鄱阳湖主要入湖口重金属的分布及潜在风险评价

于2011年5月在鄱阳湖的主要入湖口采集了水样和表层沉积物，测定并分析了其中Cu、Zn、Pb、Cd 4种重金属元素的含量和分布。同时采用地积累指数法、潜在生态危害指数法和生态毒性效应等评价方法对沉积物中重金属的污染状况进行了分析评价。结果显示：鄱阳湖主要入湖口水体重金属Cu、Zn、Pb、Cd含量均符合国家渔业水质标准要求，除修河的Pb和信江、饶河入湖口的Cd含量属于国家地表水Ⅱ类水质外，其它所有样地的4种重金属含量均低于国家地表水I类标准限值。沉积物中4种重金属含量均超过鄱阳湖相应背景值且呈积累富集的趋势，其中信江入湖口、饶河入湖口以及三江口已受到重金属的严重污染，潜在生态危害均为中等，而污染最轻的区域为南主湖区。揭示重金属污染程度顺序为Cu＞Zn＞Pb＞Cd；单个重金属潜在生态风险顺序为Cd＞Cu＞Pb＞Zn。进一步的生态毒性效应评价结果表明，虽然鄱阳湖主要入湖口沉积物已经受到重金属污染，但对多数底栖生物未产生明显毒害     

Partitioning of metals in sediments from the Odiel River (Spain)

The Odiel River runs through an area known as the Iberian pyrite belt in the province of Huelva in the southwestern corner of the Iberian Peninsula. Its waters are acidic and contain large amounts of heavy metals from erosion and mining activity. In addition, the Odiel River estuary is one of the most industrialized areas in southern Spain and, consequently, receives the discharge of industrial and urban waste. Seventeen sediment samples from the Odiel and its main tributaries were analyzed for this study. The chemical partitioning of metals (Cu, Zn, Cd, Pb, Fe, Ni, Cr and Co) in each sample was determined in four fractions (acid-soluble, reducible, oxidizable and residual). The total content of each of the metals was also determined. The results showed high concentrations of Fe, Cu, Zn, Pb and Cd, undoubtedly as a result of contamination from the mining and industrial activity mentioned above. However, the concentrations of the other metals analyzed were low since there are no sources of pollution by them in the Odiel River. Based on the chemical distribution of metals, we found that Cd, Zn and Cu are the most mobile metals (i.e., metals that can pass easily into the water under changing environmental conditions). Cd is the metal that showed the highest percentages in the acid-soluble fraction (the most labile) and the lowest in the residual fraction. However, Pb, Fe, Cr and Ni are present in the greatest percentages in the residual fraction, which implies that these metals are strongly linked to the sediments.     

Acid mine drainage pollution in the Tinto and Odiel rivers (Iberian Pyrite Belt, SW Spain) and bioavailability of the transported metals to the Huelva Estuary

The Tinto and Odiel rivers are seriously affected by acid mine drainage (AMD) from the long-term mining activities in Iberian Pyrite Belt (IPB). As a consequence, the Huelva estuary is heavily contaminated by metals and metalloids. This study presents an estimation of the seasonal variation, and the dissolved contaminant load transported by both rivers from February 2002 to September 2004. Besides, toxicity and bioaccumulation tests with the sediments of the estuary have been conducted in order to measure the mobility of the toxic metals. Results show that the Tinto and Odiel rivers transport enormous quantities of dissolved metals to the estuary: 7900 t yr(-1) of Iron (Fe), 5800 t yr(-1) Aluminium (Al), 3500 t yr(-1) Zinc (Zn), 1700 t yr(-1) Copper (Cu), 1600 t yr(-1) Manganese (Mn) and minor quantities of other metals and metalloids. These values represent 37% of the global gross flux of dissolved Zn transported by rivers in to the ocean, and 15% of the global gross flux of dissolved Cu. These metals and metalloids usually sink in the estuarine sediments due to pH and salinity changes. The increase of salinity in the estuary favours the adsorption and trapping of metals. For this reason, the mobility and bioavailability of metals such as Zn, Cd and Cu is higher in sediments located in the area of fresh water influence that in sediments located in the marine influenced area of the estuary, showing a higher percentage of fractionation and bioaccumulation of these metals in the station influenced by the fresh water environment.     

