Pollution and Control of Tetracyclines and Heavy Metals Residues in Animal Manure

Veterinary antibiotics and trace heavy metals are widely used as feed additives in the livestock and poultry industries for growth promotion. However, overuse or misuse of veterinary antibiotics and heavy metals resulted in high concentrations of these residues in animal manure. Along with the rapid development of concentrated operations of livestock and poultry in China, residues of tetracyclines and heavy metals such as copper, zinc and arsenic in animal manure and its combined pollution may pose great threat potential to environment and human health. Through literature review, this paper summarizes residues of tetracyclines, including tetracycline, oxytetracycline and chlortetracycline, and trace heavy metals, including copper, zinc and arsenic in animal manure, as well as their distribution in different regions of China. The present paper also summarizes degradation, transformation and impacts of these two kinds of substances in biological animal manure treatment processes, e.g composting and anaerobic digestion. Along with land application of animal manure generated from concentrated animal farms, high level tetracyclines and copper accumulated in agricultural soil, and it might form complex under certain circumstance which strongly affect their mobility and their bioavailability. It should be noted that a big challenge would be encountered due to resistant bacteria and resistant genes resulted from antibiotics and heavy metals residues in animal manure and land application of animal manure.