Assessment of metal pollution in the Anzali Wetland sediments using chemical partitioning method and pollution indices

Metal pollution in aquatic ecosystems is of immense importance. Under various environment circumstances, the metal contents of sediments can enter into the overlying water body leading to severe toxicity. This study aims to determine metal concentrations in sediments of Anzali International Wetland in Iran. Chemical partitioning method is used to determine the portion of anthropogenic pollution and the mobility potential of each metal. The intensity of metal pollution in sediments of the wetland is assessed using three reliable indices. The results of chemical partitioning reveal that cadmium bear the highest risk of being released into the aquatic environment and high amount of manganese in sulfide bond phase implies the initiation of redox state in aquatic environment of the Anzali Wetland. The results of chemical partitioning studies show that Pb, Cd, Mn and As have the highest anthropogenic portion. Cluster analysis also confirms the results of chemical partitioning and indicates that the mentioned metals can be originated from anthropogenic sources. Sediment pollution indices, including, Igeo,IPOLL, and m-ERM-Q reveal that metals are in the range of low to moderate pollution and also show that the highest metal pollution is in the eastern and central parts of the wetland. This can be ascribed to rivers which are the recipient of industrial, agricultural and municipal wastewaters and flow into these parts of the wetland.

Microplastic pollution in surface water and sediments of Qinghai-Tibet Plateau: Current status and causes

To study the current status and causes of the microplastic pollution in surface water of the Qinghai-Tibet Plateau,this paper compared the average microplastic abundance in sediments and surface water of the Qinghai-Tibet Plateau and the results are as follows.First,the average microplastic abundance in surface water of the independent rivers and the whole area is 247−2686 items/m^(3) and 856 items/m^(3),respectively.The average microplastic abundance in sediments of independent rivers or lakes and the whole area is 0−933 items/m^(2) and 362 items/m^(2),respectively.Meanwhile,the degree of microplastic pollution in river sediments is higher than that in lake sediments,and the rivers suffering from microplastic pollution mainly include the Brahmaputra River,Tongtian River,and Nujiang River.Second,compared with the microplastic pollution in other areas of the world,the levelof microplastic pollution in the lakes and rivers of the Qinghai-Tibet plateau is not lower than that of well-developed areas with more intensive human activities.Finally,this study suggests that relevant government departments of the Qinghai-Tibet Plateau should strengthen waste management strategies while developing tourism and that much attention should be paid to the impacts of microplastics in the water environment.

Source analysis and risk evaluation of heavy metal in the river sediment of polymetallic mining area:Taking the Tonglüshan skarn type Cu-Fe-Au deposit as an example,Hubei section of the Yangtze River Basin,China

In this paper,25 sampling points of overlying deposits in Tonglushan mining area,Daye City,Hubei Province,China were tested for heavy metal content to explore pollution characteristics,pollution sources and ecological risks of heavy metals in sediments.A geo-accumulation index method was used to evaluate the degree of heavy metal pollution in the sediment.The mean sediment quality guideline quotient was used for evaluating the ecological risk level of heavy metal in the sediment.And a method of correlation analysis,clustering analysis,and principal component analysis was used for preliminary analysis on the source of heavy metal in the sediment.It was indicated that there was extremely heavy metal pollution in the sediment,among which Cd was extremely polluted,Cu strongly contaminated,Zn,As,and Hg moderately contaminated,and Pb,Cr,and Ni were slightly contaminated.It was also indicated by the mean sediment quality guideline-quotient result that there was a high ecological risk of heavy metals in the sediment,and 64%of the sample sites had extremely high hidden biotoxic effects.For distribution,the contamination of branches was worse than that of the main channel of Daye Dagang,and the deposition of each heavy metal was mainly influenced by the distance from this sample site to the sewage draining exit of a tailings pond.The source analysis showed that the heavy metals in the sediment come from pollution discharging of mining and beneficiation companies,tailings ponds,smelting companies,and transport vehicles.In the study area,due to the influence of heavy metal discharging from these sources,the ecotoxicity of heavy metals in the sediment was extremely high,and Cd was the most toxic pollutant.The research figured out the key restoration area and elements for ecological restoration in the sediment of the Tonglüshan mining area,which could be referenced by monitoring and governance of heavy metal pollution in the sediment of the polymetallic mining area.

