钦州湾水质污染时空变化特征及驱动因素

于2015年4月和9月在钦州湾海域进行了2个航次的环境调查，获取了表层海水温度、盐度、pH、DO、COD、Chl a、石油烃、营养盐和重金属等指标数据，应用主成分分析法研究该海湾水质状况，并探讨影响该海区水质的主要驱动因子。通过主成分分析从18项调查指标中筛选提取出前4个主成分，可以解释原始变量信息73.68%的结果。主成分综合得分分析表明，钦州湾2015年4月水质污染比9月严重，空间分布上由内湾向外湾水质污染呈递减趋势，茅尾海水质污染严重。河流输入、鱼虾贝类养殖、浮游植物消长及水动力过程是影响钦州湾水质时空变化的重要因素。相关分析表明，影响钦州湾水质污染的主要驱动因子是氮营养盐、盐度、pH、Cd和Zn。陆源输入和养殖活动是主要污染源，应加强钦江、茅岭江的水环境保护，科学规划内湾养殖规模，进而改善钦州湾水质状况。

Spatio-temporal variation characteristics and driving factors of water pollution in Qinzhou bay

Two surveys were investigated in Qinzhou bay during April and September 2015 for collecting the surface seawater information on 18 environmental indicators including temperature, salinity, pH, dissolved oxygen, chemical oxygen demand, chlorophyll a, petroleum hydrocarbon, nutrients and heavy metal. Principal component analysis (PCA) was applied to analyze the collected data, and the potential driving variables effect the water quality were assessed. Four principal components were extracted from the 18 environmental variables, which explained 73.68% of the total variance in the original data set. The PCA indicated that pollution was more serious in the inner bay (Maowei sea) than that in the outer bay. The most serious pollution was in April, followed by September. River input, aquaculture, phytoplankton growth, and hydrodynamics might be the significant factors influencing the spatial-temporal variation of water quality in Qinzhou bay. The correlation analysis suggested that total nitrogen, salinity, pH, Cd and Zn were the main factors influencing the water quality. Terrestrial inputs and aquaculture activities were the main sources of the Maowei sea pollution. Management measures should be taken to protect environments along the Qinjiang River and Maolingjiang River and plan scientifically cultivation scale in order to improve the water quality in the Qinzhou bay.