珠江口表层沉积物重金属潜在生态风险及生物富集评价

基于2019年珠江口海域表层沉积物Hg、As、Cu、Pb、Cd、Zn、Cr的分析结果对沉积物重金属污染现状及潜在生态风险进行评价,结合总有机碳TOC、粒度等探讨海域重金属的污染特征及来源,并评估各项重金属元素在底栖生物体内的富集程度。结果表明,所有站点表层沉积物中Hg和Cr含量均符合一类海洋沉积物质量标准,As、Cd、Pb、Cu和Zn满足二类以上标准。Hg和Cd为主要生态风险贡献因子,均有部分站点属较高和中等潜在生态风险范畴,综合潜在生态风险指数(RI)均值属中等潜在生态风险范畴,近岸海域尤其北部、西部RI值较高。7项重金属含量两两间呈极显著正相关,显示重金属污染具有相近来源,且重金属含量均与TOC含量呈极显著正相关,而与粒度无明显相关性。7项重金属元素在甲壳类和鱼类体内均没有富集,Cd在双壳类体内出现较强富集。     

长江口海域表层沉积物重金属元素的潜在生态风险评价

根据三峡水库一期蓄水3 a后(2006年)长江口海域表层沉积物样品中元素(Cd,Cr,Cu,Pb,Zn,Al,As,Ca和Sr等)质量比和黏土组分百分含量,采用Hakanson潜在生态风险指数法,分析了长江口海域表层沉积物中重金属元素(Cd,Cr,Cu,Pb,Zn和As)的污染程度,评价了长江口海域表层沉积物的环境质量现状,定量分析了长江口海域表层沉积物的潜在生态风险程度,并结合2003年的资料,讨论了三峡水库一期蓄水3 a后长江口海域的环境变化。结果表明,长江口海域表层沉积物环境质量状况良好,6种重金属元素的污染程度排序为:AsCrCdZnCuPb;表层沉积物的潜在生态风险程度为"轻度",6种重金属元素的潜在生态风险程度排序为:CdAsCuCrPbZn。从区域差异来看,杭州湾口外泥质区和长江口外东北偏北海域表层沉积物中重金属元素(As,Cr,Zn,Cu和Pb)的污染指数和潜在生态风险指数均出现相对高值。从元素差异来看,Cd的污染指数和潜在生态风险指数高值区的分布明显异于其他重金属元素,说明Cd存在与其他重金属元素不同的富集机制,很可能是因为Cd更易受悬浮体浓度、有机质含量以及水体盐度的影响。与2003年的资料相比,三峡水库一期蓄水3 a后(2006年)表层沉积物总体潜在生态风险程度和重金属元素(除Cd之外)潜在生态风险指数的高值区均未发生显著变化。     

惠州海域沉积物重金属污染与潜在生态风险

为了解惠州近岸海域沉积物重金属的污染特征,于2016-08采集表层沉积物12个,分析了沉积物中Cu,Zn,Pb,Cd,Cr,Hg,As的含量,采用地积累指数法(Igeo)和潜在生态风险指数法(Eir)进行重金属污染现状和生态风险评价。结果表明:参照国家《海洋沉积物质量》标准(GB 18668—2002),惠州近岸海域沉积物质量整体良好,沉积物中7种重金属元素含量符合第一、二类标准。地积累指数法和潜在生态风险指数法评价结果显示,惠州近岸海域沉积物7种重金属元素的污染程度为CdZnAsCuPbHgCr,Cd在所有样点都是偏中度污染及以上,Pb,Cr,Hg三种元素皆为无污染;沉积物中7种重金属元素的潜在生态风险系数(E_r~i)由高到低依次为CdHgAsCuPbZnCr,Cd具有极强生态风险,沉积物重金属处于强生态风险状态(RI平均值为370.22),Cd是主要的生态风险贡献因子。沉积物中Cu,Zn,Pb,Cr四种元素显著相关,具有同源性;有机碳显著作用于沉积物重金属含量和分布。     

