印染废水处理过程及排放水对草履虫遗传毒性评价

Evaluation on Genetic Toxicity of Dyeing Wastewater during Treatment Process and Effluent on Paramecium caudatum

草履虫作为指示生物评估印染废水处理过程及排放水的毒性效应。急性毒性结果显示,原水、厌氧工段印染废水、好氧工段印染废水对草履虫的半数致死浓度(24h-LC50)分别为54%、41%、98%;遗传毒性结果显示,印染废水原水、经处理的排放水在6.25%、12.25%稀释梯度下对草履虫造成的DNA损伤较对照组呈显著升高(p<0.01),而排放水对草履虫的DNA损伤较原水无显著性差异;草履虫增殖速率结果显示,印染废水排放水50%稀释梯度下对草履虫增殖速率有抑制作用。暴露于印染废水排放水中10%的草履虫其游动行为发生改变。以上结果表明,印染废水在经过处理后,理化指标均达到国家印染废水行业排放标准,但排放水仍对草履虫产生急性毒性,且遗传毒性较原水没有显著降低。水生生物毒性测试能有效补充理化指标评价,为印染废水行业全面达标排放提供依据。

The effect of toxicity of dyeing effluent was evaluated by Paramecium caudatum. The results of a- cute toxicity showed that 24h-LC50of tank and effluent＇s water samples were 54%, 41%, 98%, respectively. The results of genetic toxicity showed that influent at concentration of 625% and effluent at concentration of 122.5% caused Paramecium caudatums＇DNA damage significantly higher than that of the control group （p 〈 0.01）. However, compared with influent, the DNA damages of effluent were no significantly different. The re- suits of growth rate showed that effluent at cocnetration of 50% inhibited Paramecium caudatums＇ growth. 10 percent of Paramecium caudatums＇swimrffmg behavior changed after exposure to effluent. Although treated dyeing effluent＇s physico-chemical indicators were in line with national dyeing wastewater discharge stand- ards, the effluent still induced acute toxicity to Paramecium caudatum, and genetic toxicity was not significant- ly reduced. Biological toxicity test can be an effective complement to evaluate the physico-chemical indicators, and provide the basis for dyeing wastewater industry＇s comprehensive discharge standards.