The effect of floods on the transport of suspended sediments and contaminants: a case study from the estuary of the Dese River (Venice Lagoon, Italy)

A flood event was investigated in a measurement section of the estuary of the Dese River, the major tributary of the Venice Lagoon (mean annual discharge=7.5 m3/s), to observe the variations induced by the flow on the physico-chemistry of the water column and the transport of particles and pollutants. The flood was generated by a typical summer storm, which had a return period of 2 years. The study was based on the continuous recording of the discharge and the measurement of both current speed and physico-chemical variables along the vertical profile. Water samples were also collected for the analysis of total and dissolved heavy metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Zn), and nutrients (TKN, N-NO3-, N-NO2-, N-NH3, total phosphorous, P-PO43-). The suspended particle matter (SPM) concentration increased in the water column during the flood, and the discharge versus SPM relationship showed a counterclockwise hysteresis. The occurrence of hysteresis was related to the delayed response of the load, deriving from the runoff on the basin soils with respect to materials mobilized from the streambed in the initial phases of the flood. The transport of most of the analysed heavy metals was driven by the SPM. The increase in concentration of this parameter significantly affected the amount of Fe, Cu, Pb, Cr, Ni, and partially Zn transported by the stream. Among nutrients, N-NO3- concentration also increased significantly during the flood, due to the runoff on agricultural surfaces. The study allowed describing the mechanisms of load generation with high flow magnitudes, highlighting the importance of floods in the transport of materials and pollutants from the drainage basin to the Venice Lagoon.     

长三角典型城郊农田土壤-浙贝母重金属迁移特征研究

城郊生态系统中土壤重金属分布及其在土壤—植物系统的迁移和富集特征是城乡共生体土壤安全研究的热点问题。以典型经济作物浙贝母(Fritillaria thunbergii)为例,基于野外采样和实验分析,对长三角代表性城郊农田中土壤—植物系统重金属的分布、富集和迁移特征开展研究。结果表明:受人类活动的影响,城郊农田土壤中重金属除Cr外,Cu、Zn、As、Cd和Pb的平均含量超过土壤背景值,并且不同重金属在空间分布上表现较高的空间异质性。除Cd和Cr外,浙贝母植株不同部位重金属含量表现为叶、茎显著高于鳞茎,叶中重金属含量可达到鳞茎的5～10倍,表明叶比鳞茎更易富集重金属。重金属迁移系数分析表明,Cr、Cu、Zn、As、Cd和Pb主要富集在浙贝母植株的地上部分,且不同重金属在植株中的迁移和富集能力具有较大的差异。浙贝母地上部分对Cr、As和Pb的富集能力较低,对Cu、Zn和Cd的富集能力相对较强。相比而言,鳞茎对不同重金属的富集能力均较弱,综合污染评价也表明,浙贝母鳞茎中重金属含量并未超过污染标准。     

天沙河沉积物中重金属污染特征与生态风险评价

采集天沙河表层沉积物,检测其中Cr、Ni、Cu、Zn、Cd和Pb 6种重金属的含量,分别采用内梅罗指数法(NI)、地累积指数法、Hakanson生态风险指数法和淡水生态系统沉积物基准法(SQGs)对沉积物中重金属污染的特征和生态风险进行评价,并对几种评价方法进行比较。结果表明：鉴于各采样点重金属的污染特征,采用内梅罗指数法和Hakanson生态风险指数法所得结果一致,杜阮河段、白沙河段及天沙河上游污染较严重,天沙河中下游污染程度相对较低;就各重金属的污染特征而言,采用地累积指数法和Hakanson生态风险指数法所得结果基本一致,Cd和Cu污染较严重,其次是Zn、Ni、Pb、Cr;而采用SQGs法的风险评价与其它方法所得结果存在一定差异,其主要原因是SQGs法基于污染物的生物毒性效应,而其他方法多反映单一重金属污染效应或多种重金属综合污染效应     

Effect of elemental sulphur on solubility of soil heavy metals and their uptake by maize

