雷州半岛近岸海域水环境质量综合评价

采用单因子指数法、富营养化指数法和模糊综合评价法定量评价雷州半岛西岸海域水体环境质量，分析其影响因素，并提出污染防治对策。结果表明：（1）表层海水中的石油类和PO4-P两项评价指标严重超标，超标率达100%；部分站位的pH、Cr6等指标存在着超标现象。（2）除站位HND5外，海域水质均处于低贫营养化水平，且西南部海域水质富营养化程度小于东北部海域，部分站位PO4-P含量超出第三类水质，存在一定的污染危险。（3）从水质排序看，西部海域水环境质量高于东部海域。模糊隶属度高值区出现在乐民港、盐灶、江洪港和蛋场港附近，以及江洪港湾内和蛋场港湾内。（4）表层海水中部分检测项目超标是受近海作业、船舶油污水和上游污染物的影响；近海作业逐年增多，海洋捕捞、海产养殖发展迅猛，造成江洪港附近海域石油类、PO4-P和部分重金属超标严重；乐民港及盐灶附近水质较差可能是由于铁山港的污染物顺流而下所致。

Comprehensive Evaluation of Water Quality in the Offshore Area of Leizhou Peninsula

Water quality of the offshore area along the western coast of Leizhou Peninsula was investigated in January, 2011. Based on the data, three aspects of the environmental quality of the investigated sea area were assessed and discussed by using the methods of single factor index, eutrophication level, and comprehensive fuzzy assessment. The results showed that: (1) the major pollution factors of the sea surface water were petroleum and active phosphate (PO4-P), 100% of which exceeded the standards, and at some sampling stations the indexes such as pH and Cr6 also exceeded standards. (2) The nutrient in the investigated area was poor, the eutrophication level in the western coast offshore area was lower than that in the eastern. The content of active phosphate (PO4-P) in some sampling stations exceeded the class III water quality standard, that meant certain risk of pollution. (3) According to the water quality sorting, water environment quality in the western coast offshore area was higher than that in the eastern. The high value of fuzzy membership grade appeared near the ports of Jianghong, Yanzao, Lemin and Danchang. (4) That the detected items exceeded the standards in surface water was influenced by offshore operations, shipping oil wastewater and the upstream pollutants. Jianghong Port is one of the ten largest fishing ports in Guangdong. In recent years, offshore operations have become more and more frequent, ocean fishing and farming have been developed greatly, in addition, there are few rivers pouring into the sea, and the hydrodynamics is relatively weak in winter, leading to that the contents of petroleum, activated phosphate and heavy metals exceed the standards. The poor water quality of the sea surface near Lemin Port is caused by the pollutants from Tieshan Port.