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1.
Bull Environ Contam Toxicol ; 106(4): 658-664, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33710387

RESUMO

Concentrations of copper (Cu), iron (Fe), manganese (Mn), nickel (Ni) and zinc (Zn) in muscle and gills of four Benthic fish species (Brachirus orientalis, Argyrops spinifer, Platycephalus indicus and Sillago sihama) from Shif Island of Iran were analyzed using flame atomic absorption spectrometry. The heavy metal levels observed in tissues varied for Cu: 2.15-820.98, Fe: 24.46-533.26, Mn: 1.80-53.17, Ni: 1.86-65.54 and Zn: 28.77-375.79 mg/kg. Significant differences were found among muscle and gill of the four fish species. Heavy metals concentration were significantly (p < 0.05) higher in the gill than in the muscles of all fish species studied. The metal levels in benthic fish species should be continuously monitored in polluted areas since benthic fish indicated a tendency to bioaccumulate pollutants in their tissues from polluted water. The indices of Estimated Daily Intake, Target Hazard Quotient and Hazard Index suggests no risk while carcinogenic risk for Ni showed unacceptable carcinogenic risk.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Animais , Cobre/análise , Monitoramento Ambiental , Brânquias/química , Irã (Geográfico) , Ferro/análise , Ilhas , Magnésio , Metais Pesados/análise , Metais Pesados/toxicidade , Músculos/química , Níquel/análise , Níquel/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Zinco/análise
2.
Ecotoxicol Environ Saf ; 212: 111986, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33540338

RESUMO

Population exposure to environmental contaminants can be precisely observed through human biomonitoring studies. The present study aimed to systematically review all the biomonitoring studies conducted in Iran on some selected carcinogen environmental pollutants. In this systematic review study, 11 carcinogen agents were selected including arsenic, cadmium, chromium, nickel, lindane, benzene, trichloroethylene (TCE), pentachlorophenol (PCP), radon-222, radium-224, - 226, - 228, and tobacco smoke. The Web of Science, PubMed, and Scopus databases were searched for peer-reviewed articles published in English. After several screening steps, data were extracted from the studies. Meta-analyses (a random-effect model using the DerSimonian-Laired method) were performed only for the biomarkers with more than three eligible articles, including cadmium in blood and breast milk, and arsenic in breast milk. Methodological quality of the studies was assessed using the Newcastle-Ottawa Quality Assessment Scale adapted for cross-sectional studies. Of the 610 articles found in the database search, 30 studies were eligible for qualitative review, and 13 were included in the meta-analysis (cadmium in blood (n = 3), cadmium in breast milk (n = 6), and arsenic in breast milk (n = 4)). The overall pooled average concentrations (95% CI) of cadmium in blood, cadmium in breast milk, and arsenic in breast milk were 0.11 (95% CI: 0.08, 0.14), 5.38 (95% CI: 3.60, 6.96), and 1.42 (95% CI: 1.02, 1.81) µg/L, respectively. These values were compared with the biomarker concentrations in other countries and health-based guideline values. This study showed that there is a need for comprehensive action plans to reduce the exposure of general population to these environmental contaminants.


Assuntos
Monitoramento Biológico , Poluentes Ambientais/análise , Arsênico/análise , Cádmio/análise , Cromo/análise , Estudos Transversais , Exposição Ambiental/análise , Poluição Ambiental/análise , Feminino , Humanos , Irã (Geográfico) , Leite Humano/química , Níquel/análise
3.
J Environ Manage ; 284: 112024, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33548751

RESUMO

The presence of moderate concentrations of impurities in the nickel-plating baths generates failures on the coated pieces. This situation entails the necessity of replacing the electroplating bath, which implies the generation of large volumes of wastewater with metallic species and high quantity of sludge. For this reason, the adsorption of the principal impurities of nickel-plating baths of an industry was analyzed in this work. Particularly, the removal of Zn2+ was studied in more detail since the presence of this metal in the baths generates black spots on the coated pieces. Different commercial materials were used as adsorbents and Zn2+ adsorption studies were carried out using both standard solutions and industrial water from the nickel-plating baths. All the adsorption tests were performed in batch systems under constant agitation and the quantification of the impurities was made by ICP-MS analysis. The bone char (BC) was an efficient adsorbent for the removal of the principal impurities of nickel-plating baths. The use of molecular simulation tools helped to understand the preferences of the hydroxyapatite (the principal component of bone char) for different metallic ions present in the industrial waters. According to both the experimental adsorption and molecular simulation results, hydroxyl and phosphate groups of bone char are responsible of the adsorption of impurities of nickel-plating baths.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Adsorção , Banhos , Galvanoplastia , Níquel/análise , Poluentes Químicos da Água/análise
4.
Food Chem ; 346: 128961, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33454576

