Showing papers on "Trace metal published in 2015"
TL;DR: Bioaccumulation patterns showed that dust exposure is one of the major routes into human body for Cd, Pb, Co, Mn and Cr, while the burden of Zn, Cu, and Ni can be more linked to dietary sources.
222 citations
TL;DR: In this paper, the authors compare the authigenic enrichment patterns of these elements with a group whose behavior is not as well defined (Cd, Cu, Zn, and Ni) in three oxygen-poor settings: the Black Sea, the Cariaco Basin (Venezuela), and the Peru Margin.
Abstract: Any effort to reconstruct Earth history using variations in authigenic enrichments of redox-sensitive and biogeochemically important trace metals must rest on a fundamental understanding of their modern oceanic and sedimentary geochemistry. Further, unravelling the multiple controls on sedimentary enrichments requires a multi-element approach. Of the range of metals studied, most is known about the behavior of Fe, Mn, and Mo. In this study, we compare the authigenic enrichment patterns of these elements with a group whose behavior is not as well defined (Cd, Cu, Zn, and Ni) in three oxygen-poor settings: the Black Sea, the Cariaco Basin (Venezuela), and the Peru Margin. These three settings span a range of biogeochemical environments, allowing us to isolate the different controls on sedimentary enrichment. Our approach, relying on the covariation of elemental enrichment factors [EF, defined for element X as: EFX = (X/Al)sample/(X/Al)lithogenic], has previously been applied to Mo and U to elucidate paleoenvironmental information on, for example, benthic redox conditions, the particulate shuttle, and the evolution of water mass chemistry. We find two key controls on trace metal enrichment. First, the concentration of an element in the lithogenic background sediment (used in calculating EFX) controls the magnitude of potential enrichment. Maximum enrichment factors of 376 and 800 are calculated for Mo (∼1 ppm in detrital sediments) and Cd (∼0.3 ppm), respectively, compared to values not greater than 17 in any setting for the other five metals (∼45 ppm to ∼4.5 wt.% in detrital sediments). Second, there is a relationship between the aqueous concentration of the element in overlying seawater and its degree of enrichment in the sediment. We further identify four important processes for delivery of trace metals to the sediment. These are: (1) cellular uptake (especially important for Zn and Cd), (2) interaction/co-precipitation with sulfide (Mo, Cu, and Cd), (3) passive scavenging via the traditional particulate shuttle (Mo, Ni, and Cu), and (4) an association with the benthic Fe redox shuttle (Mn, Ni). Finally, we summarize the oceanic mass balance of Cd and Mo and place the first constraints on the contribution of reducing sediments to the oceanic mass balance of Cu, Zn, and Ni. We show that reducing sediments are the ultimate repository for up to half the total output flux of these elements from the oceanic dissolved pool.
177 citations
TL;DR: The batch and semi-continuous experiments confirmed that the addition of EDDS bonded to trace metals prior to their supplementation could obtain a 50% reduction of optimal metals dosage, providing a feasible method to reduce trace metals dosage without the degeneration of process performance of anaerobic digestion.
158 citations
TL;DR: In this paper, the authors investigated whether pyrolysis affects the total quantity of polycyclic aromatic hydrocarbons (PAHs) in sewage sludge-derived biochars.
Abstract: The presence of contaminants considerably restricts the application of sewage sludge for the fertilisation and reclamation of soils. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment and vary widely in sewage sludge depending on the input of industrial effluents. The objective of the study was the investigation whether the pyrolysis affect (reduces or adds) the total quantity of PAHs in sewage sludge-derived biochars and whether the pyrolysis changes the PAHs spectrum in terms of relative contributions of more hazardous components. Additionally, the trace metal content was determined before and after pyrolysis as well as the ecotoxicological parameters test towards plant (Lepidium sativum), bacteria (Vibrio fischeri) and crustacean (Daphnia magna). Sewage sludges conversion to biochar significantly reduced the content of PAHs (from 8- to 25-fold depending on pyrolysis temperature and kind of sludge). The exception was the content of naphthalene. Naphthalene was predominant in sewage sludge-derived biochars. However the concentration of the most hazardous 5- and 6-rings PAHs in sewage sludge-derived biochars was much lower compared to sewage sludge. The pyrolysis of sewage sludges caused also a significant reduction of their toxicity towards the test organisms. Only in the case of crustacean it was observed that the extracts from some biochars, obtained at higher temperatures (600 °C and 700 °C) were more toxic to D. magna than extracts from sewage sludge. In turn, after pyrolysis an increase was noted for trace metals content (Pb, Cd, Zn, Cu, Ni and Cr).
