Effects of cadmium, zinc and nitrogen status on non-protein thiols in the macroalgae Enteromorpha spp. from the Scheldt Estuary (SW Netherlands, Belgium) and Thermaikos Gulf (N Aegean Sea, Greece)

Enteromorpha prolifera (Scheldt Estuary) and E. linza (Thermaikos Gulf) were incubated at three salinities with 100 and 200microgL(-1)Cd and Zn. The objective was to measure effects of Cd, Zn and nitrogen (N) status on the pools of metal-binding non-protein thiols: glutathione and phytochelatins, (gamma-glutamyl-cysteinyl)(n)-glycine (PC). In E. linza, ammonium pools were higher, but amino acid pools, total N and protein contents were lower than in E. prolifera. Reduced glutathione (GSH) pools were positively correlated with free glutamate and protein contents. In E. linza GSH pools increased and the ratio of reduced to oxidized glutathione (GSH:(GSH+0.5GSSG)), an indicator of oxidative stress, decreased with Cd contents, indicating Cd-induced glutathione oxidation. Total glutathione pools (reduced plus oxidized) ranged from 16nmolSgdwt(-1) in controls (at 0.5micromolCdgdwt(-1)) to 179nmolSgdwt(-1) (at 1.9micromolCdgdwt(-1)) at the highest cadmium dosage. Cadmium stimulated PC synthesis in E. prolifera which suggests that in N-rich algae, glutathione pools were high enough for PC synthesis. In both species GSH and protein increased with Zn contents, whereas GSH:(GSH+0.5GSSG) decreased, which would indicate Zn-induced oxidative stress; in E. linza, at the highest salinity the glutathione redox ratio decreased from 0.61 (at 2.9micromolZngdwt(-1)) to 0.26 (at 4.9nmolSgdwt(-1)) (at 0.5molCdgdwt(-1)). PCs were not synthesized in response to Zn, which may have resulted in Zn-induced GSH oxidation. The presence of both oxidative effects (Cd, Zn) and detoxification (Cd) could be identified by observing the responses of glutathione and PC pools to metal stress.     

Municipal wastewater contamination in the Southern California Bight. Part II. Cytosolic distribution of contaminants and biochemical effects in fish livers

The objective of this study was to examine the cytosolic distribution of metals and oxygenated organic metabolites (MTBs), and biochemical effects, in livers of fish collected from both highly contaminated and less contaminated southern California coastal sites. Cytosolic extracts were separated by Sephadex G-75 column chromatography into high molecular weight (> 20 000 daltons) enzyme-containing (ENZ) pools, medium molecular weight (3000–20000 daltons) metallothionein- or metallothionein-like-containing (MT) pools, and low molecular weight (< 3000 daltons) glutathione-containing (GSH) pools.Concentrations of Cd, Cu and Zn were frequently lower in cytosolic pools of longspine combfish, yellowchin sculpin, and California tonguefish from highly contaminated Palos Verdes (PV) relative to those from less contaminated Santa Monica Bay (SMB) despite much higher concentrations of these metals in sediments at PV. Patterns of cytosolic metal distribution differed more between metals than between species or sampling locations. Most Cd, Cu and Zn occurred in the MT pools of these three species, with the exception of Zn in California tonguefish which occurred predominately in the ENZ pool. In all three species, ENZ-Cu showed positive slopes when regressed against total cytosolic Cu, while ENZ-Cd showed no significant slopes when regressed against total cytosolic Cd. Patterns for Zn were the least consistent among species, with higher ENZ-Zn slopes occurring in fish livers with lower cytosolic Zn concentrations.The largest portion of DDT and PCB oxygenated MTBs occurred in GSH pools of scorpionfish livers from PV or less contaminated Cortes Bank (CB). Concentrations of MTBs in ENZ- and MT-pools of CB scorpionfish livers showed positive slopes when regressed against total cytosolic- and GSH-MTBs.Positive slopes for regressions of ENZ-Cu, -Zn and -MTBs against total cytosolic concentrations are consistent with the model of an equilibrium-dependent exchange of these among cytosolic pools.The lower metal concentrations, higher glutathione concentrations, and higher catalase activities found in fish from PV relative to those from SMB are in accordance with effects known to result from exposure to organic contaminants.     

