Effects Of Reclamation On Heavy Metal Pollution In Coastal Areas

With the development of the intensity and scope of reclamation activities,heavy metal pollution in coastal areas has become increasingly serious over the past few decades.As the heavy metal pollution,which has the characteristics of latency,longer retention and poor mobility,can present a great threat to the soil environment,the virtuous cycle of ecosystem,the sustainable development of society,and even the survival of human beings,it has received much attention from environmentalists.As an important wetland resource in China,heavy metal pollution in Yancheng coastal area has been widely concerned all over the world.In Yancheng coastal area,this research not only discusses the current pollution situation(total concentrations and pollution indice)of Cd,Cu,Pb and Zn in different land use types generated by reclamation(natural habitats(NH),embankment reclamation(ER),farmlands(FL),aquacultural ponds(AP),and industrial habitats(IH)),but also analyzes their potential hazard by the availability index and desorption rate.Meanwhile,with ArcGIS,heavy metal pollution was interpolated.Integrating ecosystem service with the spatial heterogeneity of heavy metal pollution through a geostatistical approach,areas with higher ecosystem service value and lower heavy metal pollution have been selected and the priority patterns for managing heavy metal pollution have been determined consequently,which aims at providing data support for the utilization and management of heavy metal pollution in the coastal areas.Research results are showed as followed:(1)In respect of the current pollution situation of heavy metals,their total concentrations in ER,AP,FL and IH are mostly higher than those in NH,especially for the significantly higher values of Cd in ER and FL,Cu in AP,FL and IH,Pb in the AP and FL as well as Zn in FL and IH.As to their pollution indice,although they are all demonstrated as unpolluted,compared with NH,the reclamation activity still exerts a significant impact on the pollution degree of Cd in FL and ER,Cu in AP,FL and IH,Pb in AP and FL,and Zn in FL and IH.(2)For the potential hazard of heavy metals in these land use types,most are not serious.However,the availability indice of Cd in AP and FL,Cu in ER as well as the desorption rate of Cd and Zn in AP are significantly higher than those in NH,and it is especially the case for Cd,the availability indice of which in FL(33%)and AP(32%)are even more than 30%.Such phenomenon may be connected to the pH and MnO in these two land use types.(3)As to the spatial distribution of heavy metal pollution,southern region is less severe than the northern region,which may be related with natural conditions and human activities.In addition,the priority areas are mainly concentrated in Yancheng Wetland National Nature Reserve,Rare Birds in the north and the southern Dafeng Nature Reserve areas,as well as the fishing ponds around northern Sheyang Salt Field,southern Simaoyou Gate,Liangduo Gate.Such priority areas,which have higher ecosystem service value and lower pollution level,should be paid more attention in the respective of the utilization and management of heavy metal pollution in the coastal areas.