A pot experiment was conducted to study the influence of elemental sulphur (S) on solubility of soil Pb, Zn and Cd and uptake by maize (Zea mays L.). Two rates of elemental sulphur (S) applied at 0 (S0) and 200 (S200) mmol kg(-1) soil with three rates of each heavy metal at Pb, 0 (Pb0), 200 (Pb200), 400 (Pb400) mg kg(-1) soil, Zn, 0 (Zn0), 100 (Zn100), 200 (Zn200) mg kg(-1) soil and Cd, 0 (Cd0), 50 (Cd50), 100 (Cd100) mg kg(-1) soil, respectively. The result showed that with S application at 200 mmol S kg(-1), soil pH decreased about 0.3 unit and the solubility of the Zn and Cd was significantly increased, but the solubility of Pb had no significant influence. The concentration of Pb, Zn and Cd in maize shoots and roots were increased with increasing rates of heavy metals. However, the concentration of Zn and Cd in shoots and roots were higher with application of S rather than without S but no significant difference was found for Pb. The highest concentration of Zn in the shoots was 2.3 times higher with application of S rather than without at the same rate of Zn, 200 mg kg(-1). Plant biomass was also significantly affected by the application of S and of heavy metals. With heavy metal addition, the shoot and root biomass were decreased with the rates of those of heavy metals increased either with or without application of S. However, the shoot biomass was significantly decreased with S application at the same rate of heavy metals except that with Zn addition. The removal of Cd and Pb by maize uptake and accumulation with application of S had no significant increase compared to that without, but the removal Zn by maize uptake from the soil increased by application of S, 90.9 microg plant(-1) contrast to 25.7 microg plant(-1) at Zn200 within a growth period of only 40 days.     

鄱阳湖表层沉积物中砷及重金属赋存形态及其潜在生态风险

重金属污染是水体沉积物污染的主要问题之一，研究沉积物中重金属元素的赋存形态，探索水体中重金属的来源，可以为水体重金属污染治理修复提供理论基础。采用BCR三步连续提取法对鄱阳湖枯水期表层沉积物中As和7种重金属元素（Cd、Co、Cr、Cu、Ni、Pb和Zn）的赋存形态进行了研究，并基于重金属风险评价代码（Risk Assessment Code, RAC）方法评估了鄱阳湖表层沉积物中的As和7种重金属元素的潜在生态风险。结果表明，鄱阳湖表层沉积物中As、Co、Cr、Cu、Ni和Zn主要以残渣态的形式存在(6160%~8518%)；Pb主要以残渣态（5097%）和铁锰氧化物结合态（4102%）为主要的赋存形态，其可提取态所占比例为4903%，具有较高的二次释放潜力；Cd的赋存形态主要以弱酸提取态（4160%）和铁锰氧化态（2719%）为主，其可提取态所占比例高达7749%，潜在生态风险较大。RAC分析结果表明，鄱阳湖表层沉积物Cd的生态风险整体上位于高风险，需要加强对鄱阳湖Cd污染的关注。所有站点Cr的弱酸提取态所占比例均低于1%，表明鄱阳湖Cr污染的生态风险为无风险，As、Ni和Pb属于低风险，而Cu、Co和Zn位于低风险至中等风险     

湖北大冶铜绿山矿区蔬菜重金属污染特征及健康风险研究

为了解湖北大冶铜绿山矿山周围地区土壤、蔬菜中Cd、Cu、Pb和As的含量水平、富集能力及通过蔬菜摄入导致的人群健康风险，采用对应采样方法采集矿山周围土壤、蔬菜样品共104件，利用ICP-MS测定上述样品中Cd、Cu、Pb和As的含量，通过综合质量评价法、富集系数和目标危险系数对研究区土壤-蔬菜系统中重金属的污染状况、富集能力及人群暴露的健康风险进行了分析。结果表明:研究区土壤重金属污染严重，Cd、Cu、Pb和As平均含量分别达2.56、363.23、121.25和35.96 mg/kg，分别为湖北省对应元素土壤背景值的15.06、11.83、4.54和2.92倍，表现为以Cd、Cu为主的多种重金属共同污染。与《食品中污染物限量》（GB2762 2012）标准比较，蔬菜中Cd、Cu和Pb含量的样本超标率分别为40%、6%和2%，而As的含量均不超标。土壤-蔬菜系统中重金属的综合质量指数达9.76，为重度污染。蔬菜中重金属富集能力的排序为：Cd > Cu > As > Pb，叶菜类蔬菜对Cd、Cu、As和Pb的富集系数均高于非叶菜类蔬菜。研究区人群通过蔬菜摄入As的目标危险系数均大于1，存在As暴露的健康风险；成人和儿童食用蔬菜而摄入重金属的总体目标危险系数分别为1.71~3.98和2.20~5.10，儿童比成人遭受的健康风险更大，并且距离矿山越近，所遭受的健康风险越大。蔬菜中重金属的复合污染已使大冶铜绿山矿山周围居民面临潜在的健康风险。 关键词： 铜绿山；蔬菜；重金属；健康风险；大冶     

