广东省陆海氮污染空间排放特征及相关性分析

Spatial characteristics and correlation analysis of Nitrogen pollution from land and sea in Guangdong province

  • 摘要: 入海河流携带的陆源总氮(TN)是广东省近岸海域溶解无机氮(DIN)污染的主要来源,摸清陆域TN排放来源结构、排海压力及其主要影响因素,对广东省氮污染治理有重要意义。本文以广东省七大流域为研究区域,基于水质监测数据与污染源统计数据分析广东省氮污染空间分布特征、来源结构、排放强度及其区域差异,并利用Pearson相关分析,揭示陆海氮污染的主要影响因素。结果表明:(1)2020—2022年,广东省河流TN浓度范围为1.10~9.19 mg/L,TN高浓度点位主要分布于珠江三角洲流域、粤东诸河流域及东江流域的下游,枯水期TN浓度总体高于丰水期;(2)广东省TN主要污染来源是生活源(占比59.79%),其次为农业源(占比36.10%)。陆源氮污染排放压力强度与海域氮污染分布状况具有空间一致性,珠江三角洲流域污染物排放量最大,其岸段承载的排放压力也最大,对应的珠江口是广东省近岸海域劣四类水质分布的主要区域。人口规模是影响TN排放的主要因素。

     

    Abstract: Total nitrogen (TN) from land-based sources is the main source of dissolved inorganic nitrogen (DIN) pollution in coastal waters of Guangdong province. Clarification of the structure, discharge pressure and main influencing factors of nitrogen emissions from the land area is needed to manage marine nitrogen pollution. We utilized observation data of water quality and statistical data of pollution sources to analyze the Spatial characteristics, source structure, emission intensity and regional differences of nitrogen pollution in Guangdong Province. Pearson correlation analysis was used to reveal the main influencing factors of nitrogen emissions. The results show that: (1) The concentrations of TN are ranged from 1.10 mg/L to 9.19 mg/L in the rivers during 2020-2022. The high concentration sites of TN were mainly distributed in the river network area of the Pearl River Delta, the rivers in eastern Guangdong, and the lower reaches of the Dongjiang Rive. The total nitrogen concentration in low water period was higher than that in wet season. (2) Domestic sewage is the main source of TN pollution in Guangdong Province, which accounting for 59.79%, followed by agricultural pollution accounting for 36.10%. The distribution of marine pollution and the intensity of land-based nitrogen pollution emission are spatially consistent. There is a largest number of pollution emissions in the the the Pearl River Delta, the shoreline sections belonging to it carry the greatest emission pressure. Correspondingly, the Pearl River estuary is the primary zone in which the water quality inferior to Class Ⅳ. Population size is the main factor affecting TN discharge in this area.

     

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