结合主成分分析法(PCA)和正定矩阵因子分解法(PMF)的鄱阳湖丰水期表层沉积物重金属源解析

为识别表层沉积物重金属的来源以及量化源贡献,选取鄱阳湖丰水期表层沉积物为研究对象,测定14种重金属(V、Cr、Co、Ni、Cu、Zn、Sr、Mo、Cd、Sb、W、Pb、Hg和As)的含量,分析其污染及空间分布特征,并利用主成分分析法(PCA)和正定矩阵因子分解法(PMF)对沉积物重金属进行源解析.结果表明:除V和Cr外,Cd、Mo、Hg、Cu、Pb、Zn、W、Sr、As、Ni、Co和Sb的平均含量分别为江西省土壤背景值的5.7、2.2、1.9、1.8、1.5、1.5、1.4、1.3、1.3、1.2、1.0和1.0倍; Cd、Hg、Cu、Mo、Pb、Sr和Zn超出江西省土壤背景值的比例相对较高,分别为100%、100%、100%、100%、97%、97%和93%,所有沉积物样品中Cd含量超过农用地土壤污染风险筛选值的比例为51%; V、Cr、Co、Ni、Cu、Zn、Sr、Mo、Sb、W、Pb、Hg和As含量呈未污染至弱污染水平,而Cd含量属于中等污染水平,接近于重污染水平.总体而言,Cd的污染相对较严重.重金属的分布具有显著的区域特征,其中Cr、Cu、Zn、Sr、Pb、Hg和As的空间分布十分相似,表现为在赣江、抚河、信江和饶河入湖口附近区域含量较高,而Co、Ni、Mo和Sb明显在湖区南部、东北部和修水入湖附近这3个区域聚集,Cd和W的空间变异性相对较大,V的含量分布相对较均匀.PCA和PMF解析结果都表明鄱阳湖丰水期表层沉积物重金属受4种来源的共同影响,其中,矿业和工业活动的影响最大,相对贡献率为38%,其次是尾矿和废渣,相对贡献率为28%,再是农业活动,相对贡献率为19%,最后是自然来源的相对贡献率为14%.     

抚仙湖沉积物重金属时空变化与人为污染评价

分析了抚仙湖表层沉积物及沉积短岩芯中10种金属元素含量,结合沉积年代学,定量研究了Cr、Cu、Ni、Pb、Zn的污染特征及时空变化规律;参考沉积物质量基准与潜在生态风险指数法探讨了表层沉积物重金属的潜在生态风险.结果表明,表层沉积物中重金属含量具有一定的空间差异性,近岸地区重金属含量总体上高于湖心区;Pb、Zn含量自1980s中期以来逐渐增加,而Cr、Cu、Ni含量呈下降趋势.重金属富集系数与聚类分析结果表明,抚仙湖沉积物主要重金属污染元素为Pb、Zn,污染开始于1980s中期,并逐渐加重.表层沉积物中Pb、Zn富集系数分别为1.6~4.1和1.4~2.6,已达到弱—中等污染程度,北部湖区污染程度略高于南部湖区;除此之外,北部湖区近岸区域Cr污染程度也略高于其他湖区.除了大气沉降来源之外,抚仙湖沉积物重金属污染还可能与入湖河流输入有关.单因子生态风险指数表明,表层沉积物中Cr、Cu、Ni、Pb、Zn具有较低的潜在生态风险;而综合潜在生态风险指数表明,表层沉积物中重金属具有中等程度的潜在生态风险,这与根据沉积物质量基准所获得的评价结果一致.     

长江中下游不同湖泊沉积物中重金属污染物的累积及其潜在生态风险评价

利用富集因子和Hakanson潜在生态风险指数法,结合年代学结果,对长江中下游湖泊太白湖、龙感湖、巢湖和西氿沉积物中重金属元素Co、Cr、Cu、Ni、Pb、Zn的富集程度进行了评价,并比较分析了上述重金属的潜在生态风险.结果表明,太白湖和龙感湖沉积物中各重金属富集程度均较低;巢湖沉积物中Co、Cr、Ni的富集程度接近中等水平,而Cu、Pb、Zn的富集已经达到中等水平;西氿沉积物中Co的富集非常低,Cr、Ni富集水平较低,Pb达到中等富集,Cu、Zn达到较高的富集水平.对4个湖泊沉积物中重金属的综合污染程度进行比较:巢湖西氿龙感湖太白湖.各湖泊沉积物中单一元素的潜在生态风险都较低,但是,根据多元素潜在生态评价指数,各湖泊沉积物中重金属存在明显不同的潜在生态风险:巢湖西氿龙感湖太白湖.总体上看,太白湖和巢湖沉积物重金属污染以及潜在生态风险自1965年以来一直在加重,而龙感湖和西氿沉积物在表层有下降的趋势.这种差异与各个湖泊流域内人类活动的方式和强度密切相关.巢湖和西氿流域内城市化、工业化发展迅速,人类活动导致大量重金属元素进入湖泊,给湖泊带来明显的污染;而龙感湖和太白湖流域人类活动主要以农业活动为主,人类活动对重金属的贡献相对较小.     