156 citations
TL;DR: In this article, the authors analyzed sulfide samples from 27 black smoker samples derived from three different seafloor hydrothermal fields: the ultramafic-hosted Logatchev Hydrothermal field on the Mid-Atlantic Ridge, the basaltic-based Turtle Pits field and the felsic hosted PACMANUS field in the Manus basin (Papua New Guinea).
136 citations
TL;DR: Samples of water and sediments were collected from 24 urban wetlands in Melbourne, Australia, in April 2010, and tested for more than 90 pesticides using a range of gas Chromatographic and liquid chromatographic techniques, sample ‘hormonal’ activity using yeast-based recombinant receptor-reporter gene bioassays, and trace metals using spectroscopic techniques.
Abstract: Samples of water and sediments were collected from 24 urban wetlands in Melbourne, Australia, in April 2010, and tested for more than 90 pesticides using a range of gas chromatographic (GC) and liquid chromatographic (LC) techniques, sample 'hormonal' activity using yeast-based recombinant receptor-reporter gene bioassays, and trace metals using spectroscopic techniques. At the time of sampling, there was almost no estrogenic activity in the water column. Twenty-three different pesticide residues were observed in one or more water samples from the 24 wetlands; chemicals observed at more than 40% of sites were simazine (100%), atrazine (79%), and metalaxyl and terbutryn (46%). Using the toxicity unit (TU) concept, less than 15% of the detected pesticides were considered to pose an individual, short-term risk to fish or zooplankton in the ponds and wetlands. However, one pesticide (fenvalerate) may have posed a possible short-term risk to fish (log10TUf > -3), and three pesticides (azoxystrobin, fenamiphos and fenvalerate) may have posed a risk to zooplankton (logTUzp between -2 and -3); all the photosystem II (PSII) inhibiting herbicides may have posed a risk to primary producers in the ponds and wetlands (log10TUap and/or log10TUalg > -3). The wetland sediments were contaminated with 16 different pesticides; no chemicals were observed at more than one third of sites, but based on frequency of detection and concentrations, bifenthrin (33%, maximum 59 μg/kg) is the priority insecticide of concern for the sediments studied. Five sites returned a TU greater than the possible effect threshold (i.e. log10TU > 1) as a result of bifenthrin contamination of their sediments. Most sediments did not exceed Australian sediment quality guideline levels for trace metals. However, more than half of the sites had threshold effect concentration quotients (TECQ) values >1 for Cu (58%), Pb (50%), Ni (67%) and Zn (63%), and 75% of sites had mean probable effect concentration quotients (PECQ) >0.2, suggesting that the collected sediments may have been having some impact on sediment-dwelling organisms.
114 citations
TL;DR: In this paper, total and soluble trace metal concentrations were determined in atmospheric aerosol and rainwater samples collected during seven cruises in the south-east Atlantic, consistent with climatological expectations.
99 citations
TL;DR: Nationwide human health risk maps are calculated by predicting the concentration of 10 trace metals in the drinking water sources of Pakistan and comparing them to guideline values and results can inform disease mitigation and water resources management regarding potential hot spots.
88 citations
TL;DR: In this article, the authors carried out sequential extractions on 15 samples of dry-drilled cuttings and core material from the gas-producing Middle Devonian Marcellus Shale and surrounding units to identify the host phases and evaluate the mobility of selected trace elements during cut-ings disposal.
87 citations
TL;DR: Analysis of the interactive effects of OA and trace metals on marine organisms with a focus on the physiological basis of these interactions shows that the responses to elevated CO2 and metals are strongly dependent on the species, developmental stage, metal biochemistry and the degree of environmental hypercapnia, and cannot be directly predicted from the CO2-induced changes in metal solubility and speciation.
