广西北部湾海域水质污染调查与分析

为全面了解广西北部湾海域水质污染状况，根据广西北部湾海域2021年8月（夏季）和2022年1月（冬季）表层海水调查数据，利用单因子污染指数法、有机污染指数法和综合污染指数法对广西北部湾海域进行水质污染分析和评价。研究表明：广西北部湾海域表层海水夏季和冬季pH、溶解态无机氮（DIN）、溶解态无机磷（DIP）和溶解氧（DO）存在不同程度超标，主要污染物为DIN和DIP，钦州湾和铁山港是各单因子主要超标海域。有机污染方面，仅夏季钦州湾湾内存在1个重度污染站位，在钦州湾和铁山港湾内出现中度污染，夏和冬两季分别占18.5%和13.6%，其余受污染海域同时出现在钦州湾、廉州湾和铁山港，夏和冬两季良好水质仅占3.7%和22.7%，均位于涠洲岛海域。综合污染方面，未发现严重污染水域，仅钦州湾在夏季出现中度污染，轻度污染在夏和冬两季分别占40.7%和31.8%，夏季除涠洲岛外其他海域均受到综合污染，冬季仅钦州湾和铁山港受到综合污染。整体而言，单因子超标率、水体有机污染和综合污染程度在夏季高于冬季，在湾内高于湾外。

Investigation and Analysis of Water Quality Pollution in Beibu Gulf of Guangxi

In order to comprehensively understand the water quality pollution status in Beibu Gulf of Guangxi, the single-factor pollution index method, organic pollution index method and comprehensive pollution index method were used to analyze and evaluate the water quality pollution based on the surface seawater survey data in Beibu Gulf of Guangxi from August 2021 (summer) and January 2022 (winter). The results showed that pH, dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) and dissolved oxygen (DO) in the surface seawater of Beibu Gulf in summer and winter exceeded the standard in varying degrees, and the main pollutants were DIN and DIP. Qinzhou Bay and Tieshan Port were the main sea areas with single factor exceeding the standard. In terms of organic pollution, there was only one severe pollution station in Qinzhou Bay in summer, and moderate pollution occurred in Qinzhou Bay and Tieshan Bay, accounting for 18.5% and 13.6% in summer and winter, respectively. The rest of the polluted sea areas appeared in Qinzhou Bay, Lianzhou Bay and Tieshan Bay at the same time. Good water quality in summer and winter accounted for only 3.7% and 22.7%, both of which located in the sea area of Weizhou Island. In terms of comprehensive pollution, no serious polluted waters were found. Only Qinzhou Bay was moderately polluted in summer, and mild pollution accounted for 40.7% and 31.8% in summer and winter, respectively. In summer, other sea areas except Weizhou Island were comprehensively polluted, and only Qinzhou Bay and Tieshan Port were comprehensively polluted in winter. On the whole, the over-standard rate of single factor, organic pollution and comprehensive pollution of water body are higher in summer than in winter, and higher in the bay than outside.