| Fujian Province is mainly situated in area along the coastal region of southeast china which its coastline is very long, Coastal wetland is one of the important resources which can provide manufacture and existence for human being, Furthermore, it is worth for environmental function, including in resisting flood, regulating flow, restoring flood and drought control, adjusting local climate, controlling soil erosion, et al. Recently, the developing scale of exploitation and utilization on coastal wetlands, the frequently disturbance such as bottom land surrounding fill ,large scale effluent and waste residuedraining into wetland caused resourse and .ecosystem of wetlands seriously damaged, So it influences the infunctin of ecosystem greatly. It turns out that the monitoring and assessment of pollution status of coastal wetland become a top emergency today. it's also urgent to implement quantitative research for pollution of coastal wetland in Fujian.For a long time, human pay less attention to the environmental function of coastal wetland ecosystem, there were rarely systematic analysis on monitoring and assessment of pollution status of coastal wetland especially, the study on heavy metals which is related closely with human health is blank in south coastal wetlands ecosystem, it is lack of quantitative research for pollution caused large blindness on protection and exploration,.However, in allusion to problems existing in present, the studies were performed by means of tracing examination all around, typical investigation and located research. This paper studied on the typical coastal wetlands in Fujian(including Sandou bay wetland in Ningde, Fuqing bay wetland in Fuqing, Xinhua bay wetland in Putian, the Estuary Wetland of Minjiang River in Fuzhou, Quanzhou bay wetland in Quanzhou and the Estuary Wetland of Jiulongjiang river in Zhangzhou), which analyses relations among Cu, Pb, Ni, Zn, Cr, Cd, Mn, extracting liquids, pH, CODCr, NH3-N and T. Based on the pollution characteristic, it was adopted comparison of multiple assessment patterns(N.L.Nemerow comprehensive pollution index , the geoaccumulation index and potential ecological risk index), a system is identified and evaluated for pollution factors and grades. Takeing this as the basis, it will provide valuable suggestions for pollution evaluation and utilization of national wetlands resourses by through exploration of each assessment method to pollution influence and the rational evaluation model. the main results for our research are as follows:(1) The main coastal wetlands in Fujian have been differently polluted by 7 kinds of heavy metals Cu, Pb, Ni, Zn, Cr, Cd and Mn, their content average values are 1.91, 4.02, 4.27, 2.73, 1.02, 11.67, 3.37 times to soil background value in Fujian, Cd is largest among them. The different element content is different, the range of Mn approachs to 2349 mg.kg-1, other element ranges of Cu, Pb, Ni, Zn, Cr, Cd is that 429, 569, 181, 529, 72 and 2.6 mg.kg-1, the variation coefficients of elements exceed 40%, the variation coefficient of Cu surpasses 100%, There were significant differences among metal elements in coastal wetlands.(2) Research on the clustering analysis in heavy mentals index in soils of the main coastal wetland in Fujian, the result indicated: the dendrogram within 0-1 type system cluster method shows that costal wetlands can be divided into three groups, the first group is Fuqing bay wetland in Fuqing, Sandou bay wetland in Ningde, the Estuary Wetland of Minjiang River, they are situated in the upper reaches of Taiwan strait; the second group is Xinhua bay wetland in Putian and Quanzhou bay wetland in Quanzhou, they are situated in the middle reaches of Taiwan strait; the third group is the Estuary Wetland of Jiulongjiang river in Zhangzhou, it is situated in the lower reaches of Taiwan strait ; The dendrogram within R-type system cluster method shows that heavy mentals can be divided into three groups, the first group is element of Cu, the second group is elements of Pb, Ni and Mn, the third group is elements of Cr, Cd and Zn.(3) Analysis on correlation of heavy metals of coastal wetlands in Fujian, the results indicated: Heavy metal pollution in soils of coastal wetlands in Fujian is not single pollution but combined pollution at different level. There was significant correlation between Cu and Pb, Cu and Mn, Cu and Cr, Cr and Mn (P>0.05). The significance level was -0.3274,0.2949,0.3701,0.3204 respectively. Among these, Cu was negatively correlated with Pb. There were distinct positive correlations between Mn and Ni,Ni and Pb (P>0.01), its significance level was was 0.3802, 0.8906 respectively; The correlation of extraction contents for heavy metals change along with the different extracting liquids and elements, they were most significant correlation among elements of heavy metals. Element Cu was significant correlation between other elements excepting for element Cr by DTPA, it was similar to that by HCL, it turned out to be combined pollution for element Cu.(4) Analysis on heavy metals extracting contents in soils by means of different extracting liquids(DTPA, HCL) for coastal wetlands in Fujian, the results indicated: Extracting contents were influenced by the chemical composition and properties in soils of coastal wetland, and its parameter was not stable. It was difficult to unify the available contents extracted by different extractants. The average of extractable content by DTPA was 0.76%～7.94% of the total contents, while the HCL-extractable was 3.21%～36.55%, varied with different kinds of extractants and elements. Moreover, the same elements extracted by different extractants (DTPA, HCL) results in different variation of extraction; The ratio of extraction and total contents varied much along with the kind of extractant and element. The ratios of the content extracted by HC1 with soil background in Fujian were all greater than that of DTPA. The result indicated that there was different in available content extracted by different kinds of extractant. The contents extracted by HC1 was relatively higher than that of DTPA.