Mineralization and biotransformation of estrone in simulated poultry litter and cow manure runoff water

Application of animal manure on agricultural lands is one of the main sources of estrogen contamination in the environment. Poultry and cow manure contain free and conjugated forms of the natural estrogens (e.g., estrone [E1] and estradiol [E2]) that can enter surface waters during runoff events. Estrone has been identified as the major form of estrogen in the environment; therefore, this study is focused on the evaluation of the degree of mineralization and fate of E1 in a simulated poultry litter and cow manure runoff water. A time-course study was conducted using simulated runoff water that consisted of 0.5 mg cow manure or poultry litter dissolved in 1 L of water spiked with radiolabeled E1 (¹⁴C-E1). Samples were analyzed for estrogen concentrations at Day 0, 0.5, 1, 2, 3, 5, and 7 using liquid chromatography with tandem mass spectrometry. In the poultry litter simulated runoff water, E1 was biotransformed to 17b-estrone-3-sulfate (E1-3S) but was eventually mineralized to ¹⁴CO₂; a total E1 mineralization of 92.2% occurred after 7 d of aerobic incubation. In contrast, the concentrations of E1 and other forms of endogenous estrogens detected in the cow manure simulated runoff water, such as E1-3S, 17a-estradiol (a-E2), and 17b-estradiol (b-E2), remained relatively constant and persisted over the 7 d of aerobic incubation.