Development of Swine Farms In Eastern China: Implications to Contamination of Soil and Water by Veterinary Antibiotics.

Contamination of soil and water from swine farms by veterinary antibiotics, as a result of improper treatment of sewage and manure, has received very little attention with the increase of swine production. The release of large amounts of antibiotics might induce antibiotic resistance genes and eventually cause human health hazards. We selected a swine farm with an annual production of 20,000 pigs typical of eastern China for the study. Samples of manure, soil, waste water, surface water and ground water from the areas surrounding of the swine farm were collected. A total of 14 antibiotics, including tetracyclines, sulfonamides, macrolides, were analyzed by HPLC-MS/MS. The predominant antibiotics in the manures were chlorotetracycline, doxycycline and tetracycline, with a highest concentration of 215mg/kg d.w. for chlorotetracycline. Approximately 80% of the total antibiotics concentration was not degraded after two months of composting. The compost will be applied to adjacent farmland, consequently resulting in soil contamination. A high concentration of chlorotetracycline of 205ug/kg has been detected in soil. Doxycycline and oxytetracycline dominated in the waste water of the swine farm. We tracked the change in concnetraton of antibiotics along the flow route from the discharge outlet to a catchment area in the valley, and observed that 60% of the antibiotics were still present in water of the catchment. Ground water sampled from five sites within a distance of 1 km from the swine farm was contaminated with doxycycline, sulfadiazine, sulfamethoxazole and erythrocin. The concentrations of these antibiotics decreased with distance from the swine farm. Environmental contamination with veterinary antibiotics due to swine production in China should receive greater attention and its potential hazards to the ecosystem should be further evaluated.