Evaluation of metal contamination in coastal sediments of the Bay of Bengal, India: geochemical and statistical approaches

Surface sediment samples collected from the inner shelf region of the Bay of Bengal, were analysed for the major elements and total and acetic acid available trace elements (Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Si, Zn) to evaluate geochemical processes influencing their distribution. Major elemental analysis showed that the sediments had high concentrations of Si and relatively low concentrations of Al and Fe. Both major elemental and trace metal concentrations indicated that the sediments represent weathered products of granite and charnockite. Normalization of metals to Al indicated relatively high enrichment factors for Pb, Cd, Zn and Cr. The higher proportions of nondetrital Pb (66%), Cd (41%) and Co (28%) reveal metal contamination due to anthropogenic inputs. Factor analysis (FA) identified six possible types of sedimentological and geochemical associations. The dominant factor accounting for 26.9% of the total variance identifies an anthropogenic input and accumulation of nondetrital Cd, Co, Cr, Ni and Pb. Association of these metals with CaCO3 reveals that shell fragments in the surface sediments are likely act as a carrier phase for nondetrital metals. The results are discussed in the context of the sources and pathways of elements in the Bay of Bengal.     

云南阳宗海沉积物重金属污染时空特征及潜在生态风险

分析了阳宗海柱状及表层沉积物中Al、Fe、Mn、Zn、Cr、Co、Ni、Cu、As、Cd、Pb等金属元素的含量,结合沉积年代学,研究了沉积物重金属污染的时空变化和潜在生态风险特征.结果表明,表层沉积物中重金属含量具有一定的空间差异性,As、Cd、Cu、Pb和Zn在中东部湖区含量较高,而Cr、Co、Ni含量高值位于南、北湖区的近岸区域;柱状沉积物中,1990s之前As、Cd、Cu、Pb和Zn含量较为稳定,1990s中后期以来,其含量逐渐增加,并在2009-2010年前后达到最大值,此后逐渐下降;而柱状沉积物中Cr、Co、Ni含量变化趋势与Al、Fe相似,总体上由下向上逐渐降低,这主要与沉积物质地(粒度)逐渐变粗有关.重金属富集系数表明,阳宗海沉积物中主要污染元素为As、Cd、Cu、Pb和Zn,1990s中后期污染程度快速增加,2009-2010年前后达到峰值,此后污染程度逐渐降低;表层沉积物中Cu为未污染至"弱"污染水平;Zn、Pb为"弱-中等"污染水平,As为"中等-强"污染水平,Cd为"弱-强"污染水平,中东部湖区污染程度高于其他湖区,这可能与该湖区缺少入湖径流、自然碎屑物质沉积速率较低以及砷污染事件等人为源的重金属贡献影响更为显著有关.生态风险评价结果表明,在2002-2010年前后沉积物重金属达到"中等-强"潜在生态危害,主要贡献因子是Cd和As,近年来其生态风险等级逐渐降低;表层沉积物中重金属在中东部湖区具有"中等"程度潜在生态危害,而其他湖区表层沉积物重金属具有较低程度的潜在生态风险.     

