【作者】 杨华；

【导师】 郭送军；

【作者基本信息】 广西大学 ， 环境科学与工程， 2017， 硕士

【摘要】 珊瑚礁区生态系统对海洋生物多样性保护以及维护区域和全球生态健康均具有极其重要的作用,然而随着人类活动的加剧,近海岸重金属污染问题日渐突出,严重影响着珊瑚礁生态系统健康。因此,本文选择南海北部的涠洲岛、三亚鹿回头和雷州半岛灯搂角珊瑚礁区,以及广东大亚湾珊瑚群落发育的海域,分析了海水、沉积物、珊瑚骨骼重金属(Hg、As、Cu、Cd、Cr、Pb和Zn)的含量分布特征及生态风险,研究的主要结论如下:(1)南海北部4个珊瑚生长区海水中重金属平均含量依次为6.92(Zn)、1.05(Pb)、0.89(Cr)、0.80(As)、0.77(Cu)、0.079(Cd)、0.055(Hg)μg/L。鹿回头与灯楼角珊瑚生长区中Pb、Hg含量较高,其平均含量均高于一类海水水质标准;大亚湾珊瑚生长区中Hg含量较高,其平均含量高于一类海水水质标准;涠洲岛珊瑚生长区中各重金属含量均低于一类海水水质标准。通过综合指数法(WQI)评价得出,4个区域WQI值均小],这表明重金属处于基本无污染水平。(2)4个珊瑚生长区沉积物中重金属平均含量分别为15.55(Zn)、8.15(Cr)、5.66(Cu)、3.75(Pb)、3.14(As)、0.07(Cd)、0.06(Hg)μg/g,灯楼角礁区中As、Cu、Cr、Pb、Zn的含量均显著高于其余3个礁区,而Hg、Cd的含量四个礁区基本持平,4个区域中各元素含量均未超过海洋沉积一类标准。生态危害指数法(ERI)评价得出,4个区域ERI值均小于150,表明重金属综合潜在生态风险处于较低水平。就单个元素对ERI的贡献率而言,Hg元素对涠洲岛、大亚湾、鹿回头、灯楼角4个区域的综合潜在风险指数的贡献率分别达69.14%、61.43%、76.28%、56.55%,因此,Hg为4个区域的主要潜在风险因子。(3)涠洲岛5种珊瑚骨骼中各元素的平均含量从大到小依次为22.66(Zn)、2.93(Cu)、1.90(Pb)、0.70(Cr)、0.14(Cd)μg/g。大亚湾 10种珊瑚骨骼中各元素的平均含量从大到小依次为34.77(Zn)、6.02(Cu)、2.29(Pb)、1.50(Cr)、0.16(Cd)μg/g。鹿回头9种珊瑚骨骼中各元素的平均含量从大到小依次为 10.68(Zn)、1.12(Cu)、0.56(Pb)、0.32(Cr)、0.04(Cd)μg/g。灯楼角6种珊瑚骨骼中各元素的平均含量从大到小依次为11.48(Zn)、1.96(Cu)、1.04(Pb)、0.70(Cr)、0.13(Cd)μg/g。单因素方差分析得出,涠洲岛礁区Cd元素的含量在珊瑚种之间存在着显著差异,其余4种重金属元素未体现出珊瑚的种间差异性;大亚湾、鹿回头、灯楼角礁区中5种重金属元素均未体现出珊瑚的种间差异性,这说明区域环境条件是影响珊瑚骨骼中重金属含量的重要因素。珊瑚对重金属的富集系数显示,4个礁区均表现为珊瑚对Cu、Zn的富集系数较高,对Cr的富集系数较低,这表明珊瑚对重金属的富集具体一定的选择性。通过区域对比可知,涠洲岛、大亚湾、鹿回头、灯楼角4个礁区珊瑚骨骼中Cu、Cd、Cr、Pb、Zn含量均处于相对较低水平,值得注意的是,涠洲岛、大亚湾礁区中Pb含量与大堡礁相比,高出其4.5～13.78倍,需引起关注。(4)南海北部珊瑚生长区重金属来源利用相关性、聚类分析,推测其可能主要来源于工业排污、船舶运输、旅游活动、养殖污染及农业生产等。更多还原

