Article for New England Water and Wastewater News

Sept. 20, 2002

By Ellen Z. Harrison, Director, Cornell Waste Management Institute

Moving Forward on Land Application

Having served as a panel member on the National Research Council committee that produced the July 2002 report “Biosolids Applied to Land: Advancing Standards and Practices,” I am very familiar with both its contents and the discussions that went into producing it. Despite diverse opinions, the committee was able to achieve unanimous consensus. That does not mean that each of us was happy with all of the language, but rather that we could live with it.

I am coming to regret agreeing to the sentence that “there is no documented scientific evidence that the Part 503 Rule has failed to protect public health” because that sentence is being misused and misconstrued. The report goes on to say “to date, epidemiological studies have not been conducted on exposed populations…Because of the anecdotal reports of adverse health effects, the public concerns, and the lack of epidemiological investigation, the committee concluded that EPA should conduct studies that examine exposure and potential health risks to worker and residential populations.” (NRC, p 4)

The committee restricted itself to reliance only on published scientific literature, so the lack of “documented scientific evidence” may well be due to the lack of such published studies. In discussion, the committee was clear that a lack of evidence does not indicate a lack of harm.

The report documented numerous areas in which there are needs for more research, testing of sludges for pathogens and contaminants and assessment of specific risks. It recognized that even with such work, municipal sewage sludges contain a complex mixture of chemicals and pathogens that “preclude the development of risk-management procedures based on these agent-specific analyses that can reliably result in acceptable levels of risk. Some form of process quality assurance and ongoing surveillance must be done to ensure that effects not anticipated by the chemical and pathogen-specific risk assessments do not occur.” (NRC, p 253)

It is dismaying to read an article such as the one by Needleman in issue 76 of New England Water and Wastewater News which misuses the NRC report to assert that land application is “safe.” He also asserts that “the report’s findings further justify EPA’s treatment of biosolids recycling as a low-priority program.” That statement is in complete conflict with the actual language of the report. Recognizing the need for significant new research and testing as well as the serious lack of enforcement capabilities, one of the report’s overarching recommendations is to “increase the resources devoted to EPA’s biosolids program.” (NRC, p 4).

Where To From Here

Many people involved in the sludge industry recognize that the research called for in the NRC report is important, worthwhile and necessary if land application is going to continue to be a viable option. It is in everyone’s interest that this work be carried out in a fair and objective process so that results are viewed as credible by all parties. The NRC report states that “stakeholders should be involved in review of the design, conduct, and interpretation of the studies. Stakeholders may include representatives of workers and management, community representatives, health care providers, and victims of disease.” (NAS p 90). Engaging stakeholders is critical both to ensure credibility of the research and because these people have knowledge and information that is important to the research.

A group of thoughtful and knowledgeable scientists volunteered considerable time to develop the NRC report and its recommendations. Rather than using (or misusing) the report, its recommendations should be studied closely and used to frame and motivate the extensive work that needs to be done. I am willing to work to join others to see that such work goes forward and hope that those involved with sludge will reach out beyond their ranks and work towards collaboration that might help to move forward the important research that needs to be done.