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1.
Aquat Toxicol ; 218: 105357, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31812648

RESUMO

Aquatic media are ultimate recipients of various contaminants including pesticides pervasively applied in agrosystems. Characterizing the ecotoxicity of pesticides and their mixtures to aquatic wildlife at field-realistic levels is thus crucial for environmental risk assessment. This study aims at assessing the effects of two current-use insecticides, imidacloprid and chlorpyrifos, on Gammarus fossarum using multi-level biomarkers. In microcosms, gammarids were exposed for 72 h to insecticides tested individually or in mixture at 0.01, 0.1 and 1 µg/L of each chemical. Multi-metric responses were assessed at the individual level (behavioural traits: locomotion, respiration and amplexus formation) and the cellular level (enzymes involved in growth, moulting, digestion and cell stress). The results showed insecticide-elicited behavioural and biochemical responses from the lowest concentration of 0.01 µg/L. Overall, single exposures stimulated behavioural traits and inhibited enzymatic activities, highlighting subtle impacts at different organizational levels but these were not dose related. For binary mixtures, antagonistic effects (i.e. less-than-additive) on biomarkers were mainly observed when compared with single exposures. Multi-variable analyses indicated the complementarity of behavioural and biochemical biomarkers in identifying sublethal biological alterations and dose-dependent multiple action sites of insecticides. Besides, the mortality observed only for the mixture at 1 µg/L demonstrated a high lethal potential of insecticides in a simple binary combination. To conclude, this study demonstrates disturbances in individual performances and cellular impairments occurring at environmentally realistic exposure levels in a non-target wild species. Since the sublethal effects, such as those identified with this multi-biomarker approach, could lead to long-term alterations in population dynamics of agricultural areas, they constitute promising early endpoints for risk assessment of insecticides.


Assuntos
Anfípodes/efeitos dos fármacos , Clorpirifos/toxicidade , Biomarcadores Ambientais/efeitos dos fármacos , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Poluentes Químicos da Água/toxicidade , Anfípodes/metabolismo , Animais , Comportamento Animal/efeitos dos fármacos , Relação Dose-Resposta a Droga , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Locomoção/efeitos dos fármacos
2.
Chemosphere ; 245: 125594, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31855766

RESUMO

This study aimed to assess how bioturbation by freshwater benthic macroinvertebrates with different biological traits alone or in combination could modify trace elements (TE) fate between sediment and water, and if water TE concentration and animal TE content impair their body stores. Three macroinvertebrate species were exposed to TE contaminated sediment for 7 days: the omnivorous Echinogammarus berilloni (Amphipoda), the sediment feeding Tubifex tubifex (Oligochaeta) and the filter feeding Pisidium sp. (Bivalvia). Treatments were one without invertebrates (control), two with amphipods or mussels alone, and the combinations amphipod-mussel, and amphipod-mussel-worms. Water TE concentration increased significantly in 2 or 3 species mesocosms, concerning mainly Rare Earth Elements, Cr, U and Pb, known to be associated to the colloidal phase. By contrast, water soluble TE were not affected by animals. For both, amphipods and mussels, TE body content increased with the number of coexisting species. For amphipods, this increase concerned both, soluble and colloid-associated TE, possibly due to intense contact and feeding from sediment and predation on tubificids. TE bioaccumulation in mussel was less important and characterized by soluble TE, with water filtration as most plausible uptake route. Protein, triglyceride and Whole Body Energy Budget increased in amphipods with the number of coexisting species (probably by feeding on mussels' feces and tubificids) whereas triglycerides declined in mussels (presumably filtration was disturbed by amphipods). This study highlights interspecific interactions as key drivers explaining both: TE bioturbation, depending on their water solubility or colloidal association, and the exposure/contamination of species through another species activity.


Assuntos
Sedimentos Geológicos/análise , Invertebrados/metabolismo , Oligoelementos/análise , Anfípodes/metabolismo , Animais , Bivalves/metabolismo , Água Doce , Invertebrados/química , Oligoquetos/metabolismo , Oligoelementos/metabolismo , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo
3.
Sci Total Environ ; 687: 907-916, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31412494

RESUMO

Mercury (Hg) is a global contaminant that poses a human health risk in its organic form, methylmercury (MeHg), through consumption of fish and fishery products. Bioaccumulation of Hg in the aquatic environment is controlled by a number of factors expected to be altered by climate change. We examined the individual and combined effects of temperature, sediment organic carbon, and salinity on the bioaccumulation of MeHg in an estuarine amphipod, Leptocheirus plumulosus, when exposed to sediment from two locations in the Gulf of Maine (Kittery and Bass Harbor) that contained different levels of MeHg and organic carbon. Higher temperatures and lower organic carbon levels individually increased uptake of MeHg by L. plumulosus as measured by the biota-sediment accumulation factor (BSAF), while the effect of salinity on BSAF differed by sediment source. Multi-factor statistical modeling using all data revealed a significant interaction between temperature and organic carbon for both sediments, in which increased temperature had a negative effect on BSAF at the lowest carbon levels and a positive effect at higher levels. Our results suggest that increased temperature and carbon loading, of a magnitude expected as a result from climate change, could be associated with a net decrease in amphipod BSAF of 50 to 71%, depending on sediment characteristics. While these are only first-order projections, our results indicate that the future fate of MeHg in marine food webs is likely to depend on a number of factors beyond Hg loading.


Assuntos
Anfípodes/metabolismo , Monitoramento Ambiental , Compostos de Metilmercúrio/metabolismo , Salinidade , Temperatura , Poluentes Químicos da Água/metabolismo , Animais , Carbono , Estuários , Cadeia Alimentar , Sedimentos Geológicos/química
4.
Aquat Toxicol ; 214: 105244, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31352074

RESUMO

High-throughput proteomics can be performed on animal sentinels for discovering key molecular biomarkers signing the physiological response and adaptation of organisms. Ecotoxicoproteomics is today amenable by means of proteogenomics to small arthropods such as Gammarids which are well known sentinels of aquatic environments. Here, we analysed two regional Gammarus pulex populations to characterize the potential proteome divergence induced in one site by natural bioavailable mono-metallic contamination (cadmium) compared to a non-contaminated site. Two RNAseq-derived protein sequence databases were established previously on male and female individuals sampled from the reference site. Here, individual proteomes were acquired on 10 male and 10 female paired organisms sampled from each site. Proteins involved in protein lipidation, carbohydrate metabolism, proteolysis, innate immunity, oxidative stress response and lipid transport were found more abundant in animals exposed to cadmium, while hemocyanins were found in lower abundance. The intrapopulation proteome variability of long-term exposed G. pulex was inflated relatively to the non-contaminated population. These results show that, while remaining a challenge for such organisms with not yet sequenced genomes, taking into account intrapopulation variability is important to better define the molecular players induced by toxic stress in a comparative field proteomics approach.


Assuntos
Anfípodes/metabolismo , Cádmio/toxicidade , Proteoma/metabolismo , Proteômica , Anfípodes/efeitos dos fármacos , Animais , Análise por Conglomerados , Feminino , Masculino , Análise de Componente Principal , Poluentes Químicos da Água/toxicidade
5.
Mar Pollut Bull ; 142: 155-163, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31232289

RESUMO

We aimed to show how the predicted pH decrease in the ocean would alter the toxicity, bioconcentration and dietary transfer of trace metal copper on seagrass ecosystems, on a short-term basis. Seagrass Zostera noltei was exposed to two pH levels (8.36 and 8.03) and three copper levels (nominal concentrations, <3, 30 and 300 µg Cu L-1) in a factorial design during 21 days, while Gammarus locusta amphipods were continuously fed with the treated seagrass leaves. We found that the toxicity and bioconcentration of copper in seagrasses were not affected by pH, yet complex copper-pH interactions were observed in the seagrass photosynthesis. We demostrated that seagrasses can act as a copper source in the food web via direct consumption by herbivores. Future research need to investigate the interactive effects on a long-term basis, and to include biochemical and molecular endpoints to provide additional insights to the complex phisiological interactions observed.


Assuntos
Anfípodes/metabolismo , Cobre/toxicidade , Poluentes Químicos da Água/toxicidade , Zosteraceae/fisiologia , Anfípodes/efeitos dos fármacos , Animais , Disponibilidade Biológica , Cobre/farmacocinética , Ecossistema , Ecotoxicologia/métodos , Cadeia Alimentar , Herbivoria , Concentração de Íons de Hidrogênio , Oceanos e Mares , Fotossíntese/efeitos dos fármacos , Água do Mar/química , Oligoelementos , Poluentes Químicos da Água/farmacocinética , Zosteraceae/efeitos dos fármacos
6.
Bull Environ Contam Toxicol ; 103(3): 447-452, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31243474

RESUMO

It was assessed the efficiency of the electrocoagulation (EC) in slaughterhouse wastewater (SW) treatment by using antioxidant parameters of Gammarus pulex. The SW was treated by EC. Superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) activities and malondialdehyde (MDA) levels in G. pulex exposed to pre- and post-treated of the SW during 24 h and 96 h were analysed. Standard methods were applied during the analysing process of the physicochemical quality parameters for both untreated and treated SW. All measured physicochemical parameters were decreased following the treatment process via EC. After the treatment process, it was observed that while SOD activities and MDA levels were decreased, CAT activities were increased and GPx activities did not exhibit any change. In conclusion, the present study demonstrated the abilities of untreated SW to promote oxidative stress in model organism. The SOD, CAT activities and MDA levels in G. pulex revealed that EC process were efficient in the SW treatment.


Assuntos
Matadouros , Anfípodes/efeitos dos fármacos , Testes de Toxicidade Aguda/métodos , Eliminação de Resíduos Líquidos , Águas Residuárias/toxicidade , Anfípodes/metabolismo , Animais , Antioxidantes/metabolismo , Eletrocoagulação , Biomarcadores Ambientais/efeitos dos fármacos , Monitoramento Ambiental , Estresse Oxidativo/efeitos dos fármacos
7.
Talanta ; 202: 221-229, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31171174

RESUMO

In Western Europe, river water quality can be assessed using sentinel species such as the amphipod Gammarus fossarum. In this work of environmental metabolomics, the objective was to develop suitable chemometrics methods, using a limited number of individuals, to assess the modification of the metabolism of G. fossarum exposed to two human pharmaceuticals. Males and females gammarids were exposed to a mixture of the anxiolytic oxazepam and the antiepileptic carbamazepine (1000 ng L-1) for 14 days under laboratory conditions according to a full factorial design 2² (repeated 5 times). They were analyzed at the single individual scale using a method including a µQuEChERS type extraction followed by a nanoliquid chromatography analysis coupled to high-resolution mass spectrometry. The molecular fingerprints obtained were investigated using XCMS. Several corrections of experimental drifts (by using lock mass and Quality Control samples) were tested prior to using APCA + method for the exploitation of the unbalanced designed data. Signal reproducibility was greatly improved by the lock mass normalisation. From the experimental design, a significant effect of both experimental factors "exposure to the mixture" and "gammarid gender" on the signals measured were highlighted by APCA+. Finally, the results obtained made it possible to identify variables responsible for each of the factor effects.


Assuntos
Anfípodes/efeitos dos fármacos , Carbamazepina/farmacologia , Nanotecnologia , Oxazepam/farmacologia , Anfípodes/metabolismo , Animais , Cromatografia Líquida , Feminino , Humanos , Masculino , Espectrometria de Massas , Análise de Componente Principal
8.
Ecotoxicol Environ Saf ; 180: 33-42, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31059905

RESUMO

Toxicokinetic (TK) models are relevant and widely used to predict chemical concentrations in biological organisms. The importance of dietary uptake for aquatic invertebrates has been increasingly assessed in recent years. However, the model parameters are estimated on limited specific laboratory data sets that are bounded by several uncertainties. The aim of this study was to implement a Bayesian framework for simultaneously estimating the parameters of a generic TK model for benthic invertebrate species from all data collected. We illustrate our approach on the bioaccumulation of PCB153 by two species with different life traits and therefore exposure routes: Chironomus riparius larvae exposed to spiked sediment for 7 days and Gammarus fossarum exposed to spiked sediment and/or leaves for 7 days and then transferred to a clean media for 7 more days. The TK models assuming first-order kinetics were fitted to the data using Bayesian inference. The median model predictions and their 95% credibility intervals showed that the model fit the data well. From a methodological point of view, this paper illustrates that simultaneously estimating all model parameters from all available data by Bayesian inference, while considering the correlation between parameters and different types of data, is a real added value for TK modeling. Moreover, we demonstrated the ability of a generic TK model considering uptake and elimination routes as modules to add according to the availability of the data measured. From an ecotoxicological point of view, we show differences in PCB153 bioaccumulation between chironomids and gammarids, explained by the different life traits of these two organisms.


Assuntos
Anfípodes/efeitos dos fármacos , Chironomidae/efeitos dos fármacos , Água Doce/química , Sedimentos Geológicos/química , Bifenilos Policlorados/toxicidade , Poluentes Químicos da Água/toxicidade , Anfípodes/metabolismo , Animais , Teorema de Bayes , Chironomidae/metabolismo , Larva/efeitos dos fármacos , Larva/metabolismo , Modelos Teóricos , Bifenilos Policlorados/metabolismo , Toxicocinética , Poluentes Químicos da Água/metabolismo
9.
PLoS One ; 14(5): e0211304, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31095563

RESUMO

Anthropogenic pressures, such as contaminant exposure, may affect stable isotope ratios in biota. These changes are driven by alterations in the nutrient allocation and metabolic pathways induced by specific stressors. In a controlled microcosm study with the amphipod Gammarus spp., we studied effects of the ß-blocker propranolol on stable isotope signatures (δ15N and δ13C), elemental composition (%C and %N), and growth (protein content and body size) as well as biomarkers of oxidative status (antioxidant capacity, ORAC; lipid peroxidation, TBARS) and neurological activity (acetylcholinesterase, AChE). Based on the known effects of propranolol exposure on cellular functions, i.e., its mode of action (MOA), we expected to observe a lower scope for growth, accompanied by a decrease in protein deposition, oxidative processes and AChE inhibition, with a resulting increase in the isotopic signatures. The observed responses in growth, biochemical and elemental variables supported most of these predictions. In particular, an increase in %N was observed in the propranolol exposures, whereas both protein allocation and body size declined. Moreover, both ORAC and TBARS levels decreased with increasing propranolol concentration, with the decrease being more pronounced for TBARS, which indicates the prevalence of the antioxidative processes. These changes resulted in a significant increase of the δ15N and δ13C values in the propranolol-exposed animals compared to the control. These findings suggest that MOA of ß-blockers may be used to predict sublethal effects in non-target species, including inhibited AChE activity, improved oxidative balance, and elevated stable isotope ratios. The latter also indicates that metabolism-driven responses to environmental contaminants can alter stable isotope signatures, which should be taken into account when interpreting trophic interactions in the food webs.


Assuntos
Antagonistas Adrenérgicos beta/farmacologia , Anfípodes/efeitos dos fármacos , Anfípodes/metabolismo , Propranolol/farmacologia , Animais , Biomarcadores , Isótopos de Carbono/metabolismo , Marcação por Isótopo , Peroxidação de Lipídeos/efeitos dos fármacos , Isótopos de Nitrogênio/metabolismo , Oxirredução/efeitos dos fármacos , Análise de Componente Principal , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo
10.
Environ Toxicol Pharmacol ; 70: 103191, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31108396

RESUMO

Sublethal effects of water-accommodated fraction (WAF) from crude oil of Neuquén basin, Northern Patagonia-Argentina, were examined on both antioxidant and detoxification system of Hyalella curvispina adults collected in Los Barreales (LB) lake and in an oil-polluted stream (DS). The effects of WAF exposure during 6, 24 and 48 h were evaluated in the glutathione content (GSH) and glutathione S-transferase (GST), catalase (CAT) and cytochrome P450 (CYP450) activities. Populations from DS and LB showed not only different basal GSH content and enzyme activities but also different behavior to WAF exposure. LB population exposed to WAF showed a significant increase in GSH content, CAT and CYP450 activities, compared to control group. DS population presented high basal levels in CAT and CYP activity compared with LB population, but their response to WAF exposure was minor. Amphipods from DS, chronically exposed to hydrocarbons, were adapted to their environment.


Assuntos
Anfípodes/efeitos dos fármacos , Hidrocarbonetos/toxicidade , Petróleo/toxicidade , Poluentes Químicos da Água/toxicidade , Anfípodes/metabolismo , Animais , Catalase/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Glutationa/metabolismo , Glutationa Transferase/metabolismo , Água , Poluição Química da Água/efeitos adversos
11.
PLoS One ; 14(4): e0206710, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30947320

RESUMO

The amphipod Hirondellea gigas inhabits the deepest regions of the oceans in extreme high-pressure conditions. However, the mechanisms by which this amphipod adapts to its high-pressure environment remain unknown. In this study, we investigated the elemental content of the exoskeleton of H. gigas specimens captured from the deepest points of the Mariana Trench. The H. gigas exoskeleton contained aluminum, as well as a major amount of calcium carbonate. Unlike other (accumulated) metals, aluminum was distributed on the surface of the exoskeleton. To investigate how H. gigas obtains aluminum, we conducted a metabolome analysis and found that gluconic acid/gluconolactone was capable of extracting metals from the sediment under the habitat conditions of H. gigas. The extracted aluminum ions are transformed into the gel state of aluminum hydroxide in alkaline seawater, and this gel covers the body to protect the amphipod. This aluminum gel is a good material for adaptation to such high-pressure environments.


Assuntos
Alumínio/metabolismo , Anfípodes , Exoesqueleto , Organismos Aquáticos , Anfípodes/metabolismo , Anfípodes/ultraestrutura , Exoesqueleto/metabolismo , Exoesqueleto/ultraestrutura , Animais , Organismos Aquáticos/metabolismo , Organismos Aquáticos/ultraestrutura , Oceano Pacífico
12.
Artigo em Inglês | MEDLINE | ID: mdl-30862023

RESUMO

Wastewater discharge is one of the main sources of micropollutants within the aquatic environment. To reduce the risks for the aquatic environment, the reduction of the chemical load of wastewater treatment plant effluent is critical. Based on this need, additional treatment methods, such as ozonation, are currently being tested in several wastewater treatment plants (WWTPs). In the present study, effects were investigated using in situ feeding experiments with Gammarus pulex and body burden analyses of frequently detected micropollutants which used a Quick Easy Cheap Effective Rugged and Safe (QuEChERS) multi-residue method to quantify internal concentrations in collected gammarids. Information obtained from these experiments complemented data from the chemical analysis of water samples and bioassays, which predominantly cover hydrophilic substances. When comparing up- and downstream feeding rates of Gammarus pulex for seven days, relative to the WWTPs, no significant acute effects were detected, although a slight trend of increased feeding rate downstream of the WWTP Aachen-Soers was observed. The chemical load released by the WWTP or at other points, or by diffuse sources, might be too low to lead to clear acute effects on G. pulex. However, some compounds found in wastewater are able to alter the microbial community on its leaves, leading to an increase in the feeding rate of G. pulex. Chemical analysis of internal concentrations of pollutants in the tissues of collected gammarids suggests a potential risk for chronic effects with the chemicals imidacloprid, thiacloprid, carbendazim, and 1H-benzotriazole when exceeding the critical toxic unit value of -3. This study has demonstrated that a combination of acute testing and measurement of the internal concentration of micropollutants that might lead to chronic effects is an efficient tool for investigating river systems, assuming all relevant factors (e.g., species or season) are taken into account.


Assuntos
Anfípodes/metabolismo , Carga Corporal (Radioterapia) , Águas Residuárias/química , Poluentes Químicos da Água/química , Animais , Rios/química
13.
Sci Total Environ ; 648: 80-89, 2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-30114591

RESUMO

The application of machine learning has recently gained interest from ecotoxicological fields for its ability to model and predict chemical and/or biological processes, such as the prediction of bioconcentration. However, comparison of different models and the prediction of bioconcentration in invertebrates has not been previously evaluated. A comparison of 24 linear and machine learning models is presented herein for the prediction of bioconcentration in fish and important factors that influenced accumulation identified. R2 and root mean square error (RMSE) for the test data (n = 110 cases) ranged from 0.23-0.73 and 0.34-1.20, respectively. Model performance was critically assessed with neural networks and tree-based learners showing the best performance. An optimised 4-layer multi-layer perceptron (14 descriptors) was selected for further testing. The model was applied for cross-species prediction of bioconcentration in a freshwater invertebrate, Gammarus pulex. The model for G. pulex showed good performance with R2 of 0.99 and 0.93 for the verification and test data, respectively. Important molecular descriptors determined to influence bioconcentration were molecular mass (MW), octanol-water distribution coefficient (logD), topological polar surface area (TPSA) and number of nitrogen atoms (nN) among others. Modelling of hazard criteria such as PBT, showed potential to replace the need for animal testing. However, the use of machine learning models in the regulatory context has been minimal to date and is critically discussed herein. The movement away from experimental estimations of accumulation to in silico modelling would enable rapid prioritisation of contaminants that may pose a risk to environmental health and the food chain.


Assuntos
Anfípodes/metabolismo , Carpas/metabolismo , Ecotoxicologia/métodos , Exposição Ambiental , Aprendizado de Máquina , Poluentes Químicos da Água/metabolismo , Animais , Modelos Biológicos , Preparações Farmacêuticas/metabolismo
14.
Environ Sci Pollut Res Int ; 26(2): 1628-1641, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30446915

RESUMO

Bioconcentration factors (BCF) for regulatory purposes are usually determined by fish flow-through tests according to technical guidance document OECD 305. Fish bioconcentration studies are time consuming, expensive, and use many laboratory animals. The aim of this study was to investigate whether the freshwater amphipod Hyalella azteca can be used as an alternative test organism for bioconcentration studies. Fourteen substances of different hydrophobicity (log Kow 2.4-7.6) were tested under flow-through conditions to determine steady state and kinetic bioconcentration factors (BCFss and BCFk). The results were compared with fish BCF estimates for the same substances described in the literature to show the relationship between both values. Bioconcentration studies with the freshwater amphipod H. azteca resulted in BCF estimates which show a strong correlation with fish BCF values (r2 = 0.69). Hyalella BCF values can be assessed in accordance with the regulatory B criterion (BCF > 2000, i.e., REACH) and thereby enable the prediction of B or non-B classification in the standard fish test. Therefore, H. azteca has a high potential to be used as alternative test organism to fish for bioconcentration studies.


Assuntos
Anfípodes/efeitos dos fármacos , Peixes , Poluentes Químicos da Água/farmacocinética , Anfípodes/metabolismo , Animais , Água Doce , Interações Hidrofóbicas e Hidrofílicas , Cinética , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química
15.
Environ Sci Process Impacts ; 20(9): 1285-1296, 2018 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-30175344

RESUMO

In undisturbed, metal-contaminated marine sediments, porewater metal concentrations are generally low due to their associations with strong binding phases such as organic matter, Fe/Mn (oxy)hydroxides and sulfides. Bioturbating fauna can alter redox conditions and, therefore, metal binding, potentially leading to increased metal bioavailability and subsequent toxicity to inhabiting organisms. Here we assessed the impacts of bioturbation (by bivalves and large amphipod species) on sediment biogeochemistry, metal bioaccumulation and toxicity to a smaller amphipod species in a metal contaminated sediment with low and high acid volatile sulfide (AVS) concentrations. Active bioturbation lowered metal toxicity to reproduction in the sediment with low-AVS (from 90% toxic (non-bioturbated) to 50% toxic (bioturbated)). This corresponded with lower dissolved metal concentrations in the overlying water column and lower metal bioaccumulation. Conversely, toxicity increased due to bioturbation in the sediment with high-AVS (40% toxic (non-bioturbated) to 80% toxic (bioturbated)), coinciding with sulfide oxidation, metal release and greater metal bioaccumulation. The results indicate that the AVS-SEM paradigm (commonly used to estimate the risks of adverse effects to benthic organisms in metal-contaminated sediments) may result in incorrect assessment outcomes in cases where bioturbating organisms rework and oxidize the sediment, or for those sediments where AVS has accumulated due to the inability of larger bioturbating benthic organisms to establish populations.


Assuntos
Anfípodes/efeitos dos fármacos , Bivalves/fisiologia , Metais Pesados/toxicidade , Sulfetos/química , Poluentes Químicos da Água/toxicidade , Anfípodes/metabolismo , Animais , Disponibilidade Biológica , Feminino , Sedimentos Geológicos/química , Masculino , Metais Pesados/metabolismo , Reprodução/efeitos dos fármacos , Poluentes Químicos da Água/metabolismo
16.
Aquat Toxicol ; 203: 159-171, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30138800

RESUMO

The amount of pollutants and nutrients entering rivers via point sources is increasing along with human population and activity. Although wastewater treatment plants (WWTPs) greatly reduce pollutant loads into the environment, excess nutrient loading is a problem in many streams. Using a Community and Ecosystem Function (CEF) approach, we quantified the effects of WWTP effluent on the performance of microbes and detritivores associated to organic matter decomposition, a key ecosystem process. We measured organic matter breakdown rates, respiration rates and exo-enzymatic activities of aquatic microbes. We also measured food consumption and growth rates and RNA to body-mass ratios (RNA:BM) of a dominant amphipod Echinogammarus berilloni. We predicted responses to follow a subsidy-stress pattern and differences between treatments to increase over time. To examine temporal effects of effluent, we performed a laboratory microcosm experiment under a range of effluent concentrations (0, 20, 40, 60, 80 and 100%), taking samples over time (days 8, 15 and 30; 4 and 10 replicates to assess microbe and detritivore performance respectively, per treatment and day). This experiment was combined with a field in situ Before-After Control-Impact Paired (BACIP) experiment whereby we added WWTP effluent poured (10 L s-1 during 20-40 min every 2 h) into a stream and collected microbial and detritivore samples at days 8 and 15 (5 and 15 replicates to assess the microbe and detritivore performance respectively, per period, reach and sampling day). Responses were clearer in the laboratory experiment, where the effluent caused a general subsidy response. Field measures did not show any significant response, probably because of the high dilution of the effluent in stream water (average of 1.6%). None of the measured variables in any of the experiments followed the predicted subsidy-stress response. Microbial breakdown, respiration rates, exo-enzymatic activities and invertebrate RNA:BM increased with effluent concentrations. Differences in microbial respiration and exo-enzymatic activities among effluent treatments increased with incubation time, whereas microbial breakdown rates and RNA:BM were consistent over time. At the end of the laboratory experiment, microbial respiration rates increased 156% and RN:BM 115% at 100% effluent concentration. Detritivore consumption and growth rates increased asymptotically, and both responses increased with by incubation time. Our results indicate that WWTP effluent stimulates microbial activities and alters detritivore performance, and stream water dilution may mitigate these effects.


Assuntos
Anfípodes/metabolismo , Bactérias/efeitos dos fármacos , Eliminação de Resíduos Líquidos , Águas Residuárias/química , Poluentes Químicos da Água/toxicidade , Purificação da Água/métodos , Anfípodes/efeitos dos fármacos , Animais , Ecossistema , Rios , Qualidade da Água
17.
PLoS One ; 13(8): e0201883, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30110360

RESUMO

Invasive predators can profoundly impact native communities, especially in insular ecosystems where functionally equivalent predators were evolutionarily absent. Beyond direct consumption, predators can affect communities indirectly by creating or altering food web linkages among existing species. Where invasive predators consume prey from multiple distinct resource channels, novel links may couple the dynamics of disjunct modules and create indirect interactions between them. Our study focuses on invasive populations of Eleutherodactylus coqui (Anura: Leptodactylidae) on Hawaii Island. Coqui actively forage in the understory and lower canopy at night but return to the forest floor and belowground retreats by day. Recent dietary studies using gut contents and naturally occurring stable isotopes indicate higher than expected consumption of litter arthropods, which in these Hawaiian forests are primarily non-native species. We used laboratory studies to observe diurnal and nocturnal foraging behavior, and experimental field additions of C4 vegetation as a litter tracer to distinguish epigaeic sources from food web pools in the C3 canopy. Lab trials revealed that prey consumption during diurnal foraging was half that consumed during nocturnal foraging. Analysis of δ13C isotopes showed incorporation of C4 carbon into litter arthropods within one month, and Bayesian mixing models estimated that 15-25% of the carbon in coqui tissue was derived from litter sources. These results support recent findings that E. coqui are not quiescent diurnally but instead actively forage. Such activity by a mobile invasive predator may introduce a novel linkage that integrates detrital and foliar resource pools, potentially distributing influences of invasive litter arthropods through the broader system to amplify impacts on native species.


Assuntos
Dieta , Espécies Introduzidas , Comportamento Predatório , Anfípodes/metabolismo , Distribuição Animal , Animais , Formigas/metabolismo , Anuros/metabolismo , Isótopos de Carbono/análise , Comportamento Alimentar , Cadeia Alimentar , Hawaii , Modelos Biológicos , Fotoperíodo
18.
Ecotoxicol Environ Saf ; 163: 84-95, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30041129

RESUMO

The current study reports a combined seasonal monitoring of the Crnica River watercourse using physico-chemical parameters and biomarkers measured in Gammarus dulensis with the aim of correlating the effects of pollution with the level of oxidative stress biomarkers in this amphipod. The pollution source is identified as a trout farm in the upper part of the Crnica River (Eastern Serbia). Physico-chemical water parameters and sediment trace element concentrations were measured in the Crnica River during three seasons. Three localities downstream [CR2, CR3, and CR4 (20 m, 400 m, and 1.3 km from the trout farm discharge, respectively)] were assessed in comparison with a reference location (CR1), 250 m upstream from the trout aquaculture in the Crnica River. Antioxidant biomarkers including the enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), and glutathione-S-transferase (GST) were determined in pooled samples of G. dulensis. Our findings showed statistically different antioxidant enzyme levels in gammarids from the first downstream locality (CR2) compared to those from other three localities. The results indicate that oxidative stress occurred to some extent despite the assumed antioxidant induction as a result of exposure to elevated levels of some elements and changed water parameters, the effects seeming in part to be mediated by suppression of SOD and CAT (during summer and autumn); and by suppression of GPX and GR (during autumn) at the CR2 locality. The activity of GST in all seasons was higher at the CR2 locality than at the other localities, suggesting the presence of some permanent xenobiotic next to the aquaculture output. Seasonal difference in the physical and chemical water parameters and sediment trace element concentrations were observed. Overall, our results indicate a locality- and season-dependent antioxidant enzymes response in G. dulensis, pointing at progressively reduced deleterious effect of trout farm outputs with movement further downstream.


Assuntos
Anfípodes/metabolismo , Aquicultura , Estresse Oxidativo , Truta , Animais , Biomarcadores/metabolismo , Catalase/metabolismo , Monitoramento Ambiental , Fazendas , Glutationa Peroxidase/metabolismo , Glutationa Redutase/metabolismo , Glutationa Transferase/metabolismo , Masculino , Rios , Estações do Ano , Sérvia , Superóxido Dismutase/metabolismo
19.
Environ Toxicol Chem ; 37(9): 2340-2349, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29802730

RESUMO

Uranium (U) mining and milling release arsenic (As), nickel (Ni) and U to receiving waters, which accumulate in sediments. The objective of the present study was to investigate if As, Ni, and U concentrations in tissue residue of Hyalella azteca, overlying water, sediment porewater, and solids could predict juvenile and adult survival and growth in conditions similar to lake sediments downstream of U mines and mills. We conducted 14-d static sediment toxicity tests spiked with U, As, and Ni salts. For U, we spiked uranyl nitrate with sodium bicarbonate to limit U precipitation once in contact with circumneutral sediment. The median lethal concentrations for As, Ni, and U of juveniles and adults based on measured concentrations in sediments were 134 and 165 µg/g, 370 and 787 µg/g, and 48 and 214 µg/g, respectively. Adult survival and growth linearly decreased with increasing bioaccumulation. For juveniles, metal accumulation linearly predicted survival. We calculated median lethal body concentrations for juveniles and adults of 5 and 36 µg As/g, 14 and 49 µg Ni/g, and 0.4 and 1.0 µg U/g. The concentrations of As, Ni, and U in tissue residue leading to a 20% decrease in adult growth were 32 µg As/g, 44 µg Ni/g, and 1 µg U/g. Overall, the present study showed that U was the most toxic element, followed by As and Ni; that juveniles were more sensitive to the 3 metals tested than adults; and that threshold body concentrations can support assessment of benthic invertebrate community impairment. Environ Toxicol Chem 2018;37:2340-2349. © 2018 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.


Assuntos
Anfípodes/metabolismo , Arsênico/toxicidade , Bioensaio/métodos , Sedimentos Geológicos/química , Níquel/toxicidade , Testes de Toxicidade , Urânio/toxicidade , Anfípodes/efeitos dos fármacos , Animais , Dose Letal Mediana , Poluentes Químicos da Água/toxicidade
20.
Sci Rep ; 8(1): 3793, 2018 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-29491422

RESUMO

Taking advantage of a large transcriptomic dataset recently obtained in the sentinel crustacean amphipod Gammarus fossarum, we developed an approach based on sequence similarity and phylogenetic reconstruction to identify key players involved in the endocrine regulation of G. fossarum. Our work identified three genes of interest: the nuclear receptors RXR and E75, and the regulator broad-complex (BR). Their involvement in the regulation of molting and reproduction, along with their sensitivity to chemical contamination were experimentally assessed by studying gene expression during the female reproductive cycle, and after laboratory exposure to model endocrine disrupting compounds (EDCs): pyriproxyfen, tebufenozide and piperonyl butoxide. RXR expression suggested a role of this gene in ecdysis and post-molting processes. E75 presented two expression peaks that suggested a role in vitellogenesis, and molting. BR expression showed no variation during molting/reproductive cycle. After exposure to the three EDCs, a strong inhibition of the inter-molt E75 peak was observed with tebufenozide, and an induction of RXR after exposure to pyriproxyfen and piperonyl butoxide. These results confirm the implication of RXR and E75 in hormonal regulation of female reproductive cycles in G. fossarum and their sensitivity towards EDCs opens the possibility of using them as specific endocrine disruption biomarkers.


Assuntos
Anfípodes/metabolismo , Biomarcadores/metabolismo , Ecdisona/farmacologia , Disruptores Endócrinos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Espécies Sentinelas/metabolismo , Anfípodes/genética , Animais , Perfilação da Expressão Gênica , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores X Retinoide/genética , Receptores X Retinoide/metabolismo , Espécies Sentinelas/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
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