Unregulated Organic Chemicals in Biosolids: Prioritization, Fate and Risk Evaluation for Land Applications

EPA Grant Number: R840245
Title: Unregulated Organic Chemicals in Biosolids: Prioritization, Fate and Risk Evaluation for Land Applications
Investigators: Olabode, Lola , Gan, Jay , Lee, Linda S. , McAvoy, Drew
Institution: Water Research Foundation , University of California Riverside , Purdue University , University of Cincinnati
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 2021 through September 30, 2024
Project Amount: $1,497,907
RFA: National Priorities: Evaluation of Pollutants in Biosolids (2021) RFA Text |  Recipients Lists
Research Category: Water Treatment , Water Quality , Water


The land application of biosolids offers multiple benefits over landfilling and incineration, and improves soil health and plant nutrition. However, biosolids contain numerous unregulated organic chemicals (UOCs) leading to concerns that may impede the beneficial use of biosolids. In particular, there are perceived risks from potential accumulation of UOCs in food and feed crops, as well as potential offsite transport that could result in groundwater or surface water contamination. This proposal is responding to Research Area #2 of the EPA National Priorities Solicitation - “Better understanding of the occurrence, fate, and transport of chemical pollutants in land-applied biosolids, particularly those that may persist and/or accumulate in soils and biota”.


To address the imminent challenges, we propose to conduct research to prioritize UOCs in biosolids based on their occurrence, mobility, persistence, and bioaccumulation, develop simple standard assays to measure mobile and bioavailable fractions of priority UOCs in biosolids, and carry out field studies at multiple locations to evaluate plant and earthworm accumulation, leaching and runoff risks of priority UOCs under different biosolids application, soil, climate and planting conditions. The prioritization study will leverage existing data and use a tiered approach to derive a short list of UOCs of greatest potential concern for offsite transport and bioaccumulation. Wth the development of standard assays, we aim to rapidly measure chemical forms that are available for offsite movement or bioaccumulation. The field
studies will consider Class A biosolids applications for food and feed crop production and Class B biosolids for non-agronomic application scenarios at multiple locations in CA, VA, IN, and IL. Accumulation of UOCs in plant and worm tissues, and downward and lateral transport will be measured to obtain realistic estimates. Data from the laboratory and field studies will be used to evaluate fate and transport models in risk assessments, leading to recommendations of best practices to minimize potential risks of UOCs in biosolids-amended fields. We will work closely with utility partners and a diverse community of stakeholders to seek input to the project scope and to effectively review and dissiminate research results and outcomes throughout the project.

Expected Results:

This project will produce a prioritized list of UOCs that have the greatest potential to pose elevated risks to human health and the environment, and standard rapid assays to measure mobile and bioavailable fractions of UOCs in biosolids. These outcomes will be informed by field data from across the U.S. to support a national scope for robust validation of the rapid assays and assessment models of potential risks of biosolids-borne UOCs following land applications. The study findings will have immediate and broad implications for the scientific community, agriculture and water sectors and the borader community in ensuring the safe reuse of biosolids through land applications in the U.S.

Supplemental Keywords:

sludge; emerging contaminants; contaminant transport.