Behavior,toxicity and diffusive flux of metals in a sediment core and pore-water from Anzali wetland

Concentrations of metals along with pH,potential redox(Eh),total dissolved solid(TDS),electrical conductivity(EC)and salinity were measured for sediments of different layers,pore and surface water in the Anzali wetland.Also,the diffusive flux of metals was calculated ad compared with the values in other aquatic bodies.The abundance of metals in sediments was Al>Fe>Ca>Ti>Mn>Zn>V>Cr>Ni>Cu>Pb>Co>As>Mo>Ag>Cd,while the pore-water results indicated a different concentration profile:Ca>Mn>Fe>Al>V>Mo>As>Ni>Cu>Co.Anzali wetland is classified within a high ecological risk.Pore-water toxicity test showed it is in non-polluted condition.Eh–pH diagrams showed that all species of elements are in a stable state in surface and pore-waters.However,Mn and Co(in some layers)are in soluble form and free ions and thus are bioavailable to the organisms.V and As are also present in the form of hydrogen compounds and Ni in the form of hydroxides,therefore,they are toxic to aquatic animals due to their solubility and ionic forms.Diffusive fluxes for As,Al,Fe,Ca,Cu,Mn,Mo,Ni and V are 0.43,1.80,48.52,43,147.50,0.12,1.47,0.15,1.28,0.21μg/m^(2)/day,respectively.Cluster analysis showed that in a solid phase of sediments,elements such as Cr,As and Ti are of petroleum and terrestrial origin.In pore-waters,Cu is of petroleum and biological origin,and Mo,As,Cu and Co are controlled by p H.

Sr-O Isotopic Composition of Sediments in the Nansha Sea Area and Palaeo-environment

The Nansha sea area is located in the place where the Pacific Ocean plate, In-dian-Australian plate and Eurasian plate meet, and therefore, its formation and evolu-tion are both constrained by those three plates. It is a semi-closed marginal sea area,which is only connected with the Indian and the Pacific Ocean by channels. TheSr-O isotopic composition of sediments in this area was systematically studied for fur-ther understanding of its formation and evolution. The range of our investigation islimited to the area of 105-118°E and 3 - 12°N. The surface sediments from 36 sta-tions, which are distributed in the above area, were analyzed. All of the

西藏当雄错盐湖碳酸盐沉积环境及其地质意义

西藏当雄错盐湖是一个碱性的富锂、硼资源盐湖,对其碳酸盐沉积物的研究有助于了解盐湖形成过程中沉积环境的变化以及锂、硼资源的富集过程。为此,本文从当雄错盐湖碳酸盐剖面自上而下采集了31件样品。对这些样品开展了铀系年龄、XRD、主-微量元素、碳-氧同位素测定以及介形类的鉴定分析。铀系年龄结果表明剖面沉积开始于(3788±120)a BP,结束于约2220 a BP。碳酸盐沉积的微量元素和稀土元素特征表明,其沉积水体为缺氧、还原环境下的咸水环境,沉积物形成于干旱、寒冷的气候环境,湖泊水体具有半开放-半封闭性质,但封闭程度较高。约3430 a BP时,当雄错水体盐度发生了较大改变。结合沉积物中介形类Candona gyrongensis的出现和沉积物的碳氧同位素特征,推测有地下淡水注入导致湖泊水体变淡和还原性减弱。当雄错水体的盐度在2220 a BP之前仍相对较低,湖水浓缩达到盐湖阶段的时间在2220 a BP以后。

潮白河流域河道底泥污染和释放特征及发展趋势研究

河道是水的主要承载体,河道底泥作为河道的重要组成部分,对整个河道的污染状态起决定性作用。因此,文章以潮白河流域为例,研究了河道底泥污染和释放特征,并对发展趋势进行了分析。通过分析底泥的组成、来源、污染特征以及释放机制,为河道污染的评估和监测提供科学依据。在外源污染得到有效控制的基础上,研究提出了采用生态清淤疏浚方式来快速减小内源污染的方法。最终,根据评价及实验结果,揭示了底泥对上覆水体的影响,并提出了科学的生态清淤方案。通过深入研究河道底泥污染和释放特征,文章为环境保护、生态恢复和人类健康提供了科学支持,为保护水环境、维护生态平衡和保障人类健康提供了有效的管理和决策依据。

