ABSTRACT
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 x L(-1, 4.55 mg x L(-1) and 86.58 mg x L(-1), respectively, while those of S. obliqnus were 19.52 mg x L(-1), 3.71 mg x L(-1) and 74.15 mg x L(-1), respectively. The mortality of C. larvae was 15% when the concentration of Cr(VI) was increased to 1,500 mg x L(-1). The 48 h-LC50 values of TCP and nitrobenzene on C. larvae were 9.29 mg x L(-1) and 98.34 mg x 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. oblignus; 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).