【Abstract】 The coral reef ecosystem plays a very important role in marine biodiversity protection,the maintenance of regional and global ecological health.With the intensification of human activities,coastal heavy metal pollution problems have become increasingly prominent and seriously affected the coral reef ecosystem health.This article focused on the analysis of the distribution characteristics and ecological risk of heavy metals(Hg,As,Cu,Cd,Cr,Pb and Zn)in the seawater,sediments and coral skeletons,the samples of which were collected from northern South China sea including Weizhou Island,Luhuitou in Hainan Islands,Dengloujiao in Leizhou Peninsula and the coral communities in Daya Bay in Guangdong province.The main research conclusions are as follows:(1)The average contents of heavy metals in the seawater of the 4 coral growth regions were 6.92(Zn),1.05(Pb),0.89(Cr),0.80(As),0.77(Cu),0.079(Cd)and 0.055(Hg)μg/L.The average contents of Pb and Hg were higher in Luhuitou and Dengloujiao than the other two regions and exceeded the First-Classed Seawater Quality Standard of China.In addition,the average content of Hg element in Daya Bay was beyond the First-Classed Seawater Quality Standard.The results of comprehensive index method(WQI)showed that:the WQI values of the 4 regions were less than 1,and the heavy metal content was in a low pollution level.(2)The average contents of heavy metals in sediments of the 4 coral growth regions were 15.55(Zn),8.15(Cr),5.66(Cu),3.75(Pb),3.14(As),0.07(Cd)and 0.06(Hg)μg/g.The contents of As,Cu,Cr,Pb and Zn in Dengloujiao region were significantly higher than those in the other 3 regions.And the contents of Hg and Cd in the 4 reef areas were basically the same.The contents of all the heavy metals did not exceed the First-Classed request of the marine sedimentary evaluation criterion.The potential ecological risk index(ERI)evaluation showed that:the ERI values of 4 regions were less than 150,which indicated that the potential ecological risk of heavy metals was at a low level.For the single element on the contribution rate of ERI,the comprehensive potential risk index contribution rate of Hg element were 69.14%,61.43%,76.28%and 56.55%in Weizhou Island,Daya Bay,Luhuitou,Dengloujiao.Therefore,Hg was the main potential risk factors.(3)In Weizhou Island,the average contents of heavy metals in 5 coral skeletons were 22.66(Zn),2.93(Cu),1.90(Pb),0.70(Cr)and 0.14(Cd)μg/g.In Daya Bay,the average contents of heavy metals in 10 coral skeletons were 34.77(Zn),6.02(Cu),2.29(Pb),1.50(Cr)and 0.16(Cd)μg/g.In Luhuitou region,the average contents of heavy metals in 9 coral skeletons were 22.66(Zn),2.93(Cu),1.90(Pb),0.70(Cr)and 0.14(Cd)μg/g.In Dengloujiao region,the average contents of heavy metals in 6 coral skeletons were 11.48(Zn),1.96(Cu),1.04(Pb),0.70(Cr)and 0.13(Cd)μg/g.Single factor analysis of variance showed that there was no significant difference between 4 heavy metals except Cd in Weizhou Island.There were no significant differences between 5 heavy metals in other 3 coral growth regions.This shows that the regional environmental conditions are important factors affecting the content of heavy metals in coral skeletons.The enrichment coefficient showed that the enrichment coefficient of Cu and Zn were higher in this 4 coral growth regions and lower enrichment coefficient of Cr.This indicates that the enrichment of heavy metals by coral was specifically selective.Through regional comparison,Cu,Cd,Cr,Pb and Zn content in coral skeleton were in latively low level in 4 coral growth regions.The content of Pb in Weizhou Island and Daya Bay was 4.5-13.78 times of that in the Great Barrier Reef,which should arouse more attention.(4)Heavy metals in the coastal coral growth regions of northern South China Sea may be mainly derived from industrial sewage,shipping,tourism,aquaculture and agricultural activities.更多还原