Fate and occurrence of steroids in swine and dairy cattle farms with different farming scales and wastes disposal systems.

Fate and occurrence of fourteen androgens, four estrogens, five glucocorticoids and five progestagens were investigated in three swine farms and three dairy cattle farms with different farming scales and wastes disposal systems in China. Twenty-one, 22, and 12 of total 28 steroids were detected in feces samples with concentrations ranging from below method limit of quantitation (<LOQ for estrone) to 8100 ± 444 ng/g (progesterone), in wastewater samples with concentrations ranging from <LOQ (estrone) to 20,700 ± 1490 ng/L (androsterone), in suspended particles with concentrations ranging from <LOQ (17β-trenbolone) to 778 ± 82.1 ng/g (5α-dihydrotestosterone) in the six farms, respectively. The steroids via swine farms and human sources were mainly originated from wastewater into the receiving environments while those steroids via cattle farms were mainly from cattle feces. The total contributions of steroids to the environment in China are estimated to be 139, 65.8 and 60.7 t/year from swine, dairy cattle and human sources, respectively.