Physico-chemical and toxicological characterization of the historic estuarine sediments: a multidisciplinary approach

The accumulation rates, the geochronology of metals and PAH contamination, and the Microtox toxicity are studied in five sediment cores (50 cm length) covering different areas of the Santander Bay, Northern Spain. Chronology given by (210)Pb and (137)Cs reveals significant differences in accumulation rates between sites (0.2-1.1 cm/year), as well as a variable degree of anthropogenic enrichment factors for Fe, Mn, Cu, Pb, Zn, Ni (from 1 to 15) and concentrations of summation Sigma 16PAHs (from 0.01 to 23.84 mg/kg dw) in sediments over the last 90 years. The results indicate the increasing contamination pressure from industrial and urban activities along the Bay. No toxic results from the Microtox test are obtained either with pore water or with normalised sediment aqueous extracts (European Norm EN 12457), suggesting low water solubility and low availability of contaminants in the studied sediments. However, the EC50 values from the Microtox Basic Solid Phase Test (BSPT) ranged from 0.03% to 2.35%, showing vertical toxicity profiles in accordance with metal and PAHs behaviour. The correlation degrees of Microtox BSPT toxicity to chemical concentration in sediment profiles are widely variable showing a high site-dependent toxicity. The oligochaete Limnodrilus hoffmeisteri has been used as a chronic bioassay over surface sediments of two of the studied sites, showing results coherent with the Microtox BSPT acute test results. Global results of the present work provide regional geochemical baselines for metals and PAHs and toxicological data now make it possible to obtain a preliminary quality assessment of the Santander Bay sediment profiles.     

An integrated approach to the toxicity assessment of Irish marine sediments: validation of established marine bioassays for the monitoring of Irish marine sediments

This paper describes the ecotoxicological evaluation of marine sediments from three sites around Ireland representative of a range of contaminant burdens. A comprehensive assessment of potential sediment toxicity requires the consideration of multiple exposure phases. In addition to the evaluation of multi-exposure phases the use of a battery of multi-trophic test species has been advocated by a number of researchers as testing of single or few organisms may not detect toxicants with a specific mode of action. The Microtox(R) solid phase test (SPT) and the 10-d acute amphipod test with Corophium volutator were used to assess whole sediment toxicity. Porewater and elutriates were assessed with the Microtox(R) acute test, the marine prasinophyte Tetraselmis suecica, and the marine copepod Tisbe battagliai. Solvent extracts were assayed with the Microtox(R) and T. battagliai acute tests. Alexandra Basin was identified as the most toxic site according to all tests, except the Microtox(R) SPT which identified the Dunmore East site as being more toxic. However, it was not possible to correlate the observed ecotoxicological effects with a specific and/or class of contaminants based on sediment chemistry alone. Therefore porewaters found to elicit significant toxicity (Dunmore East and Alexandra Basin) with the test battery were selected for further TIE assessment with T. battalgiai and the Microtox(R) system. The results of this study have important implications for risk assessment in estuarine and coastal waters in Ireland, where, at present the monitoring of sediment and water quality is predominantly reliant on chemical analysis alone.     

Impact of dredging in a shallow coastal lagoon: Microtox Basic Solid-Phase Test, trace metals and Corophium bioassay

The aim of this work was to measure survival of the amphipod Corophium insidiosum and luminescence inhibition in the marine bacterium Vibrio fisheri on surface sediment samples collected from a shallow coastal lagoon (Pialassa Baiona, northern Adriatic Italian coast) before execution of dredging operations to deepen the main inner channel of the lagoon and restore the water circulation. Trace metal (Cd, Cu, Cr, Hg, Ni, Pb) concentrations, grain size and organic carbon matter content as loss of ignition were also measured. Toxicity testing with V. fisheri was carried out according to the Microtox Basic Solid-Phase Test (BSPT) protocol. The preliminary outcomes of this work show that: (a) the investigated area can be categorised as moderately degraded; (b) there is no evident spatial pattern in sediment toxicity and trace metal concentrations; (c) Microtox responses are not biased by sediment characteristics such as silt, clay and organic matter content.     