RESUMO

OBJECTIVE: To assess the levels of heavy metals and their antagonists in dairy products available in the markets of São Luís, northeastern Brazil. METHODS: Chemical analysis of the heavy metals copper(Cu), lead(Pb), mercury(Hg), and nickel(Ni) and their antagonists iron(Fe), zinc(Zn), calcium(Ca), selenium(Se), and cobalt(Co) contained in dairy products using inductively coupled plasma optical emission spectrometry (ICP-OES). RESULTS: The main heavy metal observed in dairy products were Hg; Pb; Se and Ni. A significant negative correlation was observed between the concentrations of Cu and Fe (rho = -0.634, p = 0.001), Cu and Zn (rho = -0.794, p = 0.000) in whole milk. A non-significant positive correlation was observed between Pb and Ca (rho = 0.387, p = 0.056), and Hg and Se (rho = 0.055, p = 0.795). CONCLUSIONS: Dairy product brands available in the markets of São Luís could be considered a source of heavy metal contamination (Hg, Pb, Se, Cu, Ni) with weak correlations with their antagonists.


Assuntos
Metais Pesados/análise , Leite/química , Espectrofotometria/métodos , Animais , Brasil , Criança , Cobre/análise , Laticínios/análise , Humanos , Mercúrio/análise , Níquel/análise , Medição de Risco , Espectrofotometria/instrumentação , Zinco/análise
5.
Food Chem ; 342: 128210, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33508898

RESUMO

This study aimed to investigate bioaccessible/dialyzable fractions of nickel in selected foods and to clarify the impact of the food digestion/absorption on the final exposure of consumers to nickel. In vitro gastrointestinal incubation experiments were conducted to estimate the bioaccessibility of nickel in different foods. For estimation of a dialyzable fraction, dialysis filtration was conducted. Highest bioaccessibility (99.6%) was observed for wheat-based breakfast cereals. Lowest bioaccessibilities was observed for dried-fruits (on average 20.4%). Highest (61.5%) and lowest (24.5%) dialyzable fractions were observed for wheat-based breakfast cereal and chocolate respectively. Bioaccessible/dialyzable fractions based exposure assessments were highlighted the overestimation of exposures calculated based on total nickel concentrations in foods. This is particularly important when exposure values were compared with toxicological thresholds in a risk characterization study. When threshold values have been obtained through animal studies in which nickel was dosed at 100% accessibility/availability, e.g. nickel salts this is even more important.


Assuntos
Análise de Alimentos , Níquel/análise , Bélgica , Diálise , Digestão , Grão Comestível/química , Frutas/química , Frutas/metabolismo , Humanos , Níquel/metabolismo , Chá/química , Chá/metabolismo , Triticum/química , Triticum/metabolismo
6.
Ecotoxicol Environ Saf ; 208: 111685, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396017

RESUMO

The wastewater utilization for irrigation purposes is common practice in peri-urban areas located in vicinity of developed cities. This water contains elements like chromium (Cr), nickel (Ni), cadmium (Cd) and nitrate (NO3-N) that poses health risk when exposed to human. In this study effect of wastewater irrigation from Chakara wastewater plant, Faisalabad on growth of wheat and health risks was assessed. Pot experiment was conducted at Institute of Soil and Environmental, University of Agriculture, Faisalabad using different concentration of wastewater as treatment 100% tap water, 25% wastewater + 75% tap water, 50% wastewater + 50% tap water, 75% wastewater + 25% tap water, 100% wastewater. The results indicated that the wastewater irrigation negatively effects the plant growth and physiological parameters. The minimum plant height, grain weight, spike length, osmotic potential and SPAD values were recorded 50.33 cm, 1.47 g plant-1, 7.00 cm, 423 and 38.91 respectively in 100% wastewater irrigation. The risk quotient (RQ TEs) for each toxic element and cumulative risk index (RI TEs) values were calculated. The cadmium risk quotient (Cd RQ) for adults was on margin and value was >1 for in 75% wastewater + 25% tap water and 100% wastewater irrigation, while the RQ for Ni and Cr was <1. Maximum RI TEs values calculated in 100% wastewater irrigation 0.424 and 0.294 for children and adults respectively. Hence it was concluded that wastewater irrigation significantly increased the accumulation rate of metals and nitrate in wheat and cause potential health risks for children and adults.


