近岸海域水质污染因子空间特征和来源研究——以浙南瑞安市近岸海域为例

Spatial characteristics and sources of water pollution in nearshore area:A case study on the nearshore area of Ruian in southern Zhejiang

近岸海域的环境污染特征和污染来源是区域海洋环境保护的两大关键问题。以浙南瑞安市近岸海域为例,于2020年5月开展16个站位的海洋环境调查和表层海水采样,通过室内分析测试,共获得12项水质参数(盐度、溶解氧、化学需氧量、无机氮、活性磷酸盐、汞、镉、铅、铬、砷、锌、铜)数据,采用污染评价、多元数理统计分析(通过SPSS实现)及空间异质性分析(通过ArcGIS实现)等方法,较深入地探究了瑞安市近岸海域环境污染的空间特征和污染来源。研究结果表明,瑞安市近岸海域水质总体情况良好,各水质参数变异系数较大,部分海域的无机氮和活性磷酸盐明显超标。采用营养指数法进行评价,得到飞云江近口段和河口段的富营养化最严重;采用氮磷比法进行评价,得到北麂列岛周边海域发生赤潮灾害的风险更大。依据聚类分析结果,可将研究海域分为污染特征各异的4个区域。依据主成分分析结果,推测瑞安市近岸海域水体中营养盐、化学需氧量的主要污染源为农业,而重金属污染的可能来源为电镀、零件加工企业和船舶等。

Pollution characteristics and pollution sources of nearshore environment are two key issues for regional Marine environment protection.In this paper,the nearshore area of the Ruian in southern Zhejiang were taken for case study.In May 2020,marine environment investigation and surface water samplings at 16 stations,and analysis of 12 water quality parameters(Salinity,Dissolved Oxygen,Chemical Oxygen Demand,Dissolved Inorganic Nitrogen,Dissolved Inorganic Phosphate,Mercury,Cadmium,Lead,Chromium,Arsenic,Zinc and Copper)for each station were carried out.The pollution evaluation,multivariate statistical methods(using SPSS)and spatial analysis(using ArcGIS)were used to explore the spatial characteristics and pollution sources.The results showed that the sea water quality of the Ruian nearshore area was generally good;however dissolved inorganic nitrogen and dissolved inorganic phosphate in water exceeded the Chinese Standard seriously(worse than the fourth class)in some areas.The evaluation results using the eutrophication index method showed that the eutrophication was the most serious in the near estuarine area of Feiyun River.The evaluation results using the nitrogen phosphorus ratio showed that there was a great risk of red tide around the Beiji islands.According to the results of cluster analysis,the study area can be divided into four parts with different pollution characteristics.According to the results of principal component analysis,the main source of nutrition and chemical oxygen demand are probably due to agriculture,while heavy metal pollution may come from electroplating,parts processing and shipping.