Abstract: Changes in the global environment such as ocean acidification (OA) may interact with anthropogenic pollutants in- cluding trace metals threatening the integrity of marine ecosystems. We analyze recent studies on the interactive effects of OA and trace metals on marine organisms with a focus on the physiological basis of these interactions. Our analysis shows that the responses to elevated CO2 and metals are strongly dependent on the species, developmental stage, metal biochemistry and the degree of environmental hypercapnia, and cannot be directly predicted from the CO2-induced changes in metal solubility and speciation. The key physiological functions affected by both the OA and trace metal exposures involve acid-base regulation, pro- tein turnover and mitochondrial bioenergetics, reflecting the sensitivity of the underlying molecular and cellular pathways to CO2 and metals. Physiological interactions between elevated CO2 and metals may impact the organisms' capacity to maintain ac- id-base homeostasis and reduce the amount of energy available for fitness-related functions such as growth, development and re- production thereby affecting survival and performance of estuarine populations. Environmental hypercapnia may also affect the marine food webs by altering predator-prey interactions and the trophic transfer of metals in the food chain. However, our under- standing of the degree to which these effects can impact the function and integrity of marine ecosystems is limited due the scar- city of the published research and its bias towards certain taxonomic groups. Future research priorities should include studies of metal x PCO2 interactions focusing on critical physiological functions (including acid-base, protein and energy homeostasis) in a greater range of ecologically and economically important marine species, as well as including the field populations naturally ex- posed (and potentially adapted) to different levels of metals and CO2 in their environments (Current Zoology 61 (4): 653-668,
85 citations
TL;DR: The findings suggest that the species may be classified as efficient metal trap for Cd in aerial parts, as indicated by higher metal accumulation in the leaves combined with BCF and translocation factor (TF) values.
Abstract: The work investigates on the potential of ten mangrove species for absorption, accumulation and partitioning of trace metal(loid)s in individual plant tissues (leaves, bark and root/pneumatophore) at two study sites of Indian Sundarban Wetland. The metal(loid) concentration in host sediments and their geochemical characteristics were also considered. Mangrove sediments showed unique potential in many- fold increase for most metal(loid)s than plant tissues due to their inherent physicochemical properties. The ranges of concentration of trace metal(loid)s for As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn in plant tissue were 0.006-0.31, 0.02-2.97, 0.10-4.80, 0.13-6.49, 4.46-48.30, 9.2-938.1, 0.02-0.13, 9.8-1726, 11-5.41, 0.04-7.64, 3.81-52.20 μg g (-1)respectively. The bio- concentration factor (BCF) showed its maximum value (15.5) in Excoecaria agallocha for Cd, suggesting that it can be considered as a high-efficient plant for heavy metal bioaccumulation. Among all metals, Cd and Zn were highly bioaccumulated in E. agallocha (2.97 and 52.2 μg g (-1) respectively. Our findings suggest that the species may be classified as efficient metal trap for Cd in aerial parts, as indicated by higher metal accumulation in the leaves combined with BCF and translocation factor (TF) values.
TL;DR: An overview of the current state of knowledge on the biogeochemistry of metallophores in trace metal acquisition is provided, and established and potential meetallophore systems are explored.
Abstract: Trace metal limitation not only affects the biological function of organisms, but also the health of ecosystems and the global cycling of elements. The enzymatic machinery of microbes helps to drive critical biogeochemical cycles at the macroscale, and in many cases, the function of metalloenzyme-mediated processes may be limited by the scarcity of essential trace metals. In response to these nutrient limitations, some organisms employ a strategy of exuding metallophores, biogenic ligands that facilitate the uptake of metal ions. For example, bacterial, fungal, and graminaceous plant species are known to use Fe(III)-binding siderophores for nutrient acquisition, providing the best known and most thoroughly studied example of metallophores. However, recent breakthroughs have suggested or established the role of metallophores in the uptake of several other metallic nutrients. Furthermore, these metallophores may influence environmental trace metal fate and transport beyond nutrient acquisition. These discoveries have resulted in a deeper understanding of trace metal geochemistry and its relationship to the cycling of carbon and nitrogen in natural systems. In this review, we provide an overview of the current state of knowledge on the biogeochemistry of metallophores in trace metal acquisition, and explore established and potential metallophore systems.
TL;DR: In this article, the importance of coastal sandy sediments and their contribution to carbon, nutrient and metal cycling was evaluated by evaluating two beach sites on Spiekeroog Island, southern North Sea, Germany, and a tidal flat margin, located in Spielerog's backbarrier area.
