珠江口表层海水中营养盐与表层沉积物中重金属的分布和影响的调查研究

发布时间：2018-06-05 19:17

本文选题：珠江口 + 营养盐　；参考：《湘潭大学》2016年硕士论文

【摘要】：珠江口地区经济发达,人口密集,生活污水及工业污染废水排放汇入珠江口海域,引起珠江口海域富营养化趋势增强和重金属污染问题日益严重。本文以珠江口海域作为研究区域,于2015年1月份和4月份进行两个航次的走航观测,采集表层水样及表层沉积物样品,对珠江口表层水体营养盐的含量和表层沉积物重金属的含量进行了分析。通过潜在性富营养化评价方法对调查区域的富营养化程度进行评价；同时,分别应用单因子污染指数法、地质累积指数法、潜在生态危害指数法对珠江河口区的潜在生态风险进行评价,分析了珠江河口水体和沉积物的污染状况以及潜在生态风险。研究结果可以为珠江口及近岸环境保护提供参考依据。主要结论如下：(1)珠江口表层海水中DIN含量平均值为0.953 mg/L,珠江口海域DIN以NO3--N为主,其次是NH4+--N,而NO2-N最低。PO43--P含量的平均值为0.014 mg/L。SiO32--Si含量的平均值为2.126 mg/L。由于受到陆源径流和海水稀释等因素的影响,各种营养盐的变化趋势基本都符合由北向南逐渐递减。珠江口表层海水Chla含量的平均值为5.548 μg/L。从Chla与营养盐之间的相关性分析可以看出,NO3-N是浮游植物生长最重要的环境因子。(2)综合两航次的潜在性富营养化评价结果,珠江口海域大部分采样站位都属于磷限制潜在性富营养(VIp营养级),各采样站位站位的N/P值普遍都大于60,有的站位甚至达到200以上,可以确定珠江口海域属于磷限制潜在性富营养化水平。(3)珠江口表层沉积物中Cr、Cd、Cu、Pb、Zn的平均含量分别为114.70mg/kg、 0.80 mg/kg、58.73 mg/kg、80.01 mg/kg、191.57 mg/kg,均高于《洋沉积物质量》(GB 18668-2002)的第一类沉积物质量标准限值,但未超过第二类标准值；Ni的平均含量为51.89 mg/kg,由于上述标准未给出Ni的相关评价标准,所以不予评价。6种重金属的含量变化趋势基本一致,由北向南逐渐降低,西部站位的含量高于东部站位。通过6种重金属的相关性分析发现,它们之间都有一定正相关性,表明它们具有一定的同源性；通过主成分分析发现,珠江口表层沉积物重金属来源主要受到人为活动的影响。(4)通过单因子污染指数与综合污染指数法、潜在生态指数法和地质累积指数法的评价显示,本次研究区域的沉积物环境已经受到一定程度的污染,其中Cd是目前珠江口表层沉积物中污染较严重的重金属污染物。
[Abstract]:In the Pearl River Estuary area , the eutrophication trend of the Pearl River Estuary and the heavy metal pollution have become more and more serious . In the Pearl River Estuary as the research area , the samples of surface water samples and surface sediments were collected , and the contents of nutrient salts and heavy metals in the surface sediments were analyzed .
Based on the correlation analysis between Chla and nutrient salts , the average contents of Cr , Cd , Cu , Pb and Zn in Pearl River Estuary are 1.95mg / L , 0.80mg / kg , 58.73 mg / kg , 80.01 mg / kg , 191.557 mg / kg , respectively .
The average content of Ni is 51.89 mg / kg . Since the above standard does not give the relevant evaluation criteria for Ni , the content change trend of six heavy metals is basically consistent , from north to south , the content of western station is higher than that of eastern station . Through the correlation analysis of six heavy metals , it is found that there is a positive correlation between them , indicating that they have certain homology ;
According to the analysis of principal components , the source of heavy metals in the surface sediments of the Pearl River Estuary is mainly influenced by man - made activities . ( 4 ) Through the evaluation of the single - factor pollution index and comprehensive pollution index method , the potential ecological index method and the geological accumulation index method , the sediment environment in this study area has been polluted to a certain extent , of which Cd is the heavy metal pollutant which has serious pollution in the surface sediments of the Pearl River Estuary .
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X55

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