Assuntos
Irrigação Agrícola/métodos , Bioacumulação/efeitos dos fármacos , Metais Pesados/toxicidade , Nitratos/toxicidade , Poluentes do Solo/toxicidade , Triticum/efeitos dos fármacos , Águas Residuárias/química , Adulto , Cádmio/análise , Cádmio/toxicidade , Criança , Cromo/análise , Cromo/toxicidade , Cidades , Grão Comestível/química , Humanos , Metais Pesados/análise , Modelos Teóricos , Níquel/análise , Níquel/toxicidade , Nitratos/análise , Paquistão , Medição de Risco , Solo/química , Poluentes do Solo/análise , Triticum/crescimento & desenvolvimento , Triticum/metabolismo , Águas Residuárias/análise
7.
Ecotoxicol Environ Saf ; 211: 111905, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33453636

RESUMO

The constant increase of heavy metals into the aqueous environment has become a contemporary global issue of concern to government authorities and the public. The study assesses the concentration, distribution, and risk assessment of heavy metals in freshwater from the Linggi River, Negeri Sembilan, Malaysia. Species sensitivity distribution (SSD) was utilised to calculate the cumulative probability distribution of toxicity from heavy metals. The aquatic organism's toxicity data obtained from the ECOTOXicology knowledgebase (ECOTOX) was used to estimate the predictive non-effects concentration (PNEC). The decreasing sequence of hazardous concentration (HC5) was manganese > aluminium > copper > lead > arsenic > cadmium > nickel > zinc > selenium, respectively. The highest heavy metal concentration was iron with a mean value of 45.77 µg L-1, followed by manganese (14.41 µg L-1) and aluminium (11.72 µg L-1). The mean heavy metal pollution index (HPI) value in this study is 11.52, implying low-level heavy metal pollutions in Linggi River. The risk quotient (RQ) approaches were applied to assess the potential risk of heavy metals. The RQ shows a medium risk of aluminium (RQm = 0.1125) and zinc (RQm = 0.1262); a low risk of arsenic (RQm = 0.0122) and manganese (RQm = 0.0687); and a negligible risk of cadmium (RQm = 0.0085), copper (RQm = 0.0054), nickel (RQm = 0.0054), lead (RQm = 0.0016) and selenium (RQm = 0.0012). The output of this study produces comprehensive pollution risk, thus provides insights for the legislators regarding exposure management and mitigation.


Assuntos
Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade , Arsênico/análise , Cádmio/análise , Cobre/análise , Ecotoxicologia , Monitoramento Ambiental , Água Doce , Ferro , Malásia , Manganês , Metais Pesados/análise , Níquel/análise , Medição de Risco , Rios , Poluentes Químicos da Água/análise , Zinco/análise
8.
Chemosphere ; 271: 129573, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33460891

RESUMO

Unscientific municipal solid waste (MSW) dumping provokes heavy metal (HM) associated ecological and human health hazards through heightened bioavailability and bioaccumulation. In this study, we focused on three important HMs Cadmium (Cd), Copper (Cu) and Nickel (Ni) and their geochemical fractions, to enable clutter free data management, analysis and interpretation. Stratified random soil sampling was carried out from twenty different locations around a Ramsar site (Deepor Beel) in Guwahati, India. The spatial concentration profiles of Cd, Cu and Ni were determined by data elicited from geochemical fractionation and the Geographic Information System (GIS). Ecological and health risks indices were used to evaluate the severity of soil pollution and assess the level of health risks. All the three HMs thus evaluated, conformed to the potential bioavailable category. Cd (54.59%) was associated mostly with the carbonate bound fraction (F3), while 25.53% of Cu and 40.60% Ni were associated with the exchangeable fraction (F2). Significant contamination levels and higher ecological risks posed by these metals were in the order Cd > Ni > Cu. Children were found to be more vulnerable towards Cd associated health risks whereas, Ni posed threats to both adults and children. Cu posed no risk to human health. Geochemical fractionation and different indices played a critical role in the integrated assessment of soil pollution, ecological and health risk assessment, and provided an empirical basis for the sustainable future planning and comprehensive adaptive management practices for MSW.