环雷州半岛近海表层沉积物有机碳分布及其控制因素分析

对环雷州半岛近海43个海底表层沉积物的总有机碳(TOC)、总氮(TN)、沉积介质条件(包括沉积物粒度)进行了分析,探讨了沉积物TOC、TN的区域分布特征以及影响有机碳分布的主要因素。结果表明,环雷州半岛近海海域海底表层沉积物有机碳含量在0~0.79%之间,平均值为0.26%。与中国其它近海海域相比,环雷州半岛大部分近海区域海底表层沉积物有机碳含量明显偏低,为有机质贫乏区,仅雷州半岛西南部流沙湾近海海域为TOC相对高值区。总氮含量也不高,在0.011%到0.100%之间,TOC与TN存在较强的正相关性,且平面上TOC与TN分布高度重合,显示氮元素主要以有机化合物形式存在。TOC/TN比值在5.1~14.3之间,表明沉积有机质具有陆源输入和海洋自生来源的混合特征,但以雷州半岛西侧北部及东侧中部海域受陆源有机质输入影响更大。大多数站位海底沉积物粒度构成以粉砂为主、粘土次之,少数站位以砂质沉积为主。沉积物有机碳含量与粘土及粉砂含量呈弱正相关性,与沉积物pH值、Eh值及砂含量呈弱负相关性,这表明海底沉积物有机质丰度受有机质来源输入、海底氧化还原状态和沉积水动力条件(沉积物粒度)等因素综合控制。     

渤海西北近岸海域表层沉积物重金属污染及评价

对取自渤海西北近岸海域的189个表层沉积物进行了重金属元素、粒度和有机碳(TOC)分析,查明了研究区重金属的分布特征和潜在污染水平。结果表明,As、Cr、Pb、Zn的空间分布比较均衡,Cd、Cu、Hg的空间变异系数较大,低值区都集中在昌黎沿海海域,高值区基本都集中在沿岸河口位置,总体上呈现出由西北部沿岸海区向东南降低的趋势。Cu、Cr、Pb、Hg与黏土含量、TOC之间表现出较强相关性。Pearson相关分析表明,黏土是重金属元素的主要载体,TOC是控制重金属元素的次要因素。根据地质累积指数法(Igeo)评价得出,渤海西北近岸海域仅在个别区域受到轻微污染,大部分区域沉积物底质环境良好。重金属富集因子(EF)显示研究区沉积物污染程度明显高于Igeo计算结果,多数重金属元素均处于中度污染水平,这可能与计算EF值时所取的区域背景值存在偏差有关。两种重金属元素评价方法同时表明Hg元素在沿岸河口位置存在一定程度污染,这与陆上人类经济活动向河口排放的污染物质经河流排入海有直接关系,说明人类经济活动给沿岸水域造成了一定程度的污染。     

岚山港临时海洋倾倒区表层沉积物重金属污染分布及影响因素分析

以2009年9月岚山港临时海洋倾倒区表层沉积物监测数据为基础,分析了该倾倒区海域表层沉积物重金属污染分布情况,发现该倾倒区海域表层沉积物重金属Cu、Pb、Zn、Cd、Cr、Hg污染分布大致表现为倾倒区范围内含量高,倾倒区外围含量低的趋势,可能是疏浚物的倾倒造成的这种分布特征。分析了岚山港临时海洋倾倒区表层沉积物重金属含量与有机碳、粒度的相关性,发现重金属含量与有机碳含量具有较高的正相关性,其中Cr与有机碳含量显著相关(P<0.01),重金属含量与粒度(沉积物黏土含量)呈正相关性。     

珠江口和北部湾附近海域沉积物重金属生态风险比较

文章对比分析了珠江口和北部湾海域附近沉积物重金属元素Zn、Pb、Cu、Cr和沉积物粒度之间的相关性,用沉积物富集系数法和潜在生态危害指数法对两个海域海底沉积物的4种重金属元素污染程度和生态风险进行了评价。结果表明,在黏土和粉砂沉积物中重金属富集程度大。Cu在两个区域均达严重污染程度,Zn、Pb、Cr在珠江口沿岸均达到中等污染程度,在北部湾部分区域达到中等污染程度。珠江口的潜在生态风险等级由低级到高级不等,北部湾生态风险等级均为低级。     

