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1.
Aquat Toxicol ; 233: 105783, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33662881

RESUMO

Pesticides occur in the environment as mixtures, yet the joint toxicity of pesticide mixtures remains largely under-explored and is usually overlooked in ecological risk assessment. In the current study, joint toxicity of a neonicotinoid insecticide (imidacloprid, IMI) and a strobilurin fungicide (azoxystrobin, AZO) was investigated with Chironomus dilutus over a wide range of concentrations and at different effect levels (organism, cell, and gene levels). The two pesticides, both individually and in combination, were found to induce oxidative stress and cause lethality in C. dilutus. Median lethal concentrations for IMI and AZO were 3.98 ± 1.17 and 52.9 ± 1.1 µg/L, respectively. Mixtures of the two pesticides presented synergetic effects at environmentally relevant concentrations whilst antagonistic effects at high concentrations, showing concentration-dependent joint toxicity. Investigation on the expressions of 12 genes (cyt b, coi, cox1, cyp4, cyp12m1, cyp9au1, cyp6fv1, cyp315, gst, Zn/Cu-sod, Mn-sod, and cat) revealed that the two pesticides impaired mitochondrial respiration, detoxification, and antioxidant system of C. dilutus, and the joint effects of the two pesticides were likely due to an interplay between their respective influences on these physiological processes. Collectively, the synergistic effects of the two pesticides at environmentally relevant concentrations highlight the importance to incorporate combined toxicity studies into ecological risk assessment of pesticides.


Assuntos
Chironomidae/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Praguicidas/toxicidade , Pirimidinas/toxicidade , Estrobilurinas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Chironomidae/citologia , Chironomidae/genética , Sinergismo Farmacológico , Peróxido de Hidrogênio/metabolismo , Dose Letal Mediana , Malondialdeído/metabolismo , Modelos Teóricos
2.
Ecotoxicol Environ Saf ; 212: 112015, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33561775

RESUMO

Osmia excavata is an important pollinator in commercial fruit orchards. Little information has been published about ecotoxicity to O. excavata, especially the larvae. To clarify the risk of commonly used insecticides with different modes of action to the larvae of O. excavata, six insecticides (clothianidin, acetamiprid, sulfoxaflor, lambda-cyhalothrin, chlorfenapyr and abamectin) were selected for evaluation of their acute lethal toxicity and sublethal effects. Clothianidin and abamectin were the two most toxic insecticides to the larvae of O. excavata with LD50 values of 0.007 (0.006-0.008) and 0.0004 (0.0003-0.0006) µg active ingredient (a.i.) bee-1, respectively. And their ecological risks were high according to the hazard quotient values (HQ > 2500). Sulfoxaflor was identified as the only safe insecticide for O. excavata (HQ < 50) under field conditions. Sublethal toxicity tests showed that larval weight was significantly decreased by ingesting food treated with clothianidin, lambda-cyhalothrin and abamectin (less than the maximum field registered concentrations on fruit trees) due to interference with consumption per larva and reduction of the efficiency of conversion of ingested food. Additionally, above three insecticides significantly prolonged larval developmental duration before cocooning and decreased eclosion rate. Overall, there results suggested that clothianidin and abamectin should not be applied, especially during the flowering phase, the application frequency of lambda-cyhalothrin should be minimized for the purpose of conserving O. excavata. Our results provided important evidences for selecting appropriate insecticides for use in fruit orchards.


Assuntos
Abelhas/efeitos dos fármacos , Inseticidas/toxicidade , Larva/efeitos dos fármacos , Animais , Abelhas/crescimento & desenvolvimento , Produtos Agrícolas/crescimento & desenvolvimento , Relação Dose-Resposta a Droga , Ecotoxicologia , Guanidinas/toxicidade , Dose Letal Mediana , Neonicotinoides/toxicidade , Nitrilos/toxicidade , Polinização , Piretrinas/toxicidade , Piridinas/toxicidade , Medição de Risco , Compostos de Enxofre/toxicidade , Tiazóis/toxicidade
3.
Arch Environ Contam Toxicol ; 80(2): 461-473, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33528594

