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1.
J Environ Qual ; 49(2): 404-416, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33016431

RESUMO

Biogeochemical processes in northern peatland ecosystems are influenced by seasonal temperature fluctuations that are changing with the climate. Methylmercury (MeHg), commonly produced in peatlands, affects downstream waters; therefore, it is important to understand how temperature transitions affect mercury (Hg) dynamics. We investigated how the freeze-thaw cycle influences belowground peat pore water total Hg (THg), MeHg, and dissolved organic carbon (DOC). Four large, intact peat columns were removed from an ombrotrophic peat bog and experimentally frozen and thawed. Pore water was sampled across seven depths in the peat columns during the freeze-thaw cycle and analyzed for THg, MeHg, and DOC concentrations. Freezing results showed increased concentrations of THg below the ice layers and limited change in MeHg concentrations. During thawing, THg concentrations significantly increased, whereas MeHg concentrations decreased. Limited bromide movement and depth decreases in THg and DOC concentrations were associated with increased bulk density and degree of humification in the peat. The experiment demonstrates the effects of the freeze-thaw cycle on Hg concentrations in northern peatlands. Changes to freeze-thaw cycles with climate change may exacerbate Hg cycling and transport processes in peatland environments.


Assuntos
Mercúrio/análise , Compostos de Metilmercúrio , Ecossistema , Congelamento , Solo
2.
Environ Monit Assess ; 192(11): 704, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33057810

RESUMO

Mercury (Hg) was measured in the muscle, liver, and gonads of Haemulopsis elongatus and Pomadasys macracanthus from Mazatlán (SE Gulf of California) to determine the relationships of the hepatosomatic index (HSI) and gonadosomatic index (GSI) of fish with Hg concentrations in the corresponding tissues. Health risk to consumers was assessed by using the hazard quotient (HQ), considering the average rate of fish consumption in Mexico and Hg concentration in the edible tissue. In H. elongatus, the highest Hg levels were measured in the liver (3.748 µg g-1); in P. macracanthus, the highest Hg concentration was quantified in the muscle (0.574 µg g-1). In P. macracanthus, the HSI was negatively correlated with Hg concentration in the liver; in H. elongatus, there was also a negative relationship between Hg levels in gonads and the GSI. Mean HQ values in Haemulopsis elongatus (0.005) and Pomadasys macracanthus (0.002) were below the value (HQ ≥ 1) of concern. The significant reduction of HSI and GSI with Hg increase in the liver and gonads may suggest that Hg bioaccumulation in these fish shows adverse physiological effects. Though HQ values in both species were below the unit, i.e., the consumption of the muscle from this species does not represent a health risk, it is necessary to carry out surveys of fish consumption rates in coastal areas of Mexico to do a more precise health risk assessment associated to Hg intake.


Assuntos
Mercúrio , Poluentes Químicos da Água , Animais , Bioacumulação , California , Monitoramento Ambiental , Mercúrio/análise , México , Medição de Risco , Poluentes Químicos da Água/análise
3.
Ecotoxicol Environ Saf ; 203: 110957, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888620

RESUMO

Due to growing commercial interest as a fishing resource and its intermediate position in the marine trophic chains as both prey and predator, cephalopods can play an important role in mercury (Hg) transfer along the marine food webs, since they can bioaccumulate this metal in its tissues. Our study aims to analyze Hg accumulation in Loligo forbesi caught in the Azores Archipelago (Portugal) quantifying Hg in different tissues (mantle and stomach), as well in the squid stomach content, in order to evaluate the efficiency of Hg transfer from prey to predator. Hg data from the tissues was used to estimate the weekly tolerable Hg intake due to squid consumption. Overall data indicate that Hg measured in the stomach tissue (0.1 ± 0.01 µg g-1) was significantly higher than Hg levels found in the mantle (0.04 ± 0.001 µg g-1) and stomach contents (0.01 ± 0.001 µg g-1). BMF (bioaccumulation factor) was >1 for all the samples, indicating a biomagnification process from prey to predator. Hg concentration in the mantle tissue was correlated with mantle size; although females present higher Hg levels than males, the difference was found to be not related to gender but rather to the fact that females had larger bodies. Finally, considering the Hg concentration found in the mantle and the permitted Hg levels, it is advisable to consume up to 1050-1890g of squid per week, according to the regulatory agencies. Thus, our results indicate that, since these doses are respected, consumption of squids from the Azorean waters do not pose a risk to humans.


