Evaluation of geochemical methods for discrimination of metal contamination in Antarctic marine sediments: a case study from Casey Station

Detecting anthropogenic metal contamination in regional surveys can be particularly difficult when there is a lack of pre-disturbance data, especially when trying to differentiate low to moderate levels of contamination from background values. Furthermore, comparisons with other regional studies are confounded by differing analytical methods used and variations in sediment properties such as grainsize. Several types of geochemical technique, including weak acid partial extraction, strong acid extractions and total digestion have been used. Attempts have been made to overcome the influence that grainsize has on chemical concentrations in heterogeneous environments by analysing the fines, typically the mud fraction (<63 microm), in an attempt to improve the detection of anthropogenic contamination. Here we compare a weak acid partial extraction using 1M HCl and total digestion methods for a regional survey of reference and impacted sites in Antarctica using both whole sediment (<2 mm) and mud (<63 microm) fractions. The 1M partial extraction on whole sediment (<2 mm) most closely distinguished weakly, or moderately, impacted sites from reference locations. It also identified small scale within-location spatial variation in metal contamination that the total digest did not detect. Compared with total digests or analysis of the <63 microm fraction alone, this method minimised the possibility of a Type II statistical error in the regional survey - that is, failing to identify a site as being contaminated when it has elevated metal concentrations. To allow inter-regional comparison of sediment chemistry data from elsewhere in Antarctica, and also more generally, we recommend a 1M HCl partial extraction on whole sediment (<2 mm).     

A study of metal and metalloid contaminant availability in Antarctic marine sediments

Previous studies of impacted sites near Casey Station, Antarctica, have revealed elevated concentrations of metals and metalloids, particularly Cd, Cu, Fe, Pb, Sn and Zn in marine sediments. However, attempts to understand the availability and mobility of contaminant elements have not provided a true understanding of speciation. The current work shows, for the first time, that sediments in Brown Bay, an embayment adjacent to the Thala Valley waste disposal site, have elevated concentrations of sulfide, well in excess of that required to bind contaminant metals such as Cd, Cu, Pb and Zn. Furthermore, sediment characterisation using the BCR sequential extraction scheme has shown metal partitioning consistent with sulfides being the controlling factor in metal availability, thus explaining the low porewater concentrations of these metals. The speciation of Sn in Brown Bay, however, is still unclear with the BCR sequential extraction scheme partitioning Sn predominantly into the residual fraction despite Sn being readily extracted by dilute HCl.     

Antifouling paint booster biocide contamination in Greek marine sediments

Organic booster biocides were recently introduced as alternatives to organotin compounds in antifouling products, after restrictions imposed on the use of tributyltin in 1987. In this study, the concentrations of three biocides commonly used as antifoulants, Irgarol 1051 (2-methylthio-4-tertiary-butylamino-6-cyclopropylamino-s-triazine), dichlofluanid (N-dichlorofluoromethylthio-N',N'-dimethyl-N-phenyl sulphamide) and chlorothalonil (2,4,5,6-tetrachloro isophthalonitrile) were determined in sediments from ports and marinas of Greece. Piraeus (Central port, Mikrolimano and Pasalimani marinas), Thessaloniki (Central port and marina), Patras (Central port and marina), Elefsina, Igoumenitsa, Aktio and Chalkida marinas were chosen as representative study sites for comparison with previous monitoring surveys of biocides in coastal sediments from other European countries. Samples were collected at the end of one boating season (October 1999), as well before and during the 2000 boating season. All the compounds monitored were detected at most of sites and seasonal dependence of biocide concentrations were found, with maxima during the period June-September, while the winter period (December-February) lower values were encountered. The concentrations levels ranged from 3 to 690 ng/g dw (dry weight). Highest levels of the biocides were found in marinas (690, 195 and 165 ng/g dw, for Irgarol, dichlofluanid and chlorothalonil respectively) while in ports lower concentrations were observed. Antifouling paints are implicated as the likely sources of biocides since agricultural applications possibly contributed for chlorothalonil and dichlofluanid inputs in a few sampling sites.     

