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1.
Environ Monit Assess ; 192(11): 672, 2020 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-33009971

RESUMO

The effects of soil compaction on porosity (α), bulk density (ρs), and saturated hydraulic conductivity (Ksat) can create a physical barrier in the soil, reducing the vertical movement of toxic elements in the soil profile. However, the indirect effects of compaction in altering the forms and availability of heavy metals in soil have not been well-studied. This study examined the influence of compaction on forms of lead (Pb) in soils with contrasting texture. Four levels of compaction were imposed on a sandy loam and a clayey soil, which were artificially contaminated based on their maximum Pb adsorption capacity. Compaction had different effects on Pb forms depending on soil texture. In the sandy loam soil, compaction had a dual beneficial effect in mitigating the impact of Pb contamination, since it decreased Ksat, reducing metal transport to deeper soil layers, and also prevented transformation to more available Pb forms (soluble and exchangeable). Instead, there was an increase in the most environmentally stable forms of Pb (inner sphere adsorption on iron and manganese oxides). In the clayey soil, compaction caused a significant increase in soluble and exchangeable Pb, accompanied by a significant reduction in environmentally stable Pb (inner sphere adsorption on gibbsite and kaolinite). In addition, studies about Pb contents under compacted soil layers should be investigated, mainly in clayey soils with edible crops, and environmental remediation practices that involve the machines traffic (for example, phytoremediation-successive cultivation of Pb-hyperaccumulating plants) should be used with care to minimise the compaction of clayey soils.


Assuntos
Metais Pesados/análise , Poluentes do Solo/análise , Monitoramento Ambiental , Chumbo , Solo
2.
Environ Monit Assess ; 192(11): 688, 2020 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-33030595

RESUMO

We assessed the levels of Pb, Cd, and Mn in contour feathers of the feral pigeon (Columba livia) and house crow (Corvus splendens) obtained from five urban/suburban locations across Sri Lanka, using the AAS following wet digestion. Our key objectives were to compare accumulation levels in the two avian species with different foraging habits and living in common locations, and to establish baseline information on the presence of these metals in multiple locations in Sri Lanka with varying levels of urbanization. Owing to reservations that have been expressed by previous workers regarding the use of feathers for assessing heavy metal pollution, we first tested the efficacy of contour feathers by using our data for comparing the coefficients of variation in metal levels within and between locations. This showed that in over 95% of the cases, variations within locations were lower than between locations, indicating that freshly shed contour feathers that were used in the present study were reliable indicators of the status of bioaccumulation of the heavy metals in the environment. In interspecific comparisons, other than in the two suburban locations, Pb was present at much higher levels in the house crow than in the feral pigeon, whereas accumulation patterns with respect to Cd and Mn were inconsistent, suggesting that granivores may not, in all situations, accumulate lower levels than scavengers in the same environment. Owing to such interspecific variations in the patterns of accumulation of different heavy metals, the selection of a single species for assessing levels of pollution from heavy metals may not be prudent. Pb and Cd levels in both species were strongly and positively associated with human population density. The levels of Pb and Cd were highest in Colombo (commercial capital). In Colombo and Kalutara, the recorded levels in the house crow exceeded the thresholds that have the potential to inflict adverse impacts on avian species.


Assuntos
Poluentes Ambientais , Metais Pesados , Animais , Monitoramento Ambiental , Poluentes Ambientais/análise , Plumas/química , Humanos , Metais Pesados/análise , Sri Lanka
3.
Water Sci Technol ; 82(5): 851-860, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33031065