洞庭湖沉积物中重金属污染特征与评价

于2003-2004年在洞庭湖湖区采集沉积物样品700个,测定了沉积物中As、Cd、Cr、Cu、Hg、Ni、Pb、Zn的含量,并用地积累指数方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.结果显示,洞庭湖各子湖区沉积物中Cd、Cr、Cu、Pb、zn的平均含量都属于国家土壤二级标准,AB、Hg、Ni属于国家土壤一级至二级土壤标准;在南洞庭湖与东洞庭湖人湖河流的三角洲的前缘是沉积物重金属积累最高的地点,而在西洞庭湖入湖河流三角洲的后缘沉积物重金属含量比前缘高.采用综合地积累指数法对洞庭湖各子湖区沉积物进行评价,结果表明:南洞庭湖(重污染)>东洞庭湖(偏重污染)>西洞庭湖(中度污染)>大通湖(中度污染)>城陵矶(轻度污染).采用主成分分析法对洞庭湖各子湖区沉积物进行分析,结果表明:南洞庭湖与东洞庭溯第一主成分贡献率分别为55.22%、56.86%,主要支配AS、Cd、Hg、Pb、zn的载荷,而第二主成分贡献率分别为30.04%、33.11%主要支配Cu、Cr、Ni的载荷:西洞庭湖、大通湖和城陵矶因沉积物重金属来源不同,主成分分析结果相差较大.     

Concentration and fractionation of trace metals in surface sediments of intertidal Bohai Bay, China

Surface sediments from intertidal Bohai Bay were sampled for the geochemical and environmental assessment of six trace metals (Cd, Cr, Cu, Ni, Pb and Zn). Results indicate that sediment grain size plays an important role in controlling the distribution and fractionation of them. Metal concentrations in clayey silt sediments are all clearly higher than in sand and silty sand ones. Cd and Pb in clayey silt sediments are more mobile than in sand and silty sand ones. Two sediment quality guidelines and two geochemical normalization methods (index of geoaccumulation and enrichment factor) were used to judge the potential risk and accumulation of metals. According to the mean probable effects level quotient, the combination of studied metals may have a 21% probability of being toxic. The sediments with high fraction of clay and silt have been contaminated by trace metals to various degrees, among which Cr contributes the most to contamination.     

Dissolved and particulate trace metals in meltwater from the Rhône glacier

Glacial meltwater and sediment at the source of the River Rhône have been analyzed to determine: 1. the partitioning of Al, Cd, Co, Cu, Cr. Fe, Mn, Ni, Pb and Zn between the water and particulate phase. 2. the particle size ranges which affect the dissolved trace metal ion composition of the meltwater and 3. the availability (potential release) of the ten trace metal ions from the sediment. Greater than 80% of the total Cd, Cu, Mn, Ni and Zn were found to be in operationally-defined (0.4 μm) dissolved forms. Fe and Al in the meltwater are primarily associated with particles in the size range 0.4–8 μm, while Cd. Cu, Mn, Ni and Zn occur with particles smaller than 0.1 μm. For the sediment, Cu, Ni and Pb were significantly present as exchangeable forms; only Cu, Ni, Pb and Zn were determined as organicallybound forms.     

Ecological risk assessment using trace elements from surface sediments of Izmit Bay (Northeastern Marmara Sea) Turkey

The aim of this study was to study ecological risk assessment of trace elements (As, Cd, Cr, Cu, Ni, Pb and Zn) in Izmit Bay surface sediments in the <63 microm fraction. Sediment samples were collected from 8 sites along the north coastline of the bay. Samples were subjected to a total digestion technique and analyzed for major (organic carbon) and minor (As, Cd, Cr, Cu, Ni, Pb and Zn) elements. Sediments heavily contaminated are evaluated by the Sediment Quality Guidelines (SQG) of US EPA. The degree of contamination (Cd) is estimated as very high at each site. Two sets of SQGs, effect range-low/effect range median values and TEL/probable effect level (PEL) values were used in our study. Sediments from the each site are judged toxic when two or more of the PEL values exceed EPA guidelines. Our results are in agreement with previously reported sediment toxicity test results.     

Study of the spatial and historical distribution of sediment inorganic contamination in the Toulon bay (France)

This study presents trace elements levels in surface and deep sediments of the Toulon bay (SE France) subjected to anthropogenic inputs (navy base, harbors, etc.). The studied elements (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) are defined as priority contaminants in aquatic systems. Fifty-five points scattered on the entire bay were sampled, allowing the determination of contaminants distribution with a high resolution. Several approaches were used to assess the degree of contamination and the potential toxicity of the Toulon bay sediments: comparison to the French legislation, surface-weighted average metal concentrations, enrichment factors (EF), geoaccumulation indices (Igeo), trace element stock calculation and comparison to sediment quality guidelines. A principal component analysis was performed to reveal common behavior of the studied contaminants. Results demonstrated the very high contamination of the small bay, especially in Hg (EF up to 1500), Cu, Pb and Zn, with export to the large bay further governed by hydrodynamics.     

