Eutrophication Level Assessment of Qinzhou Bay Coastal Waters in June

【Objective】The survey and assessment on the eutrophication level of Qinzhou bay coastal waters were conducted.【Methods】15sea water samples were collected by Guangxi Qinzhou Bay in June 2010.The concentration of COD,DIN and PO4-P were determined.The pollution status of sea water was assessed by the index technique of single factor.The eutrophication level of sea water was assessed by the method of eutrophication index and potential eutrophication assessment model.【Results】The mean concentration of COD,DIN and PO4-P of Qinzhou bay coastal waters were 1.00mg/L,0.12mg/L,and 0.012mg/L,respectively.The mean concentration of COD was meet the national sea water quality standard of the first category.The over standard rate of the mean concentration of DIN and PO4-P was20%.The mean eutrophication index of Qinzhou bay coastal waters was 0.47.The eutrophication grade of Qinzhou bay coast wasⅡ degree.【Conclusion】The sea water of Qinzhou bay coast was polluted by DIN and PO4-P.The eutrophication level of Qinzhou bay coast was pool nutrient.The eutrophication degree of Qinzhou bay coast was mainly affected by the land-source pollutant and mariculture.