Search

The aim of this work was to investigate the characteristics of estrogen degradation in livestock manures during composting. Natu⁃ ral estrogens containing estriol（E3）and 17β-estradiol（17β-E2）, were detected in chicken, pig, and cow manures from farms in Nanjing. The synthetic estrogen, containing ethinyloestradiol（EE2）and bisphenol A（BPA）, were also detected. Experimental composting of three livestock manures was conducted, and the concentrations of four estrogens were detected at 0, 2, 4, 8, 16 days, and 32 days. Cow manure, as a representative of all manures, was composted under different turning frequencies（i.e., never turned, turned once every two days, and turned twice every day）to study the impact of turning frequency on estrogen degradation. The results showed a high concentration of native estrogens detected in all three livestock manures. Chicken and cow manures contained synthetic estrogen. The EEQ values of estrogen in chicken, pig, and cow manures were 3 595.86, 268.84 μg·kg-1, and 1 207.12 μg·kg-1, respectively. A high contamination risk existed in all three livestock manures. The residual rates of EEQ in chicken, pig, and cow manures were 10.1%, 10.6%, and 0 after 32 d of composting, which showed that composting could significantly reduce the risk of estrogen contamination. The initial concentration of estrogen had a significant impact on their degradation when various estrogens were detected in livestock manures. The estrogen with the highest concentration degraded faster than other estrogens. Furthermore, estrogen degradation changed with microbial activity in the manure piles. Microbial activity was most active during the mid-stage of composting, and the degradation rate of estrogens was higher during this period than during the early and later stages. Turning the cow manure pile increased its oxygen content, which significantly accelerated estrogen degradation. Thus, turning the manure pile during composting was effective. However, there was little difference in rate of estrogen degradation between turning once every two days and turning twice per day, and the increase in turning frequency did not significantly influence manure composting. [ABSTRACT FROM AUTHOR]

Understanding estrogen contamination characteristics of organic fertilizers derived from livestock manures is important for organic fertilizer production and contamination control. In the present study, 17 organic fertilizers derived from chicken, swine, and cow manures were collected from a market. Organic matter, nitrogen, phosphorus, and potassium contents of organic fertilizers were determined. The concentration of estriol（E3）, 17β-estradiol（17β-E2）, bisphenol A（BPA）, and ethinyl estradiol（EE2）were detected by SPE-HPLC/FLD. At the same time, we compared the estrogen concentrations in organic fertilizers with fresh livestock manures. Results showed that organic fertilizers with low organic matter were detected in the organic fertilizer samples derived from chicken, swine, and cow manures. The average value（dry weight）of E3, 17β-E2, and BPA in organic fertilizers derived from chicken manures were 270.22, 2.71 μg·kg-1, and 87.93 μg· kg-1, respectively. The average values of E3, 17β-E2, BPA, and EE2 in organic fertilizers derived from swine manures were 609.71, 41.84, 32.69 μg·kg-1, and 46.74 μg·kg-1, respectively. The average value of E3 in organic fertilizers derived from cow manures was 50.96 μg· kg-1. Organic fertilizers had a large risk of estrogen contamination, and the risk of E3 contamination was higher than that of the other estro⁃ gens. Additionally, the concentration and detection rates of estrogen in cow organic fertilizers were lower and safer. The detection rates of E3, 17β-E2, BPA, and EE2 in organic fertilizers were 47.06%, 11.76%, 17.65%, and 5.88%, respectively, while detection rates were 67.74%, 70.97%, 70.97%, and 58.06% in fresh livestock manures, respectively. The detection rates of estrogen in organic fertilizers were lower than that of fresh livestock manures. The conclusion is that there are estrogen residues in organic fertilizers derived from livestock manures, which needs further attention. [ABSTRACT FROM AUTHOR]