RESUMO

The microalgae treatment system is an economically and environmentally friendly option for wastewater treatment. However, the effects of heavy metal toxicity on microalgae cells can limit the use of microalgae in the treatment of industrial effluents rich in heavy metals. In this work, we studied the effect of Ni, Cu, Al, Hg and Pb, added as single-metal solutions to the microalgae culture medium, on the growth of 20 indigenous strains belonging to a wide variety of microalgae genera. Ni and Cu were the most toxic to the strains tested. A highly tolerant strain of the Phacus genera was selected. We determined the effect of multiple combinations of Ni, Al and Pb on the cell growth of the selected strain and on the removal capacity of each metal from the microalgae culture medium. Phacus was able to grow in the multi-metal solution (Ni, 5.00 mg/L; Al, 9.94 mg/L and Pb 1.00 mg/L) and to efficiently remove the metals, with removal capacities of 8.82 ±0.16 mg/g for Ni, 2.09 ± 0.05 mg/g for Pb and 16.90 ± 0.53 mg/g for Al. The reductions of Ni, Al and Pb concentrations were 66.67, 64.28 and 79.17% respectively.


Assuntos
Metais Pesados , Microalgas , Biodegradação Ambiental , Chumbo/toxicidade , Metais Pesados/análise , Metais Pesados/toxicidade , Águas Residuárias
4.
Environ Monit Assess ; 192(11): 699, 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33044641

RESUMO

The present study was intended to determine the potentially toxic elements (PTEs) concentration in fly ash (FA), soil, plant, and vegetable to assess the impacts of pollution on the nearby areas of coal-fired thermal power plant (TPP). The PTEs concentrations (mg/kg) in FA were Cr (48-74) > Pb (41-65) > Cd (7.4-9.7) > As (3.19-4.43) > Hg (0.518-0.598). The contamination factor (Cf) for Cd was highest in agricultural soil (Cf = 22) followed by roadside soil (Cf = 20), and forest soil (Cf = 15), which showed that the soil was strongly polluted due to the presence of Cd. The ecological risk index (ERI) in the topsoil of roadside area was also very high (1130), due to the high value of ecological risk factor of Cd (898) and Hg (213). The health risk associated with the intake of soil containing PTEs were also estimated by calculating hazard index (HI), and the values showed that the risk posed to children was minimum (HI < 1). But in case of roadside area, the HI was very close to one (0.975) indicating that the prolong exposure may pose severe health risk. The bioaccumulation coefficient of all PTEs for Albizia lebbeck and Madhuca longifolia were < 1, indicating less PTEs accumulation in the plant species. The hazard quotient of all PTEs (except of Hg) through vegetable consumption (Allium cepa and Raphanus sativus) was > 1, which signifies that the long-time consumption of contaminated vegetables may cause severe risk to the people.


Assuntos
Metais Pesados , Poluentes do Solo , Criança , Carvão Mineral , Monitoramento Ambiental , Humanos , Índia , Metais Pesados/análise , Centrais Elétricas , Medição de Risco , Solo , Poluentes do Solo/análise , Verduras
5.
Environ Monit Assess ; 192(11): 705, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-33063182

RESUMO

The present study aimed at evaluating the levels of microbiological contamination, total petroleum hydrocarbons (TPHs), and heavy metals (As, Cd, Hg, and Pb) in the edible tissues of commonly consumed fish (8 species) collected from the marine area of Tripoli, Northern Lebanon. Total coliform levels in all sampled fish, and Escherichia coli levels in Liza ramada only, exceeded the permissible limits set by FAO/WHO 2002. Staphylococcus aureus counts were within the recommended thresholds, while sulfate-reducing bacteria levels were the highest in fish of the genus Liza. Salmonella species and Listeria monocytogenes were not detected in all fish analyzed. Analysis of heavy metals levels showed that arsenic exhibited the highest levels among the assessed metals in all genera. Levels of As in Epinephelus, Diplodus, Oblada, and Liza were above the acceptable limits, while Cd levels were below the permissible limits set by the European Commission. Significant negative correlation was found between levels of As and Hg in muscle tissues and fish size (length). Levels of TPHs were the highest in fish of the genus Epinephelus. Significant difference in TPHs contamination was found within three fish genera, with Epinephelus being the most contaminated.


