大风江口海域沉积物酸可挥发性硫化物、重金属分布及风险评价  

Distribution and Risk Assessment of Acid Volatile Sulfide and Heavy Metals in Sediments of Dafengjiang River Estuary

作　　者：徐程 杨斌 朱雪菁[2] 钟木凤 杨建文 亢振军[2] 宁志铭 XU Cheng;YANG Bin;ZHU Xuejing;ZHONG Mufeng;YANG Jianwen;KANG Zhenjun;NING Zhiming(College of Chemistry and Bioengineering,Guilin University of Technology,Guilin 541000,China;Guangxi Key Laboratory of Marine Disaster in the Beibu Gulf,Beibu Gulf University,Qinzhou 535011,China;Guangxi Laboratory on the Study of Coral Reefs in the South China Sea,Guangxi University,Nanning 530004,China)

机构地区：[1]桂林理工大学化学与生物工程学院,广西桂林541000 [2]北部湾大学,广西北部湾海洋灾害研究重点实验室,广西钦州535011 [3]广西大学,广西南海珊瑚礁研究重点实验室,广西南宁530004

出　　处：《环境科学研究》2020年第6期1530-1538,共9页Research of Environmental Sciences

基　　金：国家自然科学基金项目(No.41706083);广西自然科学基金项目(No.2017GXNSFBA198135);广西南海珊瑚礁研究重点实验室开放基金项目(No.GXLSCRSCS2018002)。

摘　　要：为了解广西北部湾典型亚热带主要入海河口区——大风江口海域沉积物重金属生物毒性生态风险现状,以2018年7月在该区域采集的10个采样点表层沉积物为基础,采用冷扩散法提取样本中酸可挥发性硫化物(acid volatile sulfides,AVS),并同步提取重金属(simultaneously extracted heavy metals,SEM),采用碘量法测定AVS含量,采用电感耦合等离子体原子发射光谱法测定同步浸提的Cr、Cu、Zn、Cd、Pb等5种重金属元素含量(同步提取的5种重金属含量之和用∑SEM表示),并利用∑SEM AVS比值法和∑SEM-AVS差值法进行沉积物重金属生态风险评价.结果表明:大风江口海域表层沉积物AVS含量范围在0.33~9.30μmol/g之间,平均值为(3.63±2.76)μmol/g,AVS含量呈现由河流向入海河口区域递减的趋势;∑SEM范围在2.12~27.08μmol/g之间,平均值为(7.61±7.32)μmol/g,∑SEM呈由河流向开阔海域先增加后递减的趋势;相比于其他海区,大风江口海域沉积物中AVS含量和∑SEM均较高.大风江口海域沉积物中AVS含量与溶出液pH(7.59~8.89)、沉积物氧化还原电位(E h)(-165~182 mV)均呈显著负相关,表明沉积环境中E h和pH越低,越有利于AVS的生成.大风江口及邻近海域表层沉积物中∑SEM AVS和∑SEM-AVS的变化范围分别为0.62~15.33和-3.49~22.90μmol/g.研究显示,大风江口海域表层沉积物中重金属具有潜在中等或高的毒性生态风险,应加强重金属污染防控.Ten surface sediment samples were collected from the Dafengjiang River Estuary(DRE),a typical subtropical estuary in the Guangxi Beibu Gulf,in July 2018,and were analyzed for acid volatile sulfides(AVS)and simultaneously extracted heavy metals(SEM)in order to understand the ecological risk of heavy metals.The concentrations of AVS were analyzed by iodimetry while the mass fraction of Cr,Cu,Zn,Cd and Pb were measured using an inductively coupled plasma atomic emission spectrometer(ICP-AES).The ecological risk assessment of heavy metals was evaluated through∑SEM AVS ratio and∑SEM-AVS differential method.The results showed that the concentrations of AVS ranged from 0.33 to 9.30μmol/g,with an average of(3.63±2.76)μmol/g,while the∑SEM ranged from 2.12 to 27.08μmol/g,with an average of(7.61±7.32)μmol/g.Although the contents of AVS showed a gradually decreasing trend from the riverine regions to the sea,∑SEM increased in the riverine area,and then decreased in the open sea area.Compared with other marginal seas in the world,the AVS and SEM in surface sediments of the DRE showed higher concentration characteristics.The pH(7.59-8.89)and oxidation-reduction potential(E h)(from-165 mV to 182 mV)were significantly correlated with AVS,suggesting that the low pH and E h were favorable to the formation of AVS in surface sediments of the study area.The variation ranges of∑SEM AVS and∑SEM-AVS were 0.62-15.33μmol/g and-3.49-22.90μmol/g in the surface sediments of the DRE and its adjacent waters,respectively.Preliminary studies indicated that the accumulation of heavy metals in surface sediments pose potential moderate-to-high ecological risk in the DRE and its adjacent waters.More attention is required to strengthen the heavy metal pollution monitoring in the study area.

关 键 词：酸可挥发性硫化物(AVS) 同步提取重金属 表层沉积物 生态风险 大风江口 

分 类 号：X55[环境科学与工程—环境工程]