Antibiotics in wastewater from multiple sources and surface water of the Yangtze River in Chongqing in China.

Antibiotic contamination attracts growing concerns because of their deleterious effects on the ecosystem and human health. In this study, 43 antibiotics in wastewater from a variety of sources and water of the Yangtze River in Chongqing City in western China were measured. Thirty compounds were detected, and their concentrations were highest in leachates from the municipal solid waste treatment facilities (landfills and incineration plants) with total concentrations of 3584-57,106 ng/L. The total concentrations in influents of municipal and industrial wastewater treatment plants (WWTPs) were comparable (401-7994 ng/L versus 640-8945 ng/L). The concentrations in raw sewage from swine farms (with a total of 10,219-39,195 ng/L) and poultry farms (1419-36,027 ng/L) were noticeably higher than those from other farms (54.0-5516 ng/L). Fluoroquinolones were the dominant antibiotics contributing over 50% in all the sources, and sulfonamides and imidazole fungicides contributed 3.2-34%, whereas tetracyclines and macrolides had minor contributions. The overall antibiotic removal rates were highest in solid waste treatment facilities (88% on average), comparable between municipal and industrial WWTPs (61%), and lowest in animal farms (39%). The mass loads to the investigated municipal WWTPs via influent wastewater ranged from 7.80 to 1531 kg/year (53.2-2482 µg/day per capital). The influent mass loads to the industrial WWTPs and farms were 3.7-50 kg/year and 0.9-5437 g/year, respectively. We estimated that the mass inventories of antibiotics from these sources to the environment via effluent discharges were approximately 2044 kg for municipal WWTPs, 61 kg for industrial WWTPs, and 34 kg for animal farms in the whole city. Antibiotic concentrations in the Yangtze River water were substantially low (< 492 ng/L, with a mean of 57.8 ng/L) suggesting dissipation during the movement.

Investigation of biological property of nanohydroxyapatite materials.

The biological effects of nanohydroxyapatites and its cell toxicity have been studied using the MTT and ALP method, infrared spectrum of absorption and electrophoresis method, respectively. The nanohydroxyapatites are prepared and made by using sol-gel method, in which the parameters of process and reaction are controlled as: pH > 9, Ca/P = 1.67, sintering temperature of 1100 degrees C and sintering time 2 hours. Studied results show that nanohydroxyapatites can interact with human serum albumin and change its second structure and weight of molecules. We find that the nanohydroxyapatites and complex of nanoHAP + nanoCrO2 can all restrain the proliferation of MG63 cells, but their toxicities are first degree or minor, the toxicity of the complex is smaller than that of pure nanohydroxyapatites.