Abstract
This study investigated the occurrence and contamination risk of estrogens in livestock manure in Jiangsu Province, China. Four estrogens-estriol (E3), 17β-estradiol (17β-E2), bisphenol A (BPA), and 17α-ethinyloestradiol (EE2)-were detected in livestock manure from hens, ducks, swine, and cows. The respective mean concentrations of each estrogen found in these manures were 289.8, 334.1, 330.3, and 33.7 μg/kg for E3; 38.6, 10.9, 52.9, and 38.8 μg/kg for 17β-E2; 63.6, 48.7, 51.9, and 11.7 μg/kg for BPA; and 14.3, 11.3, 25.1, and 21.8 μg/kg for EE2. Estrogens were most frequently detected at high concentrations in the manure of finishing pigs, followed by the manure of growing pigs and piglets. Estrogens can be partially degraded after banking up for seven days; yet, great quantities of estrogens remain in livestock manure. The total estradiol equivalent quantity (EEQt) estimated to be present in aquatic environments but originating from livestock waste was 10.5 ng/L, which was greater than the hazard baseline value (1 ng/L) and also higher than the proposed lowest observable effect concentration (10 ng/L) of E2 in aquatic environments. The results of our study demonstrate that livestock waste is an important source of estrogens, which may potentially affect the hormonal metabolism of aquatic organisms.