粤东南澳岛近岸海域表层沉积物碳、氮、磷分布特征及污染评价

Distribution Characteristics and Pollution Assessment of Carbon,Nitrogen and Phosphorus in Surface Sediments of Nan'ao Island,Eastern Guangdong Province

关键词:  南澳岛近岸海域  表层沉积物  总有机碳  总氮  总磷  分布规律  污染评价  影响因素

Key words:  Nan'ao Island coastal  surface sediments  total organic carbon  total nitrogen  total phosphorus  distribution characteristics  pollution assessment  influencing factors

摘要:

本研究旨在了解粤东南澳岛近岸海域表层沉积物中总有机碳(TOC)、总氮(TN)和总磷(TP)的分布情况及污染状况，为该海域环境保护和治理提供科学依据。实验以粤东南澳岛近岸海域32个表层沉积物样品为研究对象，分析其TOC、TN和TP的含量及分布特征，采用单因子污染指数法和内梅罗综合污染指数法对TOC、TN和TP的污染程度进行评价，基于表层沉积物中TOC和TN的摩尔比值探讨其有机质的来源，并在此基础上探讨表层沉积物中TOC、TN和TP的富集影响因素。研究结果表明，南澳岛近岸海域表层沉积物中TOC、TN和TP含量分别为0.180%-0.920%、0.006%-0.210%和0.015%-0.059%，表现出南澳岛南北两侧高、东西两侧低，南澳岛以东由岸及海，含量逐渐降低的分布特征；与国内相邻海域相比，南澳岛近岸海域表层沉积物TOC、TN和TP含量处于较低水平。根据TOC和TN摩尔比值推断，南澳岛近岸海域表层沉积物中有机质以海源和陆源混合输入为主。南澳岛近岸海域表层沉积物未受TOC和TP污染，但大部分区域受到TN污染；40.6%的表层沉积物处于较清洁及以上水平，59.4%的表层沉积物为轻度污染到中度污染状态，未发现有重度污染情况。南澳岛近岸海域表层沉积物中TOC、TN和TP的含量水平主要受水动力、粒径以及人为因素影响，人为因素主要为渔业养殖和陆源排污。

Abstract:

This study aims to understand the distribution and pollution status of Total Organic Carbon (TOC),Total Nitrogen (TN) and Total Phosphorus (TP) in the surface sediments of the coastal area of Nan'ao Island in southeast Guangdong Province,and to provide scientific basis for environmental protection and management of the sea area.In this article,32 surface sediment samples collected from the coastal waters of Nan'ao Island in the southeast of Guangdong Province were taken as the research objects,and the contents and distribution characteristics of TOC,TN and TP were analyzed.The pollution degree of TOC,TN and TP was evaluated by the single factor pollution index method and Nemerow comprehensive pollution index method.Meanwhile,the source of organic matter in the surface sediment and the enrichment factors of TOC,TN and TP in the surface sediments were discussed based on the molar ratio of TOC to TN.The results show that the contents of TOC,TN and TP in the sediments of Nan'ao Island coastal area are 0.180%-0.920%,0.006%-0.210%,and 0.015%-0.059%,respectively,indicating that high on the north and south sides of the island,and low on the east and west sides.On the east side of Nan'ao Island from the shore to the sea,the content is gradually decreasing.Compared with the adjacent sea areas in China,the TOC,TN and TP contents of surface sediments in the coastal areas of Nan'ao Island were at a low level.According to the molar ratio of TOC and TN,it is inferred that the organic matter in the surface sediments of the offshore area of Nan'ao Island is dominated by the mixed input of marine and terrestrial sources.The surface sediments in the offshore area of Nan'ao Island are not polluted by TOC and TP,but most of the area is polluted by TN.40.6% of surface sediments are at relatively clean and above levels,59.4% of the surface sediments are mildly polluted to moderately polluted,and no severe pollution is found.The content levels of TOC,TN and TP in the surface sediments of the offshore area of Nan'ao Island are mainly affected by hydrodynamics,particle size and human factors.The human factors are mainly fishery aquaculture and terrestrial sewage discharge.