Use of Reclaimed Water and Sludge in Food Crop Production 1996
National Research Council's Water Science and Technology Board (WSTB)
NATIONAL ACADEMIES OF SCIENCE
Albert Page - Committee Chair Conflict Co-chair part 503 Peer Review Committee that
approve the science behind the sludge marketing rule.
When EPA first promulgated criteria for land application of municipal wastewater sludges to cropland in 1979, some food
processors questioned the safety of selling food crops grown on sludge-amended soils and their liability. In response,
the principal federal agencies involved-EPA, the U.S. Food and Drug Administration (FDA), and the U.S. Department of
Agriculture (USDA)-developed a Joint Statement of Federal Policy in 1981 to assure that current high standards of food
quality would not be compromised by the use of high quality sludges and proper management practices. EPA did not
keep the agreement in the final Part 503.
Use of Reclaimed Water and Sludge in Food Crop Production
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Preface
In early 1993, the U.S. Environmental Protection Agency's (EPA) Office of Wastewater Compliance and Enforcement
suggested to the National Research Council's Water Science and Technology Board (WSTB) that it should consider
undertaking a study of public health and public perception issues associated with the use of treated municipal
wastewater and sludge in the production of crops for human consumption. At the time, EPA was just finalizing the Part
503 Sludge Rule, Standards for the Use or Disposal of Sewage Sludge , and one of the major implementation concerns
was with the food processing industry's reluctance to accept the practice. When EPA first promulgated criteria for land
application of municipal wastewater sludges to cropland in 1979, some food processors questioned the safety of selling
food crops grown on sludge-amended soils and their liability. In response, the principal federal agencies involved-EPA,
the U.S. Food and Drug Administration (FDA), and the U.S. Department of Agriculture (USDA)-developed a Joint
Statement of Federal Policy in 1981 to assure that current high standards of food quality would not be compromised by
the use of high quality sludges and proper management practices. Nevertheless, the food processing industry remains
concerned about safety and market acceptability, and at least one company has adopted an official policy that bans the
purchase of any crops grown on fields receiving municipal sewage sludge or treated municipal wastewater. With the
issuance of the Part 503 Sludge Ru le in 1993, public concerns with a number of technical, regulatory, and
environmental issues have surfaced. Because cropland application of both sludge and wastewater represent important
management options, municipal wastewater management officials have a vital interest in the feasibility of these practices.
Therefore, in mid-1993, WSTB formed a committee representing diverse expertise and perspectives to conduct an
independent study of the safety and practicality of the use of these materials for the production of crops for huma n
consumption. The study sought to review (1) the historical development, rationale, and scope of the practice of treating
municipal wastewater and sludge in the United States; (2) wastewater treatment technologies and procedures for
agricultural use of these materials; (3) effects on soils, crop production, and ground water; (4) public health concerns
about microbiological agents and toxic chemicals; (5) existing regulations and guidelines; and (6) economic, liability, and
institutional issues. The committee based its re- view on existing published literature and discussions with experts in the
field. The committee was not constituted to conduct an independent risk assessment of possible health effects, but
instead to review the method and procedures used by EPA in its extensive risk assessment, which was the basis for the
Part 503 Sludge Rule.
The committee met five times over a 17-month period including field visits to the Irvine Ranch Water District in California,
the CONSERV II Water Reclamation Program of Orange County and Orlando, Florida, and the Disney World , Florida
reuse programs. The committee also held a one-day workshop at Rutgers University in New Brunswick, New Jersey to
hear from researchers, public interest groups, farm credit bureaus, farmers, and state and city planners on land
application of municipal sludge in the Northeast.
The committee focused primarily on the issues surrounding the use of treated municipal wastewater effluents and
treated sludge in food crop production, concentrating on the uptake of chemical constituents and pathogens by food
crops. The study did not include an investigation of what happens after the crops are harvested (e.g., processing of
food products). Further, the committee was not constituted to evaluate site-specific implementation of wastewater
effluent and sludge reuse projects, or to compare the relative merits and risks of various other forms of disposal or
beneficial uses. However, the committee recognized that in addition to the safety and practicality of using these
materials on food crops, there are many implementation issues involved with the agricultural use of municipal
wastewater and sludge including the degree to which the regulations are implemented and enforced, the public
confidence in local reuse programs, local nuisance and traffic problems, environmental and product liability issues, and
overall public perceptions. In several of these areas, this report notes particular findings that should receive the
attention of federal, state, and local authorities responsible for implementing reuse projects .
It is hoped that this report will be particularly useful to food processors, states, and municipalities in assessing the use of
treated municipal wastewater and sludge in producing crops for human consumption. It highlights public concerns and
regulatory issues likely to be faced, and also identifies some additional areas for research.
The Committee on the Use of Treated Municipal Wastewater Effluents and Sludge in the Production of Crops for Human
Consumption consisted of 14 members with experience in soil and crop science, agricultural engineering,
wastewater and sludge treatment, soil microbiology, toxicology, ecology, infectious disease, public health, economics,
law, and other relevant fields. The committee gained insights from a far larger group by inviting guests to its meetings,
participating in field trips, and reviewing the literature. My great appreciation goes to the committee, each of whom gave
significant time and energy to create this report. Additionally, I would like to thank Rufus Chaney and Richard Bord for
providing their time and resources to the study. I want to thank the staff of the WSTB, especially Gary Krauss, study
director, and Mary Beth Morris, project assistant. I would also like to thank the study sponsors: the EPA, the U.S. Bureau
of Reclamation, the USDA, the FDA, the National Water Research Institute, the Water Environment Research
Foundation, the National Food Processors Association, the Association of Metropolitan Sewerage Agencies, California's
Eastern Municipal Water District, the Metropolitan Water Districts of Southern California, Bio Gro Division of
Wheelabrator Water Technologies, and N-Viro International Corporation. Without this support, the study would not have
occurred.
Albert Page
University of California, Riverside