Research & Development

Contamination of Biosolids in Agroecosystems

Tractor harvesting fields

R&D on PFAS Contamination of Biosolids in Agroecosystems

Thanks to a grant from the Foundation for Food and Agricultural Research (FFAR) we are conducting a three-year study. This project addresses the issue of pollution of surface and groundwater in farms treated with biosolids from wastewater treatment plants (WWTPs) containing polyfluoroalkyl substances (PFAS).

Testing For PFAS In Biosolids

PFAS comprise a group of over 4000 chemicals that are used in a wide range of industrial applications and represent a risk to human health. They are often found in high concentrations in WWTP discharge and sludge . About 50% of the 7 million tons of WWT sludge produced nationally is applied in farms as a source of organic matter and nutrients. WWTPs are critical to keeping the nation’s waters clean. Processed solid waste material is a residual of wastewater treatment, and the byproducts labeled biosolids are characterized as treated, tested, and determined safe for land application. While rich in organic matter and nutrients, WWTP sludge and biosolids can contain heavy metals, pathogens and other pollutants which are regulated. Some of these contaminants are removed or destroyed during processing, however current treatment technologies do not remove PFAS. To date, the US EPA has not limited PFAS in biosolids or developed a standard for determining safe levels.

Impact on Farmers

Beyond the potential threat to the nation’s waters, the ultimate burden of PFAS contamination through untreated WWTP biosolids falls on farmers. First and foremost, they risk contaminating shallow aquifers and surface waters often used as a drinking water source for their household or livestock. In addition, farmers are fearful of consumer backlash related to contaminated farm products. Evidence of a link between PFAS-laced sludge and vegetation emerged in 2008, when the US EPA found elevated levels of several PFAS compounds in vegetation and water bodies near where an Alabama utility had spread sludge biosolids on 5,000 acres of farmland. Studies have documented PFAS absorption by some crops from biosolids. In Maine, a dairy farm was forced to shut down after sludge spread on the land was linked to high levels of PFAS in the milk. Within this context, this proposal addresses the need to empower farmers to learn about the risk of introducing contaminated biosolids to their farms. Currently, farms are a major end point in the journey of PFAS and data are needed to guide regulations and standards for safe PFAS levels in WWTP-derived biosolids.

Our Study

Our study includes two components: first, the development of a non-targeted analytical method that will advance the quantification of total organo-fluorine compounds in water and soil matrices; and second, a field study to examine the presence, concentration, and temporal dynamics of PFAS in farm fields at multiple levels including surface runoff, soil pore-water and connected surface and groundwaters. The collaboration between Stroud Water Research Center and STRIDE will bring together the expertise and set of tools needed for the success of this project.

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