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To investigate the pollution caused by microplastics (MPs) in agricultural systems and their possible mechanisms of action, the distribution characteristics of MPs in the surface soils of 56 sites in paddy fields of three towns in Xiangtan City, Hunan Province, China, were determined. Fourteen sites were randomly selected to collect rice grains after harvest. The effect of MPs on the migration of bisphenol A (BPA) and cadmium (Cd) from soil to rice grains were analyzed. Four forms of aging MPs were detected in soils：films, particles, fragments, and fibers. The abundance of MPs in the three towns was similar, ranging from 48 items·kg-1 to 1 771 items·kg-1 ; the main components were polyethylene (PE) and polyvinyl chloride (PVC), accounting for 46.77% and 24.19%, respectively, and the content of polycarbonate (PC) was significantly lower than that of ethylene terephthalate (PET) (2.51 μg·kg-1 and 113.35 μg·kg-1, respectively) . BPA in depolymerized soils showed a more significant positive correlation with the content of BPA in rice grains than in un-depolymerized soils (P<0.01), indicating a potential risk of secondary release of BPA during the aging of MPs in the environment. In addition, the Cd content in soils also exhibited a significant positive correlation (P<0.001) with the abundance of MPs, promoting the transformation of Cd from soils to rice grains. This study contributes to the overall and objective evaluation of the pollution and health risks posed by MPs in agricultural systems. [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]