Abstract: In order to evaluate the importance of coastal sandy sediments and their contribution to carbon, nutrient and metal cycling we investigated two beach sites on Spiekeroog Island, southern North Sea, Germany, and a tidal flat margin, located in Spiekeroog's backbarrier area. We also analyzed seawater and fresh groundwater on Spiekeroog Island, to better define endmember concentrations, which influence our study sites. Intertidal sandy flats and beaches are characterized by pore water advection. Seawater enters the sediment during flood and pore water drains out during ebb and at low tide. This pore water circulation leads to continuous supply of fresh organic substrate to the sediments. Remineralization products of microbial degradation processes, i.e. nutrients, and dissolved trace metals from the reduction of particulate metal oxides, are enriched in the pore water compared to open seawater concentrations. The spatial distribution of dissolved organic carbon (DOC), nutrients (PO43−, NO3−, NO2−, NH4+, Si(OH)4 and total alkalinity), trace metals (dissolved Fe and Mn) as well as sulfate suggests that the exposed beach sites are subject to relatively fast pore water advection, which leads to organic matter and oxygen replenishment. Frequent pore water exchange further leads to comparatively low nutrient concentrations. Sulfate reduction does not appear to play a major role during organic matter degradation. High nitrate concentrations indicate that redox conditions are oxic within the duneward freshwater influenced section, while ammonification, denitrification, manganese and iron reduction seem to prevail in the ammonium-dominated seawater circulation zone. In contrast, the sheltered tidal flat margin site exhibits a different sedimentology (coarser beach sands versus finer tidal flat sands) and nutrients, dissolved manganese and DOC accumulate in the pore water. Ammonium is the dominant pore water nitrogen species and intense sulfate reduction leads to the formation of sulfide, which precipitates dissolved iron as iron sulfide. These findings are due to slower advective pore water exchange in the tidal flat sediments. This study illustrates how different energy regimes affect biogeochemical cycling in intertidal permeable sediments.
TL;DR: It is found that the migration of anthropogenic trace metals was mainly controlled by the tide in the Laizhou Bay, and an effective strategies and remedial measures should be designed and undertaken to prevent further anthropogenic Cd and As pollutions in this area in the future.
Abstract: Spatial distribution, ecological risk, pollutant source, and transportation of trace metals in surface sediments, as well as the sediment properties, were analyzed in this study to assess the pollution status of trace metal in the Laizhou Bay, China. Results of provenance analyses indicate that surface sediments were primarily from weathering products carried by the surrounding short rivers and partially from loess matters carried by the Yellow River. Variations of trace metal concentrations were mostly controlled by the accumulation of weathering products, organic matters, and the hydrodynamics. Geoaccumulation index suggests that no Cr pollution occurred in the study area, and Cu, Pb, and Zn pollutions appeared only at a few stations. Comparatively, Cd and As pollutions were at noticeably weak to moderate level at many stations. The combination of six trace metals in this study had a 21 % probability of being toxic in our study area based on sediment quality guidelines. Enrichment factors (EFs) and statistical analyses indicate that Cu, Pb, and Zn were primarily derived from the natural process of weathering. By contrast, Cd, As, and Cr (especially Cd and As) were provided by the anthropogenic activities to a large extent. Due to the dilution of coarse-grained sediments, there was even no contamination at some of stations that were obviously influenced by humans. Based on the current study of transportation process of fine-grained sediments in combination with the spatial distribution of EFs, it is found that the migration of anthropogenic trace metals was mainly controlled by the tide in the Laizhou Bay. The study suggests that an effective strategies and remedial measures should be designed and undertaken to prevent further anthropogenic Cd and As pollutions in this area in the future.
TL;DR: The combined process was found to be an efficient method to remove trace metals and improve dewaterability of contaminated dredged sediments.
TL;DR: The work suggests that the trace metals present in sediments posed adverse effects on the sediment-dwelling organisms and ecological risk was considered on the consensus based Sediment Quality Guidelines (SQGs).
TL;DR: Results from litter-soil-plant compartments suggest that soil is this metal's best transfer source, and sludge spread appears to be responsible for the observed bioaccumulation for Cu and Cd after 28days of exposure.
