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Biosolids Program Review

Every day new chemicals are produced and utilized in commercial applications and consumer goods. As these chemicals are integrated into new consumer products, new research is conducted to determine what effects they may have on human health and the environment. As a result, the chemicals in our wastewater are continually changing, which requires continual review of these chemicals, improved analytical laboratory methods and new research to ensure today’s biosolids program and practices are protective of public health and the environment.  

The EPA’s Biosolids Program is subject to regular reviews to determine if it is protective of public health and the environment. As required in the Clean Water Act, EPA is required to conduct a review of its biosolids program at least every two years. The results of these biennial reviews are available on EPA’s website.

The EPA’s Office of Inspector General conducted a review of EPA’s Biosolids program in 2018. The title of their report stated, “EPA unable to assess the impact of hundreds of unregulated pollutants in land-applied biosolids on human health and the environment.” Unfortunately, this review did not include a significant portion of the research that has been conducted on chemicals in biosolids. After the report was released, EPA’s water quality director and EPA’s biosolids program staff worked with the Office of Inspector General to resolve the issues identified in the inspector’s report. In July 2019, the EPA’s Office of Inspector General released the final findings stating “…all recommendations for the subject report are now considered resolved.”

The National Academy of Sciences has conducted two reviews of the biosolids program. The first was conducted in early 1993 when EPA was developing the rules and standards of today’s biosolids program. The Academy’s second review was completed in 2002 and came to the following conclusion: “With proper management, biosolids land application is protective of public health and the environment and it provides a resource value for crop production…”

Does land application of biosolids put me at risk?

A wide variety of chemicals have been detected in various biosolids across the country. These chemicals come from industrial sources, consumer products, pharmaceuticals, and household chemicals. The specific chemicals and their concentrations in a given municipality’s biosolids are dictated by the industries and households that discharge to the wastewater treatment plant. As a result, the concentration of chemicals identified in biosolids in the news stories may not necessarily be representative of what could be found in the biosolids being applied to a field.

Several risk assessments have been conducted on the land application of biosolids. These studies have found that the land application of biosolids does not present an undue risk to human health or the environment at this time. The concentrations of the chemicals that have been found in biosolids in Oregon are significantly lower than what we are typically exposed to in our own homes.

Risk and how is it assessed

Risk depends on three factors: How much of a chemical is present; how toxic is the chemical; and how much contact (exposure) a person or ecological organism has with the chemical. Risk assessments evaluate the likelihood of adverse effects that may occur as a result of exposure to one or more chemicals. This process looks at what happens to the chemical when it is released to the environment, the toxicity of the chemical, and the concentration of the chemical that different individuals or organisms may be exposed to in different scenarios.

More information on risk assessments and some of those conducted on biosolids

The presence of a chemical does not always mean “health hazard”

One of the main misconceptions concerning chemicals is the notion that if a potentially hazardous chemical is present in something than it is not safe to use. This is not always true. Different forms or concentrations of a chemical can have different effects. The detected presence of a contaminant does not equate to a health hazard risk. For example, arsenic is a naturally occurring element in the environment that can cause skin, lung, and bladder cancer as well as constriction of blood vessels and decreased nerve function. Low levels of arsenic are commonly found in apples. This does not mean that apples are bad. The health benefits of regular consumption of apples are extensively studied and are widely accepted. So even though arsenic is in apples, it does not mean that apples will increase your risk of cancer or other health concerns. In fact, current research indicates that regular consumption of apples will actually help prevent some cancers and health concerns
Every day new chemicals are produced and new research is conducted to determine what effects they may have on human health and the environment. As a result, we continue to monitor and evaluate the biosolids program and stay attuned to this new science to ensure today’s practices are protective. Based on current research the federal and Oregon’s biosolids programs are protective of public health and the environment.


Pat Heins
Biosolids and Water Reuse Coordinator