三亚东部近岸海域表层沉积物重金属元素地球化学特征及环境质量评价

本文对三亚东部近岸海域表层沉积物中7种重金属元素的地球化学特征和空间分布特征进行了研究,并应用地积累指数法和尼梅罗综合指数法对各重金属的污染程度进行了评价。研究发现, 三亚东部近岸海域表层沉积物中重金属含量总体较低,符合《海洋沉积物质量》一类标准,大多数重金属元素含量的空间分布主要受元素的“粒度控制律”制约,其物质来源主要为陆源细粒沉积。地积累指数法和尼梅罗综合指数法的评价结果均表明,研究区表层沉积物的重金属未达到污染程度,属清洁状态,环境质量良好。     

南海西北部浅海沉积物重金属污染的综合评价

利用在南海西北部北部湾和海南岛周边海域采集的492个站位的底质沉积物样品,以同一海区内同时采集的柱状样品的底层样品和"清洁区"样品中各重金属元素含量值作为背景值,运用潜在生态危害指数法、沉积物富集系数法和ArcGIS软件,对其Cd、Zn、Pb、Cu和Crs种重金属元素分布特征及其上述2种污染指数的分布图进行了分析和比较...     

曹妃甸表层沉积物和底栖生物重金属的污染特征与生物积累

利用2014-06曹妃甸近岸海域14个采样站位沉积物和底栖生物体7种重金属(Cu,Pb,Zn,Cd,Cr,Hg和As)单因子污染指数、富集系数、潜在生态风险因子和生物-沉积物积累因子,评估了曹妃甸近岸海域表层沉积物重金属的污染现状、潜在生态风险水平和生物-沉积物积累程度。结果表明:曹妃甸近岸海域表层沉积物中重金属元素含量大小顺序为ZnCrPbCuAsCdHg;空间分布上呈现靠近曹妃甸填海区域含量高、远离其区域含量低的趋势。重金属元素污染程度由高到低为Cd,Hg,Zn,Pb,Cu,Cr,As,其中Cd的污染程度为轻微污染,其余重金属元素富集污染程均为无污染。综合潜在生态风险等级"较低"水平,其中Cd元素是较大的潜在风险因子。底栖生物生物体重金属元素含量大小顺序依次为ZnCuAsCdCrHgPb,Cd在2种双壳类贝类生物体内具有较强的累积作用,是沉积物重金属含量的6.64倍,其余均显示没有累积。     

Grain size composition and transport of sedimentary organic carbon in the Changjiang River (Yangtze River) Estuary and Hangzhou Bay and their adjacent waters

Surface sediments from the Changjiang River(Yangtze River) Estuary,Hangzhou Bay,and their adjacent waters were analyzed for their grain size distribution,organic carbon(OC) concentration,and stable carbon isotope composition(δ13C).Based on this analysis,about 36 surface sediment samples were selected from various environments and separated into sand(0.250 mm,0.125–0.250 mm,0.063–0.125 mm) and silt(0.025–0.063 mm)fractions by wet-sieving fractionation methods,and further into silt-(0.004–0.025 mm) and clay-sized(0.004mm) fractions by centrifugal fractionation.Sediments of six grain size categories were analyzed for their OC andδ13C contents to explore the grain size composition and transport paths of sedimentary OC in the study area.From fine to coarse fractions,the OC content was 1.18%,0.51%,0.46%,0.42%,0.99%,and 0.48%,respectively,while theδ13C was –21.64‰,–22.03‰,–22.52‰,–22.46‰,–22.36‰,and –22.28‰,respectively.In each size category,the OC contribution was 42.96%,26.06%,9.82%,5.75%,7.09%,and 8.33%,respectively.The OC content in clay and fine silt fractions(0.025 mm) was about 69.02%.High OC concentrations were mainly found in offshore modern sediments in the northeast of the Changjiang River Estuary,in modern sediments in the lower estuary of the Changjiang River and Hangzhou Bay,and in Cyclonic Eddy modern sediments to the southwest of the Cheju Island.Integrating the distribution of terrestrial OC content of each grain size category with the δ13C of the bulk sediment indicated that the terrestrial organic material in the Changjiang River Estuary was transported seaward and dispersed to the Cyclonic Eddy modern sediments to the southwest of the Cheju Island via two pathways:one was a result of the Changjiang River Diluted Water(CDW) northeastward extending branch driven by the North Jiangsu Coastal Current and the Yellow Sea Coastal Current,while the other one was the result of the CDW southward extending branch driven by the Taiwan Warm Current.     