TL;DR: In this article, a diffusive gradients in thin film probe developed comprises diffusive gel layer of silver iodide (AgI) and a back-up Microchelex resin gel layer.
Abstract: A novel diffusive gradients in thin film probe developed comprises diffusive gel layer of silver iodide (AgI) and a back-up Microchelex resin gel layer. 2D high-resolution images of sulfide and trace metals were determined respectively on the AgI gel by densitometric analysis and on the Microchelex resin layer with laser-ablation-inductively-coupled plasma mass spectrometry (LA-ICP-MS). We investigated the validity of the analytical procedures used for the determination of sulfide and trace metals. We found low relative standard deviations on replicate measurements, linear trace-metal calibration curves between the LA-ICP-MS signal and the true trace-metal concentration in the resin gel, and a good agreement of the sulfide results obtained with the AgI resin gel and with other analytical methods. The method was applied on anoxic sediment pore waters in an estuarine and marine system. Simultaneous remobilization of sulfide and trace metals was observed in the marine sediment.
TL;DR: While DIM and HRI values suggest that the consumption of plants grown in PG-amended soils is nearly free of risks, there are other sources of metal exposures such as dust inhalation, dermal contact, and ingestion (for children) of metal-contaminated soils, which were not included in this study.
Abstract: Phosphogypsum (PG) is a waste produced by the phosphate fertilizer industry that has relatively high concentrations of some heavy metals (eg, Cd, Cr, Cu, Pb, V, and Zn) The present study was conducted to investigate heavy metal contamination in soils and vegetables (tomatoes and green peppers) and to evaluate the possible health risks associated with the consumption of vegetables grown in PG-amended soils The enrichment factor values indicated that Pb, Cr, Cu, Ni, Zn, and V were depleted to minimally enriched, and Cd was moderately enriched The pollution load index values indicated that the PG-amended soils were strongly polluted with Cd, moderately polluted with Cr and Ni, and slightly polluted with Pb, Cu, Zn and V The geo-accumulation index values indicated that the PG-amended soils were uncontaminated with Pb, Cr, Cu, Ni, Zn, V, and moderately contaminated with Cd The trace metal transfer for Cd, Cr, Pb, and Zn concentrations was below what are considered as acceptable limits ( Pb > Cd > Cr The biological absorption coefficients in plants are, in order of highest to lowest, Pb > Zn > Cd > Cr, which suggests that Pb is more bioavailable to plants than Cd, Cr, and Zn Furthermore, this study highlights that both adults and children consuming vegetables (eg, tomatoes and green peppers) grown in PG-amended soils ingest significant amounts of the metals studied However, the daily intake of metals (DIM) and the health risk index (HRI) values are <1, indicating a relative absence of health risks associated with the consumption of vegetables/fruits grown in PG-amended soils However, while DIM and HRI values suggest that the consumption of plants grown in PG-amended soils is nearly free of risks, there are other sources of metal exposures such as dust inhalation, dermal contact, and ingestion (for children) of metal-contaminated soils, which were not included in this study
TL;DR: Interestingly, fluorescence in situ hybridization (FISH) showed that a large number of dense, large aggregates of n-damo bacteria were formed by cell adhesion in the SBR reactor after using the improved medium, and to the authors' knowledge this is the first discovery of large aggregate of n
TL;DR: The different kinetics and ratios of aerosol metal dissolution have implications for phytoplankton nutrition, and highlight the need for unified extraction protocols that simulate aerosolMetal dissolution in the surface ocean.