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     

Geochemistry and bioavailability of metals in sediments from northern San Francisco Bay

In this study, metals (Be, Cr, Mn, Fe, Ni, Cu, Zn, Ag, Cd, Pb and Hg) in the fine-grained fraction (<63 microm) from 12 sites at different locations in northern San Francisco Bay over a year period from March 2000 to March 2001 were analyzed after acid extraction. The results showed that metal concentrations in the sediments varied from site to site, whereas some of them were found elevated with respect to the sediment of Tomales Bay, CA, which has little contamination history, indicating an enrichment of the metals in the sediment samples analyzed. Sediment toxicity and bioaccumulation evaluation by a clam species, Macoma nasuta, exposed to the sediment samples collected from the six sampling sites was carried out. The results showed that the sediment samples tested significantly reduced clam survival. Toxicity of the sediments to the clam was, in part, related to elevated metal concentrations in the sediments. In order to examine geochemistry of the metals and to understand potential correlations between metal concentrations and geochemical matrix elements of the sediments, bioavailability and toxicity of the metals, detailed analysis of metal concentrations associated with total organic carbon and the Fe-oxy-hydroxides in the sediment samples was performed. The analysis showed that sediment geochemistry appeared to influence metal bioavailability and may have important impacts on the toxicity of these metals to the clam.     

An integrated approach to the toxicity assessment of Irish marine sediments: application of porewater Toxicity Identification Evaluation (TIE) to Irish marine sediments

An integrated approach to the ecotoxicological assessment of Irish marine sediments was carried out between 2004 and 2007. Phase I Toxicity Identification Evaluation (TIE) of sediment porewaters from two sites on the east coast of Ireland were conducted. Initial Tier I screening of three Irish sites identified the need for TIE after significant toxicity was observed with Tisbe battagliai and the Microtox assay at two of the assayed sites (Alexandra Basin and Dunmore East). Porewaters classified as toxic were characterised using four manipulations, ethylenediaminetetraacetic acid (EDTA) chelation, sodium thiosulphate addition, C(18) Solid Phase Extraction (SPE) and Cation Exchange (CE) SPE. Prior to initial testing, and TIE manipulations, all porewater samples were frozen at -20 degrees C for several months until required. After initial Tier I testing Alexandra Basin porewater was classified as highly toxic by both assays while Dunmore East porewater only warranted a TIE with T. battagliai. Results of TIE manipulations for Alexandra Basin porewater and the Microtox Basic test were inconclusive. The toxicity of the porewater in this assay was significantly reduced after freezing. Three experimental episodes were conducted with one month between each for the Alexandra Basin porewater. After each month of freezing the baseline toxicity was further reduced in the Microtox assay, therefore it was not possible to draw accurate conclusions on the nature of the active contaminants in the sample. However, toxicity to T. battalgiai did not change after storage of the porewater. The C(18) and CE SPE decreased the toxicity of Alexandra Basin porewater to the copepod indicating that both organic and cationic compounds (e.g. metals) were active in the sample. Dunmore East porewater was assayed with T. battalgiai and again a combination of organic and inorganic compounds were found to be partly responsible for the observed toxicity (C(18), CE SPE and EDTA reduced toxicity). Results from these TIEs provide insight into the complexity of interpreting marine TIE data from porewater studies where mixtures of unknown substances are present.     