Heavy metal distribution in marine sediments from the southwest coast of Spain

The latest version (1999) of the BCR-sequential extraction technique was used to determine the distribution of metals (Cu, Zn, Cd, Pb, Fe, Ni, Cr, and Mn) with major sedimentary phases (acid-soluble, reducible, oxidisable and residual) in samples from the southwest coast of Spain. The total metal content was also determined. The results showed that an extensive area along the coast (35 km long), near the joint mouth of the Tinto and Odiel Rivers, contains sediments with high concentrations of metals, with maximums of 649 mg/kg of Zn, 336 mg/kg of Cu, 197 mg/kg of Pb and 2.5 mg/kg of Cd. The values found for Cr, Ni and Mn are comparable to those in unpolluted areas. Based on the chemical distribution of metals, we found that Zn is the most mobile (i.e., it can pass easily into the water under changing environmental conditions). This metal showed the highest percentages in the acid-soluble fraction (the most labile), especially in the central coastal area, where the samples contained over 50% of this element associated with this fraction. This area close to the Tinto and Odiel river mouths also shows a significant increase in the mobility of Cd and Cu. In both cases the amount present in the residual fraction is lower, and the acid-soluble fraction is increased for Cd and the oxidisable fraction for Cu. However, the highest percentages of Fe, Cr and Ni are found in the residual fraction (84%, 89% and 75%, respectively), which implies that these metals are strongly bound to the sediments.     

Trace metal contamination of sediments in an e-waste processing village in China

This study examined trace metal contamination of sediments in Guiyu, China where primitive e-waste processing activities have been carried out. It was found that some river sediments in Guiyu were contaminated with Cd (n.d.-10.3mg/kg), Cu (17.0-4540mg/kg), Ni (12.4-543mg/kg), Pb (28.6-590mg/kg), and Zn (51.3-324mg/kg). The (206)Pb/(207)Pb and (208)Pb/(207)Pb ratios of the Pb-contaminated sediments of Lianjiang (1.1787+/-0.0057 and 2.4531+/-0.0095, respectively) were lower than those of Nanyang River (1.1996+/-0.0059 and 2.4855+/-0.0082, respectively), indicating a significant input of non-indigenous Pb with low (206)Pb/(207)Pb and (208)Pb/(207)Pb ratios. Copper, Pb and Zn in the non-residual fractions noticeably increased in the contaminated sediments compared to those in the uncontaminated sediments. A genuine concern is associated with potential transport of the contaminated sediments downstream and enhanced solubility and mobility of trace metals in the non-residual fractions.     

Heavy metal contamination in water and sediments of an estuary in southeastern Turkey

The geochemical characteristics of some heavy metals (Cr, Cd, Pb, Zn and Ni) in the river and sea sediments, in the soil and in the river and groundwater of an estuary on the southeast coast of Turkey have been studied. In the sea sediments, the wastes from a chromium factory control these metal concentrations. The heavy metal contamination in the river sediments results from an existing chromite mine at the northern part of the area. These heavy metals are concentrated in the soil, but they do not penetrate into the groundwater because of the low permeability of the unsaturated zone in the region.     

潮间带沉积物中酸可挥发性硫化物提取方法的优化研究

沉积物中酸可挥发性硫化物(AVS)对某些重金属(如Cd、Pb等)的生物有效性具有强烈影响,因此沉积物中的AVS已成为水环境中重金属研究和质量评价的热点.通过改变实验装置,对实验中的吸收液、N2流量、反应酸量、水浴温度和反应时间进行对比研究且作出了优化选择,并利用优化方法分析了渤海湾天津段潮间带沉积物中AVS的含量.结果...     

Passive samplers versus surfactant extraction for the evaluation of PAH availability in sediments with variable levels of contamination

The purpose of this study was to test the efficiency of passive solid samplers, polyoxymethylene (POM) strips and polydimethylsiloxane (PDMS) silicon tubing, to predict the bioavailability of native PAHs in contaminated sediments. Results were compared with worm bioaccumulation data and solid/liquid extraction using the surfactant Brij((R)) 700 (B700). The two passive samplers were found to act differently. The PDMS sampler overestimated the availability of PAHs in all studied sediments. The POM method provided results in accordance with those obtained with the B700 extraction. However, POM and B700 methods underestimated PAH availability in low contaminated sediments where biological factors (digestible organic matter) become important. Bioavailability of total PAHs was correctly predicted by POM and B700 in highly contaminated aluminum smelter sediments. A closer examination of individual PAH results indicated that both techniques overestimated the availability of large molecules with logK(ow)>6 suggesting a biological mechanism limiting uptake of larger PAHs which seems to be related to the molecular size of compounds.     

Heavy metal contamination in surface sediments from lakes and their surrounding topsoils of China

Environmental Science and Pollution Research - Due to rapid urbanization, industrialization, agricultural development, and mining activities, soil heavy metal pollution has become a severe issue in...     

