Effect Of Combined Pollution Of Tetracycline And Copper On Soil Nitrification And Plant Grow

With the rapid development of livestock and poultry breeding industry, a large quantity of manure which contained high concentration of Cu and antibiotics were produced. Land application of those wastes from intensive-farming often result in high concentrations of tetracyclines (TCs) and metals accumulating in agricultural soils. But little study was addressed on the combined pollution between antibiotics and heavy metals in soils. In this thesis tetracycline and Cu as the model pollutant were selected. The environmental behaviors and their ecotoxicity on soil were studied. The combined effect of tetracycline and Cu on soil nitrogen (N) nitrification and wheat toxicity were conducted by culture experiments. The main results are summarized as following:(1) The tetracycline didn't significantly affect the accumulative nitrification in the early period of incubation, but in the later period tetracycline and copper inhibit nitrogen nitrify markedly. When tetracycline and copper coexisted, Cu decreased the toxicity of tetracycline slightly, but Cu play the leading role in the soil nitrifying process.(2) The copper and tetracycline did not significantly affect wheat germination, both pollutants prohibited wheat root elongation and sprout length obviously. The presence of copper decreased the toxicity of tetracycline.(3) The uptake of Cu in rape increased with the increasing of soil copper concentration. The presence of tetracycline did not affect the uptake of Cu in rape in the early period, but significantly inhibit in later grow period. Available concentration of copper increased with the increasing of the addition copper content, which did not affected by tetracycline. The uptake of Cu in rape was positively related to the available copper content.(4) Tetracycline and copper significantly inhibit the activity of urease in Wushan soil. Cu inhibits the activity of sucrase, but not significantly. The inhibition effects of tetracycline and copper combined pollution was better than single tetracycline or copper pollution. In tetracycline and copper contaminated soil, the activity of acid phosphatase and alkaline phosphatase were not obvious with the increase of contamination. The presence of copper significantly inhibits the activity of urease in red soil, strengthening with the increasing content of copper. The tetracycline did not significantly affect urease activity. The activity of acid phosphatase was also inhibited by copper, and lowered with the increasing content of copper. The presence of tetracycline decreased the toxicity of copper to urease and acid phosphatase activity.