Mussels as bioindicators of trace metal pollution in the Danube Delta of Romania

Specimens of mussels species Anodonta anatina, Unio pictorum, U. tumidus and surfical sediment samples were collected in the summers of 1994 and 1995 from twelve lakes in the Danube Delta, Romania. Whole mussel tissues were analyzed for metals (Ag, As, Cd, Co, Cu, Cr, Ni, Pb, Se and Zn), and sediment samples were subjected to weak acid extraction and to a sequential extraction procedure, and analyzed for Cr, Cu, Ni and Zn. Total mean Cu and Ag concentrations were statistically greater in Unio species than in Anodonta species, but other metal levels did not significantly differ between mussel species. There was a ten fold variation for Cd and Pb and five fold variation for Zn, Ag and Co concentrations in mussels among lakes. Mean concentrations of As, Cu, Se and Zn in mussel tissues varied two fold among lakes. Zn, Co and Cd concentrations in mussels were significantly negatively correlated with distance gradients from the origin of the Delta and with distance from main channels of the Danube. Other metal concentrations in mussels did not correlate with either distance gradient. Trace metal levels in mussel tissues were correlated with those in weak acid and in sequential extractions of sediment. Zn concentrations in the carbonate fraction was the best predictor of Zn concentrations in mussels. Cu and Ni levels in the organic matter and sulfide fraction were the best estimators of Cu and Ni concentrations in mussels. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effects of Total Soft Tissue and Shell Thickness on the Accumulation of Heavy Metals (Cd,Cu, Pb,and Zn) in the Green-Lipped Mussel Perna viridis

The effects of the total soft tissue dry weight and shell thickness and on the accumulation of Cd, Cu, Pb, and Zn were determined in the green-lipped mussel Perna viridis. In agreement with Boyden's formula (1977), our results showed that the plotting of metal concentrations against the total soft tissue dry weight and shell thickness of the mussel on a double logarithmic basis gave negative coefficients especially for Cd, Pb, and Zn. Therefore, the smaller mussels (lower total soft tissue dry weight) had higher concentrations of Cd, Pb, and Zn than the larger ones. Since shell thickness could be considered to estimate of the age of the mussel, it was also found that the younger mussels accumulated more Cd, Pb, and Zn than the older ones. This indicated that P. viridis has a different metabolic strategy for each of the metals studied which may be related to age. However, the accumulation of Cu was hardly affected by the sizes and ages of the mussel. This indicated that the accumulation pathways of Cu and the processes affecting the bioavailability of Cu to the mussel are different from those for Cd, Pb, and Zn.     

Heavy Metal Accumulation and Distribution in Organs of the Mussel Crenomytilus grayanus from Upwelling Areas of the Sea of Okhotsk and the Sea of Japan

The subcellular and cytosolic distribution of Zn, Fe, Ni, Cu, Mn, Cd, and Pb in the digestive gland and kidney of the mussel Crenomytilus grayanus from upwelling areas of the Sea of Okhotsk and the Sea of Japan was studied. Cd, Zn, Pb, and Ni have accumulated in the kidneys of mussels from these areas. When the concentrations of both essential and toxic metals in the mussel organs had increased significantly, their redistribution into the cytosol took place. Gel chromatography of cytosolic proteins in the kidneys of mussels sampled in the area with a strong stationary upwelling revealed metallothioneins. This is uncommon for bivalve mollusks from unpolluted areas. High molecular weight proteins act as preliminary ligands for Cd.     

Risk assessment of heavy metals contamination in sediment and aquatic animals in downstream waters affected by historical gold extraction in Northeast China

To assess the risk of heavy metals contamination on the aquatic ecosystem in downstream waters of a gold field in Northeast China, samples of sediment, fish, shrimp, and mussels were collected to determine heavy metals concentrations. According to I_geo, more attention should be given to Hg, Pb, and Cu pollution in sediment of Weisha River. For aquatic animals, the greatest contents of Hg, Cu, and Pb were found in samples collected from Weisha River, while the maximum values of Zn, Cd, and Cr were found in Hongshi Reservoir, Banmiao River, and Songhua Lake, respectively. The Hg and Pb contents in fish were found in the order of predatory fish > omnivorous fish > herbivorous fish, although for other metals no significant difference was observed among the three trophic levels. The contents of metals in Oriental river prawn and Chinese pond mussel were greater than that in fish, except for Pb. The Target Hazard Quotient and Hazard Index of metals showed that the Carnivorous and Omnivorous fish from Songhua Lake and Hongshi Reservoir, as well as all fish from Banmiao River and Weisha River, were not suitable for consuming in the view of the combined risk of all metals.     

