Occurrence of free estrogens, conjugated estrogens, and bisphenol A in fresh livestock excreta and their removal by composting in North China

An efficient pretreatment and analytical method was developed to investigate the occurrence and fate of four free estrogens (estrone (E1), 17β-estradiol (17β-E2), estriol (E3), and 17α-ethinylestradiol (EE2)), four conjugated estrogens (estrone-3-sulfate sodium salt (E1-3S), 17β-estradiol-3-sulfate sodium salt (E2-3S), estrone-3-glucuronide sodium salt (E1-3G), and 17β-estradiol-3-glucuronide sodium salt (E2-3G)), and bisphenol A (BPA) in three livestock farms raising beef cattle, cows, sheep, swine, and chickens in Qi County, which is located in North China. The results demonstrated that one cow and one beef cattle excreted 956.25-1,270.41 and 244.38-319.99 μg/day of total (free and conjugated) estrogen, respectively, primarily through feces (greater than 91 %), while swine excreted 260.09-289.99 μg/day of estrogens, primarily through urine (98-99 %). The total estrogen excreted in sheep and broiler chicken feces was calculated to be 21.64-28.67 and 4.62-5.40 μg/day, respectively. It was determined that conjugated estrogens contributed to 21.1-21.9 % of the total estrogen excreted in cow feces and more than 98 % of the total estrogen excreted in swine urine. After composting, the concentration of total estrogen decreased by 18.7-59.6 %; however, increased levels of BPA were measured. In treated compost samples, estrogens were detected at concentrations up to 74.0 ng/g, which indicates a potential risk of estrogens entering the surrounding environment.