四溴双酚A在土壤中的降解动态及其对土壤微生物数量和酶活性的影响

Degradation dynamics of tetrabromobisphenol A in soil and its effects on soil microorganisms and enzymatic activity

采用实验室模拟方法研究了阻燃剂四溴双酚A在土壤中的降解动态及其对土壤微生物的影响.结果表明,四溴双酚A在实验土壤中降解符合一级反应动力学方程,浓度为1、20、100 mg·kg^(-1)的四溴双酚A在土壤中的降解半衰期为65—82 d,四溴双酚A对土壤微生物的毒性作用与浓度呈正相关.四溴双酚A对土壤中细菌产生抑制作用,浓度越高抑制作用越显著,而且100 mg·kg^(-1)和对照相比呈显著性差异,这种抑制作用一直持续至第30天.第50—90天,施药处理组由抑制作用变为促进作用;对土壤中放线菌的影响趋势和细菌基本一致,亦表现出先抑制后促进的作用;实验结果表明,对土壤真菌的影响较小,高浓度处理具有先促进后抑制再促进真菌生长繁殖的作用.四溴双酚A对脲酶活性具有先抑制后促进的作用,高浓度四溴双酚A对土壤脱氢酶活性具有显著的抑制作用,对土壤中酸性磷酸酶活性具有先促进后抑制的作用,对土壤碱性磷酸酶影响较小,对土壤过氧化氢酶活性影响较小,添加低浓度四溴双酚A的处理与对照无显著性差异,而高浓度处理具有先抑制后促进的作用.实验结果表明,四溴双酚A在土壤中降解半衰期较长,为难降解有机污染物,100mg·kg^(-1)浓度的四溴双酚A对土壤微生物数量和酶活性影响较大.

Degradation dynamics and toxicity of TBBPA to soil microorganisms were studied,by lab simulation experiments. The results showed that its degradation process in the soil could be well described with the first order kinetic equation; and its half-life in the soil was found to be 65—82 d. Toxicity of TBBPA on soil microorganism was positive by correlated with the concentration.It inhibited the growth of bacteria in the soil,and the higher the concentration,the more obvious the toxic effect.Furthermore, the effect with 100 mg·kg-1 treatment was very significant as compared with the Control （CK）, and the inhibition persisted until the 30th day. In the period of 50—90 days,the effect changed to promotion with TBBPA treatment. The effect on actinomycetes was quite similar to that on bacteria,firstly inhibiting and then promoting. The number of fungi was less influenced; it was promoted in the treatment with high concentration firstly and then inhibited. The urease activity was inhibited firstly and then promoted. The inhibition of high concentration TBBPA on the dehydrogenase activity was remarkably significant,and TBBPA firstly promoted the acid phosphatase activity in the soil and afterward inhibited it. But the alkaline phosphatase and catalase activity of soil was less influenced by TBBPA, and the effect with low concentration TBBPA was not significantly CK. At high concentrations TBBPA first showed inhibition, then promotion. To sum up,TBBPA has relatively long half life,and hence belongs to persistent organic pollutants. It has some toxic effects on soil microbes even when only 100 mg·kg-1 is applied.