Risk Assessment for “Round One” in Support of 40 CFR Part 503

In 1989, the U.S. Environmental Protection Agency proposed a regulation for sewage sludge, Standards for the Use or Disposal of Sewage Sludge, at 40 CFR Part 503 (commonly called “Part 503”). The proposed rule included a draft risk assessment for pollutants found in sewage sludge. Between 1989 and 1993, the EPA incorporated public comments, the results of the 1988 National Sewage Sludge Survey, and expertise on risk assessment to develop an updated risk assessment and rule. In 1993, the EPA published the final rule with the final risk assessment. This regulation is often called “Round One” because the agency planned to identify additional pollutants in sewage sludge that may pose risk, conduct risk assessments, and propose additional regulations as necessary.

The following guide was prepared to provide an understanding of the risk assessment process that was conducted as a basis for the Part 503 biosolids rule. The document 1) describes the risk assessment procedures used to develop Part 503 pollutant limits; 2) provides historical accounting and discussion of the steps taken during risk assessment; 3) discusses the issues that arose during the risk assessment process and their resolutions; 4) explains assumptions and policy decisions; and 5) answers commonly asked questions.

A Guide to the Biosolids Risk Assessments for the EPA Part 503 Rule (pdf) (19.7 MB, September 1995, EPA 832-B-93-005)

Technical supports documents which provide the risk assessment and the technical data and justifications:

Learn more about Standards for the Use or Disposal of Sewage Sludge (40 CFR Part 503).

Risk Assessment for “Round One” in Support of 40 CFR Part 503

Biosolids