Research Of PH Effect To Lead Pollution In Suzhou Greek's Sediment And It's Biomarkers

Suzhou greek is the mother river of Shanghai, and it's sediment is the main storage of heavy metals .With the development of economy , a large number of contaminations input to the river which lead to the deterioration of water quality . Now the heavy metal pollution of Suzhou greek becomes the hot issue of many studies . Within these studies the results showed environmental condition changes could result a dramatic release of heavy metal from the sediment. We desired to find out the effect of variation of pH to the sediment of Suzhou greek throw our studies , including the release concentration of Pb²⁺ and the transformations of different chemical states . Our Results showed that variation of pH could cause significant release of Lead . The releasing speed of Lead was higher in the beginning , but it dropped after 3 days . Lead that released from the sediment was accumulated during the period of study .With the dropping of pH from 7.0 to 5.5 , the capacity of released Lead increased . There would be a turning point of release around pH 5.5 , below pH5.5 would cause a dramatic decrease of Lead release . From pH7.0 to 8.0 the concentration of Lead decreased with the increase of pH in the earlier period of study , after 5 days the total concentration of Lead increased in samples of pH7.5 and 8.0 . The sequential extraction results showed that the predominant chemical states of Lead in the sediment were FeMnOX and RES after 7 days of release . Lead which combined with carbonates would released from the sediment with the dropping of pH from 7.0 to 4.5 , because of the decomposition of carbonates . When PH increased from 7.0 to 8.0 the Lead which exist in SD/OM would easily released according to the decomposition of humus.Recently , researches which dealt with the heavy metal pollution of Suzhou greek were mainly carried out in the physical and chemical ways. Although it could reflect the recent condition of pollution , it could not preview the potential damage to the hole aquatic system . With our effort we wanted to determine some feasible biomarkers to monitor the Lead pollution in Suzhou greek. The results showed that the accumulation of Pb²⁺ in spleen of Carassius auratu would cause the oxidant damage to the tissue and stimulate the increase of SOD and CAT activities in the range of our study . Activity of GPx significantly increased (P<0.05) within conducts of 0.5 mg/L and 1.0 mg/L after 3 days of exposure . GPx of 0.1mg/L 0.5 mg/L and 1.0 mg/L significantly rised (P<0.05) after 6 days of exposure . But after 9 days the GPx of 1.0 mg/L dropped prominently (P<0.05) , only accounted for 75% of CK and the GPx activity of 2.0 mg/L reduced to 9.33U/mgprot (P<0.01) . During 9 days of exposure GSTs presented a similar tendency with GPx , in the earlier 3 days the GSTs of 1.0 mg/L and 2.0 mg/L were significantly induced by the accumulation of Pb²⁺ . After 6 days GSTs activities of lower concentrations were also highly induced . But it decreased dramatically (P<0.05) after 9 days . GPT tend to be induced within 9 days , lower concentrations of Pb²⁺ also caused the increase of activity after 9 days . AKP were induced within 6 days but it was restrained after 9 days . Na⁺K⁺—ATPase showed a obvious connection with concentrations of Pb²⁺ and time last of exposure . In the earlier 3 days Na⁺K⁺—ATPase of 2.0 mg/L reached 7.59U/mgprot (P<0.05) , but after 9 days Na⁺K⁺—ATPase of differet conducts in our research showed a tendency of decrease . All above showed these enzymes could be biomarkers of Lead pollution of. Suzhou greek . The sequence of the sensitivities of these enzymes could be: GSTs >AKP >Na⁺K⁺—ATPase> GPX > SOD/CAT/GPT.All above conclude that there would be a risk of Lead release from the sediment of Suzhou greek with the variation of pH and we can use enzymes such as SOD, CAT, GPx, GSTs and GPT ,AKP ,Na⁺K⁺—ATPase as the biomarkers to monitor the pollution condition of heavy metal Lead in Suzhou greek .