Mobilization of metals from riverine suspended matter in seawater

Suspended matter from rivers in the Russian Far East was leached by seawater to assess the extent of Zn, Cd, Pb, and Cu release from the land-derived solids to estuarine and coastal waters. The concentration of solids in the leaching experiments was 0.25 g/l. The suspended matter used varied in metal content from background levels to heavily contaminated.The concentration of Zn, Cd, Pb, and Cu in the leaching solution after 1, 4, 24, 48, and 96 h was determined by anodic stripping voltammetry. Measurable Cd was transferred from river suspended matter to seawater with both background and elevated Cd concentrations, though the amount of Cd released was different. The increase in Zn and Pb in solution was observed only at the enriched concentration of metals in the suspended solids. The Cu transfer into solution was more pronounced from material with elevated Cu concentration, but the amount of degradable organic matter in the solid phase was more important.The losses of metals from the riverine solids varied from 60% to 80% of total concentration for Cd to negligible for Pb, independent of contamination. The Zn loss depended on the initial concentration in the solids and decreased from 11–16% for the heavily contaminated suspended matter to 3–8% for the moderately enriched ones and to negligible for the pristine solids. Cu loss varied from 1% to 30% of total content, with no clear dependence on concentration in the suspended matter.The significance of additional input of dissolved metals to estuarine and coastal waters from remobilization was assessed by comparison with the initial concentration of dissolved metals in river water. Such experiments could be used to assess the water quality impact of atmospheric fallout of contaminated solids and storm drainage from the urbanized areas, in addition to river suspended matter studies.     

Relevance of intracellular partitioning of metals in prey to differential metal bioaccumulation among populations of mummichogs (Fundulus heteroclitus)

Intracellular partitioning of trace metals is critical to metal tolerance in aquatic organisms and may also influence metal trophic transfer in ecosystems. In this study, we tested the relevance of metal (Cd, Cu, Pb, and Zn) intracellular partitioning in prey as an indicator of metal trophic availability to benthic forage fish, mummichogs (Fundulus heteroclitus), in chronically metal-polluted salt marshes in New York, USA. Two common prey of mummichogs in the study area, Palaemonetes pugio and Nereis acuminata, generally stored increasingly higher proportions of non-essential metals (particularly Pb) in insoluble (less trophically available) cellular components, as the whole body burdens increased. In contrast, intracellular partitioning of essential metals (Cu and Zn) in invertebrate prey varied relatively little among sites. Differential Cd and Pb intracellular partitioning patterns within P. pugio among sites were significantly associated with Cd and Pb whole body burdens in mummichogs, respectively (i.e., prey-driven bioreduction of metals), while bioaccumulation of Cu and Zn in mummichogs was similar among populations. The findings in this study suggest that metal intracellular partitioning within prey may be partially responsible for metal trophic availability to a predator in metal-polluted habitats, while there was also evidence that some predator-dependent processes may offset differential trophic availabilities from prey.     

The pathway and fate of the heavy metal mixture in Xiamen marine experiment enclosures

The pathway and fate of heavy metals were studied in 10m3 enclosures at Xiamen Bay in 1985. The dissolved metals added are removed rather quickly during the first days, and their half-removal times ( t1/2) (d) are as follows: Pb 5. 4-5. 8, Hg 6. 7-14, Zn 11-22, Cu 16 - 29, and Cd 30-89. Zinc is transferred biologically to particles during phytoplankton bloom. The main Fate of added metals after 27 days is as follows; over 80% Cd and 60% Cu remain in dissolved phase, more than 60% Pb and 50% Hg transfer to settling settlement, while Zn is equally distributed in dissolved phase and settling settlement. The wall uptake is less than 2% of the total metals added. Organic materials play an essential role in the partition and the transfer of heavy metals in water column. Terrigenous and autochthonous particles show different affinities to different metals. Most heavy metals associate weakly with zooplankton. The Binding of Cd, Pb, Zn and Cu to the particles shows distinctive features related to the diagenetic     

