印染废水处理过程及排放水对草履虫遗传毒性评价

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。

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

The effect of toxicity of dyeing effluent was evaluated by Paramecium caudatum . The results of acute toxicity showed that 24h-LC₅₀ of tank and effluent's water samples were 54%, 41%, 98%, respectively. The results of genetic toxicity showed that influent at concentration of 6.25% and effluent at concentration of 12.25% caused Paramecium caudatum s' 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 results of growth rate showed that effluent at cocnetration of 50% inhibited Paramecium caudatum s' growth. 10 percent of Paramecium caudatum s' swimming behavior changed after exposure to effluent. Although treated dyeing effluent's physico-chemical indicators were in line with national dyeing wastewater discharge standards, the effluent still induced acute toxicity to Paramecium caudatum , and genetic toxicity was not significantly 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.