RESUMO

When oil is spilled into the environment its toxicity is affected by abiotic conditions. The cumulative and interactive stressors of chemical contaminants and environmental factors are especially relevant in estuaries where tidal fluctuations cause wide variability in salinity, temperature, and ultraviolet (UV) light penetration, which is an important modifying factor for polycyclic aromatic hydrocarbon (PAH) toxicity. Characterizing the interactions of multiple stressors on oil toxicity will improve prediction of environmental impacts under various spill scenarios. This study examined changes in crude oil toxicity with temperature, salinity, and UV light. Oil exposures included high-energy, water-accommodated fractions (HEWAFs) and thin oil sheens. Larval (24-48 h post hatch) estuarine species representing different trophic levels and habitats were evaluated. Mean 96 h LC50 values for oil prepared as a HEWAF and tested under standard conditions (20 ppt, 25 °C, No-UV) were 62.5 µg/L tPAH50 (mud snails), 198.5 µg/L (grass shrimp), and 774.5 µg/L (sheepshead minnows). Thin oil sheen 96 h LC50 values were 5.3 µg/L tPAH50 (mud snails), 14.7 µg/L (grass shrimp), and 22.0 µg/L (sheepshead minnows) under standard conditions. UV light significantly increased the toxicity of oil in all species tested. Oil toxicity also was greater under elevated temperature and lower salinity. Multi-stressor (oil combined with either increased temperature, decreased salinity, or both) LC50 values were reduced to 3 µg/L tPAH50 for HEWAFs and < 1.0 µg/L tPAH50 for thin oil sheens. Environmental conditions at the time of an oil spill will significantly influence oil toxicity and organismal response and should be taken into consideration in toxicity testing and oil spill damage assessments.


Assuntos
Larva/efeitos dos fármacos , Poluição por Petróleo , Petróleo/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Crustáceos , Peixes Listrados/fisiologia , Dose Letal Mediana , Louisiana , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Salinidade , Caramujos/efeitos dos fármacos , Temperatura , Testes de Toxicidade , Raios Ultravioleta
4.
Exp Parasitol ; 223: 108076, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33460625

RESUMO

The present study was conducted to assess the mosquitocidal efficiency of compound isolated from Blumea mollis (D. Don) Merr against Culex quinquefasciatus. Eggs and larvae of Cx. uinquefasciatus were exposed to different concentrations 0.5, 1.0, 1.5 and 2.0 ppm of compounds prepared using DMSO. Compound 1 was identified as (4R, 5S)-4-hydroxy-7-tigloyloxy carvotanacetone, from which new derivative was synthesized and confirmed as (4R, 5S)-4-acetoxy-7-tigloyloxy carvotanacetone. Both the compounds presented larvicidal and ovicidal activities. Compounds 1 and 2 at 2-ppm concentration showed 64% and 78% larval mortality in 24 h, respectively. The LC50and LC90values of compounds 1 and 2 on Cx. quinquefasciatus larvae were 1.73, 1.27 and 4.59, 3.33 ppm, respectively. The eluted compound 1 and synthesized compound 2 presented 68% and 77% of ovicidal activity, respectively, against eggs of Cx. quinquefasciatus at 120 h post-treatment. Histopathological studies of the compound-treated larvae revealed serious damage on the larval midgut cells. Furthermore, compounds 1 and 2 was tested for toxicity study and the results showed both the compounds were found to be harmless to non-target organism Poecilia reticulata. Computational analysis of compound 2 showed strong binding interaction with the AChE1 of Cx. quinquefasciatus. These results clearly suggest that compounds from Blumea mollis could act as good mosquitocidal agents against Cx.quinquefasciatus and compound 2 was first time reported.