小麦不同生育时期Cd、Cr、Pb污染监测指标体系

以小麦为供试材料,分别采用发芽试验、溶液培养、土柱栽培等毒理试验方法,研究了小麦萌芽期、幼苗期及成株期受重金属污染毒害的指标体系。结果表明,①小麦根伸长抑制率可作为萌芽期重金属污染评价的一项生物指标;Cd、Cr、Pb对小麦根生长的7d半效应浓度(EC50)值分别为1.39、0.20mmo.lL-1和2.75mmol.L-1,据此得到3种重金属对小麦同一性状的毒性次序为CrCdPb;此外各性状抑制率与胁迫浓度的关系可用双曲线模型y=x/(a+x/100)或指数曲线模型y=a(1-exp(-bx))较好模拟。②Cd、Cr、Pb单一污染胁迫对小麦幼苗性状的毒性次序均以影响叶面积和冠部干重为主,表明叶面积和冠部干重为幼苗期污染监测的敏感指标;重金属对除根干重外所有性状的毒性次序:CrCdPb,该毒性次序是根据引起50%抑制的临界浓度即EC50值确定的;各性状抑制率与胁迫浓度的关系可用直线模型、或双曲线模型、或指数曲线模型较好模拟。③重金属单一污染胁迫造成小麦籽粒产量下降幅度是CdCrPb;二元互作对产量影响的重要性次序为CdCrCdPbCrPb;在Cd、Cr、Pb复合污染胁迫条件下,穗数可以作为成株期重金属污染监测的首选指标。以上指标可为农田小麦重金属污染的监测和综合治理提供一些理论依据。     

Soil Heavy Metal Pollution Assessment Near the Largest Landfill of China

To assess the extent and potential hazards of heavy metal pollution at Shanghai Laogang Landfill, the largest landfill in China, surface soil samples were collected near the landfill and concentrations of Cu, Zn, Cd, Pb, and Cr were determined. The results revealed that the concentrations of heavy metals, except Pb, were higher in the surface soil near the landfill than in the background soil. Principal component analysis and hierarchical cluster analysis suggested that the enrichment of Cu in soil was probably related to agricultural activities and Cd and Pb to landfill leachates, whereas Zn and Cr concentrations were probably controlled by soil matrix characteristics. The pollution indices (PIs) of the metals were: Cd > Cu > Cr > Zn > Pb. Among the five measured metals, Cd showed the largest toxic response and might cause higher ecological hazards than other metals. The integrated potential eco-risk index (RI) of the five metals ranged from 26.0 to 104.9, suggesting a low-level eco-risk potential. This study indicated the accumulations of Cu, Zn, Cd, Pb, and Cr did not reach high pollution levels, and therefore posed a low eco-risk potential in surface soil near the landfill.     

Sources and Contamination of Heavy Metals in Sediments of Kabul River: The Role of Organic Matter in Metals Retention and Accumulation

In this study, sediment samples were collected from Kabul River (Pakistan) and analyzed for heavy metals including zinc (Zn), cadmium (Cd), chromium (Cr), nickel (Ni) and lead (Pb). The physico-chemical characteristics were also determined which are known to influence the metal accumulation within the sediment matrix. Heavy metal concentrations (mg kg^?1, dry weight basis) in the sediment were in the order of Zn > Cr > Ni > Pb > Cd. Heavy metal concentrations were found in moderately polluted category set by U. S. Environmental Protection Agency (USEPA). However, Cr and Ni concentrations exceeded the screening levels at the sites where a larger volume of industrial effluents enter into Kabul River. Higher concentrations of almost all the tested metals were detected at locations of greater industrial and sewage entry points. Sediment organic matter (OM) exhibited strong correlation with Pb (R² = 0.80), Ni (R² = 0.67) and Zn (R² = 0.46), indicating that OM plays a significant role in metal retention and accumulation. The findings of this study showed that Kabul River is reasonably contaminated with selected heavy metals released from anthropogenic sources. In the study area, sewage discharge was the major source of heavy metals including Zn and Pb, which were observed at locations where sewage effluents enter into the river.     