Validation of a GC-MS/MS method for simultaneous determination of 86 persistent organic pollutants in marine sediments by pressurized liquid extraction followed by stir bar sorptive extraction

A multiresidue method for the analysis of 86 persistent pollutants in marine sediments at ultra-trace level has been developed and validated using pressurized liquid extraction (PLE) and stir-bar sorptive extraction (SBSE) coupled with thermal desorption and gas chromatography-triple quadrupole mass spectrometry (TD-GC-MS/MS QqQ). The compounds analyzed belong to various families such as polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polybrominated diphenylethers, organophosphorus and organochlorine pesticides and other pesticides such as urons, and triazines. The analytes have very different polarities and log K_ow values, which is an important parameter in the optimization of a SBSE method. Due to PLE high efficiency and throughput rates, along with the proven ability for multiresidue analysis and excellent sensitivity of SBSE, we present an efficient method. The limits of quantification obtained ranged from 0.014 to 1.0 ng g⁻¹, with detection limits below pg g⁻¹ levels. In order to validate the proposed methodology, quality parameters such as recovery, linearity and reproducibility were studied. Recoveries ranged from 63% to 119%, reproducibility (in terms of Relative Standard Deviation for ten determinations) was lower than 35% in all cases, and determination coefficients higher than 0.990 for all analytes. The main factors that affect PLE, SBSE and GC-MS/MS procedures were optimized. The method was applied to the analysis of nine marine sediments obtained from the nine main submarine wastewater discharge points (emissaries) presents along the coast of Tenerife Island (Canary Islands, Spain).     

Application of principal component analysis for the estimation of source of heavy metal contamination in surface sediments from the Rybnik Reservoir

The concentrations of metals, loss of ignition and nutrient (N, P) were determined in the bottom sediments of the Rybnik Reservoir (southern Poland). The mean concentrations of the metals in the bottom sediments were: Cd 25.8 microgram/g, Cu 451.7 microgram/g, Zn 1583.4 microgram/g, Ni 71.1 microgram/g, Pb 118.6 microgram/g, Cr 129.8 microgram/g, Fe 38782 microgram/g and Mn 2018.7 microgram/g. The bottom sediments are very heavily loaded with zinc, manganese, copper, nickel, phosphorus and lead (percentage enrichment factor), and cadmium, phosphorus and zinc (index of geoaccumulation). The increase of cadmium, lead, nickel and zinc concentrations was connected with the inflow of the contaminated water of the river Ruda and long-range transport. The contamination of the reservoir with copper and manganese resulted mainly from atmospheric precipitation. The variability of the bottom sediment loading with metals during the investigations was affected in the first place by changes in the concentration of iron, but also those elements whose concentrations in the bottom sediment were elevated compared to the concentrations in shale--cadmium, nickel and lead.     

Assessment of heavy metal contamination in Hindon River sediments: a chemometric and geochemical approach

The aim of this study was to assess the level of heavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in the surface sediments of the Hindon River, India that receives both treated and untreated municipal and industrial discharges generated in and around Ghaziabad, India. Mean metals concentrations (mg kg⁻¹) were in the range of; Cu: 21.70-280.33, Cd: 0.29-6.29, Fe: 4151.75-17318.75, Zn: 22.22.50-288.29, Ni: 13.90-57.66, Mn: 49.55-516.97, Cr: 17.48-33.70 and Pb: 27.56-313.57 respectively. Chemometric analysis was applied to identify contribution sources by heavy metals while geochemical approaches (enrichment factor and geo-accumulation index) were exploited for the assessment of the enrichment and contamination level of heavy metals in the river sediments. Chemometric analysis suggested anthropic origin of Cu, Cd, Pb, Zn, and Ni while Fe showed lithogenic origin. Mn and Cr was associated and controlled by mixed origin. Geochemical approach confirms the anthropogenic influence of heavy metal pollution in the river sediments. The study suggests that a complementary approach that integrates chemometric analysis, sediment quality criteria, and geochemical investigation should be considered in order to provide a more accurate appraisal of the heavy metal pollution in river sediments. Consequently, it may serve to undertake and design effective strategies and remedial measures to prevent further deterioration of the river ecosystem in future.     

