典型重金属对用于污泥捕食颤蚓科蠕虫活性影响

Effect of representative heavy metals on activity of tubificid worms as sludge predator

蠕虫捕食法是近年来新兴的污泥生物减量技术.采用急性毒性试验和总抗氧化能力分析,围绕污泥中两种典型的重金属—Zn和Pb,探讨其对于污泥捕食者—颤蚓科蠕虫(水丝蚓)的生理活性的影响.结果表明,Zn2+对蠕虫的毒性大于Pb2+,两种重金属对蠕虫的毒性表现出显著的质量浓度-效应和时间-效应关系,蠕虫生存的安全Zn2+和Pb2+质量浓度分别为0.26 mg/L和2.51 mg/L.蠕虫的总抗氧化活力在较高的Zn2+和Pb2+质量浓度下受到抑制,在污泥中则发生略有增加的现象,说明蠕虫具有的抗氧化防御系统使其能够适应污泥环境的污染.上述研究结果证实此类蠕虫对污泥中的重金属具有抵御能力,但实际应用时应关注污泥上清液中的重金属质量浓度,保障蠕虫的生存.

Worm predation,a novel biological option for sludge reduction has been developed in recent years.Acute toxicologic test and total antioxidant capacity analysis were conducted to investigate the effect of heavy metals contenting in sludge on the predator-tubificid worm with Zn and Pb as representative heavy metals.The results showed that the toxicity of Zn2＋ was higher than that of Pb2 ＋,and their toxic effect on worms significantly related to the metal concentration and exposure time,the safe concentrations of Zn2 ＋ and Pb2 ＋ for worms were 0.26 mg/L and 2.51 mg/L,respectively.The total antioxidant capacity of worms was sharply restrained at high concentrations of Zn2＋ or Pb2＋,by contrast with the slightly increased total antioxidant capacity of worms living in sewage sludge,indicating these worms can adapt the pollution in sewage sludge by their antioxidant defense system.All the results demonstrated that such worms can resist the Zn and Pb concentrations in sludge,and for ensuring the worm survival,the metal concentrations in supernatant of the worms should be concerned.