Detection and variation of steroidal estrogens in intensive dairy farm marsh irrigation areas

Steroidal estrogen production has become an emerging source of environmental pollution, due to the huge demand for meat products as the rapid development of intensive farms. Therefore, it is necessary to establish quantitative analysis for steroidal estrogens in complex fractions of digestate and soil, in order to explore the changes of steroidal estrogens in different seasons. In this study, a solid phase extraction-liquid chromatography tandem mass spectrometry (SPE-LC-MS/MS) was developed for the analysis of five steroidal estrogens (estrone, 17α-estradiol, 17β-estradiol, estriol, and sodium estrone sulfate) in digestate and soil from the methane irrigation area of dairy farms. Sample pretreatments were made on the complex matrix characteristics of methane and soil. The treated samples were analyzed by multi-response monitoring in the negative ion mode with an electrospray ionization source. The results showed that there was good linearity of the assay, where the detection limits were 0.09-0.39 ng/L, the quantification limits were 0.24-1.18 ng/L, and the recoveries ranged from 74.56% to 91.84%. This technology was effectively used for the determination of trace estrogens in methane and soil. The frequency and concentration of estrone, 17α-estradiol, and 17β-estradiol were higher in the methane irrigation area soil samples from dairy farms, while the frequency and concentration of estriol and sodium estrone sulfate were lower. The average concentrations of estrone and 17α-estradiol increased from summer to winter, indicating a weak degradation of estrogens, due to the lower temperature and lower activity of anaerobic bacteria. The concentration of 17β-E2 showed a decreasing trend, indicating that 17β-E2 was more easily converted under anaerobic conditions. In the anaerobic tank effluent, the concentration of each substance was ranked in order: estrone, 17β-estradiol , 17α-estradiol , estrone sodium sulfate > estriol in the anaerobic pond effluent, whereas, in the aerobic pond effluent: 17β-estradiol ,17α-estradiol ,estrone ,estrone sodium sulfate ,estriol. Soil adsorbed estrogens and the concentration of estrogens in soil was lower than that in the digestate, as a result of the synergistic effect of transport, transformation, and degradation of soil Steroid Estrogens (SEs). The surface soil and the subsoil showed the same magnitude of estrogen concentrations, where estrogens migrated with the soil and then accumulated. 17β-E2 and E1 mainly presented in the surface soil, while 17α-E2 was detected less frequently at a lower mean concentration, indicating a stronger migration capacity in the soil, where the soil was less adsorbed to 17α-E2. The concentration of each estrogen was detected higher in summer and gradually decreased with the seasonal change. The reason was that the higher temperature and vigorous crop growth in summer contributed to the increase in the number of methane watering, while reduced, as the temperature decreased in winter. There was a large difference in estrogen concentration from summer to autumn, where the estrogen in the surface soil was easy to lose or migrate longitudinally under the runoff in summer. In the soil at different depths, the concentration of each substance was in order of: 17β-estradiol, estrone, 17α-estradiol, sodium estrone sulfate, but no estriol was detected. There was a seasonal trend of decline in the concentration of estrogen in the soil. The experimental findings can provide an insightful theoretical basis and data support for the estrogen detection and distribution in complex substrates.