Assuntos
Metais Pesados , Poluentes do Solo , Adulto , Cádmio/análise , Criança , Cobre/análise , Monitoramento Ambiental , Humanos , Índia , Metais Pesados/análise , Níquel/análise , Medição de Risco , Solo , Poluentes do Solo/análise , Resíduos Sólidos
9.
Chemosphere ; 263: 128208, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297167

RESUMO

The low concentration of nickel in electroplating wastewater is difficult to treat to meet the discharge standard. In this study, a commercial cation exchange membrane was used to combine the electrodialysis on a titanium plate anode sintered ruthenium-iridium and the electrodeposition on a stainless steel cathode to reduce the nickel concentration to less 0.1 mg L-1. The electrolytic properties of the electrodialysis combined with the electrodeposition were investigated at different cell voltages, electrolysis time, initial electrolyte pH, electrolyte flow rates and initial Ni2+ concentrations. The results indicated that the Ni2+ concentration in the anolyte and the catholyte could be reduced to 0.015 and 0.085 mg L-1, respectively, with the initial Ni2+ concentration of 1.0 mg L-1, which could meet the most strict Ni2+ discharge standard of 0.1 mg L-1. The electrodeposition of Ni2+ on the cathode enhanced the migration of the Ni2+ in the electrolytes, which was beneficial to decrease the energy consumption. Therefore, the combination of electrodialysis and electrodeposition was promising to reduce the low concentration of Ni2+ in the electroplating wastewater.


Assuntos
Galvanoplastia , Águas Residuárias , Eletrólise , Íons , Níquel/análise , Águas Residuárias/análise
10.
Ecotoxicol Environ Saf ; 209: 111808, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33360289

RESUMO

One of the fundamental objectives in modern ecology is to decipher how bacterial communities in natural environment respond to anthropogenic activities. In recent times consequences of marine pollution, especially with heavy metals (HMs) have received increasing attention. However, insights into the response of bacterial communities to HMs in coastal sediments of India remain scarce. Here, we analyzed HMs content in three areas, along the southern coastal region of India. Based on the calculated pollution indices viz., enrichment factor (EF), contamination factor (CF), geo-accumulation index (Igeo) and sediment quality guidelines (SQGs), the studied areas were classified as uncontaminated, moderately contaminated and significantly contaminated. To explore the response of bacterial community to HMs, sediment-associated microbiota was investigated using high-throughput 16S rRNA gene amplicon sequencing. The obtained metataxonomic results revealed that bacterial diversity and community composition varied considerably in significantly contaminated area than moderately contaminated and uncontaminated areas. Proportion of bacterial classes was higher for Gammaproteobacteria, Betaproteobacteria and Actinobacteria, but lower for Alphaproteobacteria and Flavobacteriia in significantly contaminated area. Also, samples of significantly contaminated area were dominated by well-documented metal-resistant bacterial genera such as Ralstonia and Arthrobacter. Canonical correspondence analysis (CCA) showed that spatial variability of bacterial community composition was strongly correlated with HMs content such as Chromium, Cadmium and Nickel. Further analysis using PICRUSt programme indicated that the predictive functional profile also varied considerably in significantly contaminated area. By linking HMs with bacterial compositional variations, the present study highlights the likely influence of HMs in shaping sedimentary microbiota of coastal regions.


Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/microbiologia , Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade , Bactérias , Cádmio/análise , Cromo/análise , Ecologia , Poluição Ambiental/análise , Sedimentos Geológicos/química , Índia , Metais Pesados/análise , Microbiota , Níquel/análise , RNA Ribossômico 16S , Poluentes Químicos da Água/análise
11.
Bull Environ Contam Toxicol ; 105(5): 777-783, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33044567

RESUMO

The capacity of Lemna minor to remediate toxic heavy metals from wastewater is reasonably well documented. In view of the pivotal role of this species in the environmental clean-up, here we evaluated the bioaccumulation potential of L. minor for cadmium (Cd), lead (Pb), and nickel (Ni) through a controlled experiment. L. minor tolerated the metals Cd, Ni, and Pb up to 0.5, 5, and 8 mg/L, respectively, and beyond these concentrations the toxicity symptoms appeared. Bio-concentration factor varied at different concentrations of heavy metals tested. Overall, L. minor showed good phytoremediation potential for all the three tested heavy metals (Cd, Ni, and Pb), though in relative terms it was more effective in extracting Ni and Cd, as compared to Pb, both in single and mixed concentrations. In view of the growing pollution in Kashmir Himalayan aquatic habitats the phytoremediation by invasive species such as L. minor promises to be one of the best choices than other native plants for cleaning up of polluted soils/water because of its fast growth rate, high abundance, easy handling, and wide distribution in Kashmir Himalayan aquatic ecosystems.


Assuntos
Organismos Aquáticos/metabolismo , Araceae/metabolismo , Bioacumulação , Metais Pesados/metabolismo , Águas Residuárias/química , Organismos Aquáticos/crescimento & desenvolvimento , Araceae/crescimento & desenvolvimento , Biodegradação Ambiental , Cádmio/análise , Cádmio/metabolismo , Ecossistema , Índia , Lagos , Chumbo/análise , Chumbo/metabolismo , Metais Pesados/análise , Níquel/análise , Níquel/metabolismo
12.
Bull Environ Contam Toxicol ; 105(5): 685-691, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33067667

RESUMO

Owls are predators that perform important ecological functions. There are several threats to owl conservation such as the bioaccumulation of chemicals through environmental contamination. The high probability of bioaccumulation in these animals is related to their role as predators and high trophic positions. The objective of this study was to quantify four elements (cadmium, chromium, nickel, and lead) as the biomarkers of environmental exposure in owls. To this end, we analyzed pellets and feathers of different owl species. These matrices were contaminated with all four elements, with chromium most commonly detected. Chromium and nickel were found in the pellets in all 10 months of the study, and May was the month with the highest concentrations of all the elements. Tyto furcata appears to bioaccumulate more elements in its feathers than Megascops spp. and Athene cunicularia. Our findings showed bioaccumulation of these four elements in owls and their environment.


Assuntos
Monitoramento Biológico/métodos , Poluição Ambiental/análise , Plumas/química , Conteúdo Gastrointestinal/química , Metais Pesados/análise , Estrigiformes/crescimento & desenvolvimento , Animais , Cádmio/análise , Cromo/análise , Refluxo Laringofaríngeo , Chumbo/análise , Metais Pesados/metabolismo , Níquel/análise
13.
Bull Environ Contam Toxicol ; 105(4): 633-638, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32960332

RESUMO

Waste disposal, metal plating, refineries, and mining operations frequently contaminate soils with nickel (Ni). We explored the effects of artificial Ni contamination (0, 56, and 180 mg Ni kg-1) on the soil biochemical indices. The lab experiment also investigated the possible use of kunai grass (Imperata cylindrica) biochar at a 0.75% dry weight basis to alleviate contamination effects. The biochemical indices such as dehydrogenase enzyme activity, acid phosphatase enzyme activity, and soil respiration rates were monitored in three replications. High level of Ni (180 mg kg-1) suppressed soil respiration rate by 37% and dehydrogenase activity by 62% up to 15 days. The acid phosphatase activity was not affected by Ni levels and was insensitive to Ni contamination. Biochar application to the Ni contaminated soil did not improve the soil's key biological properties. The beneficial effects of biochar could be limited to improvements in soil chemical properties and not on index biological properties.