湛江南柳河入海排污口邻近海域沉积物重金属污染评价

对南柳河排污口邻近海域表层沉积物中重金属的含量分布、富集状况进行分析,并采用潜在生态危害指数法进行评价。结果表明:Cu,Pb,Zn,Cd,Hg含量分布呈现由西北到东南递减的变化特点;5种重金属元素的富集程度均较重,且程度由大到小依次为Pb>Zn>Cu>Hg>Cd;生态危害评价显示,Pb,Cu,Zn等元素属于轻微生态危害,Hg,Cd等元素属于中等生态危害,5种元素生态危害程度由重到轻依次为Hg>Cd>Pb>Cu>Zn。     

黄河口沉积物重金属含量变化特征研究

在黄河口的平水期、枯水期和丰水期采集沉积物样品。分析了铜、铅、锌、镉、铬、砷、汞浓度.结果表明,黄河口沉积物样品中的重金属含量由河到海呈现先上升后下降的趋势,平水期和枯水期Cd、Cr、As呈显著相关(0.01水平)。重金属含量为平水期>枯水期>丰水期。水文特征严重影响到沉积物中重金属的迁移。沉积物中重金属含量和沉积物的粒度密切相关.粒度越小重金属含量越高,反映了河流沉积的特征。沉积物中重金属浓度较低。各项目基本上都符合海洋沉积物质量一类标准。     

Speciation, distribution, and potential ecological risk assessment of heavy metals in Xiamen Bay surface sediment

Based on the survey of surface sediment in Xiamen Bay in October 2011, the speciation, distribution, and potential ecological risk assessment of heavy metals （Cu, Pb, Zn, Cd, and Cr） in this area were studied us-ing the sequential extraction method and ecological risk assessment method. The results indicated：（1） the total concentrations of these heavy metals were influenced by runoff, industrial wastewater, and sewage, and were all higher in the coastal area than the offshore area while the highest area of Pb was a little far-ther away from the coastal water due to atmosphere deposition;（2） sequential extractions suggested that Cu was mainly composed with residual and Fe/Mn-oxide bound fractions, Pb was bound to Fe/Mn-oxide, Zn and Cr were dominated by residual, and Cd bound to exchangeable and carbonate fractions; （3） the order of migration and transformation sequence was Cd＆gt;Pb＆gt;Cu＆gt;Zn＆gt;Cr and the degree of pollution was Cd＆gt;Pb＆gt;Cu＆gt;Zn＆gt;Cr;and （4） the ratios of the secondary and primary phases showed that Zn and Cr were both clean, Cu may be polluted, Pb was moderately polluted, while Cd was heavily polluted.     

海水养殖池沉积物中重金属形态和生物酶活性的关系研究

以连云港市对虾养殖池表层沉积物为研究对象,采用Tessier连续萃取法,研究了表层沉积物中重金属(Cu、Zn、Pb、Cd、Cr、As、Mn)的赋存形态和酶(脲酶、碱性磷酸酶、过氧化氢酶、转化酶)活性的相关性。结果表明,重金属Cu和Zn以有机-硫化物结合态为主要的赋存形态,Pb以铁锰氧化物态为主要的赋存形态,Cd以可交换态(平均33.47%)和碳酸盐结合态(平均31.16%)为主要存在形态,Cr和As主要以残渣态存在,Mn的铁锰氧化物态比例最高。脲酶的活性范围为0.45—8.96mg/(g·24h),碱性磷酸酶活性范围为2.45—6.69mg/(g·24h),过氧化氢酶活性范围为0.14—2.36m L/(g·min),转化酶活性范围为0.45—10.45mg/(g·24h)。脲酶活性与Cd、As的可交换态、Cd的碳酸盐结合态、Cu、As的铁锰氧化物态、Zn、Pb、Cd、Mn的有机硫化物态之间显著相关;碱性磷酸酶活性与Zn、Cd的铁锰氧化物态显著相关;过氧化氢酶活性与Cd的可交换态、碳酸盐结合态及残渣态、Cu、Cd、As的铁锰氧化物态、Zn、Pb、Cd、Mn的有机硫结合态之间显著相关;转化酶活性与Cu、Cd、As的可交换态、Cd的碳酸盐结合态、Cu、Cd、As的铁锰氧化物态、Zn、Pb、Cd、Mn的有机硫化物态、Cd、As的残渣态之间显著相关。酶活性可以用来指示海水养殖池沉积物中重金属的形态转化过程。     