Assuntos
Metais Pesados , Petróleo , Poluentes Químicos da Água , Animais , Monitoramento Ambiental , Contaminação de Alimentos/análise , Hidrocarbonetos , Líbano , Metais Pesados/análise , Poluentes Químicos da Água/análise
6.
Environ Monit Assess ; 192(10): 658, 2020 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-32974766

RESUMO

Batan Bay in Aklan, Philippines supports a population largely dependent on coastal fisheries. The development of aquaculture technologies coupled with over-crowded fish pens has negatively affected its natural dynamics and environmental quality. Land-use activities including ports and shipyard further aggravate the problem by contributing to chemical pollution. The present study applied sequential extraction techniques to determine the geochemical speciation of metals in fishpond sediments. Samples were processed and analyzed for Cu, Cd, and Pb using flame atomic absorption spectroscopy. Copper (Cu) showed the highest concentration (10.61-66.81 µg/g-dry weight of sediment). Lead (Pb) content ranged from below detection limit to 15.14 µg/g, while Cd concentration ranged from below detection limit to 2.50 µg/g. Fractionation study showed that the Cu present in the fishpond sediments is mostly non-residual (50.03-73.34%) and significantly associated with the oxidizable fraction (33.89-64.75%). In contrast, the residual fraction served as the dominant host of Pb (33.55-62.68%) in the sediments. Comparison of the results with US EPA and NOAA sediment quality guidelines also revealed that the Batan Bay sediments may be considered generally non-polluted with respect Cu, Pb, and Cd, and not expected to cause adverse effects to aquatic organisms under normal conditions. However, under certain redox conditions, most of the sites may be considered moderately polluted as a result of Cu mobilization from the non-residual fractions of the sediments. Overall, geochemical speciation studies in an important fishery area like Batan Bay will provide valuable insights into the availability of metal contaminants to aquatic organisms under certain environmental conditions.


Assuntos
Metais Pesados/análise , Poluentes Químicos da Água/análise , Baías , Cádmio , Monitoramento Ambiental , Sedimentos Geológicos , Chumbo , Filipinas
7.
Sci Total Environ ; 741: 140446, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32887013

RESUMO

Soil enzymes play a key role in the circulation of nutrients and the functioning of the ecosystem. The aim of the study was to assess how the tree species of urban agglomerations affect soil quality and enzymatic activity (dehydrogenases DEH, catalase CAT, alkaline AlP and acid AcP phosphatase, protease PR, ß-glucosidase GLU, and urease UR). To this end, soil samples were taken from beneath nine park trees. The risk of soil contamination by selected heavy metals (Pb, Ni, Cd) was also investigated against the background of the selected physicochemical properties. Enzyme activity results were used to calculate multi-parametric indices of soil quality: availability factor (AF), enzymatic pH indicator (AlP/AcP), biological index of fertility (BIF), geometric mean (GMea), alternation index (Al3), biochemical soil activity (BA16 and BA17). The results showed statistically significant differences in physicochemical and enzymatic properties of soil depending on tree species. Correlation analysis showed that the content of total organic carbon (TOC), total nirogen (TN), total phosphorus (TP) and humus (OM) in soil significantly influenced the activity of the studied enzymes and glomalin content. AF coefficient values (1.84%-18.19%) suggest that the bioavailability of available phosphorus (AP) was sufficient. The Pb, Ni, Cd content results were found to be low and did not exceed the permissible concentrations. DEH, CAT and AlP activity were highest under common hawthorn, and AcP, GLU and PR under northern white cedar. The calculated enzymatic indicators proved to be a sensitive and accurate indicator of the dynamics of changes taking place in the city park soil. Based on the results, an attempt can be made to assess the planning of sustainable development of studied areas of urban parks.