Development and application of an innovative expert decision support system to manage sediments and to assess environmental risk in freshwater ecosystems

With the aim of supporting decision makers to manage contamination in freshwater environments, an innovative expert decision support system (EDSS) was developed. The EDSS was applied in a sediment quality assessment along the Bormida river (NW, Italy) which has been heavily contaminated by an upstream industrial site for more than a century. Sampling sites were classified by means of comparing chemical concentrations with effect-based target values (threshold and probable effect concentrations). The level of each contaminant and the combined toxic pressure were used to rank sites into three categories: (i) uncontaminated (8 sites), (ii) mildly contaminated (4) and (iii) heavily contaminated (19). In heavily contaminated sediments, an environmental risk index (EnvRI) was determined by means of integrating chemical data with ecotoxicological and ecological parameters (triad approach). In addition a sediment risk index (SedRI) was computed from combining chemical and ecotoxicological data. Eight sites exhibited EnvRI values ≥ 0.25, the safety threshold level (range of EnvRI values: 0.14–0.31) whereas SedRI exceeded the safety threshold level at 6 sites (range of SedRI values: 0.16–0.36). At sites classified as mildly contaminated, sublethal biomarkers were integrated with chemical data into a biological vulnerability index (BVI), which exceeded the safety threshold level at one site (BVI value: 0.28). Finally, potential human risk was assessed in selected stations (11 sites) by integrating genotoxicity biomarkers (GTI index falling in the range 0.00–0.53). General conclusions drawn from the EDSS data include: (i) in sites classified as heavily contaminated, only a few exhibited some significant, yet limited, effects on biodiversity; (ii) restrictions in re-using sediments from heavily contaminated sites found little support in ecotoxicological data; (iii) in the majority of the sites classified as mildly contaminated, tested organisms exhibited low response levels; (iv) preliminary results on genotoxicity biomarkers indicate possible negative consequences for humans if exposed to river sediments from target areas.     

A bioassay approach to determine the dioxin-like activity in sediment extracts from the Danube River: ethoxyresorufin-O-deethylase induction in gill filaments and liver of three-spined sticklebacks (Gasterosteus aculeatus L.)

Sediment samples from the upper Danube River in Germany have previously been characterized as ecotoxicologically hazardous and contaminants in these sediments may contribute to the observed decline of fish populations in this river section. For the investigation of sediment toxicity there is a need for development, standardization and implementation of in vivo test systems using vertebrates. Therefore, the main objective of this study was to apply and evaluate a recently established fish gill EROD assay as a biomarker in sediment toxicity assessment by using extracts of well characterised sediment samples from the upper Danube River. This to our knowledge is the first application of this novel assay to sediment extracts. Sediments from four different sites along the upper Danube River were Soxhlet-extracted with acetone and dissolved in DMSO. Three-spined sticklebacks (Gasterosteus aculeatus L.) were exposed for 48 h to various concentrations of the extracts, to the positive control beta-naphthoflavone or to the solvent. Measurements of EROD activity in gill filaments and liver microsomes followed the exposure. Concentration-dependent induction of EROD in both gill and liver was found for all sediment extracts. The highest EROD-inducing potency was determined for extracts of sediments from the sites "Opfinger See" and "Sigmaringen" and the EROD activities in gill and liver correlated well. The results from the gill and liver assays were in accordance with in vitro results of previous investigations. The EROD activities measured in the present study corresponded with the concentrations of PAHs, PCBs and PCDD/Fs in the sediment samples derived in a previous study. The sticklebacks in this study were in the reproductive phase and a stronger EROD induction was obtained in the females than in the males. Implementation of the EROD assay in testing of sediment extracts gave highly reliable results which make this assay an ecotoxicologically relevant method for assessment of contamination with Ah receptor agonists in sediments.     

