Cadmium (Cd) is a toxic heavy metal that accumulates in living systems. Exposure can occur occupationally or environmentally. Workers within the electroplating, battery production, and pigment industries are at the highest risk for exposure and have been reported to have increased levels of Cd in their blood and urine. Environmental exposure can be the result of anthropogenic activities or smoking. Cd has a long half-life and bio accumulates in plants, invertebrates, and vertebrates. The toxic effects following exposure include growth retardation and organ system toxicity, with kidney and liver toxicity most reported with in higher organisms. At the molecular level, Cd leads to the production of reactive oxygen species, DNA damage, and inhibition of DNA repair. This article gives a brief overview of the correlations between exposure to cadmium occupationally and environmentally and levels measured in blood and urine. It also examines the bioaccumulation of cadmium in aquatic invertebrates and vertebrates indicating that accumulation varies not only by location but also within and between various species. (C) 2019 Elsevier B.V.

据2014年5月和8月福建安海湾9个站位的调查资料，分析海水、水中悬浮物和表层沉积物中Cu、Pb、Zn、Cd、Hg等5种重金属和类金属As的含量及分布特征，用单因子指数法、潜在生态危害评价法评价湾内重金属污染程度。结果表明，海水分布从湾顶往湾内和湾口逐渐降低，以湾顶值最高；水中悬浮物Cu、Pb、Zn、As、Hg含量以AH5站最高，Cd含量以AH6站最高，并向周边逐渐降低；表层沉积物含量从AH5站向湾内及湾口逐渐降低。部分站位海水和沉积物中Cu、Zn含量相对偏高，Pb、Cd、As、Hg含量均符合海水及沉积物质量标准的第一类要求。安海湾海域不同介质中悬浮物的含量最高，表层沉积物次之，海水的含量最低。水中悬浮物8月含量潜在生态危害程度远大于5月，以AH5站的潜在生态危害程度最强，主要潜在生态危害元素为Cd和Hg;表层沉积物以AH1、AH5站的潜在生态危害程度稍强，主要潜在生态危害元素为Cd、Hg次之。安海湾海域环境受到不同程度的重金属污染，陆源重金属污染物排放成为主要来源，本研究为安海湾海域生态环境防治提供科学依据。

The present study, seasonal pollution of heavy metals (Pb, Cd, Cr and Cu) in water, sediment, tissues of fish Carassius carassius and oyster Crassostrea gigas were determined at seven sampling sites from Meiliang Bay, Taihu Lake during one year calendar, 2016. The total heavy metal concentrations in water samples were higher in winter and summer than in spring and autumn season, whereas in sediment they were higher in winter and summer seasons, respectively. The trend of metal mean contents found in the fish and oyster were in decreasing order of Pb > Cu > Cr > Cd and Pb > Cu > Cr > Cd, respectively. The tissues of fish and oyster captured during winter and summer accumulated a higher significant different amount of metals relative to other season, which was attributed to a higher influx of agricultural waste, sewage and sludge by heavy rainfall and floods. In addition, the pollution load index (PLI) values were above one (>1), indicating an advanced decline of the sediment quality, and contamination factor (CF) confirmed that the sediment samples were moderate to high contamination by Pb and Cr. Thus, comparative studies with seasonal pollution of heavy metals in Meiliang Bay of Lake Taihu regions indicate considerable heavy metal enrichment in water, sediments as well as in various organs of fish and oyster. Finally, our results indicated that the metal concentration values increased statistically significant different related to season (p < 0.001). The determination of heavy metal stress biomarkers in fish along with seasonal variations may serve as a convenient approach during pollution bio-monitoring programme.Copyright © 2017 Elsevier Ltd. All rights reserved.