Assuntos
Metais Pesados/análise , Poluentes do Solo/análise , Cidades , Ecossistema , Parques Recreativos , Solo , Árvores
8.
Mar Pollut Bull ; 159: 111466, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32892913

RESUMO

This study identifies the impact of river sediments on coastal ecosystems in the southwestern coastal region of Korea. Surface sediments were analyzed for their spatial distributions of organic matter, nutrients, and heavy metal concentrations. Furthermore, pollutants were identified according to the pollution load index (PLI) and potential ecological risk index (RI). Concentrations did not show serious pollution levels compared to generalized guidelines; however, some sites exceeded the PLI pollution standard, and were also identified as potential ecological risks. Through cluster analyses the sediment sites were classified into three groups: rivers with relatively high concentrations of organic matter and nutrients, rivers affected largely by artificial heavy metal pollution, and rivers with low levels of pollution by organic matter, nutrients, and heavy metals. It is evident that continuous monitoring and management are required to prevent major pollution from industrial complexes, agriculture, and commercial activities in the regions near these rivers.


Assuntos
Metais Pesados/análise , Poluentes Químicos da Água/análise , China , Ecossistema , Monitoramento Ambiental , Sedimentos Geológicos , República da Coreia , Medição de Risco , Rios
9.
Mar Pollut Bull ; 159: 111482, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32892917

RESUMO

Microplastics have received widespread attention as an emerging contaminant, but limited information was available during wetland restoration. The occurrence and characteristics of microplastics and their interaction with heavy metals in surface sediments from the Jinjiang Estuarine restored mangrove wetland were investigated. The abundance of microplastics ranged from 490 ± 127.3 to 1170 ± 99.0 items/500 g dry sediment, and the restored regions were much higher than mudflats, indicating mangrove restoration promoted its accumulation. Polyethylene terephthalate (PET), polyethylene (PE) and polypropylene (PP) were the main materials of microplastics after Raman spectroscopy identification. SEM-EDS images illustrated the mechanical erosion and chemical weathering on microplastics' surface, and Cr, Zn, Pb, and Cd were observed in elemental composition. The contents of Cr, Ni, Cu, Zn, Pb, As, and Cd accumulated in microplastics were not correlated with their total concentrations in sediments except for Hg, indicating that they might not be derived from sediments.


Assuntos
Metais Pesados/análise , Poluentes Químicos da Água/análise , China , Monitoramento Ambiental , Estuários , Sedimentos Geológicos , Microplásticos , Plásticos , Áreas Alagadas
10.
Mar Pollut Bull ; 159: 111492, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32892924

RESUMO

The concentrations of the heavy metals Cu, Pb, Zn, As, Cr, Co, and Ni of a total of 187 surface sediment samples collected from the western Taiwan Strait were analyzed. The distribution characteristics and degree of contamination of these elements were investigated. The mean concentrations of Cu, Pb, Zn, As, Cr, Co, and Ni in the surface sediments of the study area were 10.2 mg/kg, 18.3 mg/kg, 51.7 mg/kg, 7.5 mg/kg, 38.7 mg/kg, 8.0 mg/kg, and 16.5 mg/kg, respectively. The heavy metals in the study area were mainly from natural sources. The regional pollution load index (PLIzone) was 0.64, indicating that there was no contamination, and an area with a relatively high PLIzone was found in the northern part of the study area. Furthermore, the impacts of the rapid development of Fujian's marine economy on the marine environment in the past decade should be further compared and analyzed.