Abstract: Atmospheric deposition is a major source of trace metals in marine surface waters and supplies vital micronutrients to phytoplankton, yet measured aerosol trace metal solubility values are operationally defined, and there are relatively few multi-element studies on aerosol-metal solubility in seawater. Here we measure the solubility of aluminum (Al), cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) from natural aerosol samples in seawater over a 7 days period to (1) evaluate the role of extraction time in trace metal dissolution behavior and (2) explore how the individual dissolution patterns could influence biota. Dissolution behavior occurs over a continuum ranging from rapid dissolution, in which the majority of soluble metal dissolved immediately upon seawater exposure (Cd and Co in our samples), to gradual dissolution, where metals dissolved slowly over time (Zn, Mn, Cu, and Al in our samples). Additionally, dissolution affected by interactions with particles was observed in which a decline in soluble metal concentration over time occurred (Fe and Pb in our samples). Natural variability in aerosol chemistry between samples can cause metals to display different dissolution kinetics in different samples, and this was particularly evident for Ni, for which samples showed a broad range of dissolution rates. The elemental molar ratio of metals in the bulk aerosols was 23,189Fe: 22,651Al: 445Mn: 348Zn: 71Cu: 48Ni: 23Pb: 9Co: 1Cd, whereas the seawater soluble molar ratio after 7 days of leaching was 11Fe: 620Al: 205Mn: 240Zn: 20Cu: 14Ni: 9Pb: 2Co: 1Cd. The different kinetics and ratios of aerosol metal dissolution have implications for phytoplankton nutrition, and highlight the need for unified extraction protocols that simulate aerosol metal dissolution in the surface ocean.
TL;DR: In this paper, the vertical and lateral changes in the chemical forms of nickel, which accumulates massively in mangrove sediments downstream from lateritized ultramafic deposits from New Caledonia, where one of nature's largest accumulations of nickel occurs.
TL;DR: The results raise questions concerning the bioavailability of contaminants released by sediments in the water column and the toxicity rate was significant in many samples in comparison with other sites studied in other Mediterranean regions.
TL;DR: In this article, trace metal characterization of aerosol and cloud water samples were performed during the Hill Cap Cloud Thuringia (HCCT) campaign during four full cloud events (FCEs) that fulfilled the conditions of a continuous air mass flow through the three stations.
Abstract: . Trace metal characterization of bulk and size-resolved aerosol and cloud water samples were performed during the Hill Cap Cloud Thuringia (HCCT) campaign. Cloud water was collected at the top of Mt. Schmucke while aerosol samples were collected at two stations upwind and downwind of Mt. Schmucke. Fourteen trace metals including Ti, V, Fe, Mn, Co, Zn, Ni, Cu, As, Sr, Rb, Pb, Cr, and Se were investigated during four full cloud events (FCEs) that fulfilled the conditions of a continuous air mass flow through the three stations. Aerosol particle trace metal concentrations were found to be lower than those observed in the same region during previous field experiments but were within a similar range to those observed in other rural regions in Europe. Fe and Zn were the most abundant elements with concentration ranges of 0.2–111.6 and 1.1–32.1 ng m−3, respectively. Fe, Mn, and Ti were mainly found in coarse mode aerosols while Zn, Pb, and As were mostly found in the fine mode. Correlation and enrichment factor analysis of trace metals revealed that trace metals such as Ti and Rb were mostly of crustal origin while trace metals such as Zn, Pb, As, Cr, Ni, V, and Cu were of anthropogenic origin. Trace metals such as Fe and Mn were of mixed origins including crustal and combustion sources. Trace metal cloud water concentration decreased from Ti, Mn, Cr, to Co with average concentrations of 9.18, 5.59, 5.54, and 0.46 μg L−1, respectively. A non-uniform distribution of soluble Fe, Cu, and Mn was observed across the cloud drop sizes. Soluble Fe and Cu were found mainly in cloud droplets with diameters between 16 and 22 μm, while Mn was found mostly in larger drops greater than 22 μm. Fe(III) was the main form of soluble Fe especially in the small and larger drops with concentrations ranging from 2.2 to 37.1 μg L−1. In contrast to other studies, Fe(II) was observed mainly in the evening hours, implying its presence was not directly related to photochemical processes. Aerosol–cloud interaction did not lead to a marked increase in soluble trace metal concentrations; rather it led to differences in the chemical composition of the aerosol due to preferential loss of aerosol particles through physical processes including cloud drop deposition to vegetative surfaces.
TL;DR: Assessment of chemical hazard to the surrounding aquatic environment should not be carried out through traditional approaches and anthropogenic portion of the metals was determined through one-step chemical sequential extraction and lithogenous portion substituted for the mean crust and shale levels in the new pollution index (RIAquatic).
