provides a brief overview of biosolids regulations and practices in Europe, treatment controls for pathogens, and biosolids end-use practices. Chapter 3 reviews the available evidence on human health effects from exposure to biosolids. Chapter 4 presents developments in risk assessment since the Part 503 rule was established and discusses current risk assessment practices used by EPA. Chapter 5 reviews EPA’s risk assessment approach to setting limits for chemical pollutants in biosolids. Chapter 6 reviews EPA’s pathogen reduction standards as well as new developments in the area of risk assessment for microbial agents. Finally, Chapter 7 explores one of the Committee’s specific charges, whether it is possible to use an integrated approach to assess the risks from a complex mixture of chemical and biological agents.

Overall Findings
The NRC’s findings are on track with what AMSA expected when the Committee was first formed. Overall, the NRC Report indicates that there is no documented scientific evidence that the Part 503 rule has failed to protect public health, but notes a critical need to update the scientific basis of the regulations to reduce uncertainty about the potential for adverse effects and to assure the public that land application is safe.

Like any set of complex environmental rules, the underlying science driving the regulations changes over time as new discoveries and advancements are made. Risk assessment methods have changed since the Part 503 regulations were developed and successful publicly owned treatment works (POTW) pretreatment programs have dramatically reduced the levels of pollutants entering treatment plants. Accordingly, the NRC makes a number of recommendations to ensure the Part 503 standards are based on current data and risk assessment methods.

The NRC Report addresses a number of issues that were also raised in a recent report from EPA’s Office of Inspector General, including the need for effective enforcement of the Part 503 standards and the need to establish a program for conducting human health investigations and tracking alleged health impacts.

The report makes four overarching recommendations to EPA:

 
Health Effects
Although the NRC found no documented causal link between biosolids and adverse human health effects, the Committee noted that there is a lack of exposure and health information on populations exposed to biosolids and that there is a need to gather epidemiological data to investigate allegations of health incidents. The Committee recommended that EPA examine potential health risks to both worker and residential populations, indicating that studies of wastewater treatment plant workers should not be used as surrogates for studies of other populations (e.g., farmers, nearby communities) exposed to biosolids. Specifically, EPA was directed to promote and support response investigations (studies in response to unusual exposures or occurrences of disease), preplanned exposure assessment studies, and a few well-designed epidemiological investigations of exposed populations to provide a means of documenting whether health effects exist that can be linked to biosolids exposure. The report also notes that greater consideration should be given to whether odors from biosolids could have adverse health effects.

Biosolids Standards and Oversight Activities
Although the Committee found no documented evidence that the Part 503 rule has failed to protect public health, the Report concluded that there is a need to address scientific and management questions and uncertainties that challenge EPA’s biosolids standards. Specifically, EPA must ensure that chemical and pathogen standards established in 1993 are supported by current scientific data and risk assessment methods, and that current prescribed management practices are effective. The Committee also recommended that EPA strengthen its biosolids oversight program by increasing the amount of funding and staff devoted to it. Other recommendations included:

The NRC recommended that EPA use a particular framework as it works to build a more robust biosolids oversight program. The framework includes procedures for assessing the reliability of biosolids treatment processes, monitoring compliance with the chemical and pathogen standards, conducting environmental hazard surveillance, and studying human exposure and health. The framework highlights opportunities for conducting environmental hazard surveillance (including a review of management control efficacy) throughout the biosolids management process and the various points in the process where human exposure can occur.

The Committee also concluded that it is not possible at this time to integrate pathogen risk assessment with chemical risk assessment, due to the data gaps and lack of risk assessment methods for complex mixtures.

Chemical Standards
The Committee found the technical basis of the 1993 chemical standards for biosolids to be outdated given the substantial advances in risk assessment since the standards were developed. The Committee noted that there are new concerns about adverse health effects and chemicals not originally considered in the analysis conducted for the Part 503 regulations. The Committee recommended that EPA reassess the standards for the regulated chemicals by conducting a revised multipathway risk assessment and conducting another chemical selection process to determine whether additional chemicals should be considered for regulation. It was also noted that any revised risk assessment must be relevant nationally, and therefore reflect regional variation in climate, hydrology, and biosolids use and characteristics. In addition, stakeholders should be included in the risk assessment process to help identify exposure pathways, local conditions that could influence exposure, and possible adverse health outcomes.

The Committee recommended a number of tasks necessary to update the scientific basis for the chemical standards:

 
Pathogen Standards
While the Committee supported EPA’s approach for establishing pathogen reduction requirements and monitoring indicator organisms, the report notes that the reliability of EPA’s prescribed treatment techniques should be better documented using current pathogen detection technology. The report makes the following recommendations for improving the scientific basis of the 1993 pathogen standards:


EPA’s Next Steps
EPA plans to publish in the Federal Register in April 2003 the Agency’s response to the report and plan of action for addressing the Committee’s recommendations. According to an agreement between EPA and the other parties involved in a thirteen-year-old lawsuit over the Agency’s biosolids regulations (Gearhart v. Whitman; See Legal Alert 02-6), the Federal Register notice will specify whether EPA is planning any regulatory or non-regulatory means of addressing the NRC recommendations, and the time frame for taking final action on any planned activities, including a schedule for proposing rules, if any. EPA will publish its final plan for responding to the NRC recommendations in the Federal Register within nine months of the first notice.

For more information on the NRC Report contact Chris Hornback, AMSA at 202/833-9106 or chornback@amsa-cleanwater.org or Lee Garrigan, AMSA, at 202/833-4655 or lgarrigan@amsa-cleanwater.org.