应用平衡分配法建立长江水系沉积物金属相对质量基准

在不同的条件下,沉积物可成为环境中污染物的“源”或“汇”,而受污染的沉积物会对水生生物带来危害。因此,需要制定沉积物质量基准(SQC),以此作为评价沉积物污染及其生态效应的基础。在过去的几年中,对利用平衡分配法来建立SQC的方法进行了广泛的研究,并被认为是最有效的方法之一。采用平衡分配法,初步建立了长江水系8种重金属及类金属(Cu, Zn, Cd, Pb, Ni, Fe, Hg,As)的沉积物相对质量基准。结果表明,上述重金属及类金属的SQC在从长江上游到下游,总体趋势上呈降低的分布特征,并由于地域环境条件的不同,存在着高SQC值单元及低SQC值单元。得出的SQC与国内已有的SQC具有可比性,但高于美国国家环保局提出的SQC,主要是由于采用平衡分配法建立的SQC是一种数值型的基准值,缺乏生物效应的校正。因此,在将其应用到沉积物污染状况评价之前,还需要进行深入的研究工作,特别是毒理学试验。     

Distribution of heavy metals in sediments of Mwanza Gulf of Lake Victoria,Tanzania

Sediment samples were analyzed for Cd, Cr, Cu, Pb, Hg and Zn by AAS. The highest concentrations (ppm) for Cu (26.1+/-4.8), Hg (0.2+/-0.05), Pb (30.7+/-5.6) and Zn (45.4+/-13.1) were found at approximately 25 m from the shoreline. Generally, heavy metals concentration in the sediment decreased with increasing distance from the shoreline except for Cd and Cr whose highest concentrations were found at approximately 2000 m from the shoreline.The data also indicated that sediment samples which were collected at the shores within the urban area of Mwanza showed elevated levels of Pb (54.6+/-11.1 ppm) and Zn (83.7+/-21.5 ppm). However, the highest concentrations of Cd (7.0+/-2.1 ppm), Cr (12. 9+/-1.0 ppm) and Hg (2.8+/-0.8 ppm) were recorded at sampling stations which were adjacent to river mouths.     

Environmental geochemistry and pollution studies of Aliaga metal industry district

The Aliaga metal industry district located 50 km northwest of Izmir City, in Turkey, includes many metal factories. The geology of the area is represented by Mesozoic flysch deposits and Cenozoic volcano sedimentary rocks. Tectonic elements are NE-SW and NW-SE trending faults and a W-NW trending fault direction that is important for water supply. Rock, soil, stream sediment, and water samples taken at various distances from the industrial area were analyzed for Fe, Ti, Mn, Cr, Pb, Cu, Ni, Zn, and Mo. According to the results, the elements in rocks are reasonable for the range of "Clarke" values, but in the soils and stream sediment, they comprise higher values than are acceptable for agricultural activities. Toxicity analyses were carried out in the drinking artesian water of Cakmakli village and wastewater samples of the factories and river water both of which are used for irrigation of the agricultural areas in and around the investigated area. The people should, however be made aware that this waste and river water is unacceptable for agriculture. Additionally, the contamination of seawater in Nemrut Bay is probably caused by contaminated river and underground water running to the sea. The chemical and toxicity analysis of drinking water samples show that they are above accepted standards and harmful. Previous air pollution studies (funnel gas emission analyses) also show that gas emission contains high amount of dust particles with high Fe, Zn, Pb, and Cu concentrations. As a result, all elements analyzed are of great importance relative to problems concerning contamination of the soil, stream sediment, ground surface water, and air by individual metals from uncontrolled processing of some metal factories.     

Correlation of field-measured toxicity with chemical concentration and pollutant availability.

Direct field toxicity tests were performed in two Louisiana waterways, Bayous Trepagnier and St. John, on sediments containing organic/heavy metal mixtures. Our approach involved bioluminescent bacterial toxicity assays (using DeltaTox, which qualitatively identifies polluted areas, and Microtox, which quantifies toxicity). Samples were more completely analyzed in our laboratory using inductively coupled plasma atomic emission spectroscopy (ICP-AES) and gas chromatography/mass spectrometry (GC/MS). Results indicate that lead is the primary toxic metal at the sites examined, though concentrations of metals fluctuate due to spatial variation and the dynamic nature of the waterways. Polycyclic aromatic hydrocarbons (PAHs) are the most abundant group of organics measured and appear to contribute to the overall toxic response. DeltaTox located toxic hotspots where there was an average light loss of 53-100%. Toxicity results from both assays agree but are well correlated with concentration measurements only for certain sediment fractions. Overall, the DeltaTox/Microtox approach appears to be rapid and cost effective for on-site hotspot identification, and may increase understanding of hazards associated with heavy metal and organic contaminants in these waterways.     

