Veterinary antibiotics and estrogen hormones in manures from concentrated animal feedlots and their potential ecological risks.

The spread of pharmaceutically active chemicals (PACs), such as antibiotics and estrogenic hormones from animal manures can pose threats to the ecologic environment. In this work, animal manure samples were collected from 71 concentrated animal feedlots in Northern China and investigated for 24 antibiotics and 4 estrogenic hormones. Results showed that these micropollutants were ubiquitous in manures with the concentration ranges of undetectable (ND)-543,445 μg/kg (mean: 44,568 μg/kg) for antibiotics and ND-249.8 μg/kg (mean: 24.78 μg/kg) for estrogens. There was a significant variation in the amounts of PACs in different animal manures. The amounts of antibiotics in manures had following order: swine (83,177 μg/kg) >chicken (52,932 μg/kg) >beef (37,120 μg/kg) >dairy (305 μg/kg), while the estrogens in dairy (mean: 39.27 μg/kg) and chicken manures (mean: 40.08 μg/kg) were higher than those in beef (2.7 μg/kg) and swine manures (1.8 μg/kg). Based on the estimated farmland application rate of manure, antibiotics and estrogens may cause high ecological risks to terrestrial organisms according to the risk quotient evaluation. Estrogens could pose a relatively higher risk than antibiotics. The toxicological effects of antibiotics and estrogens to the terrestrial environment should receive more intensive study.