Statistical comparison and correlation of zinc and lead in estuarine sediments along the western coast of Mauritius

Cr, Zn and Pb were quantified using atomic absorption spectrometry (AAS) from urban and rural estuarine sediments collected along the western coast of Mauritius during the period July 2002-January 2003. The mean concentration of Cr (225.4 mg kg(-1)), Zn (107.0 mg kg(-1)) and Pb (27.0 mg kg(-1)) in sediments along the six estuaries can be considered below those from contaminated estuarine sediments. Zn and Pb were significantly higher in urban sediments downstream St. Louis River compared to a rural estuary at Tamarin at 5% significance level. Zn was also significantly lower in Tamarin compared to Petite Riviere Noire estuary. Cr was however not significantly different in sediments from the six estuaries and could be considered of basaltic origin and were correlated to neither lead nor zinc. The concentration of Zn and Pb were greatest in the more urbanised upper and lower reaches of the St. Louis estuary during the period of study and were also significantly positively correlated in the estuarine sediments indicating that the cycling of Pb and Zn were linked indicating a common source for Pb and Zn. The potential sources of Pb and Zn in the urban estuarine sediments were considered to arise from road runoff causing significant quantities to be trapped. At present, compared to contaminant levels found in the UK and elsewhere, Mauritius still looks relatively uncontaminated but there is growing concern about heavy metal contamination in urban estuaries. There is therefore a need for long-term studies in estuarine management to involve integrated strategies in which water-sediment interactions in estuaries need to be considered and international standards for sediment quality developed. Such studies undertaken in the future would further the understanding of the biogeochemical processes of estuarine systems in Mauritius which could then be used in environmental development schemes and effective coastal zone management.     

南淝河表层水中重金属空间分布、污染评价及来源

根据南淝河丰水期和枯水期水质的调查数据,采用单因子水质指数法和改进后的模糊综合评价法对水中重金属元素的污染进行了评价,确定了主要污染因子和优先控制断面,并利用主成分分析法对重金属污染进行了溯源分析。结果表明:Cr、Cu、Pb的含量平均值均为枯水期高于丰水期,而As、Cd的含量平均值均为枯水期低于丰水期。单因子水质指数法评价结果显示南淝河重金属污染的主要污染因子是Cd,丰水期和枯水期各采样点Cd的含量均达到地表水Ⅴ类水标准,最高值达到地表水Ⅴ类标准值的2.6倍。改进后模糊综合评价法评价结果显示南淝河水质丰水期基本属于地表水环境质量标准Ⅱ类水标准,潜山北路大桥断面污染最严重,属于优先控制断面,枯水期各断面水质均属于Ⅲ类水标准,整体上南淝河水质达到了水体功能区目标。主成分分析法结果显示,南淝河重金属污染的主要来源是流域内的农药化肥、机械制造和电镀行业的废水以及河道的行船。     

