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Environmental Health - Toxic Substances

Research Projects - Emerging Contaminants

Land Application of Municipal Biosolids

Biosolids being transferred from a dump truck to a spreader.
Biosolids being transferred from a dump truck to a spreader prior to being applied to an agricultural field. Biosolids are rich in plant nutrients. Farmers, landscapers, and homeowners use about 50 percent of the annual production as fertilizer for plants. Photo credit: Dana Kolpin, USGS.
(Click on photo for larger version)

Biosolids and products derived from biosolids are a potential source of pharmaceuticals and other emerging contaminants to the environment. Wastewater treatment plants (WWTPs) in the United States generate approximately 7 million dry tons of sludge each year. Because this sludge, commonly called biosolids, is rich in plant nutrients, it is frequently applied to soils to fertilize plants and to improve the quality of soil. The mass of biosolids applied to soils is substantial, approaching 3 million dry tons throughout the United States in 1998. These biosolids and biosolids composts are used widely in both residential and commercial landscaping and in row-crop agriculture. Because a variety of pharmaceuticals and other organic chemicals have been found in the wastewater discharged from WWTPs, questions have been raised about the presence of these chemicals in biosolids. The application of municipal biosolids on land may be a widespread source of emerging contaminants to surface and ground water.

USGS scientists and their collaborators are conducting the following projects:

  • The development of analytical methods for characterizing the potential emerging contaminants in biosolids-derived composts and other products. Ongoing research includes expanding the range of biosolids and biosolids products characterized as part of the Source Characterization Study.
  • Sampling biosolids to characterize occurrence of emerging contaminants. This investigation involved purchasing nine different biosolids and analyzing the samples for 87 organic chemicals found in cleaners, personal care products, pharmaceuticals, and other products. The results of the analysis found 55 of the 87 organic chemicals measured were detected in at least one of the nine biosolid samples collected, with as many as 45 chemicals found in a single sample.
  • A USGS scientist bagging up samples of biosolids
    A USGS scientist bagging up large amounts of biosolids to be used for the development of methods to detect the presence of emerging contaminant compounds in solid material. Clean sampling protocols are used to prevent cross-contamination of samples.
    (Click on photo for larger version)
    An investigation to assess the ability of a range of wastewater treatment technologies to remove selected pharmaceuticals and other emerging contaminants from municipal sewage. The project consists of sampling various stages of the liquid and solid waste treatment processes including raw influent, treated effluent, and biosolids. The study is designed to provide baseline data on the occurrence and concentration of targeted estrogenic (compounds that act chemically like the hormone estrogen) and pharmaceutically active compounds.  In addition, the study will provide a bioassay-based measure of total estrogenic activity of biosolids samples. Bioassays are laboratory tests that use biological material (tissue, cells, plants, …) to test for chemical toxicity or, in this case, the potential for estrogenic activity. Total estrogenic activity will give an indication of the potential for endocrine disruption in animals exposed to biosolids. This study will result in a greater understanding of the fate and occurrence of pharmaceuticals in the wastewater effluent and biosolids from WWTPs. The USGS is collaborating with Metcalf & Eddy and the University of Arizona's Department of Chemical and Environmental Engineering on this project with funding from the Water Environment Research Foundation (WERF).
  • An extension of the work to characterize biosolids is an investigation to determine the persistence and vertical transport in the soil zone of emerging contaminants derived from biosolids applied to the land surface. The project consists of an experiment where biosolids are applied to a field that has never received applications of biosolids. The absence of a background concentration of emerging contaminants in the soil will allow for accurately tracking the possible downward transport of contaminants in the soil zone. The USGS is collaborating with Colorado State University-Pueblo on this project.

Project Headlines

Household Chemicals and Drugs Found in Biosolids from Wastewater Treatment Plants

Available Publications

Furlong, E.T., Kinney, C.A., Ferrer, I., Werner, S.L, Ratterman, G. Determination of human health pharmaceuticals and antimicrobials in terrestrial and aquatic solids. (in progress)

Kinney, C.A., Furlong, E.T., Zaugg, S.D., Burkhardt, M.R., Werner, S.L., Cahill, J.D., and Jorgensen, G.R., 2006, Survey of organic wastewater contaminants in biosolids destined for land application: Environmental Science and Technology, v. 40, no. 23, p. 7207-7215, doi:10.1021/es0603406

Tindall, J.A., Lull, K.J., and Gaggiani, N.G., 1994, Effects of land disposal of municipal sewage sludge on fate of nitrates in soil, streambed sediment and water quality: Journal of Hydrology, v. 163, no. 1-2, p. 147-185, doi:10.1016/0022-1694(94)90027-2.

More Information

  • Project contact: Ed Furlong

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