Abstract: Sediment samples were collected from the Petrochemical Special Economic Zone of Mahshahr Bay, Persian Gulf, and analyzed for possible trace metal contamination by means of a chemical partitioning method The heavy metal contents in the sediments follow the order of Al > Sr > Mn > Zn > Ni > Ba > Cr > Cu > As > Co The degree of sediment contamination was evaluated using pollution load index (PLI), modified degree of contamination (mC d), geo-accumulation index (I geo), and enrichment factor (EF) All these indices compare present concentrations of metals to their background levels in crust and shale In a specific area with high geological background like Mahshahr Bay, such a comparison may lead to erroneous conclusions Due to the remarkable contribution of lithogenous fraction, as the natural component, to the bulk concentration of trace metals in the sediments of such an area, assessment of chemical hazard to the surrounding aquatic environment should not be carried out through traditional approaches In the present study, anthropogenic portion of the metals was determined through one-step chemical sequential extraction and lithogenous portion substituted for the mean crust and shale levels in the new pollution index (RIAquatic) PLI, mC d, and I geo revealed overall low values, but EF, pollution index (I POLL), and newly developed pollution index were relatively high for all samples
TL;DR: In this paper, the distribution of trace metals in the world's largest mangrove ecosystem, Sundarban, in India and Bangladesh, was analyzed using a speciation technique to document the bioavailability and environmental hazards associated with operationally defined chemical forms of trace metal.
Abstract: The study was conducted to highlight the distribution of trace metals in the world’s largest mangrove ecosystem, Sundarban, in India and Bangladesh. A speciation technique was used to document the bioavailability and environmental hazards associated with operationally defined chemical forms of trace metals. Seven sediment cores were selected to study the speciation of selected trace metals (Fe, Mn, Cu and Zn) in the sedimentary mangrove environment. A modified European Community Bureau of Reference (BCR) three-step sequential extraction procedure was used to target chemical forms. Texture analysis showed that the hydrodynamic conditions prevailing in the region are high in energy that leads to the deposition of sediment fractions in the following order: silt > clay > sand. The fine-grained sediments have the potential for binding trace metals. The trace metal content was higher in the fine-grained fraction that was dominant in the Indian Sundarban (IS) than Bangladesh Sundarban (BS). The ranges of concentrations of four trace metals were as follows: 38,760–52,829 μg g−1 for Fe, 424–770 μg g−1 for Mn, 36–82 μg g−1 for Cu and 55–83 μg g−1 for Zn in IS, while in BS, the ranges were 29,081–45,025 μg g−1 for Fe, 342–792 μg g−1 for Mn, 12–45 μg g−1 for Cu and 29–75 μg g−1 for Zn. Speciation suggested the dominance of Mn in the acid-soluble fraction (>68 % IS; >52 % BS) while Fe (>83 % IS; >80 % BS), Cu (>56 % IS; >60 % BS) and Zn (>77 % IS; >80 % BS) dominated in the residual fraction. The speciation pattern showed that due to low organic carbon (OC) content (<0.99 % IS; <1.52 % BS), the Fe–Mn oxyhydroxide fraction (fraction 2) acts as a scavenging phase for Fe, Cu and Zn. The Risk Assessment Code (RAC) showed moderate to very high risk with respect to Cu and Mn, whereas Fe and Zn were in the low-risk category suggesting an anthropogenic influence with respect to Cu and Mn. The dominance of Cu and Mn in the non-residual fraction suggests anthropogenic sources, such as port-related activities and sewage runoff. The study highlights the dominance of anthropogenic activity and lack of freshwater flow in IS compared to BS, which affects the speciation profile of trace metals in the mangrove sediments.
TL;DR: The estimated weekly intake of Cd, As, Hg, Pb, Fe, and Zn from consuming edible fungi was lower than the provisional tolerable weekly intake, which provides useful information for consumers and regulators about levels of trace metals in edible fungi.
