Hormones, sterols, and fecal indicator bacteria in groundwater, soil, and subsurface drainage following a high single application of municipal biosolids to a field

A land application of dewatered municipal biosolids (DMB) was conducted on an agricultural field in fall 2008 at a rate of 22 Mg dry weight (dw) ha−1. Pre- and post- application, hormone, sterol and fecal indicator bacteria concentrations were measured in tile drainage water, groundwater (2, 4, 6 m depth), surface soil cores, and DMB aggregates incorporated in the soil (∼0.2 m depth) for a period of roughly 1 year post-application. Hormones and sterols were detected up to 1 year post-application in soil and in DMB aggregates. Hormone (androsterone, desogestrel, estrone) contamination was detected briefly in tile water samples (22 d and ∼2 months post-app), at low ng L−1 concentrations (2–34 ng L−1). Hormones were not detected in groundwater. Sterols were detected in tile water throughout the study period post-application, and multiple fecal sterol ratios suggested biosolids as the source. Coprostanol concentrations in tile water peaked at >1000 ng L−1 (22 d post-app) and were still >100 ng L−1 at 6 months post-application. Fecal indicator bacteria were detected throughout the study period in tile water, groundwater (⩽2 m depth), soil and DMB aggregate samples. These bacteria were strongly linearly related to coprostanol in tile water (R2 > 0.92, p < 0.05). The limited transport of hormones and sterols to tile drainage networks may be attributed to a combination of the hydrophobicity of these compounds and limited macroporosity of the field soil. This transitory contamination from hormones and sterols is unlikely to result in any significant pulse exposure risk in subsurface drainage and groundwater.

► Single high rate land application of dewatered biosolids not high risk for hormone and sterol contamination in water.
► Limited detection of steroidal hormones and fecal sterols in subsurface drainage.
► No detection of steroidal hormones in groundwater.
► Fecal sterol ratios useful for tracking transport of biosolid-borne contaminants in tile drainage and soil.