Temporal and spatial variation on heavy metal concentrations in the oyster Ostrea equestris on the northern coast of Rio De Janeiro State, Brazil.

Heavy metal (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) concentrations were determined by ICP-AES in Ostrea equestris from three beaches (Barra do Furado, Buena, and Ponta do Retiro) on the northern coast of Rio de Janeiro State. The average concentration was 0.8 +/- 0.18, 0.4 +/- 0.21, 58 +/- 25.6, 249 +/- 52.3, 11 +/- 1.31, 0.55 +/- 0.16, 0.13 +/- 0.11, and 1131 +/- 321 microg x g(-1) dry weight for Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn respectively. Significant spatial variation (p < 0.05) between the samples areas occurred for Cr, Pb, and Zn with higher values in Barra do Furado; and for Cu in Ponta do Retiro. Significant temporal variations (p < 0.05) were observed for all metals except Cu. Temporal variability may be related to changes in the inputs of metals associated with suspended particles. Concentrations were similar to those found in areas under low pollution impact, except for Zn, the high concentrations of which probably reflect the physiological characteristics of these organisms.     

Source analysis and health risk of heavy metals in the different seasons from Taizihe River,China

Twenty five water samples were collected along the Taizihe River, the concentration and health risks of Zn, Cu, Pb, Cr and Cd were detected and evaluated, and the pollution sources was analyzed through principal components analyses. The results indicated that the order of average concentration of heavy metals was follows: Pb > Cr > Cu > Zn and Cd. Among that, the concentrations of Zn, Cu and Cr were at the permissible levels, but Pb and Cd exceeded grade V standard at some sites. The concentrations of Zn and Cu in the wet season were significant higher than that in the dry season (p < 0.05), but the average concentrations of Pb, Cr and Cd were not significantly different in the two seasons (p > 0.05). The annual average risks of human health caused by Cd and Cr were 10⁻³/a and 10⁻⁴/a, respectively, which were higher than the recommended maximum acceptable risk level. The human health risk values of Zn, Pb and Cu were all concentrated at 10⁻⁸/a or 10⁻⁹/a levels, which did not exceed the recommended standard. On the whole, Cd and Cr were the main health risk pollutants of Taizihe River. Pollution sources of Pb was different from other heavy metals in wet and dry season, Cd and Cr were similar in the wet and dry season. The mainly pollution source of heavy metals was industry, especially mining, metal smelting and electroplating industry.     

背角无齿蚌对养殖池塘底泥释放重金属的净化效果

通过建立微型生态系统, 分析养殖池塘底泥释放重金属的特征及背角无齿蚌(Anodonta woodiana)对底泥释放重金属的净化效果。底泥对Al、Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Mo和Pb的最大释放量分别为636、1.5、70.9、34951、10.3、36.9、34.0、53.2、72.4、48.8和3.0 μg·kg-1 dw; 蚌能够对Al、Cr、Mn、Co、Cu、Zn、As和Mo产生净化作用(P<0.05), 最大去除率分别可达到84.7%、98.0%、33.3%、14.3%、23.5%、69.4%、50.0%和13.0%, 响应面优化分析显示养殖密度和处理时间分别为40 只·m-3和24.49 d、25 只·m-3和23.96 d, Al和As去除率可提升至93.8%和60.5%; Al、Cr、Fe、Co、Cu、Zn、As和Mo的净化效果与养殖数量相关, Al、Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Mo和Pb的净化效果与处理时间相关, Cr、Co、Ni、Cu和Zn的净化效果与两者交互作用相关(P<0.05)。提示背角无齿蚌有潜力防控池塘底泥重金属污染。     

