Livestock wastes from family-operated farms are potential important sources of potentially toxic elements, antibiotics, and estrogens in rural areas in North China.

The open-air storage and disposal of livestock waste from family-operated livestock farms can be a potential health threat to rural residents. In this study, the occurrence and seasonal distribution of 8 potentially toxic elements, 24 antibiotics, and 4 estrogens were investigated in 44 waste samples from 11 rural farms in North China. The results showed that these micropollutants were ubiquitous in livestock waste, with concentration ranges of 238.9-4555 mg/kg for potentially toxic elements, not detected (ND) to 286,672 µg/kg for antibiotics and ND to 229.5 µg/kg for estrogens. The pollutants in animal wastes showed seasonal variation. Since these wastes are directly applicable to nearby farmland without treatment, the risks those wastes pose to farmland soils were also evaluated. Risk assessment results showed that Zn, Cd, Hg, FF and DC in swine manures were at high risk, while total estrogens in chicken and dairy cattle manures were at high risk. The results will provide important data for the regulation of animal wastes produced by small-scale livestock farms in rural areas of China.