滇池现代沉积物中磷的地球化学及其对环境影响

湖泊沉积物中 ,磷是产生富营养化的重要元素。湖泊中磷元素含量、地球化学行为以及它的复杂矿物学特征 ,使人们对磷的研究极为重视。滇池湖中总磷超标 10 .3倍 ,底泥沉积物中P2 O5平均含量 0 .5 2 % ,最高可达1.92 %。滇池地处磷矿区 ,是磷质来源最丰富的湖泊 ,统计表明 ,磷含量每年在不断增长。滇池沉积物中磷主要以吸附态、有机态、铁结合态、钙结合态、铝结合态等几种形式存在。这些形态磷在底泥中是不稳定的 ,它们在环境改变条件下 ,又将磷释放到水体中。微生物在磷的循环过程中起了重要作用 ,乳酸菌对不溶性磷酸盐的分解 ,使湖泊中可溶磷含量增高。聚磷菌对磷元素的富集以及聚磷菌死亡后发生有机磷的矿化作用 ,是湖泊中水合磷酸盐矿物沉积的重要途径。当湖泊中这种不稳定的水合磷酸盐矿物在条件具备的情况下 ,经沉积物覆盖成岩作用后 。

武汉东湖沉积物的环境地球化学

武汉东湖沉积物的地球化学过程受到人类活动的较大影响。本文报道该湖沉积物的沉积性状和ＣＮ、Ｐ、Ｓｉ、Ｃａ、Ｍｇ、Ｆｅ、Ａｌ、Ｍｎ、Ｃｕ、Ｐｂ、Ｚｎ、Ｃｄ诸元素在沉积层序中的分布，研究了这些元素的地球化学。通过对东湖污染状况和类型的分析，指出营养物质的积累是导致湖泊生态环境恶化的重要原因，提出可用磷含量作为划分东湖沉积物污染程度的指标的观点。

天然有机质及其在地表环境中的重要性

天然有机质是地表各种环境介质中的重要化学组分,分布广泛.越来越多的研究已经表明:它在地表生态系统的物理、化学和生物过程中都起着十分重要的作用;它与生态系统的各个重要环节密切相关,是生态系统中能量与物质循环的重要途径.因此,天然有机质不仅是生物地球化学、生态学和环境科学等研究领域的重要内容之一,而且也是环境污染的评价、预测和治理研究中的基础理论问题,是目前环境质量、毒理学、环境立法和管理研究共同关注的科学问题.本文主要以陆地地表淡水湖泊与河流水环境为例,对天然有机质的来源、化学结构、循环特征,与养分循环的耦合关系,对有毒金属元素和有机污染物迁移转化和毒性影响机理等几个方面的研究进展进行了简要的总结;针对我国水体富营养化和环境污染等重要环境问题,阐述当前应该采取的研究思路和存在的主要科学内容,并对现代有机环境与生物地球化学学科的研究趋势进行了展望.

水环境中泥沙作用研究进展及分析

首先分析了泥沙在微观和宏观方面 ,对污染物迁移转化过程中的影响。泥沙通过吸附、解吸作用 ,同时通过泥沙运动 ,共同影响着污染物的赋存状态 ,从而影响着水体环境质量的变化。本文系统总结了在泥沙吸附解吸污染物机理、影响因素、数学模型等方面 ,已经进行的研究工作所取得的成果 ,并讨论了有待进一步研究的内容。

沉积物中有机质的环境行为研究进展

水体沉积物是重金属、有毒有机化合物等环境污染物及C、N、P等营养元素的汇和释放源 ,而有机质对这些污染物和营养元素在沉积物中的迁移、转化等地球化学行为中起着至关重要的作用 .本文就近期有关沉积物中有机质的环境地球化学行为方面的研究进行了综述 ,重点评述了有关沉积物中有机质本身的来源、性质、迁移和矿化及其环境效应等方面的研究进展 .

贵州石炭系“清镇式”铁矿沉积地球化学特征

贵州中部清镇、修文、开阳等地石炭系铝土矿底部的铁矿被称为"清镇式铁矿",铁矿层被认为是湖泊沉积产物。笔者等对其地质地球化学研究发现,清镇林歹、卫城和龙里长冲等地"清镇式铁矿"的铁质岩主要由赤铁矿、菱铁矿组成;在清镇含铁岩系中稀土元素具有较高的富集,ΣREE75.71×10-6～859.45×10-6,铁质岩中Zr、Ga、Ge、Sc、Ti元素富集,其中金属Sc含量在20×10-6左右,具有开发利用价值。铁质岩的Sr/Ba值均大于1,Th/U值在2～7之间,与二叠系山西式铁矿类似,表明铁质岩沉积受到海水的影响,是潟湖环境下沉积的产物。稀土球粒陨石标准化曲线具有强烈的Eu负异常和Ce弱负异常。清镇式铁矿菱铁矿δ13CPDB为-3.21‰～-7.24‰,比其他沉积型、沉积变质型铁矿低。