通过对2014—2018年在福建中东部共1 265批次贝类样品开展的卫生监测抽检的数据进行分析，并利用《2018年海水贝类产品卫生监测检测项目、方法及限量值》对贝类质量安全水平进行评估，结果表明：监测区域内的海水养殖贝类样品大多符合一类生产区标准，部分符合二类生产区标准，少量符合三类生产区标准，总体处于较好水平。监测的太平洋牡蛎、缢蛏、菲律宾蛤仔、贻贝、美洲帘蛤、文蛤6 种养殖贝类中缢蛏对铅的富集能力高于其他品种，而太平洋牡蛎和贻贝对镉的富集能力较其他品种相对较强。

为了解福建省中北部海域捕捞水产品的重金属污染现状及摄入风险，分别于2014年和2015年采集了该区域的鱼类和甲壳类，共18种160个主要水产品，调查研究了铅、镉、总汞和无机砰4种重金属的含量，并采用单因子污染指数（Pi、重金属污染指数（MPI)、每周可耐受摄入量（PTWI) 和致癌、非致癌年风险（Rcig 、Rnig) 指标分别评价捕捞水产品的污染程度、食用安全性和健康风险。研究结果表明，目前福建中北部海域捕捞水产品中铅、总汞和无机砰都符合国家标准规定，但重金属镉存在污染，超标率为9.4% ; Pi结果显示，鱼类受重金属污染影响不显著，基本上处于正常范围内，甲壳类中口虾蛄和梭子蟹中镉含量达到重污染水平，其他重金属含量处于正常范围内；MPI结果显示，甲壳类重金属污染高于鱼类；食用安全评价表明，通过食用捕捞水产品摄入的4种重金属平均含量均低于每周可耐受摄入量，但个别甲壳类（梭子蟹和口虾蛄）的镉摄入量超过了PTWI (成人）值，存在较高风险；健康风险模型结果显示，所有样品均未超过国际辐射防护委员会（ICRP) 推荐的最大可接受水平（5. 0 x l0 -5a -1 ) 。总体上看，当前，福建省捕捞水产品可放心食用，但是重金属镉的潜在食用安全风险需引起重视。

Between 1990 and 1994, samples of three shellfish species (i.e. blue crab, Callinectes sapidus;crayfish, Procambarus acutis; and river shrimp, Macrobrachium ohionii) and 16 fish species and were collected at six sites along the lower Mississippi River by the Louisiana Department of Environmental Quality, Office of Water Resources in coordination with the US Environmental Protection Agency. The fish species included: bigmouth buffalo (Ictiobus cyanellus); blue catfish (Ictalurus furcatus); carp (Cyprinus carpio); channel catfish (Ictalurus punctatus); cobia (Rachycentron canadum); flathead catfish (Pylodictis olivaris); freshwater drum (Aplodinotus grunniens); largemouth bass (Micropterus salmoides); long nose gar (Lepisosteus osseus); red drum (Sciaenops ocellatus); red snapper (Lutjanus campechanus); smallmouth buffalo (Ictiobus bubalus); spotted gar (Lepisosteus oculatus); striped bass (Morone saxatilis); white bass (Morone chrysops); and white crappie (Pomoxis annularis). Organic compound and heavy metal concentrations were measured in 161 composite fish tissue samples where each composite included three to 10 individual fish. Nineteen chemicals, found at measurable levels in sample tissues, were used in calculations of lifetime excess cancer and non-cancer risks due to fish consumption. We calculated: 574 chemical-specific cancer risks; 41 total cancer risks; and 697 margins of exposure based on a consumption rate of one 8-ounce meal per week (0.032 kg/day), a body weight of 70 kg and reported cancer potency factors and reference doses. We identified nine species of concern (blue catfish, carp, channel catfish, cobia, crayfish, flathead catfish, red drum, spotted gar and striped bass) based on total cancer risk greater than 10(-4) or margin of exposure greater than 1, and whether or not samples collected in subsequent years resulted in lower risks. The compounds primarily responsible for the elevated risks were aldrin, dieldrin, alpha-benzene hexachloride, gamma-benzene hexachloride, heptachlor epoxide, arsenic and mercury.Copyright 2002 Elsevier Science B.V.