Health risk assessment of heavy metals in shellfish collected from Fujian,China

Abstract

With industrialization and human activities, shellfish may be contaminated by various pollutants such as heavy metals. This study aims at the concentrations of As, Cr, Mn, Ni, Cu, Zn, Cd, Sn, Sb and Pb in shellfish collected from Fujian of China, and the risk of heavy metals in shellfish on human health based on target hazard quotients (THQ). Results showed that the THQ values of the elements were far below 1, except for As with an average value of 1.148 in razor clam. No detrimental health effects of heavy metals on humans health was observed by daily consumption of mussel and oyster, but the exposed population to short-necked clam, scallop and razor clam might experience noncarcinogenic health risks because each of the total THQ values was above 1 for the three shellfish.     

Biological monitoring of heavy metal pollution in the region of Lake Balaton, (Hungary)

The concentrations of toxic heavy metals (Hg, Cd, Cr, Cu, Zn and Pb) were measured by atomic absorption spectrophotometry in the gills of mussels (Unio pictorum L.) both living in Lake Balaton as well as transferred to various parts of tributaries of the Lake. The measurements were performed separately with two-week intervals during the course of several months. It was found that (1) the concentration of the studied metals varied with time at each location, less variation occurred in the mussels living in the Lake itself. (2) There were both increases and decreases in the heavy metal concentration of the gills, presumably reflecting the changing level of pollution of the water. It is concluded that mussels can be used as biological indicators for detecting temporal variations in the degree of toxic heavy metal contamination in surface waters, and are good objects for signalizing local events of pollution.     

Distribution and Risk Assessment of Heavy Metals in Sediments of the Pearl River Estuary,Southern China

Sediment cores collected at six freshwater discharge outlets of the Pearl River Estuary were analyzed for metal (Al, Fe, Cr, Pb, and Cd) concentration and risk assessment. The contents of Cr, Pb, Fe, and Al in these samples were measured by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), and Cd was measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The result showed that the concentration ranged (in mg/kg dry weight) as follows: Al, 7,880–97,700; Fe, 30,100–51,900; Cd, 0.23–1.09; Cr, 48.7–109; Pb, 22.3–70.2; respectively. The sediments of different particle size were measured and the result showed that the pelitic fraction (< 0.05 mm) was more enriched in heavy metals. Cd and Pb showed a similar spatial distribution in the sediment, which reflected similar anthropogenic origins. In addition, the temporal distribution of Cr, Pb, and Cd showed a light increase from the 1970s to the 2000s. Furthermore, the enrichment factor (EF) and the geo-accumulation index (I_geo) were used to comprehensively evaluate the pollution degree of heavy metals. The findings will be useful in proposing measures for strategic environmental control in estuaries.     

Assessment of heavy metal pollution and human health risk in urban soils of a coal mining city in East China

The aims of this study were to determine the concentrations, distribution, potential ecological risk (PER), and human health risk (Risk) of heavy metals in urban soils from a coal mining city in China. A total of 36 topsoil samples from Huainan city, Anhui, East China, were collected and analyzed for As, Hg, Pb, Cd, Cr, and Cu. The PER was calculated to assess the pollution level. The hazard index (HI) and carcinogenic risk were used to assess the human health risk of heavy metals in the study area. The average concentration of As, Hg, Pb, Cd, Cr, and Cu were 12.54, 0.21, 24.21, 0.19, 49.39, and 21.74 mg kg^?1, respectively. The correlations between heavy metals indicated that Cu, Cr, Cd, and Pb mainly originated from automobile exhaust emissions, coal gangue, fly ash, and industrial wastewater, and that As and Hg mainly came from coal combustion exhaust. The PER index values of heavy metals decreased in the following order: Hg > Cd > As> Cu > Pb > Cr. The HI and Risk values indicated that the noncarcinogenic and carcinogenic risks of selected metals in the urban soil were both below the threshold values.     

