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1.
Chemosphere ; 239: 124608, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31499312

RESUMO

Freshwater systems are faced with a myriad of stressors including geomorphological alterations, nutrient overloading and pollution. Previous studies in marine fish showed polyaromatic hydrocarbons (PAHs) to be cardiotoxic. However, the cardiotoxicity of anthropogenic pollutants in freshwater fishes is unclear and has not been examined across multiple levels of cardiac organization. Here we investigated the effect of phenanthrene (Phe), a pervasive anthropogenic pollutant on a sentinel freshwater species, the brown trout (Salmo trutta). We first examined the electrical activity of the whole heart and found prolongation (∼8.6%) of the QT interval (time between ventricular depolarization and repolarization) of the electrocardiogram (ECG) and prolongation (∼13.2%) of the monophasic action potential duration (MAPD) following ascending doses of Phe. At the tissue level, Phe significantly reduced trabecular force generation by ∼24% at concentration 15 µM and above, suggesting Phe reduces cellular calcium cycling. This finding was supported by florescent microscopy showing a reduction (∼39%) in the intracellular calcium transient amplitude following Phe exposure in isolated brown trout ventricular myocytes. Single-cell electrophysiology was used to reveal the mechanism underlying contractile and electrical dysfunction following Phe exposure. A Phe-dependent reduction (∼38%) in the L-type Ca2+ current accounts, at least in part, for the lowered Ca2+ transient and force production. Prolongation of the MAPD and QT interval was explained by a reduction (∼70%) in the repolarising delayed rectifier K+ current following Phe exposure. Taken together, our study shows a direct impact of Phe across multiple levels of cardiac organization in a key freshwater salmonid.


Assuntos
Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/patologia , Fenantrenos/toxicidade , Truta/fisiologia , Poluentes Químicos da Água/toxicidade , Animais , Cardiotoxicidade , Eletrocardiografia , Água Doce/química
2.
Ecotoxicol Environ Saf ; 187: 109673, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31698196

RESUMO

The herbicide glyphosate [N- (phosphonomethyl) glycine; PMG] and the insecticide chlorpyrifos [O, O-diethyl O- (3,5,6-trichloro-2-pyridinyl) -phosphorothioate, CPF] are widely used in agricultural practices around the world and can reach aquatic environments. Therefore, it is necessary to characterize the toxicity of these pesticides on non-target species. The use of biomarkers as a tool to assess responses of organisms exposed to pollutants requires the understanding of their natural fluctuation and the dose-response relationship. In the present work, the effect of the exposure to PMG and CPF on the acetylcholinesterase activity (AChE, biomarker of neurotoxicity) in Cnesterodon decemmaculatus, a native teleost, was evaluated in different environmental conditions. Semi-static bioassays of acute toxicity were carried out under controlled conditions during the four weather seasons of the year using animals of homogeneous size. Circannual rhythms in the basal levels of AChE activity in homogenates of the anterior section were confirmed. Statistically significant average inhibition of AChE activity (47.1 ±â€¯0.7% for 1 µg CPF × L-1; 69.7 ±â€¯2.5% for 5 µg CPF × L-1; 23.1 ±â€¯1.1% for 1 mg PMG × L-1 and 32.9 ±â€¯3.3% for 10 mg PMG × L-1) was determined during summer, winter and spring weather seasons. Interestingly, animals exhibit an increased susceptibility to exposure during the autumn season (inhibition of 55.4 ±â€¯0.6% for 1 µg CPF × L-1; 81.9 ±â€¯3.3% for 5 µg CPF × L-1; 41.4 ±â€¯1.7% for 1 mg PMG × L-1 and 61.1 ±â€¯0.3% for 10 mg PMG × L-1). A different sensitivity of the enzyme between seasons was evaluated by in vitro tests. The inhibition pattern for chlorpyrifos-oxon (CPF-oxon, the active metabolite of CPF) was not affected when test was performed using homogenates of unexposed specimens of summer or autumn. Otherwise, PMG in vitro inhibitory effect was not observed in a wide range of concentrations. The results confirm that AChE activity is a sensitive biomarker for exposure to CPF and PMG, even at environmentally relevant concentrations. Finally, this work highlights the existence of seasonal variations in the dose-response relationship, which could be due to variations in the metabolism of the pollutants.


Assuntos
Acetilcolinesterase/metabolismo , Clorpirifos/análogos & derivados , Inibidores da Colinesterase/toxicidade , Ciprinodontiformes/metabolismo , Glicina/análogos & derivados , Estações do Ano , Poluentes Químicos da Água/toxicidade , Animais , Biomarcadores/metabolismo , Clorpirifos/toxicidade , Relação Dose-Resposta a Droga , Água Doce/química , Glicina/toxicidade
3.
Chemosphere ; 240: 124949, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31568949

RESUMO

Pharmaceutically active compounds are of great concern due to their detection frequency in the environment and the unexpected risks. In this study, the simultaneous removal of mixed pharmaceuticals by microalgae was explored using a typical freshwater diatom Navicula sp. Results showed that Navicula sp. could efficiently remove atenolol, carbamazepine, ibuprofen and naproxen with the efficiencies of >90% after 21 d of exposure. As compared to the removal efficiencies of each pharmaceutical in the individual pharmaceutical treatments, the degradation of sulfamethoxazole, bezafibrate, and naproxen was improved in the mixed treatment, whereas the removal efficiencies of carbamazepine and atenolol decreased. Additionally, the presence of hydrophobic pharmaceuticals (i.e., ibuprofen and naproxen) accelerated the degradation of carbamazepine and sulfamethoxazole and inhibited the removal of atenolol in the mixture with the combination of six pharmaceuticals, while the addition of other pharmaceuticals show no significant effect on the removal of ibuprofen and naproxen. The bioaccumulation of pharmaceuticals in Navicula sp. increased as their log KOW values decreased. Four bezafibrate metabolites were identified and the degradation pathways of bezafibrate in diatom were proposed. It is the first report on the metabolism of BEZ in diatom, and further studies on the environmental risk of the metabolites should be investigated.


Assuntos
Bezafibrato/análise , Biodegradação Ambiental , Diatomáceas/metabolismo , Preparações Farmacêuticas/análise , Preparações Farmacêuticas/metabolismo , Poluentes Químicos da Água/análise , Atenolol/análise , Carbamazepina/análise , Água Doce/química , Ibuprofeno/análise , Inativação Metabólica , Naproxeno/análise , Sulfametoxazol/análise
4.
Chemosphere ; 239: 124741, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31518921

RESUMO

In many parts of the world, wastewater irrigation has become a common practice because of freshwater scarcity and to increase resource reuse efficiency. Wastewater irrigation has positive impacts on livelihoods and at the same time, it has adverse impacts related to environmental pollution. Hydrochemical processes and groundwater behaviour need to be analyzed for a thorough understanding of the geochemical evolution in the wastewater irrigated systems. The current study focuses on a micro-watershed in the peri-urban Hyderabad of India, where farmers practice intensive wastewater irrigation. To evaluate the major factors that control groundwater geochemical processes, we analyzed the chemical composition of the wastewater used for irrigation and groundwater samples on a monthly basis for one hydrological year. The groundwater samples were collected in three settings of the watershed: wastewater irrigated area, groundwater irrigated area and upstream peri-urban area. The collected groundwater and wastewater samples were analyzed for major anions, cations and nutrients. We systematically investigated the anthropogenic influences and hydrogeochemical processes such as cation exchange, precipitation and dissolution of minerals using saturated indices, and freshwater-wastewater mixtures at the aquifer interface. Saturation indices of halite, gypsum and fluorite are exhibiting mineral dissolution and calcite and dolomite display mineral precipitation. Overall, the results suggest that the groundwater geochemistry of the watershed is largely controlled by long-term wastewater irrigation, local rainfall patterns and water-rock interactions. The study results can provide the basis for local decision-makers to develop sustainable groundwater management strategies and to control the aquifer pollution influenced by wastewater irrigation.


Assuntos
Irrigação Agrícola/métodos , Água Subterrânea/química , Águas Residuárias , Ânions/análise , Carbonato de Cálcio/química , Sulfato de Cálcio/química , Cátions/análise , Meio Ambiente , Monitoramento Ambiental/métodos , Água Doce/química , Água Subterrânea/análise , Hidrologia/métodos , Índia , Magnésio/química , Salinidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Qualidade da Água
5.
Ecotoxicol Environ Saf ; 188: 109916, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31733936

RESUMO

Methylparaben (MeP) is one of the most used preservatives in the industry; however, the toxic effects on aquatic ecosystems are still poorly understood. Therefore, this study was conducted (1) to identify and compare the toxic effects of MeP on physiological parameters of different green microalgae species, using suitable mathematical models; and (2) to estimate a PNEC value for MeP in freshwater ecosystems, adopting either the deterministic or the probabilistic approaches. Toxicity tests were carried out with three green microalgae (Pseudopediastrum boryanum, Desmodesmus communis, Raphidocelis subcapitata), in which different endpoints such as growth rate, chlorophyll-a, and cell viability were measured and compared through the effective concentration which caused a response in x% of test organisms (ECx). ECx were obtained by adjusting different non-linear regression models for each microalgae dataset. Chlorophyll-a endpoint resulted in the lowest EC50 values, respectively 125, 81.2, 18.3 mg L-1 for D. communis, P. boryanum and R. subcapitata, showing R. subicapitata as the most sensitive, and D. communis as the most tolerant species to MeP (P < 0.05). PNEC was estimated from the present study and previous reports resulting in 5.7 and 65 µg L-1, respectively for the deterministic (PNECd) and the probabilistic (PNECp) approach. The development of chronic assays using test organisms from different ecological groups is encouraged to provide robust PNECp. In this meantime, we recommend the use of the estimated PNECd to support MeP risk assessments and policy formulation.


Assuntos
Clorófitas/efeitos dos fármacos , Água Doce/química , Microalgas/efeitos dos fármacos , Parabenos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Relação Dose-Resposta a Droga , Ecossistema , Modelos Teóricos , Dinâmica não Linear , Parabenos/análise , Testes de Toxicidade , Poluentes Químicos da Água/análise
6.
Ecotoxicol Environ Saf ; 188: 109945, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31753309

RESUMO

Cyanobacterial harmful algal blooms dominated by Microcystis frequently produce microcystins, a family of toxins capable of inflicting harm to pelagic and benthic freshwater invertebrates. Research on the effect of microcystins on invertebrates is inconclusive; from one perspective, studies suggest invertebrates can coexist in toxic blooms; however, studies have also measured negative food-associated effects from microcystins. To test the latter perspective, we examined the reproduction, growth, and survival of laboratory-cultured Ceriodaphnia dubia, Daphnia magna, and Hexagenia spp. exposed to cell-bound microcystins through a series of life-cycle bioassays. Test organisms were exposed to a concentration gradient ranging from 0.5 µg L-1 to 300 µg L-1 microcystins, which corresponds to values typically found in freshwaters during bloom season. Lethal concentrations in C. dubia (LC50 = 5.53 µg L-1) and D. magna (LC50 = 85.72 µg L-1) exposed to microcystins were among the lowest recorded to date, and reproductive effects were observed at concentrations as low as 2.5 µg L-1. Length of D. magna was significantly impacted in microcystin treatments great than 2.5 µg L-1. No lethality or growth impairments were observed in Hexagenia. This information will improve our understanding of the risks posed by microcystins to food webs in freshwaters.


Assuntos
Daphnia/efeitos dos fármacos , Ephemeroptera/efeitos dos fármacos , Água Doce/química , Microcistinas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Daphnia/crescimento & desenvolvimento , Ephemeroptera/crescimento & desenvolvimento , Cadeia Alimentar , Proliferação Nociva de Algas , Dose Letal Mediana , Estágios do Ciclo de Vida , Reprodução/efeitos dos fármacos
7.
Environ Monit Assess ; 192(1): 31, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31823064

RESUMO

A three-dimensional contaminant transport model of heavy metal (copper) was coupled with the hydrodynamics and suspended sediment transport module to simulate the transport and distribution of heavy metal (copper) of the Danshui River estuarine system in northern Taiwan. The coupled model was validated with observational data including the water level, tidal current, salinity, suspended sediment concentration, and copper concentration. The model simulation results quantitatively reproduce the measurements. Furthermore, the validated model was employed to explore the influences of the freshwater discharge and suspended sediment on the distribution of copper concentrations in the tidal estuarine system. The results demonstrate that a high freshwater discharge results in a decreasing copper concentration, while a low freshwater discharge raises the copper concentration along the estuarine system. If the suspended sediment transport module was excluded in the model simulations, the predicted copper concentration underestimated the measured data. The distribution of copper concentrations without the suspended sediment transport module was lower than that with the suspended sediment transport module. The simulated results indicate that the freshwater discharge and suspended sediment play crucial roles in affecting the distribution of copper concentrations in the tidal estuarine system.


Assuntos
Monitoramento Ambiental , Metais Pesados/análise , Águas Salinas/química , Poluentes Químicos da Água/análise , Simulação por Computador , Cobre/análise , Cobre/metabolismo , Água Doce/química , Sedimentos Geológicos/química , Hidrodinâmica , Metais Pesados/metabolismo , Modelos Teóricos , Taiwan , Poluentes Químicos da Água/metabolismo
8.
Environ Monit Assess ; 192(1): 8, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31797148

RESUMO

Bisphenol-A (BPA) is a chemical used in the production of polycarbonate plastic and epoxy resins that may be related to the occurrence of human endocrine disorders. The present study aims to indicate a microalgae for use in ecotoxicological tests concerning BPA contamination of aquatic environments by analyzing its toxicity for the freshwater species Pseudokirchneriella subcapitata, and the two marine species Tetraselmis chuii and Skeletonema costatum. The standardization of the test involved determination of suitable nominal concentrations of BPA and the most appropriate species for use as biomarkers. S. costatum and P. subcapitata demonstrated resistance to BPA, features that are not of interest for toxicity markers. T. chuii presented an adequate sensitivity to BPA, compatible with parameters used in human toxicology for this substance, and is indicated as a potential biomarker for the presence of BPA in marine environments. The IC50 of T. chuii was 2.5 µM with R2 = 0.9, indicating reliability to demonstrate that low concentrations of BPA has significant toxicity to this species.


Assuntos
Compostos Benzidrílicos/toxicidade , Ecotoxicologia/métodos , Microalgas/efeitos dos fármacos , Fenóis/toxicidade , Poluentes Químicos da Água/toxicidade , Clorófitas/efeitos dos fármacos , Diatomáceas/efeitos dos fármacos , Água Doce/química , Reprodutibilidade dos Testes
9.
Environ Monit Assess ; 191(12): 781, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31786659

RESUMO

Prolonged consumption of fluoride-contaminated water poses health problems like dental and skeletal fluorosis in many parts of the world including India. In regions with acute water scarcity, it demands immediate intervention like de-fluoridation of water before consumption. In the current study, fluoride-resistant bacteria were isolated from fluoride-contaminated groundwater and soil samples collected from Dungarpur district, India, for their potential use in defluoridation. Out of a total of 53 bacterial isolates that were recovered and screened for fluoride resistance, three highly fluoride-resistant isolates DWC1, DWC2 and DWB5, resistant to up to 9200 mg L-1, 7200 mg L-1 and 5200 mg L-1 fluoride respectively, were characterized and identified as Aeromonas sp., Brevibacterium sp. and Paenibacillus sp. respectively. The fluoride removal capacity of isolates DWC1, DWC2, DWB5 and a consortium of all the three isolates was found to be 68.7%, 73.4%, 76.7 % and 70.1% respectively on nutrient broth supplemented with NaF (2000 mg L-1) after 8 days of incubation. Defluoridation conditions for the strain showing the best result (Paenibacillus sp.) were optimized for real fluoride-rich water collected from Ajmer District, India, using the Taguchi design of experiment. A defluoridation of up to 73.3% was observed at 40 °C temperature and pH 8 with inoculum: water ratio of 2:1 after 8 days of incubation. To the best of our knowledge, the defluoridation capacity of Paenibacillus sp. is the highest reported in literature to date for real water samples and could be investigated in further detail for commercial application.


Assuntos
Bactérias , Fluoretos , Água Doce , Purificação da Água , Bactérias/efeitos dos fármacos , Bactérias/metabolismo , Farmacorresistência Bacteriana , Fluoretos/análise , Fluoretos/metabolismo , Fluoretos/farmacologia , Água Doce/química , Água Doce/microbiologia , Índia , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo , Poluição da Água , Purificação da Água/métodos
10.
Huan Jing Ke Xue ; 40(6): 2657-2666, 2019 Jun 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854657

RESUMO

Dissolved organic matter (DOM) in karst water is one of the most important carbon sink components, whose origins, distributions, and transport processes are of significance to carbon sink studies. Chromophoric dissolved organic matter (CDOM) can be utilized to express the composition and structural properties of DOM. In this paper, water samples were collected monthly from Xueyu Cave in a karst underground river from both inside and outside the cave. The changes in hydrochemistry and CDOM spectral characteristics as well as the influencing factors for CDOM changes were studied, with the aim of providing experimental support for carbon sink fluxes in karst processes. The main results were as follows. ① The dominant type of CDOM in Xueyu Cave karst water consisted of small molecular weight organic matter that was autochthonously derived and easily bio-degraded, and the tryptophan-like and tyrosine-like components accounted for more than 60% of the total CDOM. ② The most effective influencing factor inside the cave was microbes, which degraded the small molecular DOM in groundwater and induced slight decreases in the TOC and DOC concentrations; they also increased the humic index (HIX). ③ However, the dominant factor outside the cave was submerged aquatic plant photosynthesis, which induced significant increases in the TOC and DOC concentrations and autochthonous small molecular weight DOM contents.


Assuntos
Cavernas , Água Doce/química , Água Subterrânea/química , Fotossíntese , Sequestro de Carbono , China , Plantas
11.
Huan Jing Ke Xue ; 40(6): 2753-2763, 2019 Jun 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854668

RESUMO

In order to study the relationship between the vertical distribution of nutrients and bacterial community structures in sediment interstitial waters of stratified reservoirs with different water temperatures, MiSeq high-throughput sequencing was used to analyze and compare the structural characteristics of sediment bacterial communities after reservoirs were built. Additionally, redundancy analysis (RDA) was used to assess the bacterial communities and environmental factors with Cannoco software. The results showed that the temperature difference between the surface and bottom layer of the Xiaowan Reservoir was 3.3℃, and the maximum thermal gradient was 0.2℃·m-1; thus, it was a typical stratified reservoir. The temperature difference between the surface and bottom layer of the Manwan Reservoir was 0.1℃; thus, it was a typical mixed reservoir. The average concentrations of NH4+-N and NO3--N in sediment interstitial waters of the Xiaowan Reservoir were 2.233 mg·L-1 and 0.030 mg·L-1, while those of Manwan were 2.569 mg·L-1 and 0.016 mg·L-1, respectively. In the different reservoirs, the concentrations of NH4+-N showed upward trends, and while variation of NO3--N was not obvious, the content of NO3--N reached a minimum value in the deep layer. In comparisons between reservoirs, only NO3--N showed a significant difference, in which Xiaowan had obviously higher concentrations than Manwan. The bacterial community structures in the Xiaowan and Manwan reservoir sediments had the same dominant bacteria at the phylum, class, and genus levels. The differences of water temperature stratification had no significant effect on nutrients and microorganisms in the sediments. Under the influence of other factors, the denitrifying bacteria in the Manwan Reservoir sediments were more abundant than those in the Xiaowan Reservoir, and the nitrifying bacteria and anammox bacteria in the Xiaowan Reservoir sediments were more abundant than those in the Manwan Reservoir. In the same reservoir, the denitrifying bacteria in the bottom of the sediments were more abundant, and the organic degradation bacteria, nitrifying bacteria, anammox bacteria, and phosphate-solubilizing bacteria were less abundant in this zone. These trends contributed to the differences of nutrients vertically in the different reservoirs.


Assuntos
Bactérias/classificação , Água Doce/química , Sedimentos Geológicos/microbiologia , Temperatura Ambiente , Microbiologia da Água , China , Água Doce/microbiologia
12.
Ecotoxicol Environ Saf ; 186: 109628, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31614301

RESUMO

The water quality in drinking water source area is essential for human health. Due to rapid urbanization and industrialization, the pollutants, especially trace elements, are continuously discharged into aquatic environment and pose a risk to human health. An extensive investigation was carried out in drinking water source area in highly urbanized Tianjin of China. Long-term monitoring data of the water body was collected on conventional physical and chemical parameters (pH, ions, TOC etc.) and metallic elements (Hg, As Cd, Pb, Co, U etc.) from 2005 to 2017. Our results showed that CaMg-Cl-SO4 and CaMg-HCO3 were the two prominent hydrochemical materials, implying that the pollution of aquatic system was mainly caused by anthropogenic activities and mineral dissolution within terms of drinking water guidelines (national and international standards), the concentrations of arsenic (As) and iron (Fe) were beyond the quality standards. Multivariate statistical approaches were applied to assess the origins of the elements. The results showed that human activities, as well as endogenous release, contributed significantly to appearance of trace elements. A transformation from low-trophic state to high-trophic state was in progress from 2005 to 2017 in Yuqiao reservoir, and most of the water was not heavily polluted by trace elements. The health risk assessment suggested that As had the potential to cause carcinogenic harm to the local residents, with daily dietary ingestion as the most predominant pathway.


Assuntos
Água Potável/normas , Exposição Ambiental/análise , Monitoramento Ambiental , Água Doce/química , Água Subterrânea/química , Poluentes Químicos da Água/análise , China , Água Potável/química , Humanos , Medição de Risco , Oligoelementos/análise , Urbanização
13.
Anal Bioanal Chem ; 411(28): 7499-7509, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31637461

RESUMO

In this study, a sensitive amplification strategy for Pb2+ detection using reduced graphene oxide (RGO) and gold nanoparticles (AuNPs) was proposed. Thiol-modified DNAzyme is specific for Pb2+ self-assembly on RGO-AuNPs-modified electrode surface. Ferrocene labeled single-stranded DNAzyme (Fc-ssDNAzyme) self-hybridizes to form a DNA hairpin structure. The amount of Fc adsorbed on the electrode surface changes after the appearance of Pb2+, leading to a change of electrical signal. This change can be sensitively identified by differential pulse voltammetry (DPV) assisted by ferricyanide ([Fe(CN)6]3-/4-) in the electrolyte. The high conductivity and specific surface area of RGO and the strong chemical bond adsorption effect between DNAzyme and AuNPs are responsible for the amplified detection of Pb2+, which realize a detection range of 0.05-400,000.0 nM and a minimum detection limit of 0.015 nM. Moreover, the selectivity test results indicated that the biosensor had specificity for Pb2+, even if there was interference from other high-concentration metal ions. This simple biosensor also exhibited good responsiveness in actual sample detection, which provides a good application prospect for field detection of Pb2+ in water. Graphical abstract.


Assuntos
Técnicas Biossensoriais , DNA Catalítico/química , Técnicas Eletroquímicas/instrumentação , Ouro/química , Grafite/química , Chumbo/análise , Nanopartículas Metálicas/química , Água Doce/química , Limite de Detecção , Reprodutibilidade dos Testes
14.
Isotopes Environ Health Stud ; 55(6): 550-565, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31645132

RESUMO

The north-east of Iran is a semi-arid region and faces a water shortage crisis. Therefore, monitoring water resources using accurate methods such as stable isotopes technique is vitally important. In this study, precipitation events were sampled in 10 stations in the Mashhad basin and the Bojnourd region in 2008, 2009, 2011, and 2015, additional surface and groundwater. These samples were analysed at the Ottawa University for both oxygen and hydrogen isotopes. In addition, the moisture sources were determined using the backward trajectories of the HYSPLIT model. The backward trajectories showed that both high- and low-latitude water bodies provide moisture for the north-east of Iran. However, the role of high-latitude water bodies including the Caspian, the Black, and the Mediterranean Seas is stronger. On the other hand, the stable isotopes showed large variations and the developed meteoric water lines deviated in both slope and intercept from the global meteoric water line. This showed that the precipitation events of the north-east of Iran were provided by various air masses and moisture sources. Finally, plotting the isotope values of the surface water resources on high- and low-latitude meteoric water lines demonstrated that these water resources were dominantly recharged by precipitation events originating from high-latitude water bodies.


Assuntos
Deutério/análise , Monitoramento Ambiental/métodos , Água Doce/análise , Isótopos de Oxigênio/análise , Chuva/química , Recursos Hídricos/provisão & distribução , Água Doce/química , Água Subterrânea/química , Irã (Geográfico) , Estações do Ano , Ciclo Hidrológico
15.
Ecotoxicol Environ Saf ; 186: 109757, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31606638

RESUMO

Contamination seems to exert a crucial role in the spatial distribution of some organisms, such as shrimps and fish. Both, especially the freshwater fish Danio rerio and the shrimp Atyaephyra desmarestii, have been tested experimentally for their avoidance response and have showed the ability to escape from toxic effects. As the behavior of avoiding or not the contamination might be altered in the presence of other factors, the aim of the current study was to verify whether the avoidance response of both species, when exposed jointly (multispecies tests), to a copper gradient is different from the avoidance response observed in monospecies tests. The avoidance was assessed in a multi-compartmented exposure system, in which a copper gradient was simulated. Organisms were tested individually and together. Both species avoided potentially toxic copper concentrations; however, shrimps were slightly more sensitive in the monospecies tests: AC50 (avoidance concentration for 50% of the population) of 60 (53-68) µg/L for the zebrafish and 50 (45-56) µg/L for the shrimp. In the multispecies tests, the sensitivity pattern changed: the avoidance response by the fish [AC50: 30 (14-46) µg/L] was greater than by the shrimps [AC50: 70 (22-141) µg/L]. Although the AC50 values are in the same order of magnitude, a slight trend to change the avoidance pattern was observed in the shrimps during multispecies test: the avoidance was lower and time-delayed. This behavioral change could be linked to the stress caused by the zebrafish sharing the space with the shrimps, perhaps increasing the territorialism of the fish, or a delay in the shrimps detecting the risk of contamination.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Cobre/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/fisiologia , Animais , Relação Dose-Resposta a Droga , Água Doce/química , Especificidade da Espécie
16.
Bull Environ Contam Toxicol ; 103(6): 789-795, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31605158

RESUMO

Copper (Cu) bioavailability varies under water conditions. In the present study, the whole life of zebrafish was divided into three different life stages (larvae, juvenile and adult) based on the growth curve, then the influences of water hardness and dissolved organic carbon (DOC) concentration on the acute toxicity of zebrafish were respectively investigated. The results indicated that the life stages had significant effects on Cu toxicity. The larvae stage was less sensitive to Cu than both the juvenile and adult stages. With the increase of water hardness, the toxicity of Cu on zebrafish was decreased, a linear relationship was observed between water hardness and Cu toxicity, and the same was true for DOC concentration. The results showed that taking the 24 days juvenile zebrafish to study the water quality criteria of Cu was stable, sensitive and economical.


Assuntos
Cobre/toxicidade , Água Doce/química , Hidrocarbonetos/toxicidade , Larva/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/crescimento & desenvolvimento , Animais , Cobre/química , Dureza , Hidrocarbonetos/química , Solubilidade , Testes de Toxicidade Aguda , Poluentes Químicos da Água/química , Qualidade da Água/normas
17.
Bull Environ Contam Toxicol ; 103(6): 766-769, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31587083

RESUMO

The ingestion of microplastics by marine species has been at least partially attributed to plastics emitting a dimethyl sulfide signature when exposed to marine conditions. Dimethyl sulfide, a member of the volatile organic sulfur compounds group, is an infochemical that many species rely on to locate and identify prey while foraging. Microplastic ingestion is also observed in freshwater systems; however, this study shows that the same dimethyl sulfide signature is not obtained by three common types of plastic (high-density polyethylene, low-density polyethylene, and polystyrene) in freshwater systems, suggesting that there may be an alternate mechanism driving plastic ingestion by freshwater species.


Assuntos
Água Doce/química , Sulfetos/química , Animais , Monitoramento Ambiental , Modelos Químicos , Polietileno/química , Poliestirenos/química , Sulfetos/análise , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química
18.
Isotopes Environ Health Stud ; 55(6): 566-587, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31578875

RESUMO

The stable isotopes of oxygen and hydrogen can provide useful insights into water origin and hydrological processes. The present study aims to investigate the characteristics of stable H/O isotopes of groundwater and surface water in a coastal area of the Vietnamese Mekong Delta. Isotopes and chloride concentrations of surface water show a highly seasonal and linearly spatial variability, depending on the distance to the sea. The seasonal variation of upstream discharge and rainfall plays an important role in changes of the isotopic compositions and chloride concentrations. Tide also influences on chloride concentrations of surface water while it does not change the isotopic compositions. Evaporation plays a crucial role in changes of isotopic compositions, while the influence of freshwater/seawater mixing on isotopic variabilities is negligible. Groundwater has a spatial heterogeneity in isotopic compositions and chloride concentrations, reflecting different recharge sources and seawater intrusion processes. Groundwater in shallow aquifers originates from rainfall and surface water with small evaporative losses, and it experienced different magnitudes of mixing with seawater. Groundwater in deep aquifers might be recharged by open-surface water evaporation in the last glacial age with minor impacts of seawater intrusion on these aquifers.


Assuntos
Monitoramento Ambiental/métodos , Água Doce/análise , Água Subterrânea/análise , Água do Mar/análise , Recursos Hídricos/provisão & distribução , Deutério/análise , Água Doce/química , Água Subterrânea/química , Isótopos de Oxigênio/análise , Água do Mar/química , Vietnã
19.
Environ Pollut ; 255(Pt 1): 113178, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31520904

RESUMO

Microplastic (MP) pollution is potentially a major threat to many aquatic organisms. Yet we currently know very little about the mechanisms responsible for the effects of small MPs on phenotypes, and the extent to which effects of MPs are modified by genetic and environmental factors. Using a multivariate approach, we studied the effects of 500 nm polystyrene microspheres on the life history and immunity of eight clones of the freshwater cladoceran Daphnia magna reared at two temperatures (18 °C/24 °C). MP exposure altered multivariate phenotypes in half of the clones we studied but had no effect on others. In the clones that were affected, individuals exposed to MPs had smaller offspring at both temperatures, and more offspring at high temperature. Differences in response to MP exposure were unrelated to differences in particle uptake, but were instead linked to an upregulation of haemocytes, particularly at high temperature. The clone-specific, context-dependent nature of our results demonstrates the importance of incorporating genetic variation and environmental context into assessments of the impact of plastic particle exposure. Our results identify immunity as an important mechanism underpinning genetically variable responses to MP pollution and may have major implications for predicting consequences of MP pollution.


Assuntos
Daphnia/efeitos dos fármacos , Daphnia/genética , Poliestirenos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Organismos Aquáticos/efeitos dos fármacos , Água Doce/química , Temperatura Alta , Poliestirenos/farmacologia , Poluentes Químicos da Água/análise
20.
Bull Environ Contam Toxicol ; 103(5): 689-696, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31506728

RESUMO

To test the toxic effects of tributyltin (TBT), Macrobrachium rosenbergii were exposed to three concentrations of TBT viz. 10 ng/L, 100 ng/L and 1000 ng/L for 90 days. The bioaccumulation of TBT level varied in hepatopancreas based upon dose dependent manner. Histopathological results revealed the reduction in basement membrane thickness, disruption of the hepatopancreatic tubules and abnormal lumen in hepatopancreas of TBT treated prawns. The ultrastructure of the control prawn showed normal architecture of cellular organelles with prominent nuclei in hepatocytes. On the other hand, many vacuoles, irregular arrangements of microvilli, swollen mitochondria, distorted rough endoplasmic reticulum cisternaes and abnormal nucleus were seen in the TBT treated group. Further, the biochemical and vitellogenin content were altered remarkably due to TBT exposure. It directly indicated that TBT had conspicuously inhibited the vitellogenesis. Therefore, it was inferred that the administration of TBT has considerably affected the hepatopancreatic functions in M. rosenbergii.


Assuntos
Bioacumulação , Água Doce/química , Hepatopâncreas/efeitos dos fármacos , Palaemonidae/efeitos dos fármacos , Compostos de Trialquitina/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Relação Dose-Resposta a Droga , Hepatopâncreas/metabolismo , Palaemonidae/metabolismo , Palaemonidae/ultraestrutura , Compostos de Trialquitina/metabolismo , Vitelogeninas/metabolismo , Poluentes Químicos da Água/metabolismo
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