Distribution Of As And Pb In Songhua River And Study Of Releasing Law From Sediment

The heavy metals pollution occupied the higher proportion in water pollution. With thechange of environmental conditions, the heavy metals in sediment would release to the water.Heavy metals were enriched and expanded in the biologic chain endangering human health sothat the pollution problem of heavy metals was more and more concerned. As the researchobjects, the As and Pb in Songhua River were investigated in this paper. The concentration ofAs and Pb was determined by ICP-MS in water, sediments and aquatic organisms.Futhermore, the release research of As and Pb in sediment was analysed by AFS, theinfluence factors, kinetics process, morphology distribution and transfer law and so on wereinvestigated.The results showed that the content distribution of As and Pb in the main stream andbranches of Songhua River had differences with the change of season. As and Pb in the waterenvironment of Songhua River was relatively constant in Harbin’s import and export. Thecontent level of As and Pb was lower in M10’s water environment. In the sediment ofSonghua River, the As content was lower than Pb, besides, the content of As and Pb graduallyincreased from the upstream to the downstream. In M6’s aquatic organisms, the enrichmentcapability of As and Pb was Clam>> Catfish≈Carp and Catfish> Clam> Carp, respectively.In M10’s aquatic organisms, the enrichment capability of As and Pb were Catfish> Carp>Silver carp. Furthermore, the weight of catfish, carp, silver carp and clams influenced theorganisms’ enrichment capability of As and Pb.By the research results, the As release quantity was higher than Pb in sediment. And pH、T、Sality and Organic acid and so on affected the release process of As and Pb in sediment.When the pH was6, the release process of As and Pb was restrained; when the T was35℃and6℃, respectively, the As andPb release process was restrained; the As release processwas restrained at the lower salty and the Pb release process was restrained at the salty≥10‰;Fulvic acid and citric acid could promote the As release rocess but restrain the Pb releaseprocess; Furthermore, the reasonable aeration rate was beneficial to the release process of Asand Pb in sediment. The kinetics analysis results indicated that the As release law accordedwith the equation of Elovich in the relatively short time, but the Pb release law could be fittedby the Elovich equation and Two-constant rate equation. In brief, As was the form of in-dissolvable state and Pb was the form of combined state, such as sulfide and organic, in thesediment. Besides with the change of environmental conditions, the form could betransformed between the different forms.In the sample ecological system composed of sediment, zebrafish and water, the Pbcontent gradually increased in sediment with the Pb content increasing in water. And that thePb could accelerate the As release process under the certain concentration of Pb in sediment.The process of zebrafish adsorbing Pb was relatively slow under the lower content of Pb inwater. In addition, the process that zebrafish adsorbed the Pb of water was gradually enhancedwith Pb content increasing.The content of As and Pb was known in water environment of Songhua River and therelease of As and Pb was controlled in sediment that indicated the results had importantsignificance. The research results could be referenced by the pollution management whichwas polluted in Songhua River basin by As and Pb. Meanwhile, the results could bereferenced by the other Water System’s pollution management.