Geochemical baselines of major, minor and trace elements in the tropical sediments of the Terengganu River basin, Malaysia

The geochemical baselines and distribution of 31 elements (Al, Fe, K, Na, Mg, Ca, Mn, Ba, Cr, Zr, Ni, Sr, Zn, Y, Li, Cu, Mo, Nb, Th, Co, Ga, W, Ta, Be, Ti, Ge, Se, Bi, Te, Sc and Re) and physico-chemical parameters of the tropical surface sediments of the Terengganu River basin, Malaysia, are reported. Sediments are sandy loam to sand in texture consisting of mostly quartz, low organic matter content (average-2.68%), low CEC (average-2.02 cmol(+)/kg) and mildly acidic pH1:5 (average-5.91). Concentrations of Mn, Fe, Ba, Cr, Ni, Cu, Mo and Se were measured to be above the environmental sediment quality criteria at various locations. Lake sediments registered significantly higher Al, Fe, Ti, Mg, Ca, Mn, Te and Sc concentrations as compared to the river sediments. Most of the elements investigated showed an association with silt size fraction (2-63 μm). Among the investigated metals, Mo and Fe concentrations showed an increasing (5-fold) and decreasing (3-fold) trend, respectively, along the river path from the upstream to the downstream depending on the stream pH-redox conditions. The enrichment factor values (EF 5) of Cr, Ni, Mo and Se indicated enrichment from anthropogenic activities. Alkali and alkali earth metals registered a significant depletion (EF values 0.7) as compared to the Earth's crust. Principal component analysis of the two main components (PC1, 87.4% and PC2, 8.7%) revealed a well-defined group of estuary sediments. Lake and river sediment sampling locations did not form defined groups revealing heterogeneity in the origin of geologic material and the in-stream geochemical processes. However, Cr, Ni, Mo and Se formed a separate group with elevated concentrations (e.g. Cr1,000 mg/kg) indicating contamination of sediments. This work presents the geochemical baselines of the tropical sediments as industrial development and urbanization along the north east coast of Peninsular Malaysia are advancing rapidly.     

Sedimentary Records of Evolution of Heavy Metals in Songhua Lake,Northeast China

In this paper, the vertical variations of heavy metal elements (including Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn) in the sediments of Songhua Lake are analyzed using sediment cores. A 70‐year evolutionary history of these heavy metal elements in Songhua Lake is described and the sources of the heavy metals in the sediments are investigated by evaluating the pollution characteristics of the metals in terms of their enrichment coefficients and geoaccumulation indexes. The results indicate that Cr, Cu, Mn, Ni, Pb, and Zn in the sediments originated mainly from basin erosion and were transported to the lake by rivers. Cd and Hg in the sediments also originated from basin erosion that occurred prior to the mid‐1990s, and these sediments have since been overlaid by artificial pollution. The distribution of heavy metals in the sediments of Songhua Lake is influenced by many factors, including sediment composition, the relative importance of fluvial input, and artificial pollution.     

Sediment geochemistry of the urban Lake Paulo Gorski

The objective of this study was to evaluate the concentration and distribution of heavy metals in the sediments of Paulo Gorski Lake, as well as the metals’ bioavailability and potential ecological risk, and to define the anthropogenic and natural heavy metal contributions to the lake. The chemical elements calcium (Ca), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), nickel (Ni), lead (Pb), and zinc (Zn) were quantified by flame atomic absorption spectrophotometry with two extraction methods to quantify the bioavailable and non-bioavailable fractions. The data were evaluated using multivariate statistics and sediment quality indices. All sediment collection points (S1, S2, S3, S4 and S5) are different in terms of the concentration of heavy metals, except for S4 and S5, which were statistically equal. The bioavailable fraction of the elements in the sediment follows the sequence Pb>Cu>Mn>Zn>Ni>Cr>phosphorus (P) for all points. The elements Co, Cr, Pb, and Zn showed moderate to considerable contamination at all points. Only points S3 and S5 had moderate ecological risk. Urbanization has been affecting Paulo Gorski Lake via the input of chemical elements, especially Co and Pb. The points most affected by heavy metal contamination are S3 and S5 when the sedimentological sensitivity factor is considered. The lake has high hydrodynamics, causing some of the contaminants that enter the system to leave it, leading to potential negative impacts downstream.     