冲绳海槽中南部柱状沉积物氧化还原敏感元素赋存机理与环境指示意义

沉积物中氧化还原敏感元素（Redox Sensitive Element,RSE）含量变化是上覆水体氧化还原环境良好的替代指标。本文通过冲绳海槽中南部两个柱状沉积物（深度:30 cm）粒度、总有机碳、总氮及其同位素含量和氧化还原敏感元素含量等指标,探究复杂环境背景下冲绳海槽柱状沉积物中RSE的赋存机理与环境指示意义。研究发现,柱状沉积物中除了Cr亏损,其他RSE均显示有不同程度的富集。“粒控效应”对冲绳海槽柱状沉积物的RSE含量影响较小;分析可知,海水表层生产力是影响沉积物氧化还原环境的主要因素,通过Mn（氢）氧化物的吸附或解吸附作用实现RSE的富集与亏损。δCe、V/Cr、Ni/Co和V/（V+Ni）等指标指示沉积物整体处于氧化?弱氧化环境。沉积物中Mn元素通过还原作用以Mn2+形式向上扩散,在25～30 cm处被含氧间隙水氧化富集形成锰峰,指示柱状沉积物0～25 cm处为氧化环境,25～30 cm处为弱氧化环境。     

海南洋浦湾近百年来人与自然相互作用下的环境沉积记录

2005年8月在海南洋浦湾内湾取得1根柱状样,在铅-210定年的基础上分析沉积物粒度、总有机碳含量及其同位素值(δ13C)、总氮含量及其同位素值(δ15N)、生物硅含量、重金属(镍、镉、铬、铜、锌、铅)含量及有机氯农药(六六六、滴滴涕)含量等参数发现,111cm至表层,沉积物中有机碳、总氮、生物硅含量升高,特别是从45cm至表层,它们的含量明显增加,说明该湾内有富营养化趋势。由有机碳与总氮的原子比和有机碳同位素指示的物源信息可知,该湾内有机质来源为藻类和陆源脉管植物的混合,且以陆源输入为主。陆源有机碳含量与总有机碳含量的相关系数为0.917。自23cm至表层有机碳同位素明显偏轻,氮同位素偏重。从111cm至表层,重金属和有机氯农药含量升高。综合分析各环境指标可知,洋浦湾近百年来环境演变可分为三个时期,即20世纪70年代以前、70年代至90年代、90年代至21世纪初,洋浦湾经历了未污染期、轻度污染期、显著污染期。     

Sources and distributions of terrigenous organic matter in a mangrove fringed small tropical estuary in South China

The sources and distributions of terrigenous organic matter (OM) were investigated in a small tropical estuary in the Hainan Island, South China. Plants, suspended particulate matter (SPM), and surface sediments samples in the estuary and coast were collected. Bulk properties [organic carbon (OC%), total nitrogen (TN%), stable carbon isotope (δ13C) and grain size] and lignin phenol concentrations were measured. OC% of mangrove plants was (43.4 ± 2.1)%, which is similar to the values reported for mangrove plants in other regions. OC% of sediment samples ranged from 0.07% to 1.42%, and they were related to the sediment texture. Lignin phenols in the sediment ranged from 5.16 mg/100 mg OC in the uppermost station to 0.51mg/100mg OC in the coast. The molar ratio of organic carbon to total nitrogen (C/N) (～7) and δ 13 C (～-31.1×10-3 ) of riverine SPM revealed that the major OM sources of riverine SPM were aquatic OM (phytoplankton and/or bacteria). Moreover, the lower lignin concentration (Λ8) and higher (Ad/Al)v of lignin phenols suggest that terrestrial OM in riverine SPM were mainly from soil. Furthermore, C/N ratio, δ13C and lignin phenols reveal that mangrove plants were the predominant OM sources of mangrove surface sediment. Based on the δ13C and lignin phenols, it can be concluded that the major OM sources in estuarine and coastal surface sediments were marine phytoplankton, riverine SPM and mangrove surface sediment. In addition, the higher (Ad/Al)v of lignin phenols in those coastal sediments indicate that seagrass might be a potential OM source in coastal sediments, however, the lower (Ad/Al)v in the estuarine sediments in turn suggests that seagrass could not be transported to the mangrove fringed region. A three-end-member model which is based on lignin concentrations and δ13C was applied to evaluate the contribution of mangroves to the organic matter preserved in the surface sediments. Around the mangrove fringed region, mangrove could contribute more than 50% to the sedimentary OM, and this value is much higher than riverine OM. Nevertheless, mangrove OM could not be efficiently transported to the coastal region. Our study suggests that mangrove forest is an important OM source in this small estuary.     