Supercritical fluid extraction of polycyclic aromatic hydrocarbons from marine sediments and soil samples

Supercritical fluid extraction (SFE) was used to extract polycyclic aromatic hydrocarbons (PAH) from a certified sample of marine sediment. This sample contains a great number of organic pollutants that are present in low concentrations. The extractions were carried out at 50 and 80 degrees C, at a pressure varying from 230 to 600 bar and using CO2 in the supercritical phase and the effect of three organic modifiers (methanol, n-hexane and toluene), added at 5%/vol, at the same temperature and pressure conditions, were then considered. PAHs were characterized by GC-MS and the recover yield was estimated for 6 PAHs that were representative of those present in the sample, according to their molecular weight and to the number of condensed rings. The analytical conditions giving the best recovery efficiency were used on an unpolluted soil sample spiked with 11 PAHs of environmental importance at a concentration similar to that certified for the sediment sample. An increase in the yield of recovered PAHs, using methanol as co-solvent, was observed while higher temperatures caused a negative effect on the quantity of recovered pollutants. The recovery yield for PAHs from the spiked soil sample was measured and found to be greater than 90%. Better recoveries were obtained for those compounds with higher molecular weight.     

Mathematical analysis of the whole core injection method accuracy for measuring phenanthrene biodegradation rates in undisturbed marine sediments

Rates of 14C-phenanthrene mineralization in contaminated, undisturbed marine sediments were measured using the whole core injection method to assess microbial natural attenuation activity as a function of sediment depth. Submerged sediments were sampled from Eagle Harbor, a marine superfund site in Puget Sound. Experiments show significant biodegradation activities (0.0012-0.0036 day(-1)) in the sediment horizons from 0 to 10 cm. The purpose and scope of this paper is to evaluate the range of experimental conditions giving valid results; a mathematical simulation described competing contaminant 14C-phenanthrene diffusion and simultaneous biodegradation (Monod kinetics), both retarded by sorption. The effect of aging was examined with two sorption models in presumed pseudo-homogenous sediments having effective properties. The simulation predictions provide quantitative guidelines for the successful use of the whole core injection method. (1) The effective Monod constant KS' in sediment is increased by a large partition coefficient KP between sediment and water and makes the apparent 14C-phenanthrene biodegradation approach first-order kinetics. (2) When KS'>1 mg(-1) l(-1), the measured 14C-phenanthrene biodegradation extent is biased by inadequately distributed injected tracer only when less than 7% of the sediment horizon is initially probed and mixed with injected tracer. (3) A short incubation time (<20 days) is necessary when a mobile indicator, e.g., gaseous 14CO2, is used. For longer incubation times, predictions show that a 14CO2 indicator diffuses to adjacent horizons, thus smearing the depth profile of biodegradation. (4) This method employing a radiolabeled tracer provides accurate biodegradation rates for freshly contaminated sediments, and represents an upper limit to the natural phenanthrene biodegradation extents if the contaminant is aged over 50 days.     

Heavy metal contamination in surface sediments of Yangtze River intertidal zone: An assessment from different indexes

Surface sediments (0-5 cm) from 59 stations within the Yangtze River intertidal zone (YRIZ) were sampled for metal contamination analysis in April and August 2005. The concentrations ranged (in mg kg⁻¹ dry weight): Al, 40,803-97,213; Fe, 20,538-49,627; Cd, 0.12-0.75; Cr, 36.9-173; Cu, 6.87-49.7; Mn, 413-1,112; Ni, 17.6-48.0; Pb, 18.3-44.1; and Zn, 47.6-154; respectively. Among the 59 sampling stations, enrichment factors (EF) indicate enrichment of Cd (52 stations), Cr (54 stations), Cu (5 stations), Ni (26 stations), Pb (5 stations) and Zn (5 stations). Geoaccumulation indexes (I_geo) also suggest individual metal contamination in localized areas. This study indicates that Cd, Cr and Ni enrichment in the YRIZ sediment is widespread whereas Cu, Mn, Pb and Zn enrichment is localized or nonexistent. Factor and cluster analyses indicate that Cd is associated with total organic carbon whereas Cu, Cr, Ni, Pb and Zn have a close association with Mn.     

Routine analysis of hydrocarbons, PCB and PAH in marine sediments using supercritical CO2 extraction

Automated Supercritical Fluid Extraction (SFE), using CO2, was tested and optimised for routine analysis of hydrocarbons (THC), polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH) in marine sediments. The aim of the exercise was to reduce the amount of solvents used and to reduce the manual handling time for each sample. The sediments contained elemental sulphur, which was removed during the extraction step using activated Cu. Similar recoveries and reproducibility where found for THC when conventional solvent extractions and SFE where compared. Modifying the CO2 with methanol was necessary to obtain extraction recoveries similar to conventional extraction methods for PCB and PAH.     

