The Research Of Heavy Metals In Surficial Sediment Of Dagu Estuary And Offshore Marine Organisms In Bohai Bay

In recent years, with the development of the China’s coastal area’s economic, heavy metals producted by industry, agriculture and human life pass various channels into the ocean, and lead to pollution of heavy metals in China’s coastal waters, and brought serious ecological stress to the coastal areas. Heavy metal pollutants can get into the river’s sediment through the complicated physical and chemical process, the pollutants such as heavy metals adsorbed on the heavy metal sediments, release pollutants to water through continuous adsorption analytic process and form the secondary pollution, what’s more, heavy metal can enter into the process of material circulation by the food chain, and accumulate in organisms, destroying the normal physiological activities.Then affect the biological community structure and composition, and change the ecological service function. Because humans lie in the high nutrition level of food chain, so heavy metal might through the human diet enter into human body, and destroys human physiological function, endanger human’s health.Based on the above reasons, this text take the sediments of Dagu estuary and offshore Marine organisms as the study’s subject, using MARS-5microwave digestion appliance to resolve the samples, and then through the ICP-MS method, to determine the content of heavy metals in the sediment and biological samples, finally, analyse the results, so as to protect the biodiversity of offshore sea area in bo hai bay, to use and develop reasonably the maritime resources, to improve the quality of products, to enhance the quality of the Marine ecological environment, to strengthen the pollution control can provide some scientific’s theory basis.The main results gotten in the article are as follows:(1) Cu and As are the main elements of heavy metal pollution in surface sediments of Dagu estuary in bohai bay, and their’s mean beyond the environment background values of bohai bay. Among them the content of Cu in B5, B6, B10point is higher than the environment background values, the maximum value is65.57mg/kg appeared in B10point, and beyond the environment background values2.5times, but not beyond the third kind provisions limit values ruled by GB18668-2002; the content of As in the B6, B8B10, beyond the environment background values, the maximum value is21.35mg/kg also appears in B10point.(2) the maximum of Pb and Cd are found in B6point, and beyond the environment background values, but obviously lower than the allowable value of the third kind limit values.the Cd’s maximum value is0.142mg/kg appeared in B6point, and beyond the background value0.11mg/kg, but no more than the third of the allowable value standard5.0mg/kg. The rest of the content are lower than at the background value. Pb;s distribution is similar with Cd. Its maximum value17.47mg/kg also appears in B6points, more than the environment background values16.55mg/kg, but are not more than the third kind of standard limited value.(3) The content of Zn is quite different between all points, but not more than the environment background values, the content of Cr, Mn and Ni all the point distribute even, and are lower than the environment background value, it is generally thought that it’s belongs to the natural sources, and illustrating that this area do not exist the Cr, Mn and Ni’s pollution.(4) The mean value of Cd is0.60mg/kg in Scapharca subcrenata beyond the top limit value0.1mg/kg ruled by GB18406.4-2001,but it is lower than the standard value1.0mg/kg set by CAC (international food codex alimentarius commission) Overall, Scapharca subcrenata in this area was polluted by Cd.(5) Overall average of Pb0.27mg/kg is no more than GB18406.4-2001ruled value, but during the process of determining the point in H2å'ŒH4, some determination value are more than the limit value0.5mg/kg. So the area has potential threat with Pb, if not controlled, can cause Pb’s pollution.(6) The six of the heavy metal elements like Zn, As, Cr, Mn, Ni and Cu in this area are no more than GB18406.4-2001ruled value in the organisms.(7) The results also show that offshore or estuary is more vulnerable polluted by the contaminant from land-sourced pollutants, so we should pay attention to the estuaries and the gulf ecological environment system’s investigation and monitoring.