Assuntos
Metais Pesados/análise , Poluentes Químicos da Água/análise , China , Monitoramento Ambiental , Sedimentos Geológicos , Medição de Risco , Taiwan
11.
Environ Monit Assess ; 192(10): 649, 2020 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-32955642

RESUMO

The objective of this study was to establish background concentrations of potentially toxic elements (PTEs) in soils from the Carajás Mineral Province (CMP), southeastern Amazonian Craton. The PTEs Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Ti, V, and Zn were digested in microwaves and quantified by optical emission spectrometry (ICP OES). The variability of physical-chemical and mineralogical attributes contributed to variation in PTE concentrations. High background concentrations of Al, Fe, Cr, Mn, Mo, Ni, Ti, and V and, in particular, the PTE concentrations of Cd, Cu, Cr, Ba, and Co were greater than the prevention values defined by the Brazilian National Council of Environment. Soil quality reference values (QRVs) were greater than those determined for most Brazilian states and soils in the state of Pará. The high background concentrations and QRVs of PTEs show that the region is strongly influenced by the source material, rich in ferruginous deposits and other associated minerals. The results are an important tool for establishing soil quality standards and public policies for environmental protection in regions naturally PTE enriched.


Assuntos
Metais Pesados/análise , Poluentes do Solo/análise , Brasil , Monitoramento Ambiental , Minerais , Solo
12.
Chemosphere ; 254: 126903, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957296

RESUMO

We used discarded oyster shells to prepare vaterite calcium carbonate microparticles and explored the removal effects and the underlying mechanism toward several heavy metal ions. The removal efficiency for each ion type was: Pb2+ (99.9%), Cr3+ (99.5%), Fe3+ (99.3%), and Cu2+ (57.1%). With the exception of Cu2+, vaterite calcium carbonate particles exhibited excellent removal performance on all tested heavy metal ions, with exceptional results for Pb2+. The factor affecting the removal efficiency of heavy metal ions is shown to involve an ion exchange reaction between calcium and the heavy metal ions resulting in recrystallization. Vaterite calcium carbonate particles prepared by this method have the advantage of low price, easy synthesis, and reduction of environmental waste. Thus, this procedure for synthesizing vaterite CaCO3 provides an environmentally responsible method for preparing materials that can be economically incorporated into common consumer products such as household drinking water filtration systems.


Assuntos
Exoesqueleto/química , Carbonato de Cálcio/química , Metais Pesados/análise , Ostreidae , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Animais , Concentração de Íons de Hidrogênio , Troca Iônica , Íons , Microesferas , Propriedades de Superfície
13.
Chemosphere ; 254: 126909, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957299

RESUMO

Soil contamination by heavy metals (HMs) is an environmental problem, and nanoremediation by using zero-valent iron nanoparticles (nZVI) has attracted increasing interest. We used ecotoxicological test and global transcriptome analysis with DNA microarrays to assess the suitability of C. elegans as a useful bioindicator to evaluate such strategy of nanoremediation in a highly polluted soil with Pb, Cd and Zn. The HMs produced devastating effect on C. elegans. nZVI treatment reversed this deleterious effect up to day 30 after application, but the reduction in the relative toxicity of HMs was lower at day 120. We stablished gene expression profile in C. elegans exposed to the polluted soil, treated and untreated with nZVI. The percentage of differentially expressed genes after treatment decreases with exposure time. After application of nZVI we found decreased toxicity, but increased biosynthesis of defensive enzymes responsive to oxidative stress. At day 14, when a decrease in toxicity has occurred, genes related to specific heavy metal detoxification mechanisms or to response to metal stress, were down regulated: gst-genes, encoding for glutathione-S-transferase, htm-1 (heavy metal tolerance factor), and pgp-5 and pgp-7, related to stress response to metals. At day 120, we found increased HMs toxicity compared to day 14, whereas the transcriptional oxidative and metal-induced responses were attenuated. These findings indicate that the profiled gene expression in C. elegans may be considered as an indicator of stress response that allows a reliable evaluation of the nanoremediation strategy.