The speciation and bioavailability of mercury in sediments of Haihe River, China

Twenty-one sediment samples in 11 sites along the Haihe River and Dagu Drainage River, Tianjin, China, were analyzed to investigate the pollution status and bioavailability of mercury (Hg). The results showed that the Haihe River was slightly polluted with Hg when flowing through Tianjin city. On the contrary, the sediments collected from Dagu Drainage River, an important drainage river in Tianjin, were found to have very high Hg concentrations and the highest concentration reached 8779.1 ng g(-1) (dry weight). The methylmercury (MeHg) concentrations accounted for 0.1-2.4% (average: 0.9%) of total mercury (HgT) and were strongly influenced by HgT (r=0.91, p=0.99, n=20) and total organic carbon (TOC; r=0.76, p=0.99, n=20) contents in sediments. Moreover, a five-step sequential selective extraction (SSE) procedure was used to study the bioavailability of Hg in sediments. The mercury in sediments existed mainly as element Hg and mercury sulfide, which accounted for 46.5% and 39.0% of HgT, respectively. The percentage of exchangeable Hg (defined as water soluble Hg plus 'human stomach acid' soluble Hg) was only 0.1-4.6%. The distribution of exchangeable Hg showed an obvious difference to that of HgT, indicating that the HgT concentrations were absolutely insufficient to evaluate the risk of Hg in sediments.     

Determining sediment quality for regulatory proposes using fish chronic bioassays

Sediment quality assessments for regulatory purposes (i.e. dredged material disposal) are characterized by linking chemical and acute ecotoxicological data. The design of chronic bioassays that incorporate more sensible endpoints than acute tests is discussed to address sediment quality for environmental quality assessment and regulatory proposes. The chronic tests use juveniles of commercial species of fish Sparus aurata and Solea senegalensis, to assess sediment toxicity in samples collected along different littoral areas in the North and the South of Spain. The organisms were exposed during 60 days and sublethal endpoints were selected including biomarkers of exposure to metals (metallothioneins - MTs) and to organic contaminants (ethoxyresorufin-O-deethylase activity - EROD activity) and biomarkers of effect (histopathology in different tissues, gill and liver). A Multivariate Analysis Approach was conducted in order to associate these biological responses with sediment metal concentration from the ports and with chemical residues in biological tissues exposed to sediments under laboratory conditions.     

Screening ecological risk assessment of persistent organic pollutants in Mediterranean sea sediments

A screening ecological risk assessment (ERA) was conducted for the first time in the Mediterranean basin in order to assess the toxicity posed to the benthic community by PCBs, DDTs and HCB in marine sediments. The characterization of the exposure was conducted by means of an extensive literature survey, generating a database with more than 2000 samples. The effects were assessed by the adoption of guidelines previously developed in the literature, because ecotoxicological information about persistent organic pollutants (POPs) in the Mediterranean sediments was lacking. Existing sediment quality guidelines (SQGs) for the target pollutants were compiled and consensus values were calculated for three different categories of toxicity, namely threshold effect concentration (TEC), probable effect concentration (PEC) and extreme effect concentration (EEC). The combination of exposure and effects characterization enabled the identification of some areas of concern in the vicinity of industrial and urban locations and in the mouths of the main Mediterranean rivers. Beyond the Mediterranean continental shelf, the level of toxicity for the benthic community was generally low. The evaluation of the toxicity induced by the mixture of the target pollutants spotted the importance of DDT contamination in the Mediterranean sediments, despite the fact that main inputs to the sea have been significantly reduced during the last decades.     

