Environmental Characteristics Of Metals And Accumulation In Shellfish In Rongcheng Bay

Coastal area is a complex and dynamic environmental system, which receiveslots of terrestrial pollutants. These pollutants include not only minerals but organicpollutants, which influence the marine environment seriously. In this dissertation, westudied the heavy metals distribution characteristic, concentration and pollution statusof sea water, sediment and marine organism, behavior of suspended particle matter(SPM) heavy metals, the space distribution of heavy metals in sediments, assessmentof sediments quality and potential influence on organisms, enrichment of heavymetals in marine bivalves.The main results as follows:The content of dissolved metals in surface waters from Rongcheng Bay than themainland of China, such as the model of the gulf of Bohai Bay and Jiaozhou Bay low,but with the natural background values than the higher content of one or two orders ofmagnitude. The content of dissolved metals in surface waters from Rongcheng Baypresent the for the offshore with high, the far side of the trend with low, except Pb.The high content of dissolved metals appear at summer and winter, but in spring andautumn the content of dissolved metals are low. The content of heavy metals insurface and bottom water is similar. According to the single factor pollution indexmethod, The content of dissolved metals in surface waters from Rongcheng Bayexcept the extremely individual overweight outside, the rest which conform to thenational water quality standards, only from the heavy metal pollution, water quality isgood.The average contents of Cu、Pb、Zn、Cr、Cd、Hg and As in surface sediment fromRongcheng Bay and the Swan Lake Inlet were lower than the class1quality standards of national marine sediments. The order for content of heavy metals was Zn＞Cr＞Pb＞As＞Cu＞Hg＞Cd and Zn＞Cr＞Pb＞As＞Cu＞Cd＞Hg, respectively. Theresults of index of geoaccumulation of heavy metals in Rongcheng Bay and the SwanLake Inlet sediments show that Zn, Cr are not contaminated by human, but Cd isserious contaminated. The pollution of Cu was serious in Swan Lake Inlet sedimentsthan Rongcheng Bay, and the similar condition of Pb, As in this two areas.The results of speciation of heavy metal in sediments from Rongcheng Bay showedthat the Zn and Cr in the sediments were mainly in residual form, suggesting thatthey had better environmental stability; while Cu and Pb were more in highly activeform，suggesting that they had greater environmental effects．Cu and Pb had highecological risk index，and especially，the potential risk of Pb should be attached moreimportance to.The results of speciation of heavy metal in sediments from Swan Lake Inletshowed that the Zn and Cr in the sediments were mainly in residual form, similar withRongcheng Bay. The Cu was mainly in reducibility form, followed by residual form.The order of the form of Pb was reducibility form (34.6%)＞acid extracted form(26.2%)＞residual form (24.7%)＞oxidable form (14.5%). The Cd was mainly inreducibility form, similar with Rongcheng Bay.The results of potential ecological assessment risk based on morphologicalresearch showed that the potential ecological assessment risk of Cd in the sedimentfrom Rongcheng Bay and the Swan Lake Inlet is the largest, followed by Pb. thepotential ecological assessment risk of Cu、Zn and Cr are low.The content of heavy metals in oysters, scallop and shot necked clam fromRongcheng Bay has the following characteristics, the order of Cu, Pb, Zn was oysters＞scallop＞shot necked clam; the order of Cr was shot necked clam＞oysters＞scallop; the order of Cd was scallop＞oysters＞shot necked clam. The results of thesingle factor pollution evaluation indicate that the heavy metal pollution of oysterswas highest degree, followed by scallop, then was shot necked clam. In the five kindsof metal element, Pb and Cd pollution degree is higher, the second for Cr and Zn, Cuminimum level of pollution.