Assessment on Water Environment Quality of Jilongshan Sea Area in Zhanjiang in Winter

Based on the water quality investigation data in December of 2010, the water environment quality of Jilongshan sea area in Zhanjiang in winter was assessed using single water quality parameter model, integrated water quality index model, organic pollution index model and eutrophication assessment model. The results show that the key pollutants are dissolved inorganic nitrogen (DIN) and chemical oxygen demand (CODmn), with their average concentrations of 1.39 and 3.74mg/L, respectively. And the averages of their single parameter pollution index are 3.48 and 0.93. Jilongshan sea area is seriously polluted by DIN. None of the sampling stations are able to meet the third-rate seawater standard in the sea area. From the evaluation results, the N/P ratio is higher than Redfield ratio. DIN is the most important contribution factor to the eutrophication. The averages of single parameter pollution index, integrated water quality index, organic pollution index and eutrophication index are 1.09, 2.58, 3.78 and 22.5, respectively. Most parts of Jilongshan sea area are polluted moderately. According to the evaluation mode of organic pollution and eutrophication index, the organic pollution degree reaches the forth level and the eutrophication degree in Jilongshan sea area is very serious.