珠江口荷包岛近岸海域沉积物重金属分布及其潜在生态危害评价

本文采用2008年在珠江口荷包岛近岸海域的调查数据,对表层沉积物重金属的分布特征及重金属与TOC的相关性进行了分析,并采用Hakanson潜在生态危害指数法对其生态危害程度进行了评价。结果表明:重金属Cd,Hg,Cr和As四种元素分布基本呈现荷包岛近岸海域较高的特点,重金属Zn,Pb和Cu的分布没有明显规律;重金属富集顺序为Cd＞Zn＞Cu＞Hg＞As＞Cr＞Pb。相关性研究表明,重金属Cu与Zn显著相关,Hg,Cr,Cd和As极显著相关;有机质是影响沉积物重金属迁移和转化的重要因素。潜在生态危害评价结果表明,荷包岛近岸海域表层沉积物重金属总体潜在生态危害轻微;各重金属生态危害程度顺序为Cd＞Hg＞As＞Pb＞Cu＞Cr＞Zn;对荷包岛近岸海域生态环境具有潜在生态危害的重金属主要是Cd和Hg。     

烟台近岸典型生态区沉积物重金属形态分布及其污染状况

运用Tessier连续提取法,对烟台海岸带3个典型生态敏感区表层沉积物重金属Cr、Cu、Cd、Pb、Zn、Ni的形态分布和污染状况进行了分析研究。结果表明,研究区域中河口区与排污口区重金属Cr、Cu、Cd、Zn和Ni的含量较高,尤其是Cd污染严重。养殖区基本符合海洋沉积物质量第1类标准;重金属Cr、Cu、Pb、Zn和N...     

辽东湾西北部海域沉积物重金属含量分析及污染评价

为了解辽东湾西北部海域沉积物重金属的分布特征及污染程度,文章基于2017年3月辽东湾西北部12个采样站位表层沉积物7种重金属含量(Hg、Cu、Pb、Cd、Zn、Cr、As)的测定,对辽东湾西北部海洋沉积物中的重金属进行了研究。SPSS用于沉积物中重金属含量统计分析并通过地累积指数和潜在生态风险指数的方法评估重金属污染和生态危害的程度。结果显示:(1)辽东湾西北部沉积物重金属含量平均值只有Cd符合海洋沉积物一类标准,变异程度由高到低依次为Hg、Cd、As、Zn、Pb、Cu,汞和镉受人为来源控制最高;(2)地累积指数法评价结果表明重金属元素污染程度由大到小依次为Hg、Cd、Zn、As、Cu、Pb;(3)潜在生态风险指数法评价结果表明,单因子潜在生态风险系数由高到低依次为Hg、Cd、As、Cu、Pb、Zn、Cr,Hg具有很强的生态风险,综合生态风险指数在233.77~4785.15,平均1224.12,处于很强的生态风险水平。文章揭示了辽东湾西北部海域沉积物重金属的分布特征,为该海域的生态环境建设提供依据。     

基于生物可利用性评估城市道路沉积物重金属生态风险

城市道路沉积物重金属风险评价是表征城市环境质量的有效途径.采用重金属化学形态和生物可利用性来评估其生态风险更合理,越来越受到人们的关注.本文采集山东省青岛市崂山区10条次干道沉积物样品,分析不同粒径沉积物中Zn、Cd、Cu、Pb的含量、化学形态和生物可利用性,采用地累积指数(Igeo)和改进的生态风险指数(RIm)评价...     