(5) Monitoring water of coastal wetlands in Fujian, the results indicates: elements Pb, Ni and Cr go beyond Sea water quality standard at 4 level on average, their contents average value is 7.6, 2.5 and 30 times to Sea water quality standard at 4 level, other elements were not overstandard excepting for element Cd. The different element content is different, Heavy metals pollution degree has obvious variation in the different coastal wetlands. Pollution degree in Sandou bay wetland for elements Cu, Pb, Cd and Mn were primacy than that of others wetlands, contents were 0.0647, 0.8619, 0.1730, 0.9256 mg/L. Element Ni was most seriously polluted in Quanzhou bay wetland, Xinghua bay wetland was not relatively serious, it reached 0.0289 mg/L; Element Zn was most seriously polluted in Xinghua bay wetland, the Estuary Wetland of Minjiang River was not relatively serious, contents reached 0.5079 and 0.0931 mg/L; other elements presented sel-ariation along with different wetlands, the range of Mn approachs to 2349 mg.kg-1, other element's ranges of Cu, Pb, Ni, Zn, Cr, Cd is that 429, 569, 181, 529, 72 and 2.6 mg/kg; the variation coefficients of elements exceed 40%, the variation coefficient of Cu surpasses 100%, There were significant differences among metal elements in coastal wetlands. The content of CODCr and NH3-N varies in different regular pattern with the change of sampling point, and the range of variation was great. The variation range of CODCr was from 2.97 to 765.20 mg/L. The wetland that were contaminated the most seriously was Xinghua bay wetland, the content had reached 765.20 mg/L. And the estuarine wetland of Min river was polluted the least, only 2.97 mg/L, the highest content of NH3-N was appeared in Fuqing bay wetland, had reached 5.838 mg/L.The order for the other sampling point was as follows: Quanzhou bay > Jiulong river > Sandu bay > Xinghua bay > Minjiang river. There were not distinct differences in the pH value of each water sample, mostly were from 6.5 to 8.0. The temperature of water sample varied much, from 10℃to 20℃, but were in accordance with the definite criterion of seawater quality, (were not out of the maximum permission level)(6) Dynamic monitoring was conducted on the heavy metal contents for all year around in the estuary wetland of Min river, the results indicated: heavy metal contents in water samples varied regularly, the contents of Cu, Pb, Ni, Zn, Cr, Cd and Mn had an ascendant tendency between February and April, then reached its maximum during May and July, and afterwards went down. On the whole, it showed an trend of high in the middle and low on the two terminal. It illustrated that heavy metal pollution in the estuary wetland of Minjiang river had an obvious seasonal variation, it was affected greatly by rainfall and the component of the water body that comes from upstream of Minjiang river.(7) Analysis on the potential ecological risk parameter of single heavy metal of coastal wetlands in Fujian Province, the results indicated: from the Hakanson potential ecological risk index method. the pollutants in the order of impacting extent of ecological risk are: Cd>Ni>Pb>Cu>Zn>Cr. The most strong contamination is Cd to which we should pay enough attention, while the other kinds of heavy metal are weak contamination. From the potential ecological risk parameter of all heavy metal, the potential ecological risk index of coastal wetlands in Fu Jian Province is of strong contamination, RI=407.93 between 300Sandu gulf wetland > Fuqing gulf wetland >Quanzhou gulf wetland >Jiulongjiang wetlands >the estuarine wetlands of min jiang, Xinghua bay wetland was seriously contaminated.(8) Analysis on different assessment methods for heavy metals of coastal wetlands in Fujian , the results indicated: the single factor pollution index of N.L.Nemerow comprehensive pollution index only reflects whether there was contamination of certain heavy metal element, but it didn't express the pollution level, index of geoaccumlation could reflect the certain pollution level in detail, but it is lack of integrated evaluation. On contrary, Cif and Eir of Hakanson potential ecological risk index avoided the disadvantage above them. It could, reflect the pollution level in an all-round way which caused by single or combined heavy metal element in certain environment quantitatively. It is relative advantaged assessment for evaluating heavy metal pollution in the coastal wetland .(9) By using the principal component to analyze the 11 indexes in the water body, the results indicated: four principal components delegate 97.171% of all water body polluted information of coastal wetlands in Fujian. The first principal component is a combined measure of Pb, Cd, Mn, Cu in water body; The second principal component is a measure of Ni, Cr , temperature and pH which are combined together; The third principal component is a combined measure of Cu, Zn and CODCr in water body; The fourth principal component is NH3-N. The general pollution level of coastal wetlands in Fujian is as follows: Sandu gulf wetland >Quanzhou gulf wetland > Xinghua gulf wetland > Jiulongjiang wetlands > Fuqing gulf wetland > the estuarine wetlands of min jiang, especially , Sandu gulf wetland was severiously polluted, the estuary wetlands of Minjiang rives was less polluted. |