Toxicity and heavy metal contamination of surficial sediments from the Bay of Thessaloniki (Northwestern Aegean Sea) Greece

Surficial sediments (the fraction < 2000 microm) from the Bay of Thessaloniki, in the Northwestern Aegean Sea, Greece were examined for heavy metal and organic carbon contents, as well as for acute LUMIStox toxicity of pore waters (PWs), wet sediment elutriates (WSEs) and dry sediment elutriates (DSEs) obtained from the solid material remaining after PW extraction. WSEs where not toxic. EC20/50 values could be measured in some DSE and PW samples. In all sediment samples, the DSE toxicity was greater than the corresponding PW toxicity. Sediment concentrations of total and labile Cd, Pb, Cu, Cr, Zn, Mn, Ni and Fe were determined and evaluated in relation to sediment quality guidelines. Pollution levels ranged from low to high for certain metals. A misfit between sediment toxicities calculated from heavy metal concentrations and those biologically measured was observed. Toxicity values were in general poorly correlated with sediment's heavy metal or organic carbon content. As significant correlation was however found between the DSE toxicity with total Ni and labile Fe, as well as for the PW toxicity with total Ni, labile Fe and labile Cr.     

用固相萃取-高效液相色谱-三重四极杆串联质谱法测定海洋沉积物中13种氟喹诺酮类抗生素

为进一步探索海洋沉积物中氟喹诺酮类抗生素的污染情况,基于固相萃取-高效液相色谱-三重四极杆串联质谱(SPE-LC-MS/MS)技术,建立了海洋沉积物中 13 种FQs的测定方法;采用高效液相色谱-三重四极杆串联质谱多反应监测离子模式(MRM)对FQs进行分离检测。结果表明：在优化实验条件下,13种FQs的质量浓度为0.50~100 μg·L⁻¹,目标化合物峰面积与内标物质峰面积之比与质量浓度的线性关系良好(R²>0.99),方法检出限为0.003~0.03 μg·kg⁻¹;在加标量为1 μg·kg⁻¹和10 μg·kg⁻¹时,空白加标的平均回收率为73.5%~124.6%和67.5%~118.5%,相对标准偏差(RSD)为1.0%~9.7%(n=7);以海洋沉积物为基质,13种目标物的加标回收率为67.7%~142.4%,RSD小于10.2%(n=6);使用该方法对广州某湾区海洋沉积物中 13 种 FQs 的残留量进行了实地检测,培氟沙星质量分数最高,为1.6 μg·kg⁻¹,氧氟沙星、环丙沙星和恩诺沙星质量分数次之,为0.7 μg·kg⁻¹。该方法实现了对海洋沉积物中 13种 FQs 的同时检测,具有快速、准确等优点,适用于海洋沉积物中13种FQs的测定。本研究成果可为海洋生态环境保护提供数据基础及技术支撑。     

Using stable lead isotopes to trace heavy metal contamination sources in sediments of Xiangjiang and Lishui Rivers in China

Lead isotopes and heavy metal concentrations were measured in two sediment cores sampled in estuaries of Xiangjiang and Lishui Rivers in Hunan province, China. The presence of anthropogenic contribution was observed in both sediments, especially in Xiangjiang sediment. In the Xiangjiang sediment, the lower ²⁰⁶Pb/²⁰⁷Pb and higher ²⁰⁸Pb/²⁰⁶Pb ratio, than natural Pb isotope signature (1.198 and 2.075 for ²⁰⁶Pb/²⁰⁷Pb and ²⁰⁸Pb/²⁰⁶Pb, respectively), indicated a significant input of non-indigenous Pb with low ²⁰⁶Pb/²⁰⁷Pb and high ²⁰⁸Pb/²⁰⁶Pb. The corresponding concentrations of heavy metals (As, Cd, Zn, Mn and Pb) were much higher than natural values, suggesting the contaminations of heavy metals from extensive ore-mining activities in the region.     

Study of metal fractionation in river sediments. A comparison between kinetic and sequential extraction procedures

The extraction kinetic of trace metals (Cd, Cu, Pb, and Zn) in river sediments by four extraction agents was studied. As extractants ammonium acetate, acetic acid, hydroxylamine and EDTA solutions were assayed. These reagents can leach the metals more or less selectively from several metal compartments of sediments. The metal leaching kinetic model permits classification of the metal species in labile and moderately-labile ones. The combination of two or more non specific reagents permits a high characterisation of metal distribution and leachability. The results obtained with this model in four river sediments were compared with data obtained by the SM&T sequential extraction procedure, in order to characterise the chemical nature of leached metal.