太湖流域沉积物中有机氯农药空间分布特征及风险评价

为了解太湖流域表层沉积物中有机氯农药的空间分布和污染特征,采集全流域111个表层沉积物样品,用GC-μECD分析了20种有机氯农药的含量,并基于沉积物质量基准法对沉积物污染风险进行评价。结果表明:太湖流域沉积物中20种有机氯农药(OCPs)的总含量介于16. 3～96. 9 ng/g dw之间,平均值为35. 0ng/g dw,其中HCHs和DDTs是主要的检出成分,平均含量分别为12. 1、7. 6 ng/g dw,两者含量之和占总OCPs的25. 5%～85. 5%。特征化合物指数法分析结果表明,HCHs主要来源于林丹,而且该区域仍然有新的DDT输入,并且大部分p,p’-DDT通过好氧生物降解为p,p’-DDE。沉积物质量基准法评价结果显示,γ-HCH、DDTs潜在生物毒性较大。     

Remobilisation of 109Cd, 65Zn and 54Mn from freshwater-labelled river sediments when mixed with seawater

A major fraction of trace metals transported by rivers is associated with sediments, especially during flooding, when erosion and resuspension increase sediment loads. Upon contact with seawater in estuaries, changes in ionic strength and pH may remobilise trace metals from sediment surfaces into more bioavailable forms. The objective of the present work was to investigate time-dependent interactions between trace metals and freshwater sediments and their potential remobilisation upon contact with seawater. Two river sediments (one organic and one inorganic) were labelled with 109Cd2+, 65Zn2+ and 54Mn2+ radioactive tracers for periods up to 6 months. Sorption of tracers occurred rapidly (> or = 80% sorption, < 1 h), followed by a slower approach to pseudoequilibrium. Kd(6 months) were estimated as 460, 480 and 2200 ml/g (inorganic sediment) compared to 5300, 4000 and 1200 ml/g (organic sediment) for 109Cd, 65Zn and 54Mn, respectively. Remobilisation of tracers from labelled sediments was studied using sequential extractions. Artificial seawater extracts simulated an estuarine environment. Subsequent extractions provided information about more strongly sorbed tracer fractions within sediments. Remobilisation of 109Cd by seawater was significant (> 65%) and least affected by sediment type or freshwater labelling time. Redistribution of Cd to strongly bound phases was minimal (4% and 1% of 109Cd in strongly oxidisable fractions). Seawater remobilisation of 65Zn was significantly greater from the organic sediment (54%) compared to the inorganic sediment (8%), where a large fraction of 65Zn (14%) became irreversibly bound. Similarly, more 54Mn was remobilised by seawater from the organic sediment than the inorganic sediment (66% and 3% remobilised, respectively), i.e., 54Mn became more strongly bound in the inorganic sediment. A simple three-box model, based on first-order differential equations, was used to describe the interaction between tracers in spiked freshwater and two operationally defined sediment fractions ("seawater exchangeable" and "seawater unexchangeable") up to 6 months of freshwater labelling. Model simulations were fitted to experiment data and apparent rate constants were calculated using numerical optimisation methods. Sorption ratios from modelling data (i.e., k1/k2) were greater for organic compared to inorganic sediments, while fixation ratios were higher in inorganic sediments. In conclusion, trace metals can be remobilised from sediments on contact with seawater in estuaries. High organic content in sediments increased initial sorption of tracers but inhibited redistribution to more strongly bound fractions over time, resulting in greater remobilisation of tracers when in contact with seawater.     