Abstract: UNLABELLED Levels of cadmium (Cd), arsenic (As), mercury (Hg), lead (Pb), iron (Fe), and zinc (Zn) were investigated in 285 samples of 9 species of edible fungi (Lentinus edodes, Auricularia auricula, Pleurotus ostreatus, Tremella fuciformis, Flammulina velutipes, Agrocybe chaxinggu, Armillaria mellea, Agaricus bisporus, and Pholiota nameko), which were collected from markets in Beijing, China. In addition, edible fungi and culture substrates were collected from 7 cultivation bases to examine the role of the substrate in trace metal accumulation. Trace metal concentrations were determined on a dry weight basis. Data showed that all the edible fungi contained trace metals, the levels of which varied among species, and there were significant positive correlations between trace metal (Cd, Pb, and As) concentrations in mushrooms and their substrates. The concentrations of Cd, As, Hg, Pb, Fe, and Zn in the tested fungi ranged from 0.005 to 13.8 mg/kg, nd to 1.62 mg/kg, nd to 0.506 mg/kg, 0.011 to 22.1 mg/kg, 46.3 to 2514 mg/kg, and 14.6 to 289 mg/kg, respectively. In general, concentrations of Cd, As, Hg, Pb, Fe, and Zn were relatively high in L. edodes, whereas Tremella fuciformis and P. nameko had relatively low levels of trace metals. Furthermore, the estimated weekly intake of trace metals was calculated and compared with the WHO/FAO provisional tolerable weekly intake. The estimated weekly intake of Cd, As, Hg, Pb, Fe, and Zn from consuming edible fungi was lower than the provisional tolerable weekly intake. PRACTICAL APPLICATION This paper reports information about trace metal concentrations in edible fungi collected from Beijing, China. This paper provides useful information for consumers and regulators about levels of trace metals in edible fungi.
TL;DR: The annual diffusive flux of Cu at HB is found to be significant and contributes to the higher than expected water column Cu concentrations observed in Boston Harbor, and a surface enrichment of solid phase trace metals was found at MB and is attributed to the persistent scavenging by Fe-oxyhydroxides.
TL;DR: Almost the whole urban area of Wuhan is facing considerable potential ecological risk caused by soil trace metals, and effective measures should be taken as soon as possible to deal with Cd enrichment, and other trace metals in soil should be reduced, so as to protect human health in this important large city.
Abstract: Surface soil samples from 467 sample sites were collected in urban area of Wuhan City in 2013, and total concentrations of five trace metals (Pb, Zn, Cu, Cr, and Cd) were measured. Multivariate and geostatistical analyses showed that concentrations of Pb, Zn, and Cu are higher along Yangtze River in the northern area of Wuhan, gradually decrease from city center to suburbs, and are mainly controlled by anthropogenic activities, while those of Cr and Cd are relatively spatially homogenous and mainly controlled by soil parent materials. Pb, Zn, Cu, and Cd have generally higher concentrations in roadsides, industrial areas, and residential areas than in school areas, greenbelts, and agricultural areas. Areas with higher road and population densities and longer urban construction history usually have higher trace metal concentrations. According to estimated results of the potential ecological risk index and Nemero synthesis pollution index, almost the whole urban area of Wuhan is facing considerable potential ecological risk caused by soil trace metals. These results reveal obvious trends of trace metal pollution, and an important impact of anthropogenic activities on the accumulation of trace metals in soil in Wuhan. Vehicular emission, industrial activities, and household wastes may be the three main sources for trace metal accumulation. Increasing vegetation cover may reduce this threat. It should be pointed out that Cd, which is strongly accumulated in soil, could be the largest soil pollution factor in Wuhan. Effective measures should be taken as soon as possible to deal with Cd enrichment, and other trace metals in soil should also be reduced, so as to protect human health in this important large city.
TL;DR: It was stated that elevated concentrations of some trace metals in snow samples were associated with frequent occurrence of south and southeast advection of highly polluted air masses toward the sampling site, suggesting a large impact of regional urban/industrial pollution plumes.
Abstract: This work presents the first results from winter field campaigns focusing on trace metals and metalloid chemistry in the snow cover from an urbanized region in central Poland. Samples were collected between January and March 2013 and trace element concentrations were determined using GF-AAS. A large inter-seasonal variability depending on anthropogenic emission, depositional processes, and meteorological conditions was observed. The highest concentration (in μg L−1) was reported for Pb (34.90), followed by Ni (31.37), Zn (31.00), Cu (13.71), Cr (2.36), As (1.58), and Cd (0.25). In addition, several major anthropogenic sources were identified based on principal component analysis (PCA), among which the most significant was the activity of industry and coal combustion for residential heating. It was stated that elevated concentrations of some trace metals in snow samples were associated with frequent occurrence of south and southeast advection of highly polluted air masses toward the sampling site, suggesting a large impact of regional urban/industrial pollution plumes.