Bioavailability of sediment-bound Cd, Cr and Zn to the green mussel Perna viridis and the Manila clam Ruditapes philippinarum

We assessed the degree to which Cd, Cr and Zn bound with sediment were assimilated by the green mussel Perna viridis and the Manila clam Ruditapes philippinarum. The influences of the metal concentration in the sediment, the presence of phytoplankton, and the oxidation condition of the sediment on metal assimilation were examined. No major difference was found for metal assimilation efficiency (AE) in sediment with different metal concentrations, except for Cd in the green mussels, in which the AE increased by 1.7x when the Cd concentration in sediment was elevated to 15x the natural background level. The higher assimilation of Cd with increasing Cd load in ingested sediment may be due to the higher desorption of Cd in the acidic gut of the bivalves. Both mussels and clams assimilated metals at a higher efficiency from the diatom diet (Thalassiosira pseudonana) than from inorganic sediment particles. The presence of algal particles had little influence on metal assimilation from ingested sediment, and conversely, the presence of sedimentary particles had little effect on metal assimilation from ingested diatom (except for Cd in the mussels). In the mussels, AEs were higher from oxic sediment than from anoxic sediment by 3.1x for Cd, 2.0x for Cr, and 1.4x for Zn, and in the clams AEs were higher from oxic sediment by 2.8x for Cd, 2.0x for Cr, and 2.0x for Zn. Our study suggested that metals associated with anoxic sediment can be potentially available to marine bivalves, and that metal AEs determined for a single diet were probably not affected by the presence of other food particles.     

佛山城市典型森林群落土壤重金属分布、流通及枯落物富集特征

富集重金属的枯落物分解可能提高重金属暴露率,增加人体接触健康风险。为了解南方城市土壤重金属在森林生态系统中的分布及流转情况,通过调查研究了佛山市8个典型森林群落土壤及枯落物重金属含量,分析了各森林群落枯落物对不同重金属的富集效应及重金属随枯落物回归土壤流通量。结果表明：1）城市森林各土壤重金属含量在不同典型群落间差异显著（P<0.05）,差异最大为Pb、Cr、Zn,As、Cu、Ni次之,Hg、Cd最小;土层深度（0-20,20-40,40-60 cm）对重金属含量影响显著（P<0.05）,差异最大为Cd、Hg,其次为As、Cu,最小为Zn、Ni、Pb、Cr。整体上,Cd、Hg、As、Pb、Zn在0-20 cm最高,表层富集特征明显,Cr和Ni在40-60 cm最高。2）8个森林群落中阴香-白楸-醉香含笑群落（CMMC）枯落物对8种重金属的综合富集系数（TBCF,66.76）最高,其中以Cd的富集效果最突出,富集系数为44.45,且对Pb、Cu、Zn也相对富集;最低的为黧蒴锥-香椿-樟树群落（CTCC）,综合富集系数（TBCF）为8.09,仅对Cd、Cr、Cu相对富集,对其余重金属富集效应不明显。3）相关分析显示,群落重金属枯落物流通量与0-60 cm土壤重金属平均含量（Cr和Ni除外）无显著相关性。本研究对城市森林建设管理及筛选重金属富集植物及群落具有较强理论及实践意义。     

Bioaccessibility of Cd,Cr, Cu,Mn, Ni,Pb, and Zn in Mediterranean mussel (Mytilus galloprovincialis Lamarck, 1819) along the southeastern Black Sea coast

The adverse effect of seafood consumption on human health is related to the bioaccessibility in contrast with the total heavy metal level in the tissues. In this study, bioaccessibility of Cd, Cr, Cu, Mn, Ni, Pb, and Zn in Mediterranean mussel (Mytilus galloprovincialis Lamarck, 1819) edible soft tissues collected along the southern Black Sea coast were investigated using in vitro digestion model. Total Pb concentration in the tissues was found to be higher than the maximum permissible limits set by European Commission. The bioaccessibility of metals in the tissues was found to be decreased in the order: Ni (83.11%) > Cu (80.47%) > Zn (76.86%) > Cd (73.32%) > Mn (69.11%) > Pb (61.07%) > Cr (58.44%). While significant positive linear regression was observed between total and bioaccessible concentrations for Mn, Pb, and Ni, significant negative linear regression was found for Cd (p < .05). The hazard quotients (HQ) calculated using bioaccessible amount were detected lower than the limit (HQ <1), which may not pose a potential hazard to humans reported by US Environmental Protection Agency. In sum, mussel consumption from sampling sites may cause a potential risk concerning human health especially for Cd and Pb in case of increased portion sizes.     