海南小海表层沉积环境及重金属污染综合评价

利用2008年在海南小海采集的30个表层沉积物样品,对其进行了TP、TN、TOC、石油类和Hg、Cd、Cu、Pb、Zn、Cr、As重金属元素含量的测定,并采用综合污染指数法和潜在生态危害指数法对该区重金属的污染程度进行了评价,结果显示:(1)研究区表层沉积物中TP含量呈中部高沿岸带低的特征,这可能是由于沿岸带初级生产力高于小海中部,所消耗的磷营养盐较多的缘故;TOC和TN的含量则表现为与TP含量分布相反的特征,即沿岸带高而中部低,这可能是由于沿岸带人为活动对小海沿岸碳、氮元素含量的影响较大的缘故。Hg、Cd、Cu、Pb、Zn、Cr和As 7种重金属元素均表现出在小海中部附近海域和北坡镇沿岸带出现高值,而在小海北边入口处和梅开-英豪沿岸带出现低值的分布特征,这可能与在北坡镇附近的工业区排水时向该海域输入了含有这些重金属元素的污染物所致,而其它区域则受工业排污影响较小,也可能与入海口的潮汐水动力的稀释作用有关。(2)研究区综合污染指数(ISQJ)、潜在生态危害污染指数(ERI)的最大值分别为2.283和240.0,平均值也较高,分别达1.494和151.0,各重金属元素的潜在生态危害系数(Eri)大小顺序为:Hg>Cd>Pb>As>Cu>Cr>Zn,反映出研究区将达到中等污染程度的现状,而某些海域的污染程度已达到重污染水平,研究区受Hg和Cd元素污染较为严重。由此可见,小海的沉积环境已受到较为严重的破坏,未来该海域应该重视重金属Hg和Cd元素的污染治理,以避免小海沉积环境的进一步恶化。     

海南岛东南浅海表层沉积物粒度特征及沉积环境

对海南岛东南浅海377组表层沉积物样品(平均水深112.3 m)开展粒度测定及沉积物类型划分,并运用统计规律及沉积输运趋势分析,探讨了底质沉积物分布格局与物质来源及沉积动力环境关系。结果表明,海南岛东南浅海沉积物类型复杂,共分布13种沉积物类型,粒度组成以粉砂和砂为主,平均粒径均值为5.73Φ,优势粒级为细粉砂级(6~8Φ),分选差。不同海域沉积物粒径差异明显,北部近岸以含砾沉积为主,中部呈NE-SW向的砂质沉积区(水深80~120 m),西南近岸滨海、北中部海域以及东南部海域多为粉砂、黏土沉积。结合地理位置、沉积物源及水动力条件差异,研究区划分为3个沉积区:I区主要以含砾粗颗粒沉积为主,受控于海南岛上径流及强风浪作用,物质来源以万泉河等河流输运及岸线侵蚀物质为主,强动力(高能)沉积环境;II区以砂沉积为主,受到表层流及风浪等共同影响,可能主要是残留滨海沉积混入了海南岛径流及岸线侵蚀、少量珠江流域及外海复杂来源等现代细粒物质的混合沉积,中等动力沉积环境;III区以细粒沉积为主,主要受华南近岸流、风浪作用及南海暖流影响,推测物质来源主要为海南岛河流输入、岸线侵蚀及复杂外海来源细粒物质的加入,弱动力(低能)沉积环境。     