Assuntos
Asteraceae/química , Culex , Inseticidas , Monoterpenos/isolamento & purificação , Mosquitos Vetores , Extratos Vegetais/isolamento & purificação , Acetilcolinesterase/química , Animais , Bioensaio , Simulação por Computador , Ésteres , Inseticidas/química , Inseticidas/isolamento & purificação , Larva , Dose Letal Mediana , Ligantes , Simulação de Acoplamento Molecular , Óvulo , Extratos Vegetais/farmacologia , Poecilia
5.
Sci Total Environ ; 764: 144288, 2021 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-33385645

RESUMO

In aquatic toxicology, methods that are chosen for exposures have profound consequences on experimental outcomes and thus can skew policy initiatives. For example, as compared to single-organism exposures, toxicity test results of group exposures may be impacted by confounding factors such as social interactions between animals or individual variation in accumulation rates. To test for differences in organismal response between group and individual toxicological exposures, we exposed Daphnia magna to copper and subsequently compared the toxicity (median lethal concentration or LC50) between groups and individuals. Results suggested that water chemistry had a larger effect on experimental outcomes than the number of animals exposed in the same tank. Methodological decisions with respect to replication type can affect toxicity tests, and LC50s calculated using different exposure types (such as group and individual exposures) may not be comparable.


Assuntos
Poluentes Químicos da Água , Animais , Cobre , Daphnia , Humanos , Dose Letal Mediana , Testes de Toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
6.
Ecotoxicol Environ Saf ; 208: 111763, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396083

RESUMO

Sulfate occurs naturally in the aquatic environment but its elevated levels can be toxic to aquatic life in freshwater environments. We investigated the toxicity of sulfate in humic, soft freshwater to whitefish (Coregonus lavaretus) from fertilization of eggs to hatching i.e. during the critical phases of whitefish early development. Anadromous Kokemäenjoki whitefish eggs and sperm during fertilization, embryos and larvae were exposed in the long-term 175-day incubation to seven different sodium sulfate (Na2SO4) concentrations from 44 to 2 000 mg SO4 L-1. Endpoint variables were the fertilization success, offspring survival and larval growth. Egg fertilization and early embryonic development were the most sensitive developmental stages of whitefish to sulfate, although the fertilization success and survival of embryos decreased only in the highest concentration of 2 000 mg SO4 L-1. The survival during late embryonic period, hatching and the 5-day larval period was high and no difference between the control and sulfate treatments were observed. LC50-values of sulfate for early embryonic period and for the entire embryonic and larval period was 1 413 and 1 161 mg L-1, respectively. The NOEC (No-observed Effect Concentration) of sulfate for the both periods was 1 207 mg L-1. The tolerance of whitefish early stages to sulfate toxicity seems to be on the same level as the tolerance of other salmonids' early stages.


Assuntos
Embrião não Mamífero/fisiologia , Desenvolvimento Embrionário/efeitos dos fármacos , Salmonidae/embriologia , Sulfatos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Água Doce/química , Larva , Dose Letal Mediana , Masculino , Salmonidae/crescimento & desenvolvimento , Espermatozoides
7.
Ecotoxicol Environ Saf ; 208: 111588, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396111

RESUMO

Rare earth elements (REEs) have been recently identified as emergent contaminants because of their numerous and increasing applications in technology. The impact of REEs on downstream ecosystems, notably aquatic organisms, is of particular concern, but has to date been largely overlooked. The purpose of this study was thus to evaluate the toxicity of lanthanide metals, lutetium (Lu) and dysprosium (Dy) in rainbow trout after 96 h of exposure. The lethal concentration (LC50) was determined and the expression of 14 genes involved in different pathways such as oxidative stress, xenobiotic detoxification, mitochondrial respiration, DNA repair, protein folding and turnover, inflammation, calcium binding and ammonia metabolism were quantified in surviving fish. In parallel, lipid peroxidation (LPO), DNA damage (DSB), metallothionein level (MT) and cyclooxygenase activity (COX) were examined. The acute 96 h-LC50 data revealed that Lu was more toxic than Dy (1.9 and 11.0 mg/L, respectively) and was able to affect all investigated pathways by changing the expression of the studied genes, to the exception of superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST). It also induced a decrease in DNA repair at concentrations 29 times below the LC50. This suggests that Lu could trigger a general stress to disrupt the cell homeostasis leading to genotoxicity without promoting oxidative stress. However, Dy induced modulation in the expression of genes involved in the protection against oxidative stress, detoxification, mitochondrial respiration, immunomodulation, protein turnover and an increase in the DNA strand breaks at concentrations 170 times lower than LC50. Changes in mRNA level transcripts could represent an early signal to prevent against toxicity of Dy, which exhibited inflammatory and genotoxic effects. This study thus provides useful knowledge enhancing our understanding of survival strategies developed by rainbow trout to cope with the presence of lanthanides in the environment.


