Analysis And Risk Assessment Of Suspended Matter And Heavy Metal Pollution In Leizhou Peninsula Reef-building Coral Reserve

As a particularly important resource in ecology,reef-building corals are mainly distributed in tropical seas.This creature,which is particularly sensitive to the benthic environment,plays a key role in guiding environmental changes around it.With the passage of time,the rapid development of coastal economy around Xuwen,especially the development of aquaculture,coastal industry and transportation,has greatly affected the marine environment around Xuwen,and various marine problems are increasing day by day.The main results of this study are as follows:1.The average content of suspended matter in the surface layer is 0.199±0.013mg/L;and the average content of suspended matter in the bottom layer is 0.204±0.016.In the study of suspended matter particle size,the difference of surface and bottom suspended matter particle size is not obvious,and the median particle size is most in the range of 0.02-30?m,mainly fine sand.The average content of chlorophyll a in surface and bottom layer is 2.38±1.91?g/L,1.99±1.91,respectively 61?g/L,It is shown that the eutrophication level in the study area is low,in which the turbidity value of the bottom layer of most stations is larger than that of the surface layer,most likely because the sediment is resuspended by winter monsoon.2.The correlation coefficient is-0.503,which indicates that the higher the content of suspended matter,the lower the turbidity value,and the positive correlation with other environmental factors.3.The heavy metal content of the surface suspended matter in the study area is Fe>Mn>Ni>Cr>Cu>Cd,the heavy metal of the bottom suspended matter is regular Fe>Mn>Ni>Cu>Cr>Cd,the study shows that the change law of the surface and the bottom layer is roughly the same,and the difference between the heavy metal content of the surface and the bottom suspended matter is not obvious.4.The correlation analysis and principal component analysis were used for heavy metals.The changes of heavy metals in the surface and bottom layer were basically the same,and according to the research results,the Cu and Cd had the same similar source,Cr?Ni?Fe?Mn had another similar source,and the specific source needed to be explored in the future research.5.Heavy metal pollution of suspended matter in most areas of Xuwen reef coral area reached a severe level.From the contribution value of potential ecological risk index of heavy metals in 25 samples,it can be found that the potential ecological risk of four heavy metals is from high to low: Cd>Ni>Cu>Cr,this phenomenon is related to land source emissions and industrial minerals.