The Study On Toxicological Effect Of Atrazine On Several Aqutic Plants And Its Degerdation

Atrazine is a herbicide, with high efficiency and low cost, which is used largely all over the world, in the process of use, it was causing a lot of water pollution and immediately dangerous to aquatic plants, furthermore, atrazine disserve all troph ic levels of fauna in water via food chains. From the security of aquatic ecosystem, the atrazine toxicological effects study about aquatic plants is necessary. The aim of this study was to investigate the atrazine toxicological effects by means of measuring the growth and physiological function of aqutic plants, and then through studyed contribution of aqutic plants to atrazine degradation by degradation experiments, proved the application material and the theory instruction on management atrazine pollution.1. Effects of atrazine stress on the activities of POD and root, contents of MDA and chlorophyll, RWC and fresh weight of Scirpus tabernaemontani,Acorus graminens,Iris pseudacorus and Lythrum salicaria with different levels of atrazine were studied. The results showed that there were significantly harmful effects on contents of MDA of I. pseudacorus with high levels of atrazine, but atrazine had impacted smaller on other indexs. The 15d-LC50 of atrazine for fresh weight was 18667.82mg/L. So atrazine had low toxicity to I. Pseudacorus. In comparison, atrazine had high toxicity to S. tabernaemontani,A.s graminens and L. salicaria, and the 15d-LC5o of atrazine for fresh weight was 29.18mg/L,184.12mg/L and 85.35mg/L respectively. There were significantly harmful effects on all the indexs with high levels of atrazine.2. For accurate simulation atrazine toxicological effects about aquatic plants under natural conditions, we cultured three aquatic plants for 180d with two atrazine levels, which seted according to atrazine maximum residues in environmental water. Evaluate atrazine toxicological effects of aquatic plants by investigate the height,tiller number and other physiological and biochemical indexs of three aquatic plants. The results were shown that three plants were all slight harmed by atrazine. Parts of indexs had significantly affected, but the height and tiller number had less changed. Three plants can survive long-term with 0.2mg/L of atrazine. In the three plants,I. pseudacorus showed the highest resistance than S. tabernaemontani and A. graminens.3. The degradation situation of atrazine were compared, and through the comparison between no plant bacteriostasis control,bacteriostasis control and nonbacteriostasis control, the effects of plant and microorganism were analyzed. The results were shown as follow. Three plants enjoyed the most part of contributions for atrazine degradation, and there were different between various conditions. The contributions of I, pseudacorus,A. graminens and L. salicaria on the degradation were 78.43%,63.0% and 67.82% respectively. Microbion had less contributions. The microbion contributions in I. pseudacorus,A. graminens and L. salicaria on the degradation were 2.80%,17.58% and 10.99% respectively. The half-life of atrazine of three plants shortened the time of degradation in natural condition about 20d. And the different betteen three plants were small. That was about 2d. Through the paper, the feasibility of using these aquatic plants for phytoremediation was proved.