Toxicological Study Of Cadmium,Chromium And Acetochlor On Spirodela Oligorrhiza

In this dissertation, the single toxic effects and joint toxic effects of Cadmium, Chromium and Acetochlor were detected in Spirodela oligorrhiza. The effects of Cadmium, Chromium and Acetochlor single pollution and combined pollution on the concent of chlorophyll, the activity of SOD, POD and the content of MDA in leaves of Spirodela oligorrhiza were studied. The thesis also discussed the absorption of heavy metal(Cd, Cr)by Spirodela oligorrhiza in water. The mainly results were summarized as follows:Under the condition of temperature 25+2℃ and light 30001x cultivation, the 96 hours of single toxicity IC50 of Cadmium, Chromium and Acetochlor to Spirodela oligorrhiza was 4.77, 15.4, 6.96mg/L. The joint toxicity of binary and triple mixtures of heavy metal and herbicide against Spirodela oligorrhiza were carried out in laboratory (1:1, C/C ) . The results showed that the 96 hours IC50 were 1.41mg/L (Cd+Acetochlor), 3.14mg/L (Cd+Cr), 3.74mg/L (Cr+Acetochlor), 0.60mg/L (Cd+Cr+Acetochlor) . According to the additive index method of marking, the additive index (AI) were 0.99, 0.16, 0.28, 2.98. They were greater to zero, The combined toxicities were synergism action. At the same time, with the increasing of the treatment concentration of Cadmium, Chromium and Acetochlor, the content of chlorophyll a decreased. The effects combined pollution heavier than those of single pollution did clearly. The results also showed synergism action.Under the condition of single pollution, with the increasing of the treatment concentration of Cadmium, Chromium and Acetochlor, the content of chlorophyll decreased evidently; the activity of SOD and POD increased first and decreased afterwards, but the POD activity of all treatment higher than blank comparison without added to pollutant; the content of MDA increased remarkable. Spirodela oligorrhiza when exposed to combined pollution, suffers much more harmful hurt than the case of single pollution.The interaction of Cadmium, Chromium and Acetochlor showed synergism action by binary-factor analysis of variance.