滴水湖沉积物中重金属污染特征与评价

分析滴水湖及其周边沉积物中Hg、As、Cu、Cd、Pb、Zn和Cr等7种重金属含量特征，并用地累积指数法、潜在生态风险指数法和主成分分析法对沉积物中的重金属污染状况进行了评价和分析。结果表明，滴水湖沉积物中As和Pb低于上海市潮滩背景值，Hg、Cd、Zn和Cr均高于潮滩背景值，50%样点的Cu高于潮滩背景值；地累积指数法评价结果表明滴水湖沉积物中Cr的平均污染水平为偏中污染，Hg、Cd和Zn为轻度污染，As、Cu和Pb为清洁水平；潜在生态风险指数法评价结果表明滴水湖沉积物重金属为中等生态风险，Hg和Cd是潜在生态风险的主要贡献元素；主成分分析结果表明，滴水湖沉积物中Hg、Cu、Cd、Pb、Zn和Cr主要来自于人为源，As主要来自底质滩涂     

Environmental contamination of heavy metals from zinc smelting areas in Hezhang County, western Guizhou, China

Total heavy metal (Cd, Cr, Cu, Pb and Zn) concentrations were evaluated in smelting waste, soil, crop and moss samples collected from the Hezhang artisanal zinc smelting areas, Guizhou, China. Soil samples from the cornfield near the smelting sites contained extremely high Cd (5.8-74 mg kg(-1)), Pb (60-14,000 mg kg(-1)) and Zn (260-16,000 mg kg(-1)) concentrations. Elevated heavy metal concentrations were also found in corn plants and total Pb (0.80-1.5 mg kg(-1)) and Cd (0.05-0.76 mg kg(-1)) concentrations in corn grain have totally or partially exceeded the national guidance limits for foodstuff. Thus, the soil-to-crop transfer of heavy metals might pose a potential health risk to the local residents. Similar to the high heavy metal levels in soil and corn, Cd, Cr, Cu, Pb and Zn concentrations in moss samples collected from the smelting sites ranged from 10 to 110, 10 to 55, 26 to 51, 400 to 1200 and 330 to 1100 mg kg(-1), respectively, exhibiting a local spatial pattern of metals deposition from the atmosphere. Based on examination of Zn/Cd and Pb/Cd ratios of the analyzed samples, we have distinguished between the flue gas dust derived and smelting waste derived metals in different environmental compartments.     

Assessment of arsenic and heavy metal concentrations in water and sediments of the Rio Grande at El Paso-Juarez metroplex region

The Rio Grande located along the US-Mexico border is affected by anthropogenic activities along its geographical course. Runoff and wind deposition of smelting residues may contribute to the pollution of the Rio Grande in the El Paso-Ciudad Juarez area. Few studies have addressed the presence or impacts of heavy metals or arsenic in this ecosystem. This study reports a survey of heavy metals (Cr, Cu, Cd, Ni, Pb, and Zn) and arsenic (As) in water and sediments of the Rio Grande collected from seven sites in the El Paso-Juarez region. Since water quality influences metal content in water, physical (temperature, flow and conductivity), and chemical (pH, dissolved oxygen, nitrates, alkalinity, and water hardness) parameters were measured at each site. Arsenic and heavy metal levels were determined using Inductively Couple Plasma (ICP) emission spectroscopy following EPA procedures. Zinc and lead were found as both total and dissolved metals in most of the samples, with concentrations of total recoverable metals reaching up to 105 and 70 microg/l, respectively. Most metals were found in sediment samples collected from four of seven sites. The highest Cu concentration (35 mg/l) was found at the American Dam site. Concentrations of metals found through this survey will be used as a reference for future studies in monitoring arsenic, heavy metals, and their impacts in the Rio Grande.     

江苏省浅水湖泊表层沉积物中重金属污染特征及其风险评价

为揭示江苏省浅水湖泊表层沉积物重金属污染特征,采集江苏省8个浅水湖泊的表层沉积物,测定了8种重金属的含量,并利用地积累指数法和潜在生态风险指数法对沉积物重金属的污染现状以及潜在生态风险程度进行评价。结果表明:江苏省8个浅水湖泊表层沉积物中Mn、Zn、Cr、Ni、Cu、As、Cd、Pb的平均含量分别为634~1 031、66~138、76.0~97.5、39.2~56.3、25.2~50.1、9.9~27.1、0.15~2.98、24.6~51.6mg/kg。地积累指数法评价结果表明,Cd是江苏省8个浅水湖泊表层沉积物中最主要的污染物,Zn、Cu、As、Pb、Ni在一些湖泊为轻度污染,Mn和Cr处于无污染水平。Hkanson潜在生态风险指数法评价结果显示,各湖泊综合潜在生态风险程度的高低顺序为:长荡湖石臼湖白马湖滆湖高邮湖洪泽湖澄湖骆马湖,长荡湖达到严重生态风险水平,石臼湖存在重生态风险,白马湖与滆湖处在中等生态风险水平,而骆马湖、洪泽湖、高邮湖以及澄湖重金属污染则处于低生态风险水平。     