Assuntos
Níquel/análise , Poluentes do Solo/análise , Carvão Vegetal , Mineração , Poaceae , Solo/química
14.
Environ Pollut ; 265(Pt A): 115059, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32806429

RESUMO

Field survey-based ecological risk assessments for trace metals are conducted to examine the necessity and/or effectiveness of management intervention, such as setting of environmental quality standards. Observational datasets often involve confounders that may bias estimation of the effects of intervention (e.g., reduction of trace-metal concentrations through regulation). The field of ecotoxicology lags behind some other research fields in understanding proper analytical procedures for causal inference from observational datasets; there are only a few field survey-based ecotoxicological studies that have explicitly controlled for confounders in their statistical analyses. In the present study, we estimated the effect of intervention in nickel concentrations on Ephemeroptera, Plecoptera, and Trichoptera richness in rivers in Japan. We also provide detailed explanations for the backgrounds of spurious associations derived from confounders and on proper analytical procedures for obtaining an unbiased estimate of the targeted intervention effect by using regression analysis. We constructed a multiple regression model based on a causal diagram for aquatic insects and environmental factors, and on "the backdoor criterion," that enabled us to determine the set of covariates required to obtain an unbiased estimate of the targeted intervention effect from regression coefficients. We found that management intervention in nickel concentrations may be ineffective compared to intervention in organic pollution, and that analysis ignoring the confounders overestimated the effect of intervention in nickel concentrations. Our results highlight the fact that confounders can lead to misjudging the necessity for management of anthropogenic chemical substances. Confounders should be explicitly specified and statistically controlled to achieve a comprehensive assessment of ecological risks for various substances.


Assuntos
Ecotoxicologia , Níquel/análise , Japão , Análise de Regressão , Rios
15.
Bone Joint J ; 102-B(7_Supple_B): 116-121, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32600200

RESUMO

AIMS: This study aimed to determine if macrophages can attach and directly affect the oxide layers of 316L stainless steel, titanium alloy (Ti6Al4V), and cobalt-chromium-molybdenum alloy (CoCrMo) by releasing components of these alloys. METHODS: Murine peritoneal macrophages were cultured and placed on stainless steel, CoCrMo, and Ti6Al4V discs into a 96-well plate. Cells were activated with interferon gamma and lipopolysaccharide. Macrophages on stainless steel discs produced significantly more nitric oxide (NO) compared to their control counterparts after eight to ten days and remained elevated for the duration of the experiment. RESULTS: On stainless steel, both nonactivated and activated cell groups were shown to have a significant increase in metal ion release for Cr, Fe, and Ni (p < 0.001, p = 0.002, and p = 0.020 respectively) compared with medium only and showed macrophage-sized corrosive pits on the stainless steel surface. On titanium alloy discs there was a significant increase in aluminum (p < 0.001) among all groups compared with medium only. CONCLUSION: These results indicated that macrophages were able to attach to and affect the oxide surface of stainless steel and titanium alloy discs. Cite this article: Bone Joint J 2020;102-B(7 Supple B):116-121.


Assuntos
Prótese Articular , Macrófagos/química , Aço Inoxidável , Titânio , Vitálio , Ligas , Animais , Sobrevivência Celular , Cromo/análise , Meios de Cultura , Íons , Ferro/análise , Camundongos , Microscopia Eletrônica de Varredura , Níquel/análise , Óxido Nítrico/análise
16.
PLoS One ; 15(6): e0233297, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32492035

RESUMO

Metal contamination of food and water resources is a known public health issue in Arctic and sub-Arctic communities due to the proximity of many communities to mining and drilling sites. In addition, permafrost thaw may release heavy metals sequestered in previously frozen soils, potentially contaminating food and water resources by increasing the concentration of metals in freshwater, plants, and wildlife. Here we assess the enrichment of selected heavy metals in Alaskan soils by synthesizing publicly available data of soil metal concentrations. We analyzed data of soil concentrations of arsenic, chromium, mercury, nickel, and lead from over 1,000 samples available through the USGS Alaskan Geochemical Database to evaluate 1) the spatial distribution of sampling locations for soil metal analysis, 2) metal concentrations in soils from different land cover types and depths, and 3) the occurrence of soils in Alaska with elevated metal concentrations relative to other soils. We found substantial clustering of sample sites in the southwestern portion of Alaska in discontinuous and sporadic permafrost, while the continuous permafrost zone in Northern Alaska and the more populous Interior are severely understudied. Metal concentration varied by land cover type but lacked consistent patterns. Concentrations of chromium, mercury, and lead were higher in soils below 10 cm depth, however these deeper soils are under-sampled. Arsenic, chromium, mercury, nickel and lead concentrations exceeded average values for US soils by one standard deviation or more in 3.7% to 18.7% of the samples in this dataset. Our analysis highlights critical gaps that impede understanding of how heavy metals in thawing permafrost soils may become mobilized and increase exposure risk for Arctic communities.


