三沙湾盐田港海水养殖海域水质调查与评价

根据2012年8月-2013年7月为期一年、每月一次的对三沙湾盐田港海水养殖海域水环境质量的监测结果,分析了该海域基本理化指标以及营养盐的特征与变化趋势,并应用有机污染评价指数(A)、营养状态指数(E)和海水营养状态质量指数(NQI)法评价了该海水养殖海域的水环境质量状况。结果表明,盐田港海域悬浮物含量符合Ⅲ类海水水质标准,pH符合Ⅲ至Ⅳ类海水水质标准。溶解无机氮(DIN)和溶解无机磷(DIP)符合Ⅳ类至劣Ⅳ类的海水水质标准,年平均值分别为0.644和0.061 mg/L,范围分别在0.256~1.147和0.027~0.103 mg/L之间。NO3-N占DIN的比例平均为82.86%。盐田港海水养殖海域的DIN和DIP的浓度已处于较高的水平。有机污染评价指数和海水营养状态指数的评价显示,盐田港海水养殖海域已经处于严重的富营养化状态,同时有机污染相当严重。分析表明盐田港海水养殖的自身污染是导致该养殖海域富营养化与有机污染严重的重要原因之一。

The survey and assessment of water environmental quality in the mariculture area in the enclosed Sansha Bay

Based on investigation data obtained from August 2012 to July 2013, the surface water temperature （SST）, salinity （S）, pH, transparency （SD）, dissolved oxygen （DO）, chemical oxygen demand （COD）, suspended solids （SS） , Chl. a and nutrients were analyzed in the mariculture area of Yantian Harbor, Sansha Bay. And the water quality and eutrophication conditions were also evaluated on the basis of organic pollution index （A）, eutrophication index （E） and nutrient quality index （NQI） methods. The results showed that the suspended solids complied with the Grade m, and the pH generally complied with the Grade m to IV, while the inorganic nitrogen （DIN） and inorganic phosphorus （DIP） complied with the Grade 1V or even worse than Grade IV according to ＂Seawater Quality Standard＂ （ GB 3097 - 1997 ）. The average concentration of DIN and DIP was 0.644 and 0.061 mg/L with the range of 0. 256 - 1. 147 and 0. 027 -0. 103 mg/L, respectively. NO3-N was the main form of DIN, which accounted for 74.83% of DIN. The DIN and DIP concentration in this mariculture area was at a higher level. The values of A, E and NQI demonstrated that the seawater was under serious eutrophication condition, and the organic pollution was also very serious. The self- pollution of mariculture was the main cause leading to serious eutrophication situation.