Study On The Enrichment And Migration Of Heavy Metals In Mangrove Sediments-Pore Water-mangrove Plant Systems In Northern Hainan Island Intertidal Zone

Mangrove wetland located in the tropical and subtropical of terrestrial and marineecotone,special growing environment makes it largely maintains the shallow ecologicalbalance.With population growth, industrialization and urbanization,Fertilizers, pesticides andother large-scale use, Wastewater and sewage industrial emissions, increase Mangrovewetland ecosystem has to absorb a lot of heavy metal pollutants,it makes heavy environmentalpressure increases.This paper is based on Dongzhai Harbor, Fuli bay,Bamen bay,XinyingHarbor,Yangpu Harbor Mangrove wetland located in the northern Hainan Island.Choose Cr,Co, Ni, Cu, Zn, As, Cd and Pb eight heavy metals as research subjects,Analysis the contentand spatial distribution characteristics of the heavy metal in sediment、Mangrove plants、thesediment pore water lacated in northern Hainan Island Mangrove intertidal zone,study therelationship between the heavy metal elements in sediments、Mangrove plants,investigate thefactors influencing the spatial distribution of elements,the conclusions are as follows.（1）The average content of surface sediments in the study area of8kinds of heavymetals Cr, Co, Ni, Cu, Zn, As, Cd, Pb respectively：63.63mg/kg、9.32mg/kg、27.32mg/kg、15.62mg/kg、57.72mg/kg、12.57mg/kg、12.57mg/kg、0.98mg/kg、16.34mg/kg.Comparedwith the background values of Hainan river sediments,In addition to the content of Pb waslower than the background value, the remaining elements are more than the backgroundvalue.Compared with other regions of the heavy metal content in surface sediments, thecontent of the surface sediments of the overall study area at a low level.（2）8kinds of heavy metal elements have substantially identical in all mangrove plantroots, stems, leaf of sampling points of the average level:Cr>Zn>Ni>Pb>Cu>As>Co>Cd.Levels heavy metal elements in different organs of the plant body generally consistent: root>stem>leaf.（3）8kinds of heavy metals in the study area in the average bioconcentration factoris lessthan1,the enrichment coefficient in order from high to low:Cd>Cu>As>Pb>Ni>Zn>Cr>Co.8kinds of heavy metal transport ability from strong to weak: Co>Cd>Cr>Zn>Cu>Pb>Ni>As.Thus, little relationship between plant bioconcentration of heavy metals and the ability to transport.（4）8kinds of heavy metals in sediment pore water samples in the study area the averagecontent from high to low：Cr>Zn>Ni>Cu>Co>Pb>As>Cd.The coefficient of variation of8kinds of heavy metals in the study area≤0.35,shows that the discrete degree of the heavymetals lower, more uniform distribution.（5）Correlation analysis of8kinds of heavy metals in sediments, mangrove plants,itshows:sediment:In addition to the element As, there are good correlation among the rest ofother heavy metal metals;Mangrove plants:In addition to As, Cd, Pb, there are goodcorrelation among the other heavy metals.Relevant laws similarity between them,These heavymetals have similar geochemical characteristics, origin or impact factors.（6）The content of8kinds of heavy metals-sediment plant-sediment pore water in thesystem are broadly consistent with the following rules:Cr,Co:sediment>Mangrove porewater>root>stem>leaf;Ni,Cu,Zn,As,Cd,Pb:sediment>Mangrove pore water>roo>stem>leaf.