Estrogenic activity in drainage water: a field study on a Swiss cattle pasture

Background Dairy cow manure applied to pastures is a significant potential source of estrogenic contamination in nearby streams. One possible pathway is through infiltration via preferential flow to drainage pipes, particularly after heavy rainfall events. In a period of 73 days in the spring of 2010, a drainage catchment in a cattle pasture in the Swiss lowlands was closely monitored. Manure was applied three times during the study, and part of the catchment was also subjected to grazing. During five field campaigns, water samples from two sampling locations were taken for 4–24 h in consecutive sampling intervals. 17β-estradiol equivalents (EEQ) were determined with the yeast estrogen screen (YES) and the ER-CALUX assay. Some water chemistry parameters, pH, conductivity, oxygen content and soil moisture tension were also monitored.