三峡库区172 m蓄水位实现后干流水体溶解态重金属含量变化特征

从2008年至2010年连续两年,对三峡库区涪陵至巴东段水体溶解态重金属含量进行监测,分析三峡水库自2008年首次以172 m高水位试验性蓄水以来水体溶解态重金属含量变化特征及其影响因素。结果表明：水体溶解态重金属含量在丰水期低水位时含量较高,而在平水期和枯水期高水位蓄水时,水体重金属含量较低,丰水期时水体溶解态重金属含量虽然相对较高,但仍然达到《地表水环境质量标准》(GB 3838 2002)Ⅰ类水域标准。重金属在水体与沉积物和消落带土壤中含量并无明显相关性,沉积物和消落带土壤重金属对水体溶解态重金属含量分布影响较小。库区水环境因素在丰水期和平水期、枯水期呈现出明显差异特征,特别是汛后水体悬浮物SS含量远低于丰水期。三峡水库水环境因素的变化对重金属的分配有着重要作用,丰水期过后三峡库区水体pH值和DO升高,水温和Eh降低,SS含量显著下降,水环境因素、气象条件、水位调度等因素的变化致使水体溶解态重金属含量降低     

横沙岛潮滩沉积物中重金属的空间分布与累积

长期以来,长江流域的工农业及城市生活排污一直没有得到有效的控制,这必将对下游河口地区的生态环境造成直接或潜在的威胁。因此,针对横沙岛目前的潮滩环境进行研究,并就潮滩质量和发展趋势进行评价非常必要。通过对横沙岛潮滩表层沉积物中重金属元素空间分布与累积的统计学分析,得知横沙岛潮滩环境总体比较清洁,但多年来受城市工业废水和生活污水排放,以及城市汽车尾气和工业粉尘干湿沉降的影响,局部地区表现出较严峻的污染形势,Cu、Zn、Cr、Pb的最高浓度分别达到背景值的2.34、4.24、2.74和1.63倍。通过对潮滩表层沉积物粒度和有机质含量的分析,指出水动力条件、潮滩生物活化作用是影响重金属空间分布和累积的主要因素。     

有色冶金区土壤-蔬菜系统重金属污染特征及健康风险分析

采用对应采样方法研究大冶有色冶炼厂周围地区土壤、蔬菜中Cd、Cu、Pb和As的含量,并对蔬菜重金属污染状况、富集能力及健康风险进行了分析。结果表明,研究区土壤重金属污染严重,Cd、Cu、Pb和As平均含量分别达5.28、193.37、93.83和36.56 mg/kg,分别为湖北省对应元素土壤背景值的31.06、6.30、3.51和2.97倍,表现为以Cd为主的多种重金属共同污染。与《食品中污染物限量》(GB2762-2012)标准比较,蔬菜中Cd和Cu含量的样本超标率分别为68%和6%,而As、Pb的含量均不超标。蔬菜中重金属富集能力的排序为:CdCuAsPb,叶菜类蔬菜对Cd、Cu、Pb和As的富集系数均高于非叶菜类蔬菜。土壤和蔬菜重金属综合质量指数达10.07,为重度污染。研究区人群通过蔬菜摄入As、Cd的目标危险系数均大于1,存在As、Cd暴露的健康风险;成人和儿童食用蔬菜而摄入重金属的TTHQ分别为2.11~5.06和2.78~6.64,儿童比成人遭受的健康风险更大,并且距离冶炼厂越近,所遭受的健康风险越大。蔬菜中重金属的复合污染已使大冶有色冶炼厂周围居民面临潜在的健康风险。     

Health concerns of consuming cockles (Cerastoderma edule L.) from a low contaminated coastal system