Spatial distribution,fractionation and ecological risk assessment of potentially toxic metals in bottom sediments of the Zarivar freshwater Lake (Northwestern Iran)

Freshwater lakes are one of the most vulnerable ecosystems to environmental contamination. This study was initiated to assess the spatial distribution, fractionation, ecological risk of selected potentially toxic metals (Pb, Zn, Cu, Cr, and Ni) in bottom sediments of the Zarivar lake, the second largest freshwater lake in Iran. The results revealed that Pb, Zn and Cu had the high spatial variability (coefficient of variation >50) across the sampling sites and their maximum concentrations (197.5 for Pb, 198.7 for Zn and 185.6 mg/kg for Cu) were observed in sampling sites from the northern, western and eastern margins of the lake. Cr and Ni with average concentrations of 28.3 and 31.38 mg/kg respectively, exhibited low spatial variability (coefficient of variation <20) and their concentrations did not vary significantly among the sampling sites. Based on the redundancy analysis (RDA), sediment organic matter was strongly correlated with Pb, Zn and Cu while Fe₂O₃ and Al₂O₃ showed a positive correlation with Ni and Cr. The calculated average enrichment factor (EF) and geoaccumulation index (I_geo) showed that the contamination level of metals can be arranged in the following order of Pb> Cu > Zn > Cr > Ni. Results from the modified five-step sequential extraction analysis indicated that 40 % of total Pb and Zn were associated with the reducible fraction, 45 % of Cu with the oxidizable fraction and more than 80 % of total Ni and Cr were retrieved from the residual fraction. It was also noticed that Pb, Zn and Cu were more incorporated into the non-residual fractions in the sites with a higher total concentration of these metals, suggesting that both total concentration and fractionation behavior of metals were influenced by their potential sources in the study area. Ecological risk assessment using the potential ecological risk index (PERI) and the modified potential ecological risk index (MPERI) showed that sediments from the eight sampling sites pose a moderate to considerable risk whereas the other sites had low ecological risk level. In comparison to sediment quality guidelines (SQGs), the effects range low (ERL) and probable effect level (PEL) values for Pb, Cu and Zn were exceeded at some sampling sites while Ni and Cr concentrations were found to be below or close to their SQGs values at all the sampling sites. Pb was generally identified as the contaminant of most concern in the study area. Taking into account the results obtained from the fractionation study and the source contribution estimate, it can be inferred that the Pb, Zn and Cu with the average contribution of 79, 54 and 64 % respectively, were mainly derived from anthropogenic sources whereas Ni and Cr with the estimated contribution of 80 and 89 % were predominately from the lithogenic source.     

南京玄武湖底泥重金属形态与环境意义

通过对玄武湖12个底泥样品采用连续提取的方法,分别获得湖中6种金属的总量和形态分布数据,并用因子分析的方法对金属总量进行统计分析.金属总量结果表明,部分样点的Ni和大部分样点的Cr、Pb、Zn超过背景值,显示有轻度污染,这与玄武湖周围的地理环境和人类活动对底泥重金属的影响有关.对金属形态分析的结果表明,在所测金属中残渣态是主要的存在形式,其次比例较高的是有机物和硫化物结合态,而Pb、Zn有潜在的生物危害性.     

Trace metals distribution pattern in floodplain sediments of a lowland river in relation to contemporary valley bottom morphodynamics

The distribution of trace metals in alluvial sediments depends on their natural background concentrations, and on the dynamics of contemporary depositional and erosional (mainly flood‐induced) processes. Geological and geochemical investigations were carried out in the valley of Vistula River near Magnuszew (central Poland). Sediment samples were collected from a depth of 35 cm and comprise sediments of all defined geomorphological features. Identification and geological interpretation of the morphodynamic sediment features was supported by aerial photographs and high‐resolution satellite images. These studies revealed that the distribution of trace metals is closely linked to the morphogenesis of the alluvial floodplain. The highest concentrations of Cu, Co, Zn, V, Cr and Ni were observed in crevasse‐splays deposits. By contrast, Sr, Pb and As were concentrated in deposits which fill oxbow lakes (partly infilled with organic deposits). The lowest concentrations of trace metals were detected in flood sediments deposited within erosional troughs. The geomorphological and sedimentological history of the fluvial features explains the pattern of heavy metal distribution on the current floodplain surface. Copyright © 2014 John Wiley & Sons, Ltd.     