厦门西海域拟疏浚沉积物中重金属含量及潜在生态危害评价

报道了厦门西海域拟疏浚沉积物中的重金属含量水平及分布,并对其污染状况进行了潜在生态危害评价,为进一步开展疏浚物去污染技术研究提供了科学依据.研究结果表明：与其他海域的相比,马銮湾及其湾口外、筼筜湖的Cd、Hg、Cr、Zn含量较高.综合来看,厦门西海域拟疏浚沉积物重金属含量不很高（RI＜150）,属于轻微生态危害.但东渡码头外的X4站、马銮湾M2站沉积物中的Cd,及马銮湾M2站和筼筜湖Y2站沉积物中的Hg含量（40≤Er ＜80）都达到中等生态危害程度.     

Environmental status of Daya Bay surface sediments inferred from a sequential extraction technique

The chemical partitioning of 12 trace metals (Ba, Cd, Co, Cu, Mn, Mo, Ni, Pb, Sc, Sr, U, Zn) in 9 surface sediments from Daya Bay, northern South China Sea, was studied by a four-step sequential extraction technique to assess their environmental/pollution status. The studied metals take on different fraction composition patterns, and some of them show significant spatial variation especially for Cd. A majority of the studied metals can be considered immobile because of their high percentages in the residual fraction. It seems that the Daya Bay surface sediments have not yet been polluted by the studied heavy metals which are used as parameters to classify marine sediment quality, i.e., Cd, Cu, Ni, Pb and Zn. For all metals except for Pb, the extent of anthropogenic influences on their total concentrations in the Daya Bay surface sediments is generally imperceptible. The metals’ potential risks to the environment were assessed, and the results showed that they have generally no risk or low risk except for Cd, Mn and Sr.     

Accumulation and cytosolic partitioning of metals in the American oyster Crassostrea virginica

The ability of the oyster to accumulate trace metals, particularly the transition metals (Cd, Cu, Zn, and Hg), from food and water has been well documented. There is little information, however, on how these metals interact to affect whole animal retention, partitioning, and binding to metallothionein (Mt). In this study oysters were exposed to Cd and Cu, both alone and in combination, and significant effects have been demonstrated on subcellular partitioning. These studies showed that Cu can displace Cd from Mt, but the Cd is not lost from the animal. Two metal-binding protein peaks have been separated by gel chromatography (<10 K and 24 K daltons). The lower molecular weight protein peak has been characterized as Mt, consisting of two isoproteins, but the higher molecular weight protein peak appears to be an aggregation of metal-binding proteins, some of which may be Mt or a Mt dimer. In environments that are contaminated with trace metals, Mt binds primarily Hg, Cu, and/or Cd and Zn, but in noncontaminated areas Mt binds primarily Zn on one of the two isoMts.     

Effects of salinity, temperature and food type on the uptake and elimination rates of cd, cr, and zn in the asiatic clamcorbicula fluminea

Laboratory radiotracer experiments were conducted to determine assimilation efficiencies (AE) from ingested algal food and oxic sediment particles, uptake rates from the dissolved phase, and the efflux rates of Cd, Cr and Zn in the Asiatic clamCorbicula fluminea. Among three elements, AE from both algal and sediment food was greatest for Cd, followed by Zn and Cr. The AEs of tested elements from algal food(Phaeodactylum tricornutum) were consistently higher than those from sediments at a given salinity and temperature. The influence of salinity (0, 4 and 8 psu) and temperature (5, 13 and 21¼) on the metal AEs was not evident for most tested elements, except Cd AEs from sediment. The rate constant of metal uptake from the dissolved phase (k _u was greatest for Cd, followed by Zn and Cr in freshwater media. However, in saline water, thek _u of Zn were greater than those of Cd. The influx rate of all tested metals increased with temperature. The efflux rate constant was greatest for Cr (0.02 d^-1), followed by Zn (0.010~0.017 d^-1) and Cd (0.006 d^-1). The efflux rate constant for Zn in clam tissues depurated in 0 psu (0.017 d^-1) was faster than that in 8 psu (0.010 d^-1). Overall results showed that the variation of salinity and temperature in estuarine systems can considerably influence the metal bioaccumulation potential in the estuarine clamC. fluminea. The relatively high Cd accumulation capacity ofC. fluminea characterized by the high AE, high dissolved influx rate and low efflux rate, suggested that this clam species can be used as an efficient biomonitor for the Cd contamination in freshwater and estuarine environments.     