Screening ecological risk assessment for the benthic community in the Venice lagoon (Italy)

According to the risk hypothesis: the sediment as source of potential risk for the benthic community, an Ecological Risk Assessment (ERA) based on the quotient method was undertaken. The exposure of the benthic community to different classes of pollutants (metals, chlorinated organic compounds and polynuclear aromatic hydrocarbons) was inferred by estimating the pollutant stocks in the top 15-cm sediment of the whole Venice lagoon, after application of geostatistic techniques. The risk was calculated by comparing the sediment exposure profiles with the ecotoxicological benchmarks for benthic organisms. Kriging based maps of the spatial distribution of the estimated risk for the benthic community over the whole lagoon were obtained. The highest risk, found in the areas nearest to the sources of contamination (e.g., the industrial district of Porto Marghera and the river mouths), was posed by mercury (40% of the sampling stations showed exposure levels higher than the Probable Effect Level), arsenic and nickel (75% of the sampling stations exceeded the Threshold Effect Level).     

江西德兴矿集区水系沉积物重金属污染分析

对矿山及其周边地区的环境进行现状调查和评价,可以为环境监测和环境保护提供客观依据,具有重要意义。以江西德兴铜多金属矿山及矿集区为研究区,开展区域水系沉积物的重金属污染研究。在德兴地区4 800 km2的范围内,系统采集水系沉积物样品330个。同时,采用X荧光光谱法、等离子原子发射光谱法等现代测试技术,分析了土壤和水系沉积物中重金属（As、Hg、Cd、Cr、Zn、Cu、Pb）的含量。样品中重金属As、Hg、Cd、Cr、Zn、Cu和Pb的含量变化范围分别为3070~1 109、0015~5430、 0035~135、7~236、22~1 770、5~4 390和15~1 685 mg/kg。通过对样品的重金属元素含量统计分析和绘制等值线图,发现该区域水系沉积物中存在不同程度的As、Hg、Cd、Zn、Cu和Pb重金属污染。污染区域主要分布在德兴铅锌和铜钼矿区德兴河下游至与乐安河交汇处、德兴河与大坞河周边地区、西北部分煤矿区.     

Concentrations of Cu and Pb in the offshore and intertidal sediments of the west coast of Peninsular Malaysia

Malaysia is now a developing country and on her way towards being an industrialised one by the year 2020. Most of her industries and urban areas are located on the west coast of Peninsular Malaysia. In addition, the offshore area of the west coast is now one of the busiest shipping lanes in the world. These two phenomena make the intertidal and offshore areas of the west coast of Peninsular Malaysia interesting for scientific studies. Therefore, this study focused on both the offshore and intertidal sediments of the west coast of Peninsular Malaysia. Sampling for sediment samples were done from the northern to the southern ends of the peninsula and these sediment samples were analysed for Cu and Pb. It was found that total Cu concentrations ranged from 0.25 to 13.8 and 0.40 to 315 microg/g dry weight (dw) for offshore and intertidal sediments, respectively. For Pb, it ranged from 3.59 to 25.4 and 0.96 to 69.8 microg/g dw for the offshore and intertidal sediments, respectively. The ranges of Cu and Pb found from the west coast of Peninsular Malaysia were low in comparison to regional data. However, some intertidal areas were identified as receiving anthropogenic Cu and Pb. Geochemical studies revealed that the 'nonresistant' fraction for Pb contributed about 70.0% to 75.0% and 54.0% of the total Pb concentration in the offshore and intertidal sediments, respectively. As for Cu, the 'nonresistant' fraction contributed about 46.2% to 60.4% and 46.3% of the total Cu concentration in the offshore and intertidal sediments, respectively. The 'nonresistant' fraction contained mostly of anthropogenic metals besides natural origins. These 'nonresistant' percentages indicated that both the offshore and intertidal areas could have received anthropogenic-derived metals, which could be influenced by physico-chemical properties of the sediments. Although the present data indicated that contamination due to Cu and Pb in the west coast of Peninsular Malaysia especially in the offshore areas were not serious, regular biomonitoring studies along the west coast of Peninsular Malaysia are recommended.