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Hormones in Land-Applied Biosolids Could Affect Aquatic Organisms

A USGS scientist prepares a tracer solution in a gas-tight bladder
Scientists setting up equipment used to apply artificial rainfall to a small test plot on a field that received an application of biosolids. The scientists captured the runoff from the plot for later chemical analysis. Photo Credit: V. Cory Stephens, USGS.

Hormones from biosolids applied to fields may be present in rainfall runoff at concentrations that are high enough to impact the health of aquatic organisms if the runoff reaches streams, report scientists from the U.S. Geological Survey (USGS) and Colorado State University in Environmental Science and Technology. Artificial rainfall runoff from agricultural test plots where biosolids were applied as fertilizer contained several different hormones (estrogens, androgens, and progesterone). The occurrence of natural and synthetic hormones in streams is a growing concern because low part-per-trillion concentrations of these chemicals have caused endocrine disruption in aquatic organisms. The study results could help wastewater-treatment-plant, water-resource, and wildlife managers design management practices that limit the impacts of biosolids application on streams and aquatic organisms.

Biosolids are created from the sludge generated by the treatment of sewage at wastewater treatment plants (WWTPs) and are known to contain natural and synthetic hormones. Biosolids are frequently applied to agricultural fields to manage the large quantities of biosolids generated by WWTPs and to improve soil nutrient and water retention characteristics. The team of scientists collaborated with a local farmer to assess the potential for seventeen different hormones (including androgens, estrogens, and progestogens) and two sterols (waxy compounds such as cholesterol) to occur in the rainfall runoff from a winter wheat field in eastern Colorado where biosolids were applied. Small test plots (6 by 6 meters) were identified both before and after biosolids application. The scientists then created artificial rain events and collected the rainfall runoff from the test plots for later chemical analysis. The winter wheat field with the test plots had no prior history of biosolid applications.

Runoff samples collected prior to biosolids application had low concentrations of two hormones (estrone as much as 2.23 nanograms per liter (ng/L) and androstenedione as much as 1.54 ng/L). In contrast, significantly higher concentrations of multiple estrogens (as much as 25.0 ng/L), androgens (as much as 216 ng/L), and progesterone (as much as 98.9 ng/L) were observed in runoff samples taken 1, 8, and 35 days after biosolids application. The observed concentrations, if they reached streams without being diluted or absorbed, are high enough to impact the health of susceptible fish. These results demonstrate that rainfall has the potential to mobilize hormones from agricultural fields where biosolids have been applied.

The USGS's Toxic Substances Hydrology Program and National Water Quality Laboratory, the Colorado Water Institute, the National Science Foundation's Faculty Early Career Development (CAREER) Program, and Colorado State University funded this study.


Yang, Y.-Y., Gray, J.L., Furlong, E.T., Davis, J.G., ReVello, R.C., and Borch, T., 2012, Steroid hormone runoff from agricultural test plots applied with municipal biosolids: Environmental Science and Technology, v. 46, no. 5, p. 2746-2754, doi:10.1021/es203896t.

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