Assuntos
Bioacumulação , Exposição Dietética/análise , Monitoramento Ambiental/métodos , Loligo/metabolismo , Mercúrio/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Feminino , Cadeia Alimentar , Humanos , Masculino , Mercúrio/análise , Portugal , Alimentos Marinhos/análise , Poluentes Químicos da Água/análise
4.
Environ Monit Assess ; 192(10): 647, 2020 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-32948923

RESUMO

The energy transfer in the aquatic food chain is an important way for mercury (Hg) to enter other trophic levels. The objective of this work was to evaluate the Hg concentrations in plankton upstream and downstream of the Samuel Hydroelectric Reservoir, Rondônia, Brazil. Phytoplankton and zooplankton samples were collected with 20-µm and 68-µm nylon nets. An aliquot was removed for taxonomic analysis and another for total mercury determination, performed by cold vapor atomic absorption spectroscopy. Water physical-chemical parameters were also measured. The Hg concentrations in total plankton (phytoplankton and zooplankton samples) obtained at the three sampling upstream stations showed the same behavior, with the highest values registered in June 2005 (232 µg kg-1, 118 µg kg-1, 128 µg kg-1). The lowest values at stations J1 and M1 were recorded in November 2005 (4 µg kg-1 and 22 µg kg-1, respectively), while the lowest values at stations M4 and M8 were recorded in October 2005 (22 µg kg-1 and 5 µg kg-1, respectively). The Hg results found in the plankton in this study corroborate the results of other recent studies in the same region. The statistical analyses revealed that Hg concentrations in plankton do not explain the distribution of these organisms at the four sampling stations of Samuel Reservoir. Graphical Abstract.


Assuntos
Mercúrio/análise , Poluentes Químicos da Água/análise , Animais , Brasil , Monitoramento Ambiental , Peixes , Cadeia Alimentar , Plâncton
5.
Chemosphere ; 254: 126904, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957297

RESUMO

Estimating bioaccessible content of mercury in soils is essential in evaluating risks that contaminated soils pose. In this study, soil samples spiked with HgCl2 through adsorption were used to test the effects of liming, soil organic matter, soil depth, and Hg concentration on the following bioaccessibility tests: dilute nitric acid at room temperature, dilute nitric acid at body temperature, Simplified Bioaccessibility Extraction Test (SBET) method, and gastric phase of the In vitro Gastrointestinal (IVG) protocol. Soil and sediment samples from Descoberto, Minas Gerais (Brazil), a city with a well-known record of Hg contamination from artisanal mining, were subjected to these bioaccessibility tests for the first time, and the different methods of estimating bioaccessible content were compared. Bioaccessible fractions in spiked samples ranged from 10% to 60%, and this high bioaccessibility was due to the highly soluble species of Hg and the short time under adsorption. In general, clay and organic matter decreased bioaccessible content. Although the soil in Descoberto is undoubtedly polluted, mercury bioaccessibility in that area is low. In general, dilute nitric acid estimated higher bioaccessible content in soil samples, whereas the SBET method estimated higher bioaccessible content in sediment samples. In multivariate analysis, two groups of bioaccessibility tests arise: one with the two nitric acid tests, and the other with SBET and the gastric phase of the IVG protocol. The addition of pepsin and glycine in the last two tests suggests a more reliable test for assessing mercury bioaccessibility.


