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1.
Rev Environ Contam Toxicol ; 249: 133-152, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30879139

RESUMO

Mercury (Hg) is an environmental contaminant that has been reported in many wildlife species worldwide. The organic form of Hg bioaccumulates in higher trophic levels, and thus, long-lived predators are at risk for higher Hg exposure. Although ecological risk assessments for contaminants such as Hg include pertinent receptor species, snakes are rarely considered, despite their high trophic status and potential to accumulate high levels of Hg. Our current knowledge of these reptiles suggests that snakes may be useful novel biomarkers to monitor contaminated environments. The few available studies show that snakes can bioaccumulate significant amounts of Hg. However, little is known about the role of snakes in Hg transport in the environment or the individual-level effects of Hg exposure in this group of reptiles. This is a major concern, as snakes often serve as important prey for a variety of taxa within ecosystems (including humans). In this review, we compiled and analyzed the results of over 30 studies to discuss the impact of Hg on snakes, specifically sources of exposure, bioaccumulation, health consequences, and specific scientific knowledge gaps regarding these moderate to high trophic predators.


Assuntos
Monitoramento Ambiental , Mercúrio/metabolismo , Serpentes/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Biomarcadores/metabolismo , Ecossistema , Humanos
2.
J Environ Sci (China) ; 85: 9-16, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31471035

RESUMO

Photoreduction characteristics of divalent inorganic mercury (Hg2+) in the presence of specific algae species are still not well known. Laboratory experiments were conducted in the present study to identify the effects of different concentrations of living/dead algae species, including Aphanizomenon flosaquae (AF) and Microcystis aeruginosa (MA), on the photoreduction rate of Hg2+ under various light conditions. The experimental results showed that percentage reduction of Hg2+ was significantly influenced by radiation wavelengths, and dramatically decreased with the presence of algae. The highest percentage reduction of Hg2+ was induced by UV-A, followed by UV-B, visible light and dark for both living and dead AF, and the order was dark > UV-A > UV-B > visible light for both living and dead MA. There were two aspects, i.e., energy and attenuation rate of light radiation and excrementitious generated from algae metabolisms, were involved in the processes of Hg2+ photoreduction with the presence of algae under different light conditions. The percentage reduction of Hg2+ decreased from 15% to 11% when living and dead AF concentrations increased by 10 times (from 106 to 105 cells/mL), and decreased from11% to ~9% in the case of living and dead MA increased. Algae can adsorb Hg2+ and decrease the concentration of free Hg2+, thus inhibiting Hg2+ photoreduction, especially under the conditions with high concentrations of algae. No significant differences were found in percentage reduction of Hg2+ between living and dead treatments of algae species. The results are of great importance for understanding the role of algae in Hg2+ photoreduction.


Assuntos
Aphanizomenon/metabolismo , Mercúrio/metabolismo , Microcystis/metabolismo , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental
3.
Sci Total Environ ; 692: 1029-1036, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31539935

RESUMO

Marine mussels have been used widely as biomonitors of coastal contamination in many countries. Due to the restrain of their geographical distributions, it is often necessary to employ more than one species of mussels within a large-scale biomonitoring program. In the present study, we compared the differences of copper (Cu) bioaccumulation in three species of marine mussels (green mussel Perna viridis, blue mussel Mytilus edulis, and hard-shelled mussel Mytilus coruscus) widely distributing along the Chinese coastal waters, under identical Cu exposure conditions. Over the 21-days exposure to dissolved Cu, the green mussels and blue mussels exhibited comparable newly accumulated Cu concentrations, possibly due to their comparable Cu uptake rate constant ku (blue mussel, 0.573 L g-1 d-1; green mussel, 0.530 L g-1 d-1) and efflux rate constant ke (blue mussel, 0.053 d-1; green mussel, 0.065 d-1). In contrast, there was no net Cu accumulation in the hard-shell mussels, which may be accounted by the lower ku (0.394 L g-1 d-1) but higher ke (0.081 d-1) than the other two mussel species. Further subcellular distribution analyses showed that the cellular debris and metallothionein-like protein (MTLP) fraction were the key binding sites for Cu, and the MTLP fraction may act as a main contributor in Cu regulation and elimination in the blue mussels and hard-shell mussels. There was no strong evidence that the subcellular partitioning and dynamics of Cu in the mussels were responsible for the difference underlying the Cu accumulation in the three species of mussels. Our comparative study thereby suggested that it may be feasible to directly compare the Cu bioavailability in the green mussels and blue mussels based on their Cu biomonitoring data. Cu biomonitoring data from the hard-shell mussels may underestimate the actual Cu bioavailability of the sampling area given its much stronger regulation of Cu bioaccumulation as compared to the other two mussel species.


Assuntos
Bivalves/metabolismo , Cobre/metabolismo , Monitoramento Ambiental , Poluentes Químicos da Água/metabolismo , Animais , Cobre/análise , Metalotioneína/metabolismo , Poluentes Químicos da Água/análise
4.
World J Microbiol Biotechnol ; 35(9): 137, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31432268

RESUMO

The presence of very high concentrations of organic pollutants, phenols, tannins and heavy metals mainly chromium in wastewater discharged from leather industries, tags it as one of the most polluting industries. The phenolic syntans discharged from tanning units have an adverse effect on living organisms and cause serious environmental pollution, thereby making it very imperative to remove it. Among various treatment methods available for removal of phenols, biodegradation is environment friendly. The present study aims at the remediation of phenolic syntan used in the leather industry employing individual as well as co-culture of Bacillus cereus and Pseudomonas aeruginosa at varying syntan concentration in the medium. Parameters such as chemical oxygen demand (COD), total organic carbon (TOC), total phenol content (TPC) and Fourier Transform Infrared Spectroscopy (FTIR) indicating biodegradation were analyzed. Promising results were observed with P. aeruginosa, which exhibited a reduction in TPC by 62-72% in all the concentrations of syntan tested just within 12 h of inoculation, whereas about 67 and 83% reduction in COD and TOC respectively was observed for 2000 ppm concentration at the end of 5 days. B. cereus also demonstrated very good reduction in the above parameters however; percentage was less as compared to P. aeruginosa. In the case of co-culture, the TPC reduction was higher than B. cereus but lesser than P. aeruginosa. The percentage reduction in TOC and COD was highest for 500 ppm which eventually decreased for subsequent concentrations.


Assuntos
Bacillus cereus/metabolismo , Resíduos Industriais , Fenóis/metabolismo , Pseudomonas aeruginosa/metabolismo , Poluentes Químicos da Água/metabolismo , Bacillus cereus/crescimento & desenvolvimento , Análise da Demanda Biológica de Oxigênio , Biotransformação , Carbono/análise , Técnicas de Cocultura , Fenóis/análise , Pseudomonas aeruginosa/crescimento & desenvolvimento , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química
5.
Sci Total Environ ; 689: 1087-1103, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31466149

RESUMO

For reliable mussel monitoring programmes based on biomarkers, regionally relevant reference values and their natural variability need to be known. The Baltic Sea exhibits high inter-regional and seasonal variability in physical factors such as salinity, temperature and primary production. The aim of this pilot study is to depict the effects of season-related environmental factors in a selected battery of biomarkers in two environmentally different subregions of the Baltic Sea to help establishing reference data for biochemical, cellular and tissue-level biomarkers. In order to achieve that, mussels were collected from reference sites in Kiel (Germany) and Tvärminne (Finland) during three seasons: summer and autumn 2016, and spring 2017. Finally, in order to characterize the ecological situation, analysis of the chemical tissue burden was performed and chlorophyll­a and particulate organic carbon concentration and temperature changes were analyzed at each sampling locality using satellite remote sensing images. An integrated biomarker response index was performed to summarize the biomarker responses of each locality and season. The biochemical endpoints showed seasonal variability regulated by temperature, food supply and reproductive cycle, while among the cellular endpoints only lipofuscin accumulation and lysosomal structural changes showed slight seasonal variation. Seasonal changes in tissue level biomarkers were observed only at the northern Baltic Sea site Tvärminne, dictated by the demanding energetic trade-off caused by reproduction. In conclusion, the characterization of the ecological variables and physico-chemical conditions at each site, is crucial to perform a reliable assessment of the effects of a hypothetical pollution scenario in the Baltic Sea. Moreover, reference levels of biomarkers and their responses to natural environmental conditions must be established.


Assuntos
Monitoramento Ambiental , Mytilus/fisiologia , Poluentes Químicos da Água/metabolismo , Animais , Países Bálticos , Biomarcadores/metabolismo , Projetos Piloto , Poluentes Químicos da Água/normas
6.
Sci Total Environ ; 691: 1190-1211, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31466201

RESUMO

Recently, the increasing concentration and persistent appearance of antibiotics traces in the water streams are considered an issue of high concern. In this context, an array of antibiotics has been categorized as pollutants of emerging concern due to their complex and highly stable bioactivity, indiscriminate usage with ultimate release into water bodies, and notable persistence in environmental matrices. Moreover, antibiotics traces containing household sewage/drain waste and pharmaceutical wastewater effluents contain a range of bioactive/toxic organic compounds, inorganic salts, pharmaceutically-active ingredients, or a mixture of all, which possesses negative influences ranging from ecological pollution to damage biodiversity. Moreover, their uncontrolled and undesirable bioaccumulation also poses a potential threat to target and non-target organisms in the environment. Aiming to tackle this issue effectively, various detection, quantification, degradation, and redefining "removal" processes have been proposed and investigated based on physical, chemical, and biological strategies. Though both useful and side effects of antibiotics on humans and animals are usually investigated thoroughly following safety and toxicity measures, however, their direct or indirect environmental impacts are not well reviewed yet. Owing to the considerable research gap, the environmental perfectives of antibiotics traces and their effects on target and non-target populations have now become the topic of research interest. Based on literature evidence, over the past several years, numerous individual studies have been performed and published covering various aspects of antibiotics. However, a comprehensive compilation on enzyme-based degradation of antibiotics is still lacking and requires careful consideration. Hence, this review summarizes up-to-date literature on enzymes as biocatalytic systems, explicitly, free as well as immobilized forms and their effective exploitation for the degradation of various antibiotics traces and other pharmaceutically-active compounds present in the water bodies. It is further envisioned that the enzyme-based strategies, for antibiotics degradation or removal, discussed herein, will help readers for a better understanding of antibiotics persistence in the environment along with the associated risks and removal measures. In summary, the current research thrust presented in this review will additionally evoke researcher to engineer robust and sustainable processes to effectively remediate antibiotics-contaminated environmental matrices.


Assuntos
Antibacterianos/análise , Poluentes Químicos da Água/análise , Antibacterianos/metabolismo , Biodegradação Ambiental , Monitoramento Ambiental , Preparações Farmacêuticas , Rios , Poluentes Químicos da Água/metabolismo
7.
Sci Total Environ ; 691: 1297-1309, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31466209

RESUMO

Per- and poly-fluorinated substances (PFAS) are widely found in freshwater ecosystems because of their resistance to degradation. Among them, several long-chain perfluoroalkyl acids bioaccumulate in aquatic vertebrates, but our understanding of the mechanisms of absorption, distribution and elimination is still limited in fish. For this purpose, we developed a 10-compartment physiologically-based toxicokinetic (PBTK) model to elucidate perfluorooctane sulfonate (PFOS) kinetics in adult rainbow trout. This PBTK model included various physiological characteristics: blood perfusion to each organ, plasmatic fraction, PFOS free fraction, and growth of individuals. The parameters were optimized using Bayesian inferences. First, only PFOS absorption by diet was considered in the model as well as its elimination by urine, bile and feces. Then two mechanistic hypotheses, assumed to govern PFOS toxicokinetics in fish, namely the enterohepatic cycle and the absorption and elimination though gills, were tested. Improvement of the model's fit to the data was studied in each organ by comparing predictions with observed data using relative error. The experimental data set was obtained from an exposure experiment, where adult rainbow trout were fed with a PFOS-spiked diet for 42 days, followed by a 35-day depuration period. In all cases, PFOS concentrations were accurately predicted in organs and feces by the model. The results of this PBTK model demonstrated that feces represented the major elimination route for PFOS while urine was a minor route. Also, PFOS branchial uptake can be substantial despite low concentrations of the compound in water, and elimination through gills should not be neglected. Finally, the enterohepatic cycle is likely to play a minor role in PFOS toxicokinetics. Overall, this PBTK model accurately described PFOS distribution in rainbow trout and provides information on the relative contribution of absorption and elimination pathways.


Assuntos
Fluorcarbonetos/metabolismo , Oncorhynchus mykiss/metabolismo , Poluentes Químicos da Água/metabolismo , Alcanossulfonatos/metabolismo , Ácidos Alcanossulfônicos/metabolismo , Animais , Caprilatos/metabolismo , Toxicocinética
8.
Sci Total Environ ; 685: 1276-1283, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31272787

RESUMO

Antarctica is still considered one of the few pristine areas in the globe. Despite this, several studies have shown phased out organic pollutants are present in several environmental abiotic and biological compartments. This study, based on blubber and fecal samples collected from five species of Antarctic pinnipeds, assessed the relationship between organochlorine pesticide (OCs) levels and trophic characterization using stable isotope analysis (δ13C and δ15N). The prevailing pollutants found in blubber were hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), Heptachlor and Aldrin (0.84-564.11 ng g-1 l.w.). We also report a high presence of HCHs, Endrin, Dichlorodiphenyltrichloroethane (DDTs) and Methoxychlor (4.50-363.86 ng g-1 d.w.) in feces suggesting a detoxification mechanism. All the species tend towards high trophic positions (3.4-4.9), but with considerable variation in trophic niche and organochlorine pesticide concentrations per sampling site. This finding suggests that differences in pesticide levels in individuals are associated to foraging ecology.


Assuntos
Caniformia/metabolismo , Monitoramento Ambiental , Hidrocarbonetos Clorados/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Regiões Antárticas , Cadeia Alimentar
9.
Sci Total Environ ; 688: 724-731, 2019 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-31255810

RESUMO

In the present study, we have produced red-mud based ceramic media (RMCM) as an adsorbent for removal of phosphate from aqueous solutions, and their application in a constructed wetland. Phosphate adsorption to RMCM was investigated by varying initial phosphate concentration, contact time, and temperature. Adsorption of phosphate to the surface of RMCM was confirmed by scanning electron microscope and energy dispersive X-ray spectroscopy. The surface area and pore volume of RMCM decreased significantly after phosphate adsorption. Experimental equilibrium data followed Langmuir and Sips model better than the Freundlich model. Kinetic data followed both pseudo first order and pseudo second order reactions. Thermodynamics suggested the phosphate adsorption process onto RMCM to be endothermic and spontaneous, and physisorption dominated. Fourier transform infrared spectrumof phosphate adsorbed RMCM did not show any PO specific bands thus ruling out role of chemical forces in phosphate adsorption. Overall, phosphate adsorption on RMCM was driven by physisorption. The RMCM promoted biomass growth and increased the surface area of roots in Iris latifolia. Together with RMCM, I. latifolia augmented removal of phosphate from aqueous solution. Based on their phosphate removal performance and plant-growth promoting effects, we believe that RMCM can be effectively used in constructed wetlands.


Assuntos
Iris (Planta)/metabolismo , Fosfatos/metabolismo , Poluentes Químicos da Água/metabolismo , Cerâmica , Plântula
10.
Ecotoxicol Environ Saf ; 182: 109393, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31299473

RESUMO

This research evaluated the influence of organic matter (OM) and CO2 addition on the bioremediation potential of two microalgae typically used for wastewater treatment: Chlorella vulgaris (CV) and Scenedesmus almeriensis (SA). The heavy metal (HM) removal efficiencies and biosorption capacities of both microalgae were determined in multimetallic solutions (As, B, Cu, Mn, and Zn) mimicking the highest pollutant conditions found in the Loa river (Northern Chile). The presence of OM decreased the total biosorption capacity, specially in As (from 2.2 to 0.0 mg/g for CV and from 2.3 to 1.7 mg/g for SA) and Cu (from 3.2 to 2.3 mg/g for CV and from 2.1 to 1.6 mg/g for SA), but its influence declined over time. CO2 addition decreased the total HM biosorption capacity for both microalgae species and inhibited CV growth. Finally, metal recovery using different eluents (HCl, NaOH, and CaCl2) was evaluated at two different concentrations. HCl 0.1 M provided the highest recovery efficiencies, which supported values over 85% of As, 92% of Cu, and ≈100% of Mn and Zn from SA. The presence of OM during the loaded stage resulted in a complete recovery of As, Cu, Mn, and Zn when using HCl 0.1 M as eluent.


Assuntos
Biodegradação Ambiental , Dióxido de Carbono/metabolismo , Chlorella vulgaris/metabolismo , Metais Pesados/metabolismo , Scenedesmus/metabolismo , Poluentes Químicos da Água/metabolismo , Chile , Metais Pesados/análise , Microalgas , Águas Residuárias , Poluentes Químicos da Água/análise
11.
Ecotoxicol Environ Saf ; 182: 109397, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31299476

RESUMO

Cadmium (Cd) is a serious threat to plants health. Though some genes have been reported to get involved in the regulation of tolerance to Cd, the mechanisms underlying this process are not fully understood. Na+/H+ antiporter (NHX1) plays an important role in Na+/H+ trafficking. The salt and cadmium stress tolerance were found to be enhanced by NHX1 in duckweed according to our previous study, however, its function in Cd2+ flux under Cd stress has not been studied. Here we explored the Cd2+ flux in wild type (WT) and NHX1 transgenic duckweed (NHX1) under Cd stress. We found that the Cd2+ influx in NHX1 duckweed was significantly declined, followed by an increased Cd2+ efflux after 20 min treatment of Cd, which resulted a less accumulation of Cd in NHX1. Reversely, inhibition of NHX1 by amiloride treatment, enhanced Cd2+ influx in NHX1 duckweed, subsequently delayed Cd2+ efflux in both genotypes of duckweed under Cd2+ shock. H+ efflux in NHX1 duckweed was lower compare with that in WT with 20 min Cd2+ shock. NHX1 also increased the pH value with Cd2+ stress in the transgenic rhizoid. These finding suggested a new function of NHX1 in regulation of Cd2+ and H+ flow during short-term Cd2+ shock.


Assuntos
Araceae/fisiologia , Cádmio/metabolismo , Poluentes Químicos da Água/metabolismo , Araceae/metabolismo , Cádmio/toxicidade , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Plantas Geneticamente Modificadas/metabolismo , Sódio/metabolismo , Trocadores de Sódio-Hidrogênio , Poluentes Químicos da Água/toxicidade
12.
Sci Total Environ ; 690: 739-747, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31301512

RESUMO

The occurrence of pharmaceuticals in the environment is a topic of concern. Carbamazepine (CBZ) is a widespread antiepileptic drug and due to its physical-chemical characteristics minimal removal is achieved in conventional water treatments, and thus has been suggested as a molecular marker of wastewater contamination in surface water and groundwater. The present study reports the biotransformation of CBZ by the bacterial strain Labrys portucalensis F11. When supplied as a sole carbon source, a 95.4% biotransformation of 42.69 µM CBZ was achieved in 30 days. In co-metabolism with acetate, complete biotransformation was attained at a faster rate. Following a target approach, the detection and identification of 14 intermediary metabolites was achieved through UPLC-QTOF/MS/MS. Biotransformation of CBZ by the bacterial strain is mostly based on oxidation, loss of -CHNO group and ketone formation reactions; a biotransformation pathway with two routes is proposed. The toxicity of untreated and treated CBZ solutions was assessed using Vibrio Fischeri and Lepidium sativum acute toxicity tests and Toxi-Chromo Test. The presence of CBZ and/or its degradations products in solution resulted in moderate toxic effect on Vibrio Fischeri, whereas the other organisms were not affected. To the best of our knowledge this is the first report that proposes the metabolic degradation pathway of CBZ by a single bacterial strain.


Assuntos
Alphaproteobacteria/metabolismo , Biodegradação Ambiental , Carbamazepina/metabolismo , Poluentes Químicos da Água/metabolismo , Anticonvulsivantes/metabolismo
13.
Sci Total Environ ; 690: 821-830, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31302547

RESUMO

Microplastics were determined in pink Bombay-duck (Harpadon nehereus), white Bombay-duck (H. translucens) and gold-stripe sardine (Sardinella gibbosa) collected from the Northern Bay of Bengal at Bangladesh. Gastrointestinal tracts of fishes (n = 25 per species) were examined for microplastics following alkali digestion protocol, microscopic observations and chemical analysis by micro-Fourier Transformed Infrared Spectroscope (µ-FTIR). A total of 443 microplastic items were found in the intestines of H. nehereus, H. translucens and S. gibbosa, averaging in the range of 3.20-8.72 items per species. Among various shapes, colours and types of microplastics, irregular (37-43%), white/transparent (26-68%) and fiber (50-55%) were dominant. The size fraction of microplastics ranging between 1 µm and 5 mm was 68-84 items/kg biomass, and µ-FTIR analysis identified 13 particles of polyethylene terephthalate and 66 particles of polyamide. The study findings raised concern that microplastics in marine fish could be a threat to public health via the food chain.


Assuntos
Monitoramento Ambiental , Peixes/metabolismo , Plásticos/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Bangladesh , Cadeia Alimentar , Plásticos/análise , Poluentes Químicos da Água/análise
14.
Sci Total Environ ; 690: 867-877, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31302551

RESUMO

Fishery targeted species living in estuaries face multiple anthropogenic pressures including habitat contamination. However, trace metal concentrations in aquatic organisms can be highly variable, making it difficult to interpret accumulation responses. Understanding sources for metal accumulation in these organisms and their biokinetics is important for management of local fisheries and ensuring safety and quality of consumed seafood, particularly in urbanised areas. In this study, we exposed Australian sand clams, school prawns and sand whiting to a combination of cadmium (Cd), manganese (Mn) and zinc (Zn) radioisotopes 1) dissolved in seawater, 2) adsorbed to suspended sediment particles and 3) in radiolabelled food. Sand clams were sensitive to Cd, Mn and Zn uptake and accumulation from all sources because of their filter feeding physiology. Mean Cd and Zn assimilation efficiencies (AE) were higher in clams fed benthic diatoms (51, 43, 63% for Cd, Mn and Zn, respectively) than clams fed an algal flagellate species (22, 32, 33% for Cd, Mn and Zn, respectively). Metal uptake by prawns from seawater was low, whereas assimilation from diet was high (67, 59, 64% mean AEs from Cd, Mn and Zn, respectively). Sand whiting did not accumulate metals from seawater, even after concentrations were increased. Assimilation from diet (labelled prawns) was also low for sand whiting, particularly for Cd and Zn (11, 26, 14% mean AEs from Cd, Mn and Zn, respectively). These results may help explain the persistence of sand whiting in contaminated estuaries. Suspended sediment exposures showed that prawns and fish are less likely than clams to be negatively affected by disturbance events such as floods, which can bring metals into estuaries. The findings of this study have implications for fisheries management, both for protection and remediation of important habitats, and to ensure safe standards for seafood consumption by humans.


Assuntos
Organismos Aquáticos/metabolismo , Pesqueiros/estatística & dados numéricos , Metais/metabolismo , Poluentes Químicos da Água/metabolismo , Cádmio/metabolismo , Manganês/metabolismo , Zinco/metabolismo
15.
Environ Pollut ; 252(Pt B): 1561-1573, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31277025

RESUMO

This review evaluates the three dynamic models (biokinetic model: BK, physiologically based pharmacokinetic model: PBPK, and toxicokinetic-toxicodynamic model: TKTD) in our understanding of the key questions in metal ecotoxicology in aquatic systems, i.e., bioaccumulation, transport and toxicity. All the models rely on the first-order kinetics principle of metal uptake and elimination. The BK model basically treats organisms as a single compartment, and is both physiologically and geochemically based. With a good understanding of each kinetic parameter, bioaccumulation of metals in any aquatic organisms can be studied holistically and mechanistically. Modeling efforts are not merely restrained from the prediction of metal accumulation in the tissues, but instead provide the direction of the key processes that need to be addressed. PBPK is more physiologically based since it mainly addresses the transportation, transformation and distribution of metals in the organisms. It can be treated conceptually as a multi-compartmental kinetic model, whereas the physiology is driving the development of any good PBPK model which is no generic for aquatic animals and contaminants. There are now increasingly applications of the PBPK modeling specifically in metal studies, which reveal many important processes that are impossible to be teased out by direct experimental measurements without adequate modeling. TKTD models further focus on metal toxicity in addition to metal bioaccumulation. The TK part links exposure and bioaccumulation, while the TD part links bioaccumulation and toxic effects. The separation of TK and TD makes it possible to model processes, e.g., toxicity modification by environmental factors, interaction between different metals, at both the toxicokinetic and toxicodynamic levels. TKTD models provide a framework for making full use of metal toxicity data, and thus provide more information for environmental risk assessments. Overall, the three models reviewed here will continue to provide guiding principles in our further studies of metal bioaccumulation and toxicity in aquatic organisms.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Metais/toxicidade , Modelos Teóricos , Oligoelementos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Organismos Aquáticos/metabolismo , Transporte Biológico , Ecotoxicologia , Cinética , Metais/metabolismo , Toxicocinética , Oligoelementos/metabolismo , Poluentes Químicos da Água/metabolismo
16.
Ecotoxicol Environ Saf ; 182: 109411, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31299475

RESUMO

The urban growth has increased sanitary sewage discharges in coastal ecosystems, negatively affecting the aquatic biota. Mangroves, one of the most human-affected coastal biomes, are areas for reproduction and nursing of several species. In order to evaluate the effects of sanitary sewage effluents in mangrove species, this study assessed the hepatic transcriptional responses of guppy fish Poecilia vivipara exposed to sanitary sewage 33% (v:v), using suppressive subtraction hybridization (SSH), high throughput sequencing of RNA (Ion-proton) and quantification of transcript levels by qPCR of some identified genes in fish kept in a sewage-contaminated environment. Genes identified are related predominantly to xenobiotic biotransformation, immune system and sexual differentiation. The qPCR results confirmed the induction of cytochrome P450 1A (CYP1A), glutathione S transferase A-like (GST A-like) methyltransferase (MET) and UDP glycosyltransferase 1A (UDPGT1A), and repression of complement component C3 (C3), doublesex and mab-3 related transcription factor 1 (DMRT1), and transferrin (TF) in the laboratory experiment. In the field exposure, the transcript levels of CYP1A, DMRT1, MET, GST A-like and UDPGT1A were higher in fishes exposed at the contaminated sites compared to the reference site. Chemical analysis in fish from the laboratory and in situ experiments, and surface sediment from the sewage-contaminated sites revealed relevant levels of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyl (PCBs) and linear alkylbenzenes (LABs). These data reinforce the use of P. vivipara as a sentinel for monitoring environmental contamination in coastal regions.


Assuntos
Monitoramento Ambiental/métodos , Fígado/efeitos dos fármacos , Poecilia/genética , Esgotos/química , Transcrição Genética/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Biotransformação , Estuários , Fígado/metabolismo , Modelos Teóricos , Poecilia/metabolismo , Poluentes Químicos da Água/metabolismo , Xenobióticos/metabolismo
17.
Sci Total Environ ; 691: 789-798, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31326802

RESUMO

Many organohalogen compounds (OHCs) are persistent organic pollutants (POPs) found in appreciable concentrations in marine predators. While production of some POPs has declined or ceased in recent decades, their capacity for global transport and bioaccumulation results in observations of unchanging or increasing concentrations in marine systems. Sea otters (Enhydra lutris) have been advocated as an environmental sentinel for contaminants due to their longevity, site fidelity and prey species that often overlap with human consumption. Using archived (1992-2010) samples of livers from Northern sea otters (n = 50) from Alaska we examine concentrations of chlordanes (CHLs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDTs), and polybrominated diphenyl ethers (PBDEs) and associated metabolites. We found some evidence for declining ΣPCBs over the two decades, however for most animals concentrations were low compared to toxicological thresholds. Six animals had relatively high concentrations of ΣPCBs (mean = 262,000 ng/g lipid weight), ΣDDTs (mean = 8,800 ng/g lw), and ΣPBDEs (mean = 4,600 ng/g lw), with four of these six animals experiencing hepatic parasitism or hepatitis. In order to assess whether differences in POP concentrations are associated with feeding ecology, we examined stable isotopes of C and N in archived muscle and whisker samples. In general, there were no significant relationships between ΣPOP concentrations and stable isotope ratios. There were small differences in stable isotope profiles in animals with high POP concentrations, although it was unclear if these differences were due to feeding ecology or disease processes. This study highlights the importance of considering feeding ecology and necropsy (health and disease status) data while conducting contaminant surveys, and confirms some previous reports of trends in OHCs in Alaska marine mammals.


Assuntos
Monitoramento Ambiental , Hidrocarbonetos Clorados/metabolismo , Lontras/metabolismo , Poluentes Químicos da Água/metabolismo , Alaska , Animais , DDT/metabolismo , Ecologia , Éteres Difenil Halogenados/metabolismo , Bifenilos Policlorados/metabolismo
18.
Environ Pollut ; 253: 841-849, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31349193

RESUMO

A rapid method based on solvent extraction followed by direct injection in liquid chromatography-quadrupole-time-of-flight-mass spectrometry (LC-Q-TOF-MS) was developed for the targeted and suspect screening of contaminants in the soft tissues of the pearl oyster Pinctada imbricata radiata. The quantification method was first validated for the targeted analysis of 21 contaminants including some pharmaceutically active compounds, with the relative recoveries ranging from 88 to 123%, and method detection limits generally below 1 ng g-1 on the wet weight (ww) basis. This targeted analysis method was then applied to oyster samples collected around the Qatari coast between 2017/2018, and none of the 21 compounds were detected in these samples. The post-acquisition data treatment based on the accurate mass measurement in both full MS scan and All Ions MS/MS was further used for mining other contaminants in oyster extracts, as well as 21 targeted compounds spiked in oyster extracts (suspect screening). The 21 spiked compounds were identified successfully and the estimated limit of identification for the individual 21 compounds ranged from 0.5 to 117 ng g-1 ww of oyster tissues. A phthalate, di(2-ethylhexyl) phthalate (DEHP) was identified to be present in oyster extracts from 2018 batches, at a concentration level significantly higher than that in procedure blanks. These results confirmed that high resolution MS data obtained using the targeted method can be exploited through suspect screening workflows to identify contaminants in the tissues of bioindicator mollusks. However, a number of false identifications could be obtained and future work will be on improving the success rate of the correct identifications using this workflow.


Assuntos
Monitoramento Ambiental/métodos , Pinctada/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Cromatografia Líquida/métodos , Moluscos , Espectrometria de Massas em Tandem/métodos
19.
Environ Pollut ; 253: 949-958, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31351303

RESUMO

Microbial transformation of arsenic (As) plays a key role in As biogeochemical cycling and affects the mobility, bioavailability, and toxicity of As. This study aims to investigate the accumulation of As in marine sediments at different water depths in the East China Sea and reveal the abundance and diversity of the aioA, arrA, arsC, and arsM genes through quantitative real-time polymerase chain reaction (qPCR) and high-throughput sequencing. Results showed that the As content in sediments ranged from 5.53 mg kg-1 to 17.70 mg kg-1, which decreased with water depth. Abundant As biotransformation genes with low diversity were identified in these sediments, of which arsM and arrA were the most abundant. Significant positive correlation exists between the arsM and arrA gene abundance and between arsC and aioA, indicating the co-occurrence of the As biotransformation genes in microbes in marine sediments. Metagenomics analysis revealed that arsM gene was mainly distributed in Alphaproteobacteria, Solibacteres, Deltaproteobacteria, Clostridia, and Bacilli in these sediments. Among the sediment properties, total N, total S, C/N, and TOC were important factors that shaped the abundance profile of the genes involved in As transformation. This study provides a picture of As biotransformation genes in marine sediments from the East China Sea, which may affect As transformation and the ultimate fate of As in a marine environment.


Assuntos
Arsênico/metabolismo , Biotransformação/genética , Sedimentos Geológicos/microbiologia , Poluentes Químicos da Água/metabolismo , Bactérias/metabolismo , China , Sequenciamento de Nucleotídeos em Larga Escala , Metagenômica
20.
Environ Pollut ; 253: 966-973, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31351305

RESUMO

In present study, the analyses of essential [copper (Cu), cobalt (Co), selenium (Se) and zinc (Zn)] and non-essential elements [mercury (Hg), lead (Pb), cadmium (Cd) and arsenic (As)] in 7 fish species consumed by the indigenous people of the European Russia Arctic were conducted. The Nenets Autonomous Region, which is located in the north-eastern part of European Russia, was chosen as a Region of interest. Within it, the Nenets indigenous group (n = 6000) constitutes approximately 10% of the total population. Nearly all of the Nenets live a traditional life with fish caught in the local waters as a subsistence resource. We found that northern pike contained twice the amount of Hg compared with roach, and 3-4 times more than other fish species commonly consumed in the Russian Arctic (namely, Arctic char, pink salmon, navaga, humpback whitefish and inconnu). Fish Hg concentrations were relatively low, but comparable to those reported in other investigations that illustrate a decreasing south-to-north trend in fish Hg concentrations. In the current study, northern pike is the only species for which Hg bioaccumulated significantly. In all fish species, both Cd and Pb were present in considerably lower concentrations than Hg. The total As concentrations observed are similar to those previously published, and it is assumed to be present primarily in non-toxic organic forms. All fish tissues were rich in the essential elements Se, Cu and Zn and, dependent on the amount fish consumed, may contribute significantly to the nutritional intake by indigenous Arctic peoples. We observed large significant differences in the molar Se/Hg ratios, which ranged from 2.3 for northern pike to 71.1 for pink salmon. Values of the latter <1 may increase the toxic potential of Hg, while those >1 appear to enhance the protection against Hg toxicity.


Assuntos
Exposição Dietética/estatística & dados numéricos , Peixes/metabolismo , Alimentos Marinhos/estatística & dados numéricos , Oligoelementos/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Regiões Árticas , Arsênico/análise , Cádmio/análise , Cobalto/análise , Cobre/análise , Cyprinidae , Humanos , Mercúrio/análise , Federação Russa , Alimentos Marinhos/análise , Selênio/análise , Oligoelementos/análise , Poluentes Químicos da Água/análise , Zinco/análise
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