武汉城市湖泊汞的环境地球化学评价

汞由于其在环境中的持久性、生物地球化学可循环性以及潜在的生态威胁性而受到格外关注。对武汉远郊、城乡结合部和市区三种环境中6个湖泊的水、沉积物和生物(鱼)中汞污染特征进行了调查采样,用原子荧光光谱仪进行了汞含量的测定。采用Hakanson提出的潜在生态危害指数法直接评价了武汉湖泊汞的生态效应。结果表明,与国家食品卫生标准鱼肉中汞含量(≤300ng/g)相比,除梁子湖乌鱼(汞含量为676ng/g)外,6个湖泊3种鱼肉中汞含量均未超标,表明武汉城市湖泊汞元素尚未造成明显的生态效应;与国家Ⅲ类水质汞含量标准(0.1μg/L)相比,除金银湖水汞含量(0.137μg/L)略有超标外,其他湖水汞含量分布在0.048～0.081μg/L之间,均在合格标准线以下,武汉地区湖水中重金属汞污染不严重,不会构成严重的环境问题;应用Hakanson评价模型,据单个金属的潜在生态危害系数,排出所研究湖泊沉积物汞污染程度的序列为:东湖>墨水湖>金银湖>梁子湖>汤逊湖>鲁湖。

西南印度洋中脊48．6°~51．7°E沉积物地球化学特征

为了深入了解西南印度洋中脊调查区表层沉积物的物质来源和沉积环境,对大洋第30航次在该区域获取的21个表层沉积物样品进行了物相鉴定和主量元素、微量元素及稀土元素含量测试,分析结果显示,样品可分为Si质沉积物和Ca质沉积物两类,其中Si质沉积物富含Si、Mg、Fe、Al,稀土元素含量特征、轻重稀土元素分馏特征,以及稀土元素的北美页岩归一化曲线均表明沉积物保留了N-MORB的特征,主要为基性岩、超基性岩的风化产物;而Ca质沉积物富Ca、LOI、Sr,稀土元素以及微量元素之间的分配均指示沉积物物源为生源主导;所有站位均显示了两类沉积物不同程度的混杂,表明物质来源具有一定的多样性,调查区总体为稳定的偏氧化环境。

控制湖泊水体化学组成的地球化学原理研究

对控制和影响湖泊水体化学组成的主要作用—大气降水、底部沉积物和水相互作用、生物化学作用、岩石土壤风化及结晶和蒸发作用等进行了讨论，并探讨了水体中某些化学成分的物源分析方法，提出了有待深入研究的典型水环境地球化学问题。

金沙江攀枝花段水系沉积物中重金属的分布特征及污染评价

对攀枝花地区金沙江水系沉积物中九个重金属元素的地球化学特征及空间分布特征进行了分析研究,并对各重金属的污染程度进行了初步评价。研究发现,重金属在支流与金沙江交汇点下游处含量高于上游处,这说明金沙江有一定的自净化能力。通过分析可知,重金属的污染程度为:Cu>V>Ti>Mn>Cr>Zn>As>Co>Pb,其中Cu、V、Ti、Mn污染严重,Pb为轻度污染。污染最严重的地区是攀钢冶金区、攀钢选矿区、攀钢采矿区以及攀钢尾矿坝。

地球化学方法示踪东亚大陆边缘源汇沉积过程与环境演变

东亚大陆边缘发育特征的河控型边缘海沉积,其源汇沉积过程的深入研究对于深入理解地球表生过程、物质循环和大陆边缘构造沉积演化特征,具有重要意义。东亚边缘海沉积地球化学研究主要集中于几方面:入海河流沉积物的地球化学组成示踪沉积物源区的风化剥蚀特征,河口陆架区沉积地球化学行为;通过大陆边缘的沉积地球化学记录,探讨不同时空尺度河流入海沉积物的通量、搬运扩散方式及其蕴含的季风气候和海区环境演化信息。目前相关研究与国际前沿水平依然存在较大差距,需要从海陆结合的地球系统科学角度,通过地球化学与其他学科方法交叉的研究手段,从整体上研究东亚大陆边缘的沉积过程,揭示从流域到河口、陆架至开阔海的沉积物源汇系统过程和环境演变规律,及东亚大陆边缘沉积和海陆相互作用的全球意义。