Commercial and recreational harvesting of shellfish within the coastal systems is usually very extensive. Since these ecosystems are frequently subjected to contamination, namely from agricultural, urban and industrial activities, and shellfish generally display a high capacity to bioaccumulate metals, populations may be at risk in terms of toxic metal exposure as a consequence of the harvesting and ingestion of near shore coastal marine organisms. Shellfish is regularly tested for concentrations of metals and other contaminants by legal authorities for commercial purposes, but although health officials use total metal as standards of food safety, only a part of the metal accumulated in shellfish is available to be assimilated and to cause toxic effect. In order to elucidate these issues an investigation on cockles inhabiting the Aveiro estuary was conducted. Element levels in sediments and wild Cerastoderma edule from sampling areas with different levels of contamination were measured; total element burden of cockles was related to accessible fraction for assimilation (TAM); element concentrations in wild C. edule were compared to EFSA (European Food Safe Authorities), USFDA (United States Food and Drug Administration) and FSANZ (Food Standards Australia and New Zealand) maximum levels (MLs); and the amount of cockle flesh needed to be consumed to exceed provisional tolerable weekly intake (PTWI) was determined. The present work showed that although sediment metal and metalloid contamination in Aveiro estuary is low the concentration of elements in C. edule does not reflect the contamination of the sediment. Aluminium (Al) and mercury (Hg) were the less and nickel (Ni), lead (Pb), zinc (Zn) and cadmium (Cd) were the most bioaccumulated metals by cockles. Comparison of MLs from international organisations with the concentration of elements in C. edule showed that arsenic (As) and Pb exceeded standard levels. The ingestion of less than 1 kg for As and 1.5 kg for Pb of cockles would result in exceeding the PTWI threshold (0.015 and 0.025 mg kg?1 week?1 respectively) in any of the areas considered in the study. Cd and Al also appear to be limiting elements for human consumption. Indeed, consumption of more than 3.1 kg and 2.1 kg of whole cockle soft part from one of the study areas during a single week would lead to exceedance of the recommended PTWI value for Cd (0.007 mg kg?1 week?1) and Al (7 mg kg?1 week?1) respectively. The health concerns to humans from cockle consumption from Aveiro estuary are discussed.     

Comparative sediment quality assessment in different littoral ecosystems from Spain (Gulf of Cadiz) and Brazil (Santos and São Vicente estuarine system)

The goal of this work was to establish comparisons among environmental degradation in different areas from Southern Spain (Gulf of Cádiz) and Brazil (Santos and S?o Vicente estuary), by using principal component analyses (PCA) to integrate sediment toxicity (amphipods mortality) and chemical-physical data (Zn, Cd, Pb, Cu, Ni, Co, V, PCBs, PAHs concentrations, OC and fines contents). The results of PCA extraction of Spanish data showed that Bay of Cádiz, CA-1 did not present contamination or degradation; CA-2 exhibited contamination by PCBs, however it was not related to the amphipods mortality. Ría of Huelva was the most impacted site, showing contamination caused principally by hydrocarbons, in HV-1 and HV-2, but heavy metals were also important contaminants at HV-1, HV-2 and HV-3. Algeciras Bay was considered as not degraded in GR-3 and -4, but in GR-3' high contamination by PAHs was found. In the Brazilian area, the most degraded sediments were found in the stations situated at the inner parts of the estuary (SSV-2, SSV-3, and SSV-4), followed by SSV-6, which is close to the Submarine Sewage Outfall of Santos - SSOS. Sediments from SSV-1 and SSV-5 did not present chemical contamination, organic contamination or significant amphipod mortality. The results of this investigation showed that both countries present environmental degradation related to PAHs: in Spain, at Ría of Huelva and Gudarranque river's estuary areas; and in Brasil, in the internal portion of the Santos and S?o Vicente estuary. The same situation is found for heavy metals, since all of the identified metals are related to toxicity in the studied areas, with few exceptions (V for both Brazil and Spain, and Cd and Co for Brazilian areas). The contamination by PCBs is more serious for Santos and S?o Vicente estuary than for the investigated areas in Gulf of Cádiz, where such compound did not relate to the toxicity.