4种重金属污染对稻田土反硝化细菌的影响

Effect of four kinds of heavy metal contamination on denitrifying bacteria in paddy soils.

在实验室条件下,研究Cd2+、As5+、Cu2+和Pb2+处理黄松稻田土、紫色稻田土和红壤稻田土后,4周内重金属污染对反硝化细菌种群数量及其反硝化活性的影响.结果表明,在1kg干土中加入0.5mg Cd2+、30mg As5+、50mg Cu2+和200mg Pb2+时,对稻田土反硝化细菌种群数量及其活性有促进作用,加入Cd2+、As5+、Cu2+和Pb2+分别超过1.0,60,500,400mg/kg干土时,对稻田土反硝化细菌种群数量及其活性有明显抑制作用.但反硝化细菌种群数量及其活性能逐渐恢复并接近对照水平,重金属污染越重,恢复所需的时间也越长.同一种重金属元素对不同水稻田土的反硝化细菌种群数量及其活性的影响也有差异.

Effects of heavy metal contamination on the population and its denitrification activity of denitrifying bacteria (DNB) were investigated after Huangsong, purple and red paddy soils were treated with Cd2+、As5+、Cu2+ and Pb2+ for four weeks under laboratory conditions. The population and its denitrification activity of DNB were promoted by adding 0.5mg Cd2+, 30mg As5+, 50mg Cu2+ and 200mg Pb2+ into 1kg dried soil; while it was inhabited markedly by adding more than 1.0mg Cd2+, 60mg As5+, 500mg Cu2+ and 200mg Pb2+ into 1kg dried soil. But the population and its denitrification activity of denitrifying bacteria could gradually recover or close to the levels of the control soil; and the higher the contamination of heavy metal, the longer the time needed. The effect of one kind of heavy metal element on the denitrifying population and its activity in various paddy soil was also different.