Establishment of Baseline Reference Geochemical Values in Tropical Soils of Western Ghats: Assessment of Periyar Basin with Special Reference to Contaminant Geochemistry

Based on the detailed geochemical studies of 184 soil samples from Periyar River Basin (PRB), a tropical monsoon dominated river basin (5398 km²) in the southern western Ghats (WGs) of India, a baseline reference data is established. The soils are mildly acidic with sandy loam and silt loam facies in non-monsoon to sandy loam and sandy clay loam in monsoon. The mean metal concentrations follow the upper continental crust and world shale values. The Geoaccumulation index (Igeo) shows unpolluted to moderately polluted category, except for Cu, Zn, and Ba, while Enrichment Factor (EF) indicates no to minor enrichment for all elements. Contamination factor (Cf) indicates low to considerable contamination for V, Rb, Sr, Ni, and low to very high contamination for Cu, Zn, and Ba. Three significant components are extracted by Principal Component Analysis (PCA), explaining 78.09% and 74.10% of the total variance for monsoon and non-monsoon seasons. Ti, Al, Fe, Ca, Na, K, V, Cr, Ni, Sr, and Ba exhibited common source of origin while anthropogenic origin is identified for Zn and Cu. The study will provide valuable information into the pedological characteristics of WGs river basins.     

The extent and historical trend of metal pollution recorded in core sediments from the artificial Lake Shihwa, Korea

The vertical distribution of trace metals in sediment cores was investigated to evaluate the extent and the historical record of metal pollution over 30 years in the artificial Lake Shihwa in Korea. A marked increase of trace metals after 1980 was observed due to the operation of two large industrial complexes and dike construction for a reclamation project. There was a decreasing trend of metal concentrations with the distance from the pollution source. The enrichment factor and pollution load index of the metals indicated that the metal pollution was mainly derived from Cu, Zn and Cd loads due to anthropogenic activities. The concentrations of Cr, Ni, Cu, Zn, As and Pb in the upper part of all core sediments exceeded the ERL criteria of NOAA. Our results indicate that inadequate planning and management of industrialization and a large reclamation project accomplished by dike construction have continued to strongly accelerate metal pollution in Lake Shihwa.     

Content and distribution of trace metals in surface sediments from the northern Bering Sea, Chukchi Sea and adjacent Arctic areas

Concentrations of trace metals (Zn, Cr, Cu, V, Cd and Pb), total organic carbon (TOC), black carbon (BC) and their granulometry were examined in 25 surface sediment samples from the northern Bering Sea, Chukchi Sea and adjacent areas. Trace metal concentrations in the sediments varied from 21.06-168.21 mg kg(-1) for Zn, 8.91-46.94 mg kg(-1) for Cr, 2.69-49.39 mg kg(-1) for Cu, 32.46-185.54 mg kg(-1) for V, 0.09-0.92 mg kg(-1) for Cd, and 0.95-15.25 mg kg(-1) for Pb. The geoaccumulation index (Igeo) indicated that trace metal contamination (Zn and Cd) existed in some stations of the study area. The distribution of grain size plays an important role in influencing the distribution of trace metals (Zn, Cr, Cu, V, and Pb) in sediments from the Chukchi Sea and adjacent areas.     

Distribution,fractionation, and contamination assessment of heavy metals in offshore surface sediments from western Xiamen Bay,China

Surface sediment samples were collected at 21 offshore sites in western Xiamen Bay, Southeast China.Total concentrations of Li, V, Cr, Co, Ni, Cu, Zn, Sr, Mn,Pb, Ba, Fe, and Ti were determined by inductively coupled plasma-optical emission spectrometry; Hg was determined by atomic fluorescence spectrometry. A modified BCR sequential extraction procedure was used to extract fractions of the above elements. Concentrations of Pb, Cr, and Hg at most sites met the primary standard criteria of Marine Sediment Quality except site S12 for Pb and S7 for Cr, while concentrations of Zn at 17 sites and Cu at seven sites exceeded the criteria. The mean concentration of Hg was three times higher than the background, with a possible source being the Jiulong River. Fe, Ti, Ba, Co, V, and Li dominated the residual phase, mainly from terrestrial input.Ni, Cr, Pb, and Hg in the non-residual phase varied largely between sites. Sr, Mn, Cu, and Zn were mainly in the nonresidual fraction. Most sites showed considerable ecological risk; exceptions were site S7(very high) and sites S10,S11, and S14(moderate). Cu showed moderate-to-high pollution and Pb exhibited no-to-low pollution, while other metals had a non-pollution status according to their ratios of secondary phase to primary phase(RSP). Results of two assessment methods showed moderate pollution and a veryhigh ecological risk for Cu, Zn, Ni, and Cr at site S7, which might be due to the local sewage treatment plant.