Assuntos
Caenorhabditis elegans/efeitos dos fármacos , Ferro/química , Metais Pesados/toxicidade , Nanopartículas/química , Estresse Oxidativo/efeitos dos fármacos , Poluentes do Solo/toxicidade , Transcrição Genética/efeitos dos fármacos , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Ecotoxicologia , Nanopartículas Metálicas , Metais Pesados/análise , Estresse Oxidativo/genética , Solo/química , Microbiologia do Solo , Poluentes do Solo/análise , Toxicogenética
14.
Ecotoxicol Environ Saf ; 203: 111055, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888617

RESUMO

The pollution level of potentially toxic elements (PTEs) in surface soils is detrimental to the ecosystem and human health. In this research, various indices such as an index of geo-accumulation (Igeo), contamination factor (CF), degree of contamination (DC), and principal component analysis (PCA) were implemented to identify and evaluate the soil PTEs pollution; and then human health risk assessment model used to establish the link between heavy metals pollution and human health in the urban region of south India. Results exhibited that the mean concentration of Cr, Cu, Ni and Zn were found to be 1.45-6.03 times greater than the geochemical background values. Cr and Cu were the most profuse PTEs measured in the soils. The pollution indices suggest that soil of the study region is mainly moderate to highly polluted. The non-carcinogenic health risk assessment proposed by the United States Environmental Protection Agency (USEPA) suggested the mean hazard indices (HIs) were below one which denotes no significant of non-carcinogenic risks to both children and adults. Furthermore, carcinogenic risk assessment results advised ~80% of cancer risk was caused by Cr contents, while other heavy metals indicate that neither children nor adults in the study region were of carcinogenic risks.


Assuntos
Carcinógenos/análise , Monitoramento Ambiental/métodos , Substâncias Perigosas/análise , Metais Pesados/análise , Poluentes do Solo/análise , Solo/química , Adulto , Carcinógenos/toxicidade , Criança , Ecossistema , Substâncias Perigosas/toxicidade , Humanos , Índia , Metais Pesados/toxicidade , Medição de Risco , Poluentes do Solo/toxicidade , Estados Unidos , United States Environmental Protection Agency , Urbanização
15.
Sci Total Environ ; 740: 140042, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32927538

RESUMO

There is increasing interest in understanding potential impacts of complex pollutant profiles to long-lived species such as the green sea turtle (Chelonia mydas), a threatened megaherbivore resident in north Australia. Dietary ingestion may be a key exposure route for metals in these animals and marine plants can accumulate metals at higher concentrations than the surrounding environment. We investigated concentrations of 19 metals and metalloids in C. mydas forage samples collected from a group of offshore coral cays and two coastal bays over a period of 2-3 years. Although no samples exceeded sediment quality guidelines, coastal forage Co, Fe, and V concentrations were up to 2-fold higher, and offshore forage Sr concentrations were ~3-fold higher, than global seagrass means. Principal Component Analysis differentiated coastal bay from coral cay forage according to patterns consistent with underlying terrigenous-type or marine carbonate-type sediment geochemistry, such that coastal bay forage was higher in Fe, Co, Mn, Cu, and Mo (and others) but forage from coral cays was higher in Sr and U. Forage from the two coastal bays was differentiated according to temporal variation in metal profiles, which may be associated with a more episodic sediment disturbance regime in one of the bays. For all study locations, some forage metal concentrations were higher than previously reported in the global literature. Our results suggest that forage metal profiles may be influenced by the presence of some metals in insoluble forms or bound to ultra-fine sediment particles adhered to forage surfaces. Metal concentrations in Great Barrier Reef forage may be present at levels higher than expected from the global seagrass literature and appear strongly influenced by underlying sediment geochemistry.


