Yeast estrogen screen assay applied in the assessment of estrogenic activity removal from dairy cattle wastewater treated by anaerobic digestion

The presence of estrogen-like endocrine disrupting chemicals (EEDC) in surface waters, soils, and groundwater has been frequently reported in the literature. Since these compounds can be excreted by humans and animals, the release of domestic sewage and animal wastewaters may be an important source of EEDC in the environment. In this context, there is a growing concern regarding the presence of these substances in the environment and their potential adverse effects on human health. However, most studies have been focused on the presence of EEDC in domestic wastewaters and the available information regarding EEDC in livestock wastewater is still limited. Therefore, this work aimed to quantify the estrogenic activity (EA) in the liquid phase of dairy cattle wastewaters and evaluate the removal of EA during anaerobic digestion, applying an adapted methodology based on the yeast estrogen screen (YES) assay, which has been widely used to analyze EA in domestic sewage. Influent and effluent dairy cattle wastewater samples from a full-scale anaerobic digester placed in an experimental farm were collected during seven months. EA concentrations in the liquid phase of raw wastewater ranged from 228 to 2182 ng.L-1 E2-eq. Anaerobic digestion was not efficient in EA removal, achieving effluent concentrations ranging from 109 to 946 ng.L-1 E2-eq. Results also indicate that the application of an estradiol-based fixed time artificial insemination protocol did not statistically contribute to the increase of EA concentrations in dairy cattle wastewater which reuse in cleaning of animal feeding operation facilities and fertigation are beneficial and economically advantageous to dairy production systems, reducing water demand in parallel to promoting organic matter and nutrient recycling. However, the potential environmental and health risks associated with the presence of EEDC in dairy cattle wastewaters should be better elucidated and evaluated.

Automated summary

The presence and removal of estrogen-like endocrine disrupting chemicals (EEDC) in dairy cattle wastewaters during anaerobic digestion were investigated in this study. The results showed that anaerobic digestion was not efficient in EEDC removal, and the application of an artificial insemination protocol did not contribute to the increase of EEDC concentrations in dairy cattle wastewater. The reuse of wastewater for cleaning and fertigation in dairy production systems can be beneficial in terms of water conservation and organic matter and nutrient recycling. However, the potential environmental and health risks associated with EEDC in dairy cattle wastewaters need further elucidation and evaluation.