Research in small scale screening methods for the hazard assessment of the toxic substances in aquatic environment

(1)探讨了降低挥发性样品对微孔板藻类检测影响的方法。使用天花板胶带和聚四氟乙烯片，可以防止邻近井的污染，与常规方法相比，不仅减少了挥发性样品的影响，而且降低了细胞收率。这些操作对IC50（50%抑制浓度）没有明显影响，表明这些技术可以提高微孔板法的性能。(2)为提高umu检测效率，开发了96孔微孔板检测方法。与原始方法相比，主要修改如下：试剂和细菌培养量、培养温度、SDS浓度、吸光度测量波长。最后利用修正的Miller方程计算微孔板实验中β -半乳糖酸酶的单位活性。(3)考察了基于形态变化的小型水螅急性毒性试验的敏感性。96h-EC50值对Cr6+的敏感性高于其他检测方法。对于某些金属，效果是短暂的，在亚致死终点表现出解毒作用，在亚致死和致死终点表现出促进作用。(4)采用Microtox、藻类生长抑制试验、umu试验、水螅急性试验和水蚤急性试验等一系列小型生物测定方法，对20种工业废水的处理效果进行了评价。85%的样本显示有不良反应。通过添加螯合剂和比较分析值，对其毒性的原因物质进行了评价。

(1) The way to diminish the effect of volatile sample on themicroplate-based algal assay was examined. The uses of ceiling tape and Teflon sheet, which prevented the contamination from the adjacent wells, were found to not only diminish the effect of volatile samples, but also lower the cell yield compared to that of usual method. These operations did not affect the IC50 (concentration of 50% inhibition) significantly, suggesting that these techniques would improve the performance of microplate method.(2) To enhance the efficiency of umu test, the 96-wells microplate-based method was developed. The major modifications from original methods are as follows, volume of reagents and bacterial culture, incubation temperature, concentration of SDS,wave length for absorbance measurement. Finally the modified Miller's equation was conducted to calculate the unit activity of beta galactocidase in microplate assay,(3) The sensitivity of small scale hydra acute toxicity test based on the morphological change was examined. The values of 96h-EC50 showed the relatively higher sensitivity to Cr6+than other assays examined. For some metals, the effect was transient, showing detoxification in sublethal endpoint and promotion in sublethal and lethal endpoints.(4) Using battery of small scale bioassays including Microtox, algal growth inhibition test, umu test, hydra acute test and daphinia acute test, the effects of 20 industrial wastewater were assessed. 85% of the samples showed any adverse effect. The causal substance for toxicity was evaluated by using the addition of chlating agent and comparing the analytical values.