Assuntos
Antozoários , Metais Pesados/análise , Tartarugas , Poluentes Químicos da Água/análise , Animais , Austrália , Baías , Monitoramento Ambiental , Sedimentos Geológicos
16.
Environ Monit Assess ; 192(10): 639, 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-32929590

RESUMO

Soil and the dominant plant species in the vicinity of Khatoon Abad copper smelter in Kerman province of Iran are examined to determine contamination, bioavailability, and ecological-health risk of potentially toxic elements (PTEs) based on 23 collected soil samples and 13 Artemisia siebri plant species. Cu, Mo, As, and Sb display a significant level of enrichment in soil. Ecological risk assessment shows that Cu, As, and Cd pose the highest ecological risk. The results of PTEs fractionation reveal that, on average, Cu, As, Cd, Pb, Zn, and Mo are mostly distributed between non-residual fractions reflecting higher mobility and potential ecological risk, while Cr, Ni, and Co are significantly distributed within the residual fraction, and do not pose a serious ecological risk. Mobility factor suggests high bioavailability of Cu for plants followed by As, Cd, Pb, Mo, Co, Ni, and Cr. Biological accumulation coefficient displays higher phytoavailability of Mo and Cd. PTEs transfer within plant follows the order of Mo > As > Pb > Zn > Cu > Ni > Co > Cr > Cd. The results of phytoavailability indicate the high tendency of Cd to bioaccumulate in Artemisia's root, while Mo, As, and Pb tend to translocate towards Artemisia's shoot. Calculated hazard index and incremental lifetime cancer risk revealed that As poses the highest non-carcinogenic health risk, and As and Pb pose the greatest carcinogenic health risk in both adults and children.


Assuntos
Metais Pesados/análise , Poluentes do Solo/análise , Adulto , Disponibilidade Biológica , Criança , Cobre , Monitoramento Ambiental , Humanos , Irã (Geográfico) , Medição de Risco , Solo
17.
J Environ Sci (China) ; 97: 120-131, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32933727

RESUMO

Despite laboratory experiments that have been performed to study internal heavy metal release, our understanding of how heavy metals release in shallow eutrophic lakes remains limited for lacking in-situ evidence. This study used automatic environmental sensors and a water sampling system to conduct high-frequency in-situ observations (1-hr intervals) of water environmental variables and to collect water samples (3-hr intervals), with which to examine the release of internal heavy metals in Lake Taihu, China. Under conditions of disturbance by strong northerly winds, sediment resuspension in both the estuary area and the lake center caused particulate heavy metal resuspension. However, the patterns of concentrations of dissolved heavy metals in these two areas were complex. The concentrations of dissolved Se and Mo increased in both areas, indicating that release of internal dissolved Se and Mo is triggered by sediment resuspension. The concentrations of dissolved Ni, Zn, As, Mn, Cu, V, and Co tended to increase in the estuary area but decrease in the lake center. The different trends between these two areas were controlled by pH and cyanobacteria, which are related to eutrophication. During the strong northerly winds, the decrease in concentrations of dissolved heavy metals in the lake center was attributable primarily to absorption by the increased suspended solids, and to growth-related assimilation or surface adsorption by the increased cyanobacteria. The findings of this study suggest that, short-term changes of environmental conditions are very important in relation to reliable monitoring and risk assessment of heavy metals in shallow eutrophic lakes.


Assuntos
Metais Pesados/análise , Poluentes Químicos da Água/análise , China , Monitoramento Ambiental , Sedimentos Geológicos , Lagos
18.
J Environ Sci (China) ; 97: 169-179, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32933732

RESUMO

Total contents of metals in soil and sediments on the Tibetan Plateau of China have been widely analyzed, but existing information is insufficient to effectively evaluate metal ecological risk because of a lack of metal bioavailability data. In this study, distribution, potential risk, mobility and bioavailability of metals in sediments of Lake Yamdrok Basin in Tibet of China were explored by combined use of total digestion, sequential extraction and the diffusive gradient in thin-films (DGT). Average concentrations of Cr, Ni, Cu, Zn, As, Cd and Pb in surface sediments were 31.25, 30.31, 22.00, 45.04, 31.32, 0.13 and 13.39 mg/kg, respectively. Higher levels of metals were found near the inflowing rivers. Residual form was dominant in Cr, Ni, Zn, Cd and Pb, and reducible form was dominant in As and Cd. Metals in surface sediments showed a low enrichment degree overall, but Cd and As had higher ecological risk levels than the other metals. Furthermore, there was a larger average proportion of exchangeable form of As (20.4%) and Cd (9.0%) than the other metals (1.7%-3.3%), implying their higher mobility and release risk. Average DGT-labile concentrations of Cr, Ni, Cu, Zn, As, Cd and Pb were 0.5, 4.5, 0.7, 25.1, 60.0, 0.22 and 1.0 µg/L, respectively. The DGT-labile As was significantly correlated with extractable As forms (p< 0.01), suggesting that extractable As in sediments acts as a "mobile pool" for bioavailable As. These results suggest potential risks of As and Cd, especially As, deserve further attention in Lake Yamdrok Basin.