The Functions of China Marginal Sea Sediments in the Cycle of Biogenic Elements

The contents of biogenic elements in China marginal sea sediments are related to their grain sizes, river transport, et al. In general, the finer the grain size is, the higher the contents of organic matter and OC, N, P are, the lower the contents of S and Si are. The biogeochemical environments of sediments are related to Eh, pH, temperature content of OC,Fe3 /Fe2 radio, water dynamics condition, grain size of sediment, S system in sediment interstitial waters, et al., and they influence the early diageneses and cycle of biogenic elements in sediments. In most regions of China marginal sea, the flux directions of S2-, HS-,3- NH4 H4SiO4, PO4 , across the sediment-water interface are from sediment to the overlying seawater, the flux directions of SO42-, HCO3-, NO3-, NO2- across the sediment-water interface are from the overlying seawater to sediment. The irrigation of living things is important in the cycle of the biogenic elements across sediment-water interfaces.     

台湾海峡西部沉积物中碳的来源及埋藏

根据2005年夏季航次观测的沉积物中总有机碳(TOC)、无机碳(CaCO3)、总氮(TN)、悬浮体颗粒有机碳(POC)、沉积物粒度数据得出,台湾海峡西部表层沉积物TOC质量分数的范围为0.01～1.79,平均值为0.37±0.24,略高于20多年前台湾海峡南部海区,而低于台湾海峡中、北部海区;TOC的质量分数湾内比湾外...     

Spatial and seasonal variations of sulphate,dissolved organic carbon,and nutrients in deep pore waters of intertidal flat sediments

Spatial and seasonal variations of sulphate, dissolved organic carbon (DOC), nutrients and metabolic products were determined down to 5 m sediment depth in pore waters of intertidal flats located in NW Germany. The impact of sediment permeability, pore water flow, and organic matter supply on deep pore water biogeochemistry was evaluated. Low sediment permeability leads to an enrichment of remineralisation products in pore waters of clay-rich sediments. In permeable sandy sediments pore water biogeochemistry differs depending on whether tidal flat margins or central parts of the tidal flat are studied. Pore water flow in tidal flat margins increases organic matter input. Substrate availability and enhanced temperatures in summer stimulate sulphate reducers down to 3.5 m sediment depth. Sulphate, DOC, and nutrient concentrations exhibit seasonal variations in deep permeable sediments of the tidal flat margin. In contrast, seasonal variations are small in deep pore waters of central parts of the sand flat. This study shows for the first time that seasonal variations in pore water chemistry are not limited to surface sediments, but may be observed down to some metres depth in permeable tidal flat margin sediments. In such systems more organic matter seems to be remineralised than deduced from surface sediment studies.     

Biological and granulometric controls on sedimentary organic matter of an intertidal mudflat

A variety of measures of organic matter concentration and quality were made on samples collected from the top few mm of intertidal mudflat sediment over the course of a year, in order to assess the relative importance of biological and sedimentological influences on sedimentary organic matter. Winter and summer were times of relatively fine-grained sediment accumulation, caused by biological deposition or stabilization processes and resulting in higher organic matter concentrations. Stable carbon isotope and Br:C ratios indicated a planktonic source of bulk organic matter. Ratios of organic carbon to specific surface area of the sediments were consistent with an organic monolayer coverage of sediment grains. Correction for changing grain size during the year showed no change in the organic concentration per unit surface area, in spite of organic matter inputs by in situ primary production, buildup of heterotroph biomass and mucus coatings, and biodeposition of organic-rich seston. There were also no indications of changes in bulk organic quality, measured as hydrolyzable carbohydrates and amino acids, in response to these biological processes. It is concluded that biological processes on a seasonal time scale affect the bulk organic matter of these sediments via a modulation of grain size rather than creation or decay of organic matter.