Assuntos
Metais Pesados/análise , Poluentes do Solo/análise , Alaska , Regiões Árticas , Arsênico/análise , Cromo/análise , Bases de Dados Factuais/estatística & dados numéricos , Monitoramento Ambiental/estatística & dados numéricos , Geografia , Aquecimento Global , Humanos , Chumbo/análise , Mercúrio/análise , Mineração , Níquel/análise , Pergelissolo/química
17.
Ann Bot ; 126(5): 905-914, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-32577727

RESUMO

BACKGROUND AND AIMS: Hybanthus austrocaledonicus (Violaceae) is a nickel (Ni) hyperaccumulator endemic to New Caledonia. One of the specimens stored at the local herbarium had a strip of bark with a remarkably green phloem tissue attached to the sheet containing over 4 wt% Ni. This study aimed to collect field samples from the original H. austrocaledonicus locality to confirm the nature of the green 'nickel-rich phloem' in this taxon and to systematically assess the occurrence of Ni hyperaccumulation in H. austrocaledonicus and Hybanthus caledonicus populations. METHODS: X-ray fluorescence spectroscopy scanning of all collections of the genus Hybanthus (236 specimens) was undertaken at the Herbarium of New Caledonia to reveal incidences of Ni accumulation in populations of H. austrocaledonicus and H. caledonicus. In parallel, micro-analytical investigations were performed via synchrotron X-ray fluorescence microscopy (XFM) and scanning electron microscopy with X-ray microanalysis (SEM-EDS). KEY RESULTS: The extensive scanning demonstrated that Ni hyperaccumulation is not a characteristic common to all populations in the endemic Hybanthus species. Synchrotron XFM revealed that Ni was exclusively concentrated in the epidermal cells of the leaf blade and petiole, conforming with the majority of (tropical) Ni hyperaccumulator plants studied to date. SEM-EDS of freeze-dried and frozen-hydrated samples revealed the presence of dense solid deposits in the phloem bundles that contained >8 wt% nickel. CONCLUSIONS: The occurrence of extremely Ni-rich green phloem tissues appears to be a characteristic feature of tropical Ni hyperaccumulator plants.


Assuntos
Níquel , Violaceae , Nova Caledônia , Níquel/análise , Floema , Folhas de Planta/química
18.
Artigo em Inglês | MEDLINE | ID: mdl-32532180

RESUMO

In the present investigation, physico-chemical characterization of composite material revealed the presence of fluffy surface structure with crystalline look and negatively charged surface functional groups. The study of adsorption flux by using dimensionless numbers φ (2.62), Nk (62.68) and λ (1.17 × 10-5) proved that adsorption of nickel ions on the surface of composite material was mostly film diffusion-limited with maximum surface area coverage coupled with weakened surface tension. The results of intraparticle diffusivity and Boyd plot model showed that at the onset of process, film diffusion was the primary mechanism involved and at the later stage intraparticle diffusion played a critical role as rate governing step. The values of film (0.65 × 10-8 cm2 sec-1) and pore diffusivity (1.8 × 10-12 cm2 sec-1) coefficients showed that the adsorption process is dependent upon two different types of diffusion namely film and pore diffusion. Overall, transport and reshuffling mechanism had no substantial role in adsorption dynamics of nickel ions on the surface of composite material. Sorption isotherm and kinetics modeling showed higher values of regression coefficients for Langmuir isotherm (R2 = 0.99) and pseudo-second-order kinetic model (R2 = 0.99) compared to other models. This showed that sorption of nickel followed monolayer coverage with chemisorption at optimized process parameters like pH 6, biosorbent dose 0.1 g/L, temperature 50 °C, agitation rate180 rpm, adsorbate concentration100 mg/L and contact time 60 minutes. The positive value of enthalpy of adsorption (ΔH = + 10.41 kJ/mole) and entropy (ΔS = +58.19 J/mol K) showed that binding of nickel ions on the surface of the composite material was endothermic with improved randomness at solid-liquid interface. The negative value of (ΔG = -6.4 to -8.67 kJ/mol) showed spontaneous nature of nickel adsorption on composite material in the liquid phase.