Assuntos
Metais Pesados/análise , Poluentes Químicos da Água/análise , Disponibilidade Biológica , China , Monitoramento Ambiental , Sedimentos Geológicos , Lagos , Medição de Risco , Tibet
19.
J Environ Sci (China) ; 97: 35-44, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32933738

RESUMO

Few studies have been carried out to connect nutrient recovery as struvite from wastewater and sustainable utilization of the recovered struvite for copper and zinc immobilization in contaminated soil. This study revealed the effect of struvite on Cu and Zn immobilization in contaminated bio-retention soil in the presence of commonly exuded plant organic acids. The research hypothesis was that the presence of both struvite and organic acids may influence the immobilization of Cu and Zn in soil. The outcome of this research confirmed that more than 99% of Cu and Zn was immobilized in bio-retention filter media by struvite application. Water-soluble Cu and Zn concentrations of struvite treated soil were less than 1.83 and 0.86 mg/kg respectively, and these concentrations were significantly lower compared to the total Cu and Zn content of 747.05 mg/kg in the contaminated soil. Application of struvite to Cu- and Zn-contaminated soil resulted in formation of compounds similar to zinc phosphate tetrahydrate (Zn3(PO4)2•4H2O) and amorphous Cu and Zn phases. Struvite was effective in heavy metal remediation in acidic soil regardless of the presence of Ca impurities in struvite and the presence of plant organic acids in soil. Overall, this study revealed that struvite recovered from wastewater treatment plants has potential for use as an amendment for heavy metal remediation in contaminated bio-retention soil.


Assuntos
Metais Pesados/análise , Poluentes do Solo/análise , Cobre , Solo , Estruvita , Zinco
20.
J Environ Manage ; 275: 111288, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32866925

RESUMO

The spatial distribution of water quality status, especially in water bodies near intensively urbanized areas, is tightly associated with patterns of human activities. For establishing a robust assessment of the sediment quality in an urban aquatic environment, the source apportionment and risk assessment of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg, and Pb in sediments from an anthropogenic-influenced lake were carried out with considering uncertainties from the analysis methods, random errors in the sample population and the spatial sediment heterogeneity. The distribution analysis of the trace metals with inverse distance weighting-determined method showed that the pollutants were concentrated in the middle and southern areas of the lake. According to the self-organizing map and constrained positive matrix factorization receptor model, agricultural sources (24.8%), industrial and vehicular sources (42.5%), and geogenic natural sources (32.7%) were the primary contributors to the given metals. The geogenic natural had the largest random errors, but the overall result was reliable according to the uncertainty analysis. Furthermore, the stochastic contamination and ecological risk models identified a moderate/considerable contamination level and a moderate ecological risk to the urban aquatic ecosystem. With consideration of uncertainties from the spatial heterogeneity, the contamination level of Hg, and the ecological risk of Cd in had a 20-30% probability of the increase.


Assuntos
Metais Pesados , Oligoelementos , Poluentes Químicos da Água , China , Ecossistema , Monitoramento Ambiental , Sedimentos Geológicos , Humanos , Metais Pesados/análise , Medição de Risco , Incerteza , Poluentes Químicos da Água/análise
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