Heavy metal uptake capacity of fresh water algae (Oedogonium westti) from aqueous solution: A mesocosm research

The green macroalgae present in freshwater ecosystems have attracted a great attention of the world scientists for removal of heavy metals from wastewater. In this mesocosm study, the uptake rates of heavy metals such as cadmium (Cd), nickel (Ni), chromium (Cr), and lead (Pb) by Oedogonium westi (O. westti) were measured. The equilibrium adsorption capabilities of O. westti were different for Cd, Ni, Cr, and Pb (0.974, 0.418, 0.620, and 0.261 mgg^–1, respectively) at 18°C and pH 5.0. Furthermore, the removal efficiencies for Cd, Cr, Ni and Pb were observed from 55–95%, 61–93%, 59–89%, and 61–96%, respectively. The highest removal efficiency was observed for Cd and Cr from aqueous solution at acidic pH and low initial metal concentrations. However, the removal efficiencies of Ni and Pb were higher at high pH and high concentrations of metals in aqueous solution. The results summarized that O. westti is a suitable candidate for removal of selected toxic heavy metals from the aqueous solutions.     

成都平原北部水稻土重金属含量状况及其潜在生态风险评价

为了解成都平原水稻土重金属含量状况和潜在的生态风险,选取成都平原北部水稻土典型区域为研究对象,采集了158个表层土壤样品,分析了土壤中pH值和Cd、Cu、As、Hg、Pb、Cr、Ni 7种重金属元素含量,以20世纪80年代测定的成都平原土壤重金属元素背景值为评价标准,采用Hakanson潜在生态危害指数法对研究区域的重金属潜在生态风险进行了评价。结果表明:研究区域水稻土Cd、Hg、Ni、Cu、Pb、Cr和As平均含量分别为0.709、0.187、32.08、34.12、31.52、82.13 mg/kg和7.25 mg/kg;Cd、Ni、Cu和Hg 4种重金属超过《土壤环境质量标准》(GB15618-1995) Ⅱ级标准值样本比例分别为87.34%、8.23%、3.80%和3.80%,Cd含量超标严重。7种重金属元素变异系数幅度为18.35%-49.03%,由大到小依次为Cd、Hg、Cu、As、Ni、Cr、Pb。75.32%的样本达到中度或较强重金属潜在生态风险,区域整体表现为中度潜在生态风险(RI平均值为198.65),Cd和Hg为高生态风险元素,对潜在生态风险贡献率分别为62.27%和20.78%,As、Pb、Cu、Ni、Cr为低生态风险元素;风险概率图显示城区周边和绵远河沿线的潜在生态风险等级较高。因此,成都平原水稻土农业生产中应采取一定的措施防控农产品Cd和Hg污染。     

Heavy metal accumulation in frogs surrounding an e-waste dump site and human health risk assessment

Abstract

This study was performed heavy metals (As, Cd, Cr, and Pb) in water, soil and frogs around an electronic-waste dump site. The bioaccumulation factors (BAFs) of heavy metals in three frog species and potential human health risks were assessed. Heavy metals were analyzed using inductively coupled plasma-optical emission spectrometry. The Cd and Pb concentrations in water samples and As and Pb concentrations in soil samples from within the e-waste dump site exceeded the standards. The heavy metal concentrations in the muscles of three frog species were as follows: Cr?>?Pb?>?As?>?Cd, and there were no significant differences among frog species except in the case of Pb (p?<?0.05). Only the Cr concentrations exceeded the food quality standards. The relative order of the BAFs for heavy metals in frogs as a result of uptake from the water and soil was Cr?>?As?>?Pb?>?Cd and Cr?>?As?>?Cd?>?Pb, respectively, which indicated that the uptake from water was greater than that from the soil. The assessment of the health risk index and carcinogenic risk (CR) indicated potential human health effects from As, Cr, and Pb via the consumption of frogs.