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Land Application of Biosolids Containing EDCs
Impact Statement: In the US, over 3 million dry tons of sewage sludge (or biosolids) are applied on agricultural lands. Biosolids may contain significant quantities of steroid hormones, alkyl phenols, and other endocrine disrupting chemicals. Through land application, these contaminants may be reintroduced into the environment where they may impact surface and ground water, soil, and sediments. The goal of this project is to characterize the fate and transport of these EDCs in the land application situation, particularly amounts in applied biosolids, degradation following application, transport down the soil column, and runoff into surface waters.
Project Description/Current Status: The regulations which govern the land application of biosolids were promulgated in 1993. Since that time, methods for treating and handling biosolids have evolved. In 2002, the National Research Council (NRC) advised that a new national survey of chemicals and pathogens in sewage sludge was needed to ensure that current practices were consistent with previous risk assessments and to determine if additional chemicals should be regulated.
As part of the response to the NRC recommendations, a large research project will evaluate aspects of biosolids land application such as air bourne odor and pathogen levels and survival of pathogens on the soil. At three sites, different types of biosolids (anaerobically digested, lime stabilized , and aerboically digested) will be applied at agronomic levels. EDCs will be studied as part of this study. Current plans are to focus on alkyl phenol ethoxylates, in a collaborative project with the Central Regional Lab of Region 5, and steroid hormones. Concentrations will be measured before and after biosolids application at various soil depths. Chemical levels will be tracked for at least a month. In addition, supporting information will also be gathered such as diversity, size, and activity of the microbial community, temperature and weather data, and co-contaminant concentrations. The data will be used to calculate removal rates and evaluate whether EDCs are transported down the soil column at these sites and for these biosolids types. In addition, data will be used to evaluate sample replication and other statistical variables. Based on this initial study, more detailed studies will be designed to focus on the most important variables.
Contact Information: For more information concerning Land Application of Biosolids, please contact: Carolyn Acheson, Ph.D. at phone (513) 569-7194, or fax (513) 569-7105 or Marc A. Mills at phone (513) 569-7322 or fax (513) 569-7105.