[Environmental quality of Guangzhou sea area]

Based on the water quality investigation data from August 2003 to August 2004, and by using single water quality parameter model, integrated water quality index model and eutrophication assessment model, this paper assessed the environmental quality of Guangzhou sea area. The results showed that the key pollutants were dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus, oil, Cu and Pb, with their annual average concentrations of 1.87 mg x L(-1), 0.049 mg x L(-1), 0.107 mg x L(-1), 6.07 microg x L(-1) and 1.43 microg x L(-1), respectively. Among the pollutants, DIN was the most important one. Its concentration exceeded the fourth standard of sea water quality, and decreased gradually from inner bay to outer bay. Under the effects of Pearl River water flow and land-based pollutants, most part of Guangzhou sea area was seriously polluted, and the annual averages of single parameter pollution index, integrated water quality index, and eutrophication index were 2.22, 6.80 and 48.44, respectively, which also decreased gradually from inner bay to outer bay, and from nearshore to offshore.