Blue crabs from a contaminated estuary (Hackensack Meadowlands-HM) and a cleaner reference site (Tuckerton-TK) were analyzed for Cr, Cu, Hg, Pb, and Zn in muscle and hepatopancreas. Crabs from each site were taken into the laboratory and fed food from the other site, or in another experiment, transplanted to the other site for eight weeks. All crabs were analyzed for metals. Overall, tissue concentrations reflected environmental conditions. Tissue differences were found for Cu, Pb and Zn (all higher in hepatopancreas), and Hg (higher in muscle). HM muscle had more Hg than TK muscle, but did not decrease after transplanting or consuming clean food. HM crabs lost Cu, Pb and Zn in hepatopancreas after being fed clean food or transplanted. TK crabs increased Hg in muscle and Cr and Zn in hepatopancreas after transplantation or being fed contaminated (HM) food. Concentrations were variable, suggesting that blue crabs may not be fully reliable bioindicators of polluted systems.Copyright (c) 2009 Elsevier Ltd. All rights reserved.

The bioabsorption and biotoxicity of cadmium are closely related to its binding form. Currently, total concentration is used as the indicator for evaluating cadmium toxicity in food, but it might not accurately reflect cadmium's toxic effects. This study attempted to evaluate the toxicity of the different forms of cadmium including cadmium-malate, cadmium-glutathione, and cadmium-metallothionein that are commonly found in food. The in vitro physiologically based extraction test (PBET) combined with Visual MINTEQ modeling was used to predict the toxicity of different forms of cadmium, and acute toxicity testing was performed in mice for validating their results. The in vivo experimental results showed that different forms of cadmium had diverse biotoxicities of which PBET was a good predictor. In particular, the simulation of cadmium ions in PBET using the MINTEQ software revealed that the free cadmium ion content in the simulated intestinal fluid had a superior linear relationship than the total cadmium concentration with the toxicology indexes. Verification using the other two forms of cadmium confirmed the accuracy of the prediction of their biotoxicity. These findings hopefully provide an important reference for a more accurate and rapid safety assessment of cadmium in food.Copyright © 2019 Elsevier B.V. All rights reserved.

Metal speciation analysis in MTs was carried out in two tropical fish species of Brazil, the freshwater fish pearl cichlid (Geophagus brasiliensis) and the marine fish white sea catfish (Netuma barba), that are presently used to monitor the effects of heavy metal pollution in aquatic ecosystems in Brazil. In order to obtain the MT fraction, liver cytosols from both fish species where subjected to size exclusion fractionation, monitoring on-line the metal signal (Cd, Cu and Zn) by ICP-MS while protein elution was followed by on-line UV detection. That MT fraction was then separated by anion-exchange (AE)-FPLC, whose optimal chromatographic conditions were optimized for the separation of the different hepatic MT isoforms existing in both fish species. Specific detection of separated metalloforms was carried out again by the hyphenation of the AE chromatographic system with the ICP-MS instrument. The analytical results showed that MTs of these fish species, unknown so far, exhibited unique characteristics in comparison with standard MTs and other fish liver MTs. In fact, MT isoforms of N. barba turned out to be very anionic, as indicated by their high retention in the Mono Q column and the strong ionic strength required to separate them. As for G. brasiliensis, cadmium was exclusively present in only one of the peaks of the MT isoforms showing a unique metal-binding behavior for MT in this fish species. The differences between the MTs among these species and the different association of metals in particular MT isoforms display the importance of the metal speciation analysis in these proteins prior to its use as bioindicators.

The effect of metal exposure on the accumulation and cytosolic speciation of metals in livers of wild populations of European eel with special emphasis on metallothioneins (MT) was studied. Four sampling sites in Flanders showing different degrees of heavy metal contamination were selected for this purpose. An on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS) was used to study the cytosolic speciation of the metals. The distribution of the metals Cd, Cu, Ni, Pb and Zn among cytosolic fractions displayed strong differences. The cytosolic concentration of Cd, Ni and Pb increased proportionally with the total liver levels. However, the cytosolic concentrations of Cu and Zn only increased above a certain liver tissue threshold level. Cd, Cu and Zn, but not Pb and Ni, were largely associated with the MT pool in correspondence with the environmental exposure and liver tissue concentrations. Most of the Pb and Ni and a considerable fraction of Cu and Zn, but not Cd, were associated to High Molecular Weight (HMW) fractions. The relative importance of the Cu and Zn in the HMW fraction decreased with increasing contamination levels while the MT pool became progressively more important. The close relationship between the cytosolic metal load and the total MT levels or the metals bound on the MT pool indicates that the metals, rather than other stress factors, are the major factor determining MT induction.