Heavy Metals Accumulated Effect Of The Eastern Chongming Wetland And Its Response To Human Activities

Wetland is considered as " the kidney of the earth".The estuary tidal wetland plays a role of "filter" in the effect of watershed pollutants from river basin. Eastern Chongming present quality situation and recent changes is concern as it’s a world natural directory wetlands and National Nature Reserve for birds.In this paper, the Eastern Chongming tidal flat sediments and sediment column as the research object, on the basis of particle size analysis, heavy metal, organic carbon content and time analysis, reveals the natural and human activities under the comprehensive action of estuarine tidal flat environment, heavy metal distribution and accumulation characteristics of heavy metals in estuarine tidal flat, factors affecting the estimation, tidal flat sedimentation rate and sediment flux, the enrichment factor of East Chongming tidal flat sediment column metal evaluation, while applying geo-accumulation index and potential ecological risk index method on surface sediments pollution evaluation. Mainly got the following conclusions:(1) The Eastern Chongming tidal flat sediment heavy metals Cu, Pb, Zn, Cr, Cd average contents were42,27,69,71,0.23ug·g-1, all over Shanghai beach background value in the Yangtze River Estuary, and among China beach, estuary wetland and global shore area category the value are in the middle status. Based on the deposition rate of field observation and determination of heavy metals in the calculated Eastern Chongming heavy metals Cu, Pb, Zn, Cr, Cd years of settlement are respectively187,121,395,312,1.04t, total deposition flux of11g (m2·a)-1.(2) According to the enrichment factors of heavy metal pollution in the column sample evaluation found that Cu, Pb, Zn elements in the basic no pollution to weak pollution range, Cd elements pollution is serious. With the passage of time, the north, section Cd pollution is reduced somewhat, while the southern section is aggravating trend;(3)Eastern Chongming cores dating show that the northern column (column length176cm), the central column samples (column length180cm) and the southern column (column length140cm) representing26a,52a and43a to the sedimentary history. Enrichment factor of heavy metal contamination in the cores evaluation found that in recent decades the overall Cu and Pb, Zn are basically at the non-polluting to the weak level of contamination within the Cd pollution is more serious.(4) Analysis showed that Eastern Chongming heavy metal distribution by material sources, human activities, hydrodynamics, sediment particle size, vegetation distribution and other factors..