3种典型污染物对水生生物的急性毒性效应及其水质基准比较

Acute Toxicity of Three Typical Pollutants to Aquatic Organisms and Their Water Quality Criteria

我国本土水生生物急性毒性数据较少,通过研究Cr(Ⅵ)、2,4,6-三氯酚和硝基苯对蛋白核小球藻(Chlorella pyrenoidosa)、斜生栅藻(Scenedesmus obliqnus)和摇蚊幼虫(Chironomidae larvae)的急性毒性效应,为制定和完善我国水质基准提供本土数据支持.结果表明,Cr(Ⅵ)、2,4,6-三氯酚和硝基苯对蛋白核小球藻的96 h半抑制效应浓度(96 h-EC50)依次为1.34、4.55和86.58 mg·L-1;对斜生栅藻的96 h-EC50依次为19.52、3.71和74.15 mg·L-1;当Cr(Ⅵ)达到1 500 mg·L-1时,摇蚊幼虫48 h死亡率仅为15%,2,4,6-三氯酚和硝基苯对摇蚊幼虫的48 h半致死效应浓度(48 h-LC50)分别为9.29 mg·L-1和98.34 mg·L-1.3种典型污染物的毒性评估结果显示,Cr(Ⅵ)对小球藻为高等毒性、对斜生栅藻为中等毒性,2,4,6-三氯酚对两种微藻均为高等毒性,硝基苯对两种微藻均为中等毒性;3种污染物对摇蚊幼虫的毒性顺序为:2,4,6-三氯酚>硝基苯>Cr(Ⅵ).

Two species of microalgae Chlorella pyrenoidosa, Scenedesmus obliqnus and a red worm Chironomidae larvae were selected as test organisms in determining the acute toxicity effects of Cr （ VI ） , 2,4,6-trichlorophenol and nitrobenzene. The results were able to provide more information on water quality criteria and more data on their toxicity to indigenous aquatic organisms in China. The 96 h- EC50 values of Cr（ VI ） , TCP and nitrobenzene on C. pyrenoidosa were 1.34 mg·L^-1 , 4.55 mg·L^-1 and 86. 58 mg·L^-1 , respectively, while those of S. obliqnus were 19.52 mg·L^-1 , 3.71 mg·L^-1 and 74. 15 mg·L^-1 , respectively. The mortality of C. larvae was 15% when the concentration of Cr（ VI ） was increased to 1 500 mg·L^-1. The 48 h-LC50 values of TCP and nitrobenzene on C. larvae were 9.29 mg·L^-1 and 98.34 mg·L^-1,respectively. These results indicated that Cr（VI） showed higher toxicity to C. pyrenoidosa, while only moderate toxicity to S. obliqnus; TCP had higher toxicity to C. pyrenoidosa and S. obliqnus; while nitrobenzene was only moderately toxic to both species of microalgae. The toxicity among the three pollutants to C. larvae was in the order of TCP 〉 nitrobenzene 〉 Cr（ VI ）.