海南花场湾表层沉积物重金属分布特征及污染评价

对海南省花场湾内表层沉积物中重金属的含量进行测定,探讨其分布特征、相关性及潜在生态危害程度.含量测定结果表明,花场湾表层沉积物中的Cu、Pb、Zn、Cr、Cd、Hg、As的含量范围分别为8.41~51.45、5.96~30.73、16.87~99.15、18.60~57.80、0.12~0.76、0.020~0.073、6.02~17.56 mg/kg,均值分别为28.19、18.35、50.48、35.75、0.32、0.05、12.71 mg/kg.相关性分析结果表明,Cu、Pb、Zn、Hg、Cr及Cd具有相同污染源,主要受养殖影响;此外,Cu、As、Hg受潮汐影响较大,Pb与Zn受渔船及潮汐影响较大,Cd与Cr受沿岸虾塘影响较大.重金属潜在生态危害评价结果表明,研究区以中等生态危害为主,其次为强生态危害与轻微生态危害,多种重金属潜在生态危害指数(RI)高值基本位于花场湾潟湖中心.单金属潜在危害系数程度较高的是Cd与Hg,潜在生态风险大小依次为:CdHgAsCuPbCrZn.     

Hepatic metallothionein as a biomaker for metal contamination: age effects and seasonal variation in European flounders (Pleuronectes flesus) from the Severn Estuary and Bristol Channel

Hepatic concentrations of metallothionein [MT] and three metals (Cu, Zn, Cd) were determined in 242 European flounders (Pleuronectes flesus) collected from power stations at Oldbury-upon-Severn and Hinkley Point, located in Severn Estuary and Bristol Channel, UK, respectively, between March 1996 and February 1998. A model involving three-factor analysis of variance (ANOVA) was used to examine variation in MT and metal concentrations with respect to season, year and site; with age-class included as a covariate in the analysis. Hepatic concentrations of MT and Cd (and to some degree, Cu, but not Zn) increased significantly with age. The model explained 38, 25, 17 and 26% of the variation in MT, Cu, Zn and Cd, respectively, with significant effects due to season, and to a lesser extent, to year. Site was only a significant factor for Cd which was higher in fish from Hinkley. Correlation between the individual concentration of MT and each metal alone, or in combination, was poor, and explained only an additional 3.0% of the residual variation in MT, most of which was attributable to Cu (2.7%). Compared to other industrialised estuaries, Cd concentrations were high (>20 micro g-1 in some individuals). The study emphasises the importance of seasonal variation and other factors in biomonitoring programmes and highlights the limitations of using [MT] as a biomarker for metal contamination in flounders from the Severn Estuary.     

The effects of glutathione depletion on reproductive success in oysters, Crassostrea virginica.

Glutathione (GSH) is a ubiquitous tripeptide that functions as a very important modulator of cellular homeostasis, including detoxification of metals and oxyradicals. Therefore, depletion of GSH may predispose organisms to pollutant stress. Reproductively active oysters (Crassostrea virginica) were exposed to buthionine sulfoximine in the laboratory to deplete gonadal GSH. The effects of metal exposures (Cd and Cu) on fertilization and developmental assays were evaluated using gametes from control and GSH-depleted adults. Fertilization success was not affected by GSH status, i.e. the fertilization rates of gametes derived from GSH-depleted adults were the same or slightly higher. However, GSH depletion did increase the susceptibility of developing embryos to metal toxicity, i.e. adverse effects on embryonic development were observed at lower metal concentrations with gametes derived from GSH-depleted adults. These effects may be related to diminished removal of free radicals or increased availability of metals. Whereas sperm penetration of embryonic membranes and fertilization success may be facilitated by free radicals, the persistence of free radicals during subsequent developmental periods may adversely affect differentiation and normal development. GSH probably also plays an important role in scavenging toxic metals and reducing metal interactions with essential developmental processes. These results suggest that parental depletion of GSH may increase the susceptibility of embryos to metal toxicity.