Assuntos
Bentonita/química , Argila/química , Modelos Teóricos , Níquel/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Difusão , Concentração de Íons de Hidrogênio , Íons , Cinética , Níquel/química , Soluções , Propriedades de Superfície , Termodinâmica , Poluentes Químicos da Água/química
19.
Environ Pollut ; 265(Pt B): 114873, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32502920

RESUMO

Accumulation and oral bioavailability of nickel (Ni) were rarely assessed for staple crops grown in high geogenic Ni soils. To assess exposure risk of geogenic Ni, soil, wheat, and rice samples were collected from a naturally high background Ni area and measured for Ni oral relative bioavailability (RBA, relative to NiSO4) using a newly developed mouse urinary Ni excretion bioassay. Results showed that soils were enriched with Ni (80.5 ± 23.0 mg kg-1, n = 58), while high Ni contents were observed in rice (2.66 ± 1.46 mg kg-1) and wheat (1.32 ± 0.78 mg kg-1) grains, with rice containing ∼2-fold higher Ni content than wheat. Ni-RBA was low in soil (14.8 ± 7.79%, n = 18), but high in wheat and rice with rice Ni-RBA (85.9 ± 19.1%, n = 9) being ∼2-fold higher than wheat (46.1 ± 21.2%, n = 16). A negative correlation (r = 0.61) was observed between Ni-RBA and iron content in rice and wheat, suggesting the low iron status of rice drives its high Ni bioavailability. The higher Ni accumulation and bioavailability for rice highlights that rice consumption was a more important contributor to daily Ni intake compared to wheat, while Ni intake from direct soil ingestion was negligible. This study suggests a potential health risk of staple crops especially rice when grown in high geogenic Ni areas.


Assuntos
Oryza , Poluentes do Solo/análise , Animais , Disponibilidade Biológica , Camundongos , Níquel/análise , Medição de Risco , Solo
20.
Chemosphere ; 257: 127102, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32534292

RESUMO

A field investigation was conducted to monitor the trace element accumulation pattern and potential in lemongrass varieties when cultivated in varying concentrations of tannery sludge contaminated soils. Regression model equations were developed to predict the trace elements concentration in lemongrass plant parts. Model efficiency values ranged between 0.53 and 0.85 for roots and 0.50 to 0.77 for shoots. R2 for all the equations was high and ranged between 0.52 and 0.95 for roots and 0.50 to 0.91 for shoots. Path analysis coefficients revealed the status of interdependence between soil properties and heavy metal concentrations in plant tissues and their translocation pattern in the same. TF > 1 for Ni and Pb was recorded in all test varieties at different tannery sludge concentrations in soil and for Cd in Suwarna variety grown in sole TS. BAF>1 and BAC>1 for Ni and Pb was observed for all test varieties. BCF>1 for Cr was found in Suwarna variety at sole tannery sludge. It can be concluded that lemongrass can accumulate lead and nickel in its harvestable plant parts. Hence, it can act as a suitable phytoextractor for the same metals. Range of essential oil content (percentage) varied in all test varieties i.e. Shikhar (1.04-1.29), Krishna (0.94-1.05), Suwarna (0.82-0.95) and Chirharit (0.87-1.06) at different tannery sludge concentrations. Moreover, heavy metal content in the essential oil of all test varieties was found to be within the permissible limits, hence cultivation of lemongrass can be recommended at metal contaminated sites with minimum risk of food chain contamination.


Assuntos
Cymbopogon/metabolismo , Poluentes do Solo/metabolismo , Oligoelementos/metabolismo , Biodegradação Ambiental , Metais Pesados/análise , Níquel/análise , Óleos Voláteis , Raízes de Plantas/química , Plantas , Esgotos , Solo , Poluentes do Solo/análise , Oligoelementos/análise
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