Assuntos
Disprósio/toxicidade , Lutécio/toxicidade , Oncorhynchus mykiss/fisiologia , Poluentes Químicos da Água/toxicidade , Animais , Catalase/metabolismo , Dano ao DNA , Reparo do DNA , Disprósio/metabolismo , Ecossistema , Glutationa Transferase/metabolismo , Dose Letal Mediana , Peroxidação de Lipídeos/efeitos dos fármacos , Lutécio/metabolismo , Metalotioneína/metabolismo , Metais Terras Raras , Oncorhynchus mykiss/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Superóxido Dismutase/metabolismo
8.
Ecotoxicol Environ Saf ; 211: 111895, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33476851

RESUMO

To investigate the defensive strategies of clam Cyclina sinensis in response to environmental ammonia exposure, we investigate the 96 h median lethal concentration (LC50-96 h) and the 96 h safe concentration (SC) of total ammonia nitrogen (TAN) for C. sinensis, and on the basis we examined glutamine synthetase (GS) activity, glutamine content, urea content and the antioxidant enzyme activities of super oxide dismutase (SOD) and catalase (CAT) in 96 h at three different levels of TAN as 0 (control), 73.94 (T1) and 227.04 mg/L (T2). Results showed that LC50-96 h and SC for C. sinensis were 65.79 and 6.58 mg/L, respectively. The LC50-96 h and SC of NH3 were 1.70 and 0.17 mg/L, respectively. Ammonia exposure had significantly effects on SOD and CAT activities in the hepatopancreas tissue. Both the level of SOD activity and CAT activity increased with increasing concentration of TAN. No significant differences between T1 and T2 were found in GS activity from 3 h to 96 h after exposed to ammonia, whereas they were significantly higher than those in the control. Both the level of glutamine content in T1 and T2 increased significantly from 6 h to 24 h after exposed to ammonia and they were significantly higher than those in the control. There were no significantly differences were found in the level of urea concentration between T1 and T2 from 6 h to 96 h, while they were significantly higher those in the control. In conclusion, enhancing hepatopancreas antioxidant responses as well as converting ammonia into glutamine and urea worked in combination to allow C. sinensi to defend against acute ammonia exposure.


Assuntos
Amônia/toxicidade , Bivalves/fisiologia , Amônia/metabolismo , Animais , Antioxidantes , Bivalves/metabolismo , Catalase , Exposição Ambiental , Glutamato-Amônia Ligase/metabolismo , Glutamina , Hepatopâncreas/metabolismo , Dose Letal Mediana , Nitrogênio/metabolismo , Alimentos Marinhos , Superóxido Dismutase/metabolismo , Ureia/metabolismo
9.
Ecotoxicol Environ Saf ; 208: 111681, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396013

RESUMO

Analysis of particulate matter originating from beef cattle feed yards on the High Plains of the United States has revealed occurrence of multiple pesticides believed to potentially impact non-Apis pollinators. Among these pesticides are those that are highly toxic to Apis mellifera (honey bees). However, little non-Apis bee species toxicity data exist; especially pertaining to beef cattle feed yard-derived pesticides. Therefore, we conducted a series of 96-h contact toxicity tests with blue orchard mason bees (Osmia lignaria) using three neonicotinoids, two pyrethroids, and two macrocyclic lactones. Neonicