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1.
Sci Total Environ ; 724: 138143, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32408439

RESUMO

Ocean acidification and warming are among the man-induced factors that most likely impact aquatic wildlife worldwide. Besides effects caused by temperature rise and lowered pH conditions, chemicals of current use can also adversely affect aquatic organisms. Both climate change and emerging pollutants, including toxic impacts in marine invertebrates, have been investigated in recent years. However, less information is available on the combined effects of these physical and chemical stressors that, in nature, occur simultaneously. Thus, this study contrasts the effects caused by the antimicrobial agent and plastic additive, Triclosan (TCS) in the related clams Ruditapes philippinarum (invasive) and Ruditapes decussatus (native) and evaluates if the impacts are influenced by combined temperature and pH modifications. Organisms were acclimated for 30 days at two conditions (control: 17 °C; pH 8.1 and climate change scenario: 21 °C, pH 7.7) in the absence of the drug (experimental period I) followed by a 7 days exposure under the same water physical parameters but either in absence (unexposed) or presence of TCS at 1 µg/L (experimental period II). Biochemical responses covering metabolic, oxidative defences and damage-related biomarkers were contrasted in clams at the end of experimental period II. The overall picture showed a well-marked antioxidant activation and higher TCS bioaccumulation of the drug under the forecasted climate scenario despite a reduction on respiration rate and unaltered metabolism in the exposed clams. Since clams are highly consumed shellfish, the consequences for higher tissue bioaccumulation of anthropogenic chemicals to final consumers should be alerted not only at present conditions but more significantly under predicted climatic conditions for humans but also for other components of the marine trophic chain.

2.
Sci Total Environ ; 715: 136804, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32006781

RESUMO

Pharmaceuticals and Personal care products (PPCPs) are frequently released into several marine matrices, representing significant environmental and ecotoxicological risks. Among the widest spread PPCPs in aquatic systems is Salicylic acid (SA), with known negative effects on marine and freshwater species. Nevertheless, the toxicity resulting from these emerging pollutants, including SA, together with climate change has still received little attention up to date. Among climate change related factors salinity is one that most affects aquatic organisms. To better understand the combined impacts of SA and salinity, the present study evaluated the biochemical alterations induced in Mytilus galloprovincialis mussels exposed to SA and different salinity levels, acting individually and in combination. The effects observed clearly highlighted that cellular damages were mainly observed at higher salinity (35), with no additive or synergistic effects derived from the combined presence of SA. Higher antioxidant capacity of mussels in the presence of SA may prevent increased LPO levels in comparison to uncontaminated mussels. Nevertheless, in the presence of SA mussels revealed loss of redox balance, regardless of the salinity level. Furthermore, mussels exposed to SA at control salinity showed increased metabolic capacity which decreased when exposed to salinities 25 and 35. These findings may indicate the protective capacity of mussels towards higher stressful conditions, with lower energy reserves expenditure when in the presence of SA and salinities out of their optimal range. Although limited cellular damages were observed, changes on mussel's redox balance, antioxidant mechanisms and metabolism derived from the combined exposure to SA and salinity changes may compromise mussel's growth and reproduction. Overall, the present study highlights the need to investigate the impacts induced by pollutants under present and future climate change scenarios, towards a more realistic environmental risk assessment.


Assuntos
Mytilus , Animais , Estresse Oxidativo , Ácido Salicílico , Salinidade , Poluentes Químicos da Água
3.
Artigo em Inglês | MEDLINE | ID: mdl-31927089

RESUMO

Pharmaceuticals and personal care products (PPCPs) are continuously dispersed into the environment, as a result of human and veterinary use, reaching aquatic coastal systems and inhabiting organisms. However, information regarding to toxic effects of these compounds towards marine invertebrates is still scarce, especially in what regards to metabolic capacity and oxidative status alterations induced in bivalves after chronic exposure. In the present study, the toxic impacts of Sodium lauryl sulfate (SLS), an anionic surfactant widely used as an emulsifying cleaning agent in household and cosmetics, were evaluated in the mussel Mytilus galloprovincialis, after exposure for 28 days to different concentrations (0.0; 0.5; 1.0; 2.0 and 4.0 mg/L). For this, effects on mussels respitation rate, metabolic capacity and oxidative status were evaluated. The obtained results indicate a significant decrease on mussel's respiration rate after exposure to different SLS concentrations, an alteration that was accompanied by a decrease of bioconcentration factor along the increasing exposure gradient, especially at the highest exposure concentration. Nonetheless, the amount of SLS accumulated in organisms originated alterations in mussel's metabolic performance, with higher metabolic capacity up to 2.0 mg/L followed by a decrease at the highest tested concentration (4.0 mg/L). Mussels exposed to SLS revealed limited antioxidant defense mecanhisms but cellular damage was only observed at the highest exposure concentration (4.0 mg/L). In fact, up to 2.0 mg/L of SLS limited toxic impacts were observed, namely in terms of oxidative stress and redox balance. However, since mussel's respiration rate was greatly affected by the presence of SLS, the present study may highlight the potential threat of SLS towards marine bivalves, limiting their filtration capacity and, thus, affecting their global physiological development (including growth and reproduction) and ultimely their biochemical performance (afecting their defense capacity towards stressful conditons).

4.
Ecotoxicol Environ Saf ; 189: 109899, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31771782

RESUMO

Diclofenac (DIC) is one of the non-steroidal anti-inflammatory drugs (NSAID) with higher consumption rates, used in both human and veterinary medicine. Previous studies already demonstrated the presence of this drug in aquatic environments and adverse effects towards inhabiting organisms. However, with the predictions of ocean acidification and warming, the impacts induced by DIC may differ from what is presently known and can be species-dependent. Thus, the present study aimed to comparatively assess the effects caused by DIC in the clams Ruditapes philippinarum and Ruditapes decussatus and evaluate if these impacts were influenced by pH and temperature. For this, organisms were acclimated for 30 days at two different temperature and pH (control conditions: pH 8.1, 17 °C; climate change forecasted scenario: pH 7.7, 20 °C) in the absence of drugs (experimental period I) followed by 7 days exposure under the same water physical parameters but in absence or presence of the pharmaceutical drug (at 1 µg/L, experimental period II). Biochemical responses covering metabolic capacity, oxidative stress and damage-related biomarkers were contrasted in clams at the end of the second experimental period. The results showed that under actual conditions, R. philippinarum individuals exposed to DIC presented enhanced antioxidant activities and reduced their respiration rate compared with non-contaminated clams. When exposed to the predicted climate change conditions, a similar response was observed in contaminated clams, but in this case clams increased their metabolic activities probably to fight the stress caused by the combination of both stressors. When R. decussatus was exposed to DIC, even at actual pH and temperature conditions, their antioxidant defences were also elevated but their baseline enzymatic activities were also naturally higher in respect to R. philippinarum. Although clams may use different strategies to prevent DIC damage, both clam species showed under low pH and high temperature limited oxidative stress impacts in line with a lower DIC bioaccumulation. The present findings reveal that predicted climate change related factors may not enhance the impacts of DIC in Ruditapes clams in a species-dependent manner although both displayed particular mechanisms to face stress.

5.
Environ Res ; 178: 108683, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31539823

RESUMO

As a consequence of their unique characteristics, the use of Engineered Nanomaterials (ENMs) is rapidly increasing in industrial, agricultural products, as well as in environmental technology. However, this fast expansion and use make likely their release into the environment with particular concerns for the aquatic ecosystems, which tend to be the ultimate sink for this type of contaminants. Considering the settling behaviour of particulates, benthic organisms are more likely to be exposed to these compounds. In this way, the present review aims to summarise the most recent data available from the literature on ENMs behaviour and fate in aquatic ecosystems, focusing on their ecotoxicological impacts towards marine and estuarine bivalves. The selection of ENMs presented here was based on the OECD's Working Party on Manufactured Nanomaterials (WPMN), which involves the safety testing and risk assessment of ENMs. Physical-chemical characteristics and properties, applications, environmental relevant concentrations and behaviour in aquatic environment, as well as their toxic impacts towards marine bivalves are discussed. Moreover, it is also identified the impacts derived from the simultaneous exposure of marine organisms to ENMs and climate changes as an ecologically relevant scenario.

6.
Aquat Toxicol ; 214: 105258, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31374405

RESUMO

A vast variety of substances currently reaches the aquatic environment, including newly developed chemicals and products. Lack of appropriate analytical methods for trace determinations in aquatic ecosystem compartments and lack of information regarding their toxicity explains existing regulation gaps. However, suspicion of their toxicity assigned them as Contaminants of Emerging Concern (CECs). Among CECs are Pharmaceuticals including Salicylic Acid (SA), which is the active metabolite of acetylsalicylic acid (ASA; aspirin). The aim of the present study was to evaluate the potential effects of SA on the mussel Mytilus galloprovincialis. For this, organisms were exposed for 28 days to different concentrations of SA (0.005; 0.05; 0.5 and 5 mg/L), resembling low to highly polluted sites, after which different physiological and biochemical parameters were evaluated to assess organism's respiration rate, neurotoxic, metabolic and oxidative stress status. Our results clearly showed that SA strongly reduced the respiration capacity of mussels. Also, SA inhibited the activity of superoxide dismutase (SOD) and catalase (CAT) enzymes, but increased the activity of glutathione peroxidase (GPx) and glutathione-S-transferases (GSTs), which prevented the occurrence of lipid peroxidation (LPO). Nevertheless, oxidative stress was confirmed by the strong decrease of the ratio between reduce glutathione (GSH) and oxidized (GSSG) glutathione in contaminated mussels. Moreover, neurotoxicity was observed in mussels exposed to SA. Overall, this study demonstrates the metabolic, neurotoxic and oxidative stress impacts of SA in M. galloprovincialis, which may result in negative consequences at the population level.


Assuntos
Mytilus/fisiologia , Ácido Salicílico/efeitos adversos , Acetilcolinesterase/metabolismo , Animais , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Biotransformação , Catalase/metabolismo , Transporte de Elétrons/efeitos dos fármacos , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Mytilus/efeitos dos fármacos , Neurotoxinas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Respiração , Superóxido Dismutase/metabolismo , Poluentes Químicos da Água/toxicidade
7.
J Environ Sci Health B ; 54(11): 883-891, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31311415

RESUMO

The characterization of soluble cholinesterases (ChEs) together with carboxylesterases (CEs) in Ficopomatus enigmaticus as suitable biomarkers of neurotoxicity was the main aim of this study. ChEs of F. enigmaticus were characterized considering enzymatic activity, substrate affinity (acetyl-, butyryl-, propionylthiocholine), kinetic parameters (Km and Vmax) and in vitro response to model inhibitors (eserine hemisulfate, iso-OMPA, BW284C51), and carbamates (carbofuran, methomyl, aldicarb, and carbaryl). CEs were characterized based on enzymatic activity, kinetic parameters and in vitro response to carbamates (carbofuran, methomyl, aldicarb, and carbaryl). Results showed that cholinesterases from F. enigmaticus showed a substrate preference for acetylthiocholine followed by propionylthiocholine; butyrylthioline was not hydrolyzed differently from other Annelida species. CE activity was in the same range of cholinesterase activity with acetylthiocholine as substrate; the enzyme activity showed high affinity for the substrate p-nytrophenyl butyrate. Carbamates inhibited ChE activity with propionylthiocholine as substrate to a higher extent than with acetylthiocoline. Also CE activity was inhibited by all tested carbamates except carbaryl. In vitro data highlighted the presence of active forms of ChEs and CEs in F. enigmaticus that could potentially be inhibited by pesticides at environmentally relevant concentration.


Assuntos
Anelídeos/enzimologia , Inibidores da Colinesterase/toxicidade , Colinesterases/química , Neurotoxinas/toxicidade , Animais , Anelídeos/efeitos dos fármacos , Biomarcadores/química , Carbamatos/química , Carbaril/química , Carbaril/toxicidade , Carbofurano/química , Carbofurano/toxicidade , Hidrolases de Éster Carboxílico/antagonistas & inibidores , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/metabolismo , Inibidores da Colinesterase/química , Colinesterases/metabolismo , Cinética , Metomil/química , Metomil/toxicidade , Neurotoxinas/química
8.
Environ Pollut ; 251: 756-765, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31121540

RESUMO

In the present study Mytilus galloprovincialis mussels were exposed for 28 days to three salinities: 30 (control), 25 and 35. Simultaneously, organisms at each salinity were exposed to either the antimicrobial agent Triclosan (TCS) or the pharmaceutical drug Diclofenac (DIC) at 1 µg/L. Salinity alone and exposure to PPCPs changed mussel's metabolic capacity and oxidative status, but no additive or synergetic effects resulting from the combined exposures were observed. Overall, the metabolic capacity of mussels was decreased when exposed to TCS and DIC under control salinity, which was less pronounced at salinities out of the control level. TCS had a notorious effect over glutathione peroxidase activity while DIC exposure enhanced catalase response. Such defence mechanisms were able to prevent cellular damage but still a clear reduction in GSH/GSSG ratio after PPCPs exposures indicates oxidative stress which could compromise bivalve's performance to further stressing events.


Assuntos
Diclofenaco/toxicidade , Mytilus/metabolismo , Salinidade , Triclosan/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Catalase/metabolismo , Metabolismo Energético/efeitos dos fármacos , Glutationa/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Alimentos Marinhos
9.
Environ Sci Pollut Res Int ; 26(20): 20742-20752, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31104242

RESUMO

Although the increased production of nanoparticles (NPs) has raised extensive concerns about the potential toxic effects on aquatic organisms, as well as the increasing evidences which documented the impact of ocean acidification (OA) on the physiology and fitness of marine invertebrates, limited number of studies reported their combined toxic effects. For these reasons, in the present study, we investigated the physiological and biochemical responses of one of the most economically important bivalve species in the World, the Manila clam Ruditapes philippinarum, after the exposure to an environmnetally relevant concentration of carboxylated carbon nanotubes and predicted OA conditions. The results showed that the organisms were not only susceptible to NPs but also to seawater acidification. Different responses between low pH and NPs for most tested biomarkers were observed, both in terms of physiological (respiration rate) and biochemical responses (metabolic capacity, oxitative status and neurotoxicity). Acidified pH significantly decreased the respiration rate and metabolism and increased the energy reserves consumption. Moreover, increase of the oxidative damage was also detected under this condition confirming that the mechanism of enhanced toxicity in the organisms should be attributed to lower aggregation state with more suspended NPs in acidified seawater, indicating that seawater acidification significantly influenced the impact of the used NPs in the exposed organisms.


Assuntos
Bivalves/fisiologia , Ácidos Carboxílicos/toxicidade , Nanotubos de Carbono/toxicidade , Água do Mar/química , Poluentes Químicos da Água/toxicidade , Animais , Disponibilidade Biológica , Biomarcadores/metabolismo , Bivalves/efeitos dos fármacos , Bivalves/metabolismo , Ácidos Carboxílicos/química , Concentração de Íons de Hidrogênio , Nanotubos de Carbono/química , Estresse Oxidativo , Poluentes Químicos da Água/química
10.
Sci Total Environ ; 666: 1178-1187, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-30970483

RESUMO

Ocean acidification events are recognized as important drivers of change in biological systems. Particularly, the impacts of acidification are more severe in estuarine systems than in surface ocean due to their shallowness, low buffering capacity, low salinity and high organic matter from land drainage. Moreover, because they are transitional areas, estuaries can be seriously impacted by a vast number of anthropogenic activities and in the last decades, carbon nanomaterials (CNMs) are considered as emerging contaminants in these ecosystems. Considering all these evidences, chronic experiment was carried out, trying to understand the possible alteration on the chemical behaviour of two different CNMs (functionalized and pristine) in predicted climate change scenarios and consequently, how these alterations could modify the sensitivity of one the most common marine and estuarine organisms (the polychaeta Hediste diversicolor) assessing a set of biomarkers related to polychaetes oxidative status as well as the metabolic performance and neurotoxicity. Our results demonstrated that all enzymes worked together to counteract seawater acidification and CNMs, however oxidative stress in the exposed polychaetes to both CNMs, especially under ocean acidification conditions, was enhanced. In fact, although the antioxidant enzymes tried to cope as compensatory response of cellular defense systems against oxidative stress, the synergistic interactive effects of pH and functionalized CNMs indicated that acidified pH significantly increased the oxidative damage (in terms of lipid peroxidation) in the cotaminated organisms. Different responses were observed in organisms submitted to pristine CNMs under pH control, where the lipid peroxidation did not increase along with the increasing exposure concentrations. The present results further demonstrated neurotoxicity caused by both CNMs, especially noticeable at acidified conditions. The mechanism of enhanced toxicity could be attributed to slighter aggregation and more suspended NMs in acidified seawater (as demonstrated by the DLS analysis). Therefore, ocean acidification may cause a higher risk of CNMs to marine ecosystems.


Assuntos
Nanotubos de Carbono/toxicidade , Neurotoxinas/toxicidade , Poliquetos/efeitos dos fármacos , Água do Mar/química , Poluentes Químicos da Água/toxicidade , Animais , Biomarcadores/metabolismo , Concentração de Íons de Hidrogênio , Estresse Oxidativo , Poliquetos/fisiologia , Portugal
11.
Artigo em Inglês | MEDLINE | ID: mdl-30807847

RESUMO

Interest on the effects of emerging contaminants over aquatic organisms has increased in the last years. Nonetheless, the toxic action of classical natural and anthropogenically-driven metals has also to be monitored, especially because they reflect real environmental situations. For that, in the present study we focused on the effects on the marine mussel Mytilus galloprovincialis of the personal care product Triclosan (TCS) and Lead (Pb), as toxic metal, under separate and co-exposure situations at environmentally relevant concentrations: TCS (1 µg/L) and Pb (50 µg/L). The consideration of an additional factor such as an increase in ambient temperature was also included to provide a forecasted scenario of climate change: from the ambient temperature at actual conditions (17 °C) to a predicted warming situation (22 °C). Water chemical characterization and some physical properties and bioaccumulation of TCS and Pb in mussels at the end of the experiment (28 days) was considered. The parameters followed up comprise the energy related system production (electron transport system) and glycogen and protein reserves. Antioxidant enzymatic defences towards reactive oxygen species (ROS) and the consequences of ROS damage over endogenous lipids (LPO) and proteins (PC). Overall the results suggested only particular responses to chemical exposures at 17 °C whereas at 22 °C the detoxification machinery was set up and this prevented the occurrence of LPO. Nonetheless, PC formation occurred under Pb and TCS + Pb co-exposure at the highest temperature. Due to the complexity of the study: 4 chemical conditions, 2 temperatures and 10 biomarkers considered, a principal component ordination (PCO) analysis was included. The results of this integrative analysis confirmed a clear effect of the temperature, more responsiveness to drugs at 22 °C and in all likelihood due to Pb presence.


Assuntos
Chumbo , Mytilus/metabolismo , Triclosan , Poluentes Químicos da Água , Poluição da Água , Animais , Antioxidantes/metabolismo , Temperatura Alta , Chumbo/farmacocinética , Chumbo/toxicidade , Oxirredutases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Triclosan/farmacocinética , Triclosan/toxicidade , Poluentes Químicos da Água/farmacocinética , Poluentes Químicos da Água/toxicidade
12.
Sci Total Environ ; 664: 626-634, 2019 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-30763843

RESUMO

Recently, anthropogenic enrichment of rare earth elements (REEs) have been reported in natural environments, due to increasing use and discharges of hospital/industrial wastewaters. Gadolinium (Gd), which is mainly used as contrast agent for magnetic resonance imaging in medical exams, may reach concentrations in water up to two orders of magnitude larger than baseline levels. Nevertheless, in marine systems scarce information is available concerning the toxicity of REE towards inhabiting organisms. This study aimed to evaluate the biochemical impact of anthropogenic Gd in the Mediterranean mussel Mytilus galloprovincialis, which is a species of commercial interest and one of the most accepted pollution bioindicator. Organisms were exposed to different concentrations of Gd (0, 15, 30, 60, 120 µg/L) for 28 days. At the end of the experiments, biomarkers related to mussels' metabolic (electron transport system activity and energy reserves content), oxidative stress status (cellular damage and the activity of antioxidant and biotransformation enzymes) and neurotoxic effects (activity of the enzyme Acetylcholinesterase) were measured, as well as Gd bioconcentration in organisms. Results showed a high content of Gd (2.5 ±â€¯0.50 µg/g) in mussels exposed to the highest concentration, contrary to those at control condition and at 15 and 30 µg/L of Gd (levels below 0.38 µg/g). Although no mortality was observed during the experimental period, exposure to Gd strongly affected the biochemical performance of M. galloprovincialis, including the decrease on mussels' metabolism, induction of oxidative stress and neurotoxicity, particularly evidenced at intermediate concentrations. These results may indicate that up to certain stressful levels, although lowering their metabolism, organisms may be able to activate defence strategies to avoid cellular injuries which, on the other hand, may compromise mussels physiological performance such as growth and reproduction success. Nevertheless, our findings support that the widespread utilization of Gd may represent an environmental risk in the future.


Assuntos
Monitoramento Ambiental/métodos , Gadolínio/análise , Mytilus/fisiologia , Poluentes Químicos da Água/análise , Animais , Antioxidantes , Biomarcadores/metabolismo , Gadolínio/metabolismo , Gadolínio/toxicidade , Estresse Oxidativo , Água do Mar , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/toxicidade
13.
Sci Total Environ ; 663: 992-999, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30771743

RESUMO

Little is known about the consequences of exposure to pharmaceuticals and personal care products (PPCPs) in elevated temperatures associated with climate change. To increase the knowledge on this topic, Mytilus galloprovincialis mussels were exposed to 1.0 µg/L of either the antimicrobial Triclosan (TCS) or the anti-inflammatory drug Diclofenac (DIC), at control (17 °C) and 4 °C raised (21 °C) temperatures for 28 days. Triclosan and DIC concentrations in the water and tissues were subsequently measured and related to biomarker responses including: energy metabolism (electron transport system (ETS) activity, glycogen and protein reserves), oxidative stress markers, glutathione balance between the reduced and the oxidised form (GSH/GSSG), and damage to proteins and lipids. Mussels responded to the increase in temperature and drug exposure by lowering their metabolic rate (decreased ETS), increasing their endogenous reserves and antioxidant defences, thus preventing oxidative stress damage, with the exception of DIC exposure at the higher temperature. In all cases, GSH/GSSG ratio was reduced in detriment of the antioxidant form at both PPCPs exposures and elevated temperature with no additive effect due to combined stressors. Overall, either drug exposure or increased temperature could compromise the ability of mussels to withstand further insults.


Assuntos
Diclofenaco/efeitos adversos , Temperatura Alta/efeitos adversos , Mytilus/efeitos dos fármacos , Triclosan/efeitos adversos , Poluentes Químicos da Água/efeitos adversos , Animais , Anti-Infecciosos Locais/efeitos adversos , Anti-Inflamatórios não Esteroides/efeitos adversos , Mytilus/metabolismo
14.
Mar Environ Res ; 145: 11-21, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30771907

RESUMO

With the increased production and research on nanoparticles, the presence of carbon nanotubes (CNTs) in aquatic systems is very likely to increase. Although it has been shown that CNTs may cause toxicity in marine organisms, to our knowledge, the possible impacts under global temperature increase is still unknown. For this reason, biochemical and physiological impacts induced in Mytilus galloprovincialis due to the presence of functionalized multi-walled CNTs (f-MWCNTs) and increased temperature were investigated in the present study. The mussels exposed to increased temperature alone presented higher metabolic capacity and expenditure of glycogen as an energy resource to fuel up defense mechanisms and thus preventing oxidative damage. Contrarily, organisms exposed to f-MWCNTs alone seemed not stressed enough to demonstrate differences in the metabolism capacity. Furthermore, f-MWCNTs seemed not able to significantly activate their antioxidant and biotransformation enzymes, which in turn may led to oxidative damage in the cells especially when organisms were exposed to a warmer temperature. In fact, at higher temperature, the antioxidant response of organisms exposed to f-MWCNTs was not effective and oxidative damage levels were observed. Nevertheless, no additive or synergetic effects were observed when mussels were exposed to both stressors simultaneously.

15.
Artigo em Inglês | MEDLINE | ID: mdl-30797982

RESUMO

The widespread use of Carbon nanotubes (CNTs) has been increasing exponentially, leading to a significant potential release into the environment. Nevertheless, the toxic effects of CNTs in natural aquatic systems are related to their ability to interact with abiotic compounds. Considering that salinity variations are one of the main challenges in the environment and thus may influence the behavior and toxicity of CNTs, a laboratory experiment was performed exposing the tube-building polychaete Diopatra neapolitana (Delle Chiaje 1841) for 28 days to pristine multi-walled carbon nanotube (MWCNTs) and carboxylated MWCNTs, maintained at control salinity 28 and low salinity 21. An innovative approach based on thermogravimetric analysis (TGA) was adopted for the first time to assess the presence of MWCNTs aggregates in the organisms. Both CNTs generated toxic impacts in terms of regenerative capacity, energy reserves and metabolic capacity as well as oxidative and neuro status, however greater toxic impacts were observed in polychaetes exposed to carboxylated MWCNTs. Moreover, both CNTs maintained under control salinity (28) generated higher toxic impacts in the polychaetes compared to individuals maintained under low salinity (21), indicating that exposed polychaetes tend to be more sensitive to the alteration induced by salinity variations on the chemical behavior of both MWCNTs in comparison to salt stress.


Assuntos
Mudança Climática , Nanotubos de Carbono/toxicidade , Poliquetos/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Estresse Oxidativo , Termogravimetria , Poluentes Químicos da Água/química
16.
Mar Environ Res ; 143: 1-9, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30420134

RESUMO

In recent years, oxidative stress has been recognized as one of the most common effects of nanoparticles in different organisms. Ficopomatus enigmaticus (Fauvel, 1923), a member of a large family of serpulidae polychates, is an important encrusting organism in a diverse set of marine habitats, from harbours to coral reefs. This species has been previously studied for ecotoxicological purposes, despite the lack of reported studies on this species biochemical response after exposure to different pollutants. For these reasons, and for the first time, a set of biomarkers related to oxidative status were assessed in polychaetes after 28 days of exposure. Furthermore, polychaetes metabolic performance and potential neurotoxicity were investigated. Results clearly demonstrated induced toxicity in the filter-feeder polychaetes after exposure to nanoparticles. Indeed, CNTs altered the biochemical and physiological status of F. enigmaticus, both in terms of energy reserves (reduction of protein and glycogen contents), oxidative status (expressed as damage in cell function such as protein carbonyl content and lipid peroxidation) and activation of antioxidant enzymes defences (Glutathione reductase, Catalase, Glutathione peroxidase and Glutathione S-transferases activities). The present study showed for the first time that this species can be used as a model organism for nanoparticle toxicology.

17.
Mar Environ Res ; 141: 186-195, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30201273

RESUMO

Salinity plays a fundamental role in naturally fluctuating environments such as estuaries influencing physiological and biochemical performance of inhabiting biota. Moreover salinity is considered one of the main factors influencing nanoparticles' stability. Thus, the aim of the present paper was to show the impacts induced by different salinities (control-28 and 21) on the chemical behavior of water dispersible multi-walled carbon nanotube (MWCNTs-COOH) and the consequent toxicity in the common ragworm Hediste diversicolor, after long term exposure. Results showed a concentration-dependent toxicity in terms of energy reserves and metabolism, oxidative status and neurotoxicity. In addition, under low salinity (21), the toxicity of the carbon NMs was similar to the impacts measured under control (28), although under salinity 28 the concentrations of MWCNTs-COOH used generated greater alterations in LPO levels and antioxidant enzymes (SOD and GPx). These results demonstrate that higher salinity caused the formation of large-size aggregates, which increased the chance of physical retention, such as gravitational sedimentation, interception and straining of f-MWCNTs generating higher cell injuries than the impacts induced in polychaetes sensitivity to these contaminates due to low salinity.

18.
Aquat Toxicol ; 202: 163-172, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30048902

RESUMO

Intertidal species are frequently exposed to environmental changes associated with multiple stressors, which they must either avoid or tolerate by developing physiological and biochemical strategies. Some of the natural environmental changes are related with the tidal cycle which forces organisms to tolerate the differences between an aquatic and an aerial environment. Furthermore, in these environments, organisms are also subjected to pollutants from anthropogenic sources. The present study evaluated the impacts in Mytilus galloprovincialis exposed to multi-walled carbon nanotubes (0.01 mg/L MWCNTs) when continuously submersed or exposed to tides (5 h of low tide, 7 h of high tide) for 14 days. Our results demonstrated that mussels were physiologically and biochemically affected by MWCNTs, especially when exposed to tides. In fact, when only exposed to the carbon nanoparticles or only exposed to tides, the stress induced was not enough to activate mussels' antioxidant defenses which resulted in oxidative damage. However, when mussels were exposed to the combination of tides and MWCNTs increased metabolism was observed, associated with a possible higher production of reactive oxygen species (ROS), leading to a significant increase in the activities of antioxidant enzymes (superoxide dismutase, SOD and glutathione peroxide, GPx) and oxidized glutathione content (GSSG), preventing the occurrence of cellular damage, expressed as no lipid peroxidation (LPO) or protein carbonylation (PC). Therefore, organisms seemed to be able to tolerate MWCNTs and air exposure during tidal regime; however, the combination of both stressors induced higher oxidative stress. These findings indicate that the increasing presence of carbon nanoparticles in marine ecosystems can induce higher toxic impacts in intertidal organisms compared to organisms continuously submerged. Also, our results may indicate that air exposure can act as a cofounding factor on the assessment of different stressors in organisms living in coastal systems.


Assuntos
Mytilus/efeitos dos fármacos , Nanotubos de Carbono/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Antioxidantes/metabolismo , Ecossistema , Glutationa/metabolismo , Mytilus/crescimento & desenvolvimento , Mytilus/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo
19.
Sci Rep ; 8(1): 8571, 2018 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-29872071

RESUMO

Salinity shifts in estuarine and coastal areas are becoming a topic of concern and are one of the main factors influencing nanoparticles behaviour in the environment. For this reason, the impacts of multi-walled carbon nanotubes (MWCNTs) under different seawater salinity conditions were evaluated on the common ragworm Hediste diversicolor, a polychaete species widely used as bioindicator of estuarine environmental quality. An innovative method to assess the presence of MWCNT aggregates in the sediments was used for the first time. Biomarkers approach was used to evaluate the metabolic capacity, oxidative status and neurotoxicity of polychaetes after long-term exposure. The results revealed an alteration of energy-related responses in contaminated polychaetes under both salinity conditions, resulting in an increase of metabolism and expenditure of their energy reserves (lower glycogen and protein contents). Moreover, a concentration-dependent toxicity (higher lipid peroxidation, lower ratio between reduced and oxidized glutathione and activation of antioxidant defences and biotransformation mechanisms) was observed in H. diversicolor, especially when exposed to low salinity. Additionally, neurotoxicity was observed by inhibition of Cholinesterases activity in organisms exposed to MWCNTs at both salinities.


Assuntos
Monitoramento Ambiental/métodos , Nanotubos de Carbono/química , Poliquetos/fisiologia , Salinidade , Água do Mar/química , Animais , Antioxidantes/metabolismo , Metabolismo Energético/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Poliquetos/efeitos dos fármacos , Poliquetos/metabolismo , Poluentes Químicos da Água/toxicidade
20.
J Hazard Mater ; 358: 484-493, 2018 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-29908840

RESUMO

Although an increasing number of studies have been published on the effects of emergent pollutants such as carbon nanoparticles, there is still scarce information on the impact of these contaminants on marine organisms when acting in combination with classical pollutants such as meta(loid)s. The present study evaluated the impacts of Arsenic and Multi-Walled Carbon Nanotubes (MWCNTs) in the clam Ruditapes philippinarum, assessing the effects induced when both contaminants were acting individually (As, NP) and as a mixture (As + NP). Metabolic capacity (electron transport system activity), oxidative stress (antioxidant and biotransformation enzymes activity and cellular damage) and neurotoxicity (Acetylcholinesterase activity) biomarkers were evaluated in clams after a 28 days exposure period. The results obtained showed that the accumulation of As was not affected by the presence of the NPs. Our results demonstrated that higher injuries were noticed in clams exposed to NPs, with higher metabolic depression and oxidative stress, regardless of the presence of As. Furthermore, higher neurotoxicity was observed in clams exposed to the combination of both contaminants in comparison to the effects of As and NPs individually.


Assuntos
Arseniatos/toxicidade , Bivalves/efeitos dos fármacos , Nanotubos de Carbono/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Acetilcolinesterase/metabolismo , Animais , Antioxidantes/metabolismo , Arseniatos/metabolismo , Biotransformação , Bivalves/metabolismo , Sinergismo Farmacológico , Poluentes Químicos da Água/metabolismo
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