Consensus Report

Biosolids Applied to Land: Advancing Standards and Practices (2002)


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Key Messages

  • Because of data gaps and lack of risk-assessment methods for complex mixtures, it is not possible at this time to integrate pathogen risk assessment with chemical risk assessment. Thus, it remains necessary to use a component-based approach to assessing risks from chemicals and pathogens in biosolids.
  • Given the variety of pathogens that have the potential to be present in biosolids, the committee supports EPA's approach to establishing pathogen reduction requirements and monitoring indicator organisms. However, the reliability of EPA's prescribed treatment techniques should be better documented using current pathogen detection technology, and more research on environmental persistence and dose-response relationships is needed to verify that current management controls for pathogens are adequate to maintain minimal exposure concentrations over an extended period of time.
  • The committee found that no substantial reassessment has been done to determine whether the chemical or pathogen standards promulgated in 1993 are supported by current scientific data and risk-assessment methods.
  • The committee found the technical basis of the 1993 chemical standards for biosolids to be outdated. EPA has not reevaluated its chemical standards since promulgation, so the data and methods used for the original regulations are well over a decade old.
  • There is a lack of exposure and health information on populations exposed to biosolids. There is a need to gather epidemiological data and to investigate allegations of health incidents. EPA needs to study more rigorously the exposure and health risks, or the lack thereof, in worker and community populations exposed to biosolids.
  • There is no documented scientific evidence that the Part 503 rule has failed to protect public health.However, additional scientific work is needed to reduce persistent uncertainty about the potential for adverse human health effects from exposure to biosolids.
  • To assure the public and to protect public health, there is a critical need to update the scientific basis of the rule to (1) ensure that the chemical and pathogen standards are supported by current scientific data and risk-assessment methods, (2) demonstrate effective enforcement of the Part 503 rule, and (3) validate the effectiveness of biosolids-management practices.