Assuntos
Argila/química , Substâncias Húmicas/análise , Mercúrio/análise , Mineração , Poluentes do Solo/análise , Solo/química , Adsorção , Disponibilidade Biológica , Brasil , Cidades , Mucosa Gástrica/metabolismo , Humanos , Mucosa Intestinal/metabolismo , Mercúrio/metabolismo , Modelos Biológicos , Ácido Nítrico/química , Poluentes do Solo/metabolismo
6.
Aquat Toxicol ; 227: 105594, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32911329

RESUMO

Diatoms are highly sensitive to perturbations in their environment and are thus useful as bioindicators for anthropogenic impacts such as pollution. However, there is no consensus about what aspects of diatom populations to measure (e.g., diversity, physiology, or morphology) and efficient and reliable survey protocols are lacking. Here, we evaluated the ecological status of diatom communities using both traditional and relatively novel methods on two islands (Deokjeok island and Daeijak island) affected by anthropogenic activities due to extensive agricultural practices and exploitation and that are under consideration for representative touristic sites in South Korea. Dissolved concentrations of metals and metalloid (As, Cu, Cr, Cd, Ni, Hg, Pb, and Zn) were below the ecological screening and toxicity reference values in water fractions but were above these values for sediment, particularly at one island, Deokjeok. The tested methods were generally consistent in finding little evidence for disruption of diatom communities, with dominance by Navicula and Gyrosigma, relatively high diversity, and typical abundance of lipid bodies and morphological deformities. However, analysis of lipid bodies and morphological deformities suggested greater potential anthropogenic disturbance at one site in Deokjeok. Future planning is required to ensure the maintenance of the near-pristine environments present on these islands.


Assuntos
Diatomáceas , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/toxicidade , Agricultura , China , Saúde Ambiental , Sedimentos Geológicos , Ilhas , Mercúrio/análise , Metais Pesados/toxicidade , República da Coreia , Medição de Risco
7.
N Z Med J ; 133(1522): 52-62, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32994616

RESUMO

AIM: Fish oil supplements are regulated in New Zealand under the Dietary Supplement Regulations (Section 42, Food Act 1981) and therefore are not subject to the same level of scrutiny and regulations as medicines. We investigated accuracy of labelling, stated health benefits of fish oil supplements sold in New Zealand, and risks relating to possible mercury content. METHOD: The amounts of omega-3 fatty acids contained per capsule were determined by an independent laboratory using gas chromatography on 10 of the most popular over-the-counter fish oil supplements sold in New Zealand and were compared with amounts stated on product labels. Information on doses recommended to achieve a specific health benefit were taken from the 10 labels as well as the company websites. These recommended doses were compared with published recommended doses identified as being effective in those health areas stipulated on the labels, based on either systematic reviews, meta-analyses and/or consensus statements. Mercury was analysed by an independent laboratory using inductively coupled plasma mass spectrometry. RESULTS: The actual amounts of EPA and DHA per capsule in 90% of the over-the-counter fish oil supplements analysed were within 10% of the amount stated on the product labels. Only one product was greater than 10% below the stated dose on the label. All products suggested benefit across heart, brain and joint health and all but two products stated a range of capsules required to achieve that health benefit (eg, 2-6 capsules). Based on the maximum number of capsules recommended (which ranged from 3-6 capsules), only three products would likely confer the dose identified as optimal for achieving a health benefit across all three health areas. Only two products recommended doses that would likely confer a health benefit both at the minimum and maximum number of capsules. More products would likely benefit brain and heart health than joint health. Mercury was not detected in any sample. CONCLUSIONS: It is reassuring that the doses of 90% of the products were accurate and that mercury was not detected in any sample; however, less than a third of the supplements would likely confer all the health benefits stated, even at the highest recommended daily doses. This paper has highlighted the ongoing challenges associated with the regulation of "health claims" associated with dietary supplements in New Zealand. Indeed, the literature on health effects is contradictory at best. Clearer definitions of the types of health statements that can be made and the research necessary to support them requires regulatory clarification.


Assuntos
Suplementos Nutricionais , Óleos de Peixe , Suplementos Nutricionais/análise , Suplementos Nutricionais/normas , Suplementos Nutricionais/estatística & dados numéricos , Contaminação de Medicamentos/estatística & dados numéricos , Ácidos Graxos Ômega-3/análise , Óleos de Peixe/análise , Óleos de Peixe/química , Óleos de Peixe/normas , Mercúrio/análise , Nova Zelândia , Rotulagem de Produtos/normas , Rotulagem de Produtos/estatística & dados numéricos
8.
Chemosphere ; 258: 127412, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947661

RESUMO

The objective of this study was development of a simple and reliable microbial toxicity test based on fermentative bacteria to assess heavy metal (Hg2+, Cu2+, Cr6+, Ni2+, As5+, or Pb2+)-contaminated water. The dominant species of test organisms used in this study was a spore-forming fermentative bacterium, Clostridium guangxiense. Toxicity of water was assessed based on inhibition of fermentative gas production of the test organisms, which was analyzed via a syringe method. Overall, the fermentative bacteria-based test kits satisfactorily identified increased toxicity of water as water was contaminated with high amounts of heavy metals; however, levels of inhibition were dissimilar depending on the species of metals. Inhibitory effects of Hg2+, Cu2+, Cr6+, and Ni2+ were considerably greater than those of As5+ and Pb2+. The 24 h half-maximum effective concentrations (EC50) for Hg2+, Cu2+, Cr6+, Ni2+, As5+, and Pb2+ were analyzed to be 0.10, 0.51, 1.09, 3.61, 101.33, and 243.45 mg/L, respectively, confirming that Hg2+, Cu2+, Cr6+, and Ni2+ are more toxic to fermentative gas production than As5+ and Pb2+. The fermentative bacteria-based toxicity test represents an improvement over other existing toxicity tests because of ease of end-point measurement, high reproducibility, and favorable on-site field applicability. These advantages make the fermentative bacteria-based test suitable for simple and reliable toxicity screening for heavy metal-contaminated water.


Assuntos
Monitoramento Ambiental/métodos , Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade , Bactérias , Clostridium , Fermentação , Mercúrio/análise , Metais Pesados/análise , Reprodutibilidade dos Testes , Poluentes Químicos da Água/análise , Poluição da Água/análise
9.
Chemosphere ; 258: 127435, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947671

RESUMO

Isotopic composition of mercury (Hg) in marine organisms and sediment cores was used to identify sources and reconstruct historical trends of contamination in the coastal-marine area of Rosignano Solvay (Italy), affected by Hg pollution from a chlor-alkali plant on the near land. Sediments show a wide range of Hg concentration and Hg isotope signatures. Particularly, coupled Hg concentration and δ202Hg values trace inputs from different sources. The two depth-profiles clearly indicate three distinct periods: "pre-industrial" (before 1941), "industrial" (between 1941 and 2007) and "post-industrial" (after 2007) ages. This is also corroborated by sediment chronology, using 210Pb dating method, validated through 137Cs. Marine organisms are characterized by Hg isotope signatures comparable to "post-industrial" surface sediments. Notably, specimens of Mullus spp. evidence isotope composition comparable to the "industrial" sediments, thus suggesting a still active role of those sediments as source of Hg for the benthic fish compartment. The small amount of MIF and the Δ199Hg/Δ201Hg ratio recorded in organisms are reasonably consistent with limited processes of MMHg demethylation in the water column.


Assuntos
Mercúrio/análise , Poluentes Químicos da Água/análise , Animais , Organismos Aquáticos , Monitoramento Ambiental , Poluição Ambiental , Peixes , Sedimentos Geológicos , Indústrias , Isótopos , Itália , Isótopos de Mercúrio/análise
10.
Chemosphere ; 258: 127413, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947681

RESUMO

Fishing is part of the traditional activities of Indigenous people in Canada. However, it is also a route of exposure to methylmercury, a known neurotoxicant, and this is a concern for those who rely on fish as part of their diet. The probable weekly intake (PWI) of methylmercury from six species of fish was calculated for Indigenous community members (N = 1406), grouped by age and sex, and compared to Canadian and international provisional reference doses to assess exposure. Mixed-effects regression models were also used to estimate the input of methylmercury into the blood, and Hazard Quotients (HQ) were used to assess potential effects. Of the species of fish in our study, walleye and lake trout contributed the most to methylmercury intake. There was a positive association between the consumption of walleye and the total blood mercury concentrations of mercury in women and men (R2A = 0.40 and 0.47, respectively), and to a lesser extent, children. Similar results were observed for the consumption of lake trout. The 95th-percentile HQ for girls (3.16) and boys (3.18) from the consumption of lake trout was relatively high, and to a lesser extent, so was the HQ for walleye and pike. The consumption of some species of fish increases the exposure to methylmercury, however, taking a balanced approach, there are health benefits associated with the consumption of fish that must be considered. To mitigate future exposure to methylmercury, we recommend follow-up blood monitoring and local-geospatial-based assessments.


Assuntos
Exposição Dietética/estatística & dados numéricos , Monitoramento Ambiental , Compostos de Metilmercúrio/toxicidade , Poluentes Químicos da Água/toxicidade , Adolescente , Animais , Baías , Canadá , Criança , Dieta , Exposição Ambiental/análise , Feminino , Peixes , Humanos , Masculino , Mercúrio/análise , Compostos de Metilmercúrio/análise , Compostos de Metilmercúrio/metabolismo , Quebeque , Alimentos Marinhos/estatística & dados numéricos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo
11.
Bull Environ Contam Toxicol ; 105(4): 626-632, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32959072

RESUMO

The paper presents results of the research on the dynamics of changes in the concentration of mercury in surface waters. The importance of mercury as an environmental pollutant results from specific properties of this metal, many sources of contamination, volatility, mobility, stability and high toxicity of its specific chemical forms. Samples of surface water collected from three rivers: the Bug, the Liwiec and the Muchawka were analysed. The Muchawka River flows into the Liwiec River, which in turn is a tributary of the Bug River. The technique of isotachophoresis was employed, using a solution of a biodegradable and environmentally non-toxic derivative of electrostatically stabilised silanates as the terminating electrolyte. The highest average mercury concentration of 0.89 µg/dm3 was determined in water samples collected from the Bug River in January, whereas the lowest concentration of 0.42 µg/dm3 was recorded in water collected from the Muchawka River in September.


Assuntos
Monitoramento Ambiental , Mercúrio/análise , Poluentes Químicos da Água/análise , Eletrólitos/análise , Rios/química
12.
Sci Total Environ ; 738: 139794, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32806376

RESUMO

The Baihua Reservoir (Guizhou Province, Southwest China) has a history of mercury contamination associated with past acetic acid production activities at the Guizhou Organic Chemical Plant (GOCP). Soil and plant samples collected from riparian zones were analyzed for total Hg (THg) and methylmercury (MeHg) using cold vapor atomic fluorescence spectroscopy. The concentrations of THg and MeHg in soil samples were in the range of 109-371 ng g-1 and 0.32-1.80 ng g-1, respectively. Soils in the riparian zones close to the pollution source (the GOCP) presented higher Hg contamination, with relatively light Hg contamination in remote areas. This suggests a decreasing trend of THg concentrations along the riparian zones, with higher concentrations closer to the pollution source. Significant correlations were found between MeHg and soil organic matter (n = 24, p = 0.01). THg concentrations varied 11.3-161 ng g-1 in aboveground areas and 11.3-193 ng g-1 in underground areas. MeHg concentrations ranged from 0.23 to 1.06 ng g-1 in aboveground areas to 0.13-1.51 ng g-1 in the below ground areas. The vegetation studied showed different concentrations of THg and MeHg and can be considered to be impacted by Hg contamination. Different concentrations of total and methyl mercury were found among the different plant species. The high Hg concentrations in soils and vegetation suggests that the ability of Hg to bioaccumulate in riparian plants is affected by plant physiological characteristics and soil mercury concentrations. Although the bioaccumulation factors (BCFs) of the studied plants were low, their transfer factors (TFs) were >1. Our findings suggest that vegetation exhibiting TFs for THg >1 have the potential for phytoextraction in Hg-impacted riparian zones.


Assuntos
Mercúrio/análise , Compostos de Metilmercúrio , China , Monitoramento Ambiental , Solo
13.
Environ Pollut ; 265(Pt B): 115079, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32806461

RESUMO

Soils, especially permafrost in the Arctic and the Tibetan Plateau, are one of the largest reservoirs of mercury (Hg) in the global environment. The Hg concentration in the grassland soils over the Tibetan Plateau and its driving factors have been less studied. This study analyzes soil total mercury (STHg) concentrations and its vertical distribution in grassland soil samples collected from the Tibetan Plateau. We adopt a nested-grid high-resolution GEOS-Chem model to simulate atmospheric Hg deposition. The relationship between STHg and soil organic carbon (SOC), as well as atmospheric deposition, are explored. Our results show that the STHg concentrations in the Tibetan Plateau are 19.8 ± 12.2 ng/g. The concentrations are higher in the south and lower in the north in the Tibetan Plateau, consistent with the previous results. Our model shows that the average deposition flux of Hg is 3.3 µg m-2 yr-1, with 57% contributed by dry deposition of elemental mercury (Hg0), followed by dry (19%) and wet (24%) deposition of divalent mercury. We calculate the Hg to carbon ratio (RHg:C) as 5.6 ± 6.5 µg Hg/g C, and the estimated STHg is 86.6 ± 101.2 Gg in alpine grasslands in the Tibetan Plateau. We find a positive relationship between STHg and SOC in the Tibetan Plateau (r2 = 0.36) and a similar positive relationship between STHg and atmospheric total Hg deposition (r2 = 0.24). A multiple linear regression involving both variables better model the observed STHg (r2 = 0.42). We conclude that SOC and atmospheric deposition influence STHg simultaneously in this region. The data provides information to quantify the size of the soil Hg pool in the Tibetan Plateau further, which has important implications for the Hg cycles in the permafrost regions as well as on the global scale.


Assuntos
Mercúrio/análise , Pergelissolo , Carbono , Monitoramento Ambiental , Pradaria , Solo , Tibet
14.
Sci Total Environ ; 739: 140034, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32758950

RESUMO

This study analyzed total mercury (THg), methylmercury (MeHg) and selenium (Se) in 114 aquatic product samples (representing 39 species) from eight coastal cities of China. The THg and MeHg levels in different parts of the same sample species were in the order of muscle ≥ skin/shell > roe, whereas Se levels were much higher in roe. Concentrations of THg, MeHg, and Se in the muscles were between 2.27-154, 0.36-135, and 57.8-1.20 × 103 ng g-1 wet weight (ww), respectively. Although significant differences in analyte concentrations were not observed among cities, they existed among three species; marine fish, freshwater fish, and shellfish. Shellfish had generally lower Hg content (mean: 20.2 ng g-1 ww THg, 6.71 ng g-1 ww MeHg, and 30.9% MeHg/THg ratio); however it had higher Se content (528 ng g-1 ww) than the other types of fish (mean: 33.3 ng g-1 ww THg, 28.2 ng g-1 ww MeHg, and 79.2% MeHg/THg ratio, 257 ng g-1 ww Se). In addition to species, the individual growth and HgSe interaction influenced Hg distribution. Evident correlations were observed between several individual body features and Hg content, and between Se and THg concentrations (p < 0.05). The greater correlation coefficient between two elements for fish indicated stronger HgSe antagonism through HgSe compound formation in fish. Relatively low THg daily intakes (mean 0.013-0.080 µg kg-1 day-1) and MeHg daily intakes (0.006-0.065 µg kg-1 day-1) along with Se:Hg molar ratios >1 and positive HBVSe values suggest that aquatic products from these sites will not pose immediate health problems to consumers. Fish was the dominating contributor for MeHg intake whereas shellfish was the dominating contributor for Se intake. To safeguard against mercury exposure, residents in these areas can appropriately increase shellfish intake (especially bivalves), rather than exclusively consuming marine fish.


Assuntos
Mercúrio/análise , Compostos de Metilmercúrio , Selênio/análise , Poluentes Químicos da Água/análise , Animais , China , Cidades , Monitoramento Ambiental , Peixes , Medição de Risco
15.
Mar Pollut Bull ; 158: 111412, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753196

RESUMO

The Conwy estuary was evaluated for sediment quality. Microtox bioassay revealed 38 of 39 sites were non-toxic. Hg ranged from 0.001 to 0.153 µg kg-1, mean 0.026 mg kg-1, Σ16 PAH from 18 to 1578 µg kg-1, mean 269 µg kg-1, Σ22 PAH, 18 to 1871 µg kg-1 mean to 312 µg kg-1, two sites had high perylene relative to ΣPAH. Σ22PAH correlated positively with TOC, clay and silt (R2 0.89, 0.92, 0.90) and negatively with sand. Multivariate statistics, delineated four spatial (site) and five variable (measurements) clusters. Spatial clustering relates to sediment grain size, in response to hydrodynamic processes in estuary; fine (clay to silt) sized sediments exhibit the highest Hg and PAH content, because these components partitioned into the fine fraction. Comparison to national and international environmental standards suggests Hg and PAH content of Conwy sediments are unlikely to harm ecology or transfer up into the human food chain.


Assuntos
Mercúrio/análise , Poluentes Químicos da Água/análise , Carbono/análise , Monitoramento Ambiental , Estuários , Sedimentos Geológicos , Humanos , Rios , Reino Unido , País de Gales
16.
Mar Pollut Bull ; 158: 111447, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753223

RESUMO

As the role of mercury is poorly known in Southern Ocean biota, the total mercury (T-Hg) concentrations were evaluated in upper/lower beaks, digestive gland, gills and mantle muscle of Adelieledone polymorpha and Pareledone turqueti, two of the most abundant octopod species around South Georgia. Beaks had the lowest T-Hg concentrations (A. polymorpha: [T-Hg]Upper = 27.2 ± 12.9 ng∙g-1 and [T-Hg]Lower = 27.5 ± 20.0 ng∙g-1; P. turqueti: [T-Hg]Upper = 34.6 ± 13.9 ng∙g-1 and [T-Hg]Lower = 56.8 ± 42.0 ng∙g-1), followed by gills and muscle. The highest values were recorded in the digestive gland (A. polymorpha: 251.6 ± 69.7 ng∙g-1; P. turqueti: 347.0 ± 177.0 ng∙g-1). Significant relationships were found between the concentrations of T-Hg in the beaks and muscle of A. polymorpha (T-Hg in muscle is 10 times higher than in beaks). This study shows that beaks can be used as proxy for T-Hg in muscle for some octopod species, and a helpful tool for estimating total Hg body burden from beaks.


Assuntos
Mercúrio/análise , Poluentes Químicos da Água/análise , Animais , Regiões Antárticas , Bico/química , Monitoramento Ambiental , Ilhas
17.
Mar Pollut Bull ; 159: 111512, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32777545

RESUMO

Swordfish is a widely consumed fish worldwide. The aim of this work was to evaluate levels of As, Zn, Mn, Fe, Cu, Al, Cr, Ni, Se, Cd, Pd and Hg in 28 samples of swordfish muscles, coming from zone of Food and Agriculture Organization (FAO) namely 37.1 and 37.2, in order to assess potential public health risks. 100% of the samples had Cd levels not detectable, 32.14% of samples exceeded European maximum limits set for Hg. Health risk assessment showed a not dangerous condition for Al (0.65% of Tolerable Weekly Intake), Ni (0.27% of Tolerable Daily Intake) and Pb (0.68% of Provisional Tolerable Weekly Intake), but very hazardous states for Hg (159.69% of Tolerable Weekly Intake) and As (1099.45% for minimum value of Benchmark Dose Limit). Target Hazard Quotient (THQ) showed dangerous values only for As and Hg. Analytical data of the present study suggest a swordfish prudent consumption.


Assuntos
Contaminação de Alimentos/análise , Mercúrio/análise , Animais , Peixes , Humanos , Mar Mediterrâneo , Medição de Risco , Alimentos Marinhos/análise
18.
Mar Pollut Bull ; 159: 111513, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32777546

RESUMO

Hydrothermal vent is the one of the main natural Hg sources to the deep ocean. Thus, we investigated which Hg speciation in the sediment core can be the past records for geothermal activities in mid-ocean ridges of the Central Indian Ocean. The result showed that the hydrothermal Hg in the core sediments was mainly associated with Fe-Mn oxides with the elevated concentrations of other hydrothermal-derived trace metals [Co + Zn + Cu]. In addition, the [Sm]/[Nd] and [Rb]/[Sr] ratios and ɛNdCHUR and 87Sr/86Sr isotopic values supported that the extremely high Hg concentrations were possibly originated from the hydrothermal vent. However, the Hg emitted from submarine volcano was mainly associated with sulfides-organic matters because the volcanos did not release Fe and Mn. Thus, our results showed that the sedimentary Hg is an independent toll for reconstruction of paleodynamics of hydrothermal and/or volcanic activities in deep sea basin of the Central Indian Ocean.


Assuntos
Fontes Hidrotermais , Mercúrio/análise , Monitoramento Ambiental , Sedimentos Geológicos , Oceano Índico
19.
Aquat Toxicol ; 226: 105567, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32745893

RESUMO

The increasing contamination of water bodies with mercury (Hg) raises concerns about the possible effects of this metal on native fish species. Our current understanding of its dynamics in fish organs remains limited. In this study, adult individuals of the native species Astyanax eigenmanniorum were exposed to three environmentally relevant HgCl2 concentrations (5, 100, and 170 µg L-1) for 96 h. To evaluate total Hg (THg) elimination, new individuals were exposed to 100 µg L-1 of HgCl2 (96 h), and at the end of the exposure period, half of the fish were placed in tanks with clean water for 168 h. In both assays, the organs were removed, and THg levels were measured using ICP-MS. The uptake of IHg in A. eigenmanniorum showed a differential accumulation in the organs. Gills, intestine, and brain were the tissues with the highest THg levels. Finally, no elimination of THg in the water was observed, but intestine and gills significantly removed the THg accumulated. Probably a Hg redistribution through the tissues could take place.


Assuntos
Characidae/metabolismo , Mercúrio/metabolismo , Poluentes Químicos da Água/metabolismo , Adulto , Animais , Bioacumulação , Encéfalo/metabolismo , Characidae/sangue , Monitoramento Ambiental , Brânquias/metabolismo , Humanos , Mucosa Intestinal/metabolismo , Mercúrio/análise , Mercúrio/toxicidade , Taxa de Depuração Metabólica , Distribuição Tecidual , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
20.
Sci Total Environ ; 743: 140564, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32758814

RESUMO

Mercury concentrations in freshwater food webs are governed by complex biogeochemical and ecological interactions that spatially vary and are often mediated by climate. The Arctic Coastal Plain of Alaska (ACP) is a heterogeneous, lake-rich landscape where variability in mercury accumulation is poorly understood. Earlier research indicated that the level of catchment influence on lakes varied spatially on the ACP, and affected mercury accumulation in lake sediments. This work sought to determine drivers of spatial variation in mercury accumulation in lake food webs on the ACP. Three lakes that were a priori identified as "high catchment influence" (Reindeer Camp region) and three lakes that were a priori identified as "low catchment influence" (Atqasuk region) were sampled, and variability in water chemistry, food web ecology, and mercury accumulation was investigated. Among-lake differences in ninespine stickleback (Pungitius pungitius) length-adjusted methylmercury concentrations were significantly explained by sulphate concentration in lake water, a tracer of catchment runoff input. This effect was mediated by fish growth, which had no pattern between regions. Together, lake water sulphate concentration and fish age-at-size (proxy for growth) accounted for nearly all of the among-lake variability in length-adjusted methylmercury concentrations in stickleback (R2adj = 0.94, p < 0.01). The percentage of total mercury as methylmercury (a proxy for net Hg methylation) was higher in sediments of more autochthonous, "low catchment influence" lakes (p < 0.05), and in the periphyton of more allochthonous, "high catchment influence" lakes (p < 0.05). The results indicate that dominant sources of primary production (littoral macrophyte/biofilm vs. pelagic phytoplankton) and food web structure (detrital vs. grazing) are regulated by catchment characteristics on the ACP, and that this ultimately influences the amount of methylmercury in the aquatic food web. These results have important implications for predicting future mercury concentrations in fish in lakes where fish growth rates and catchment inputs may change in response to a changing climate.


Assuntos
Mercúrio/análise , Smegmamorpha , Poluentes Químicos da Água/análise , Alaska , Animais , Regiões Árticas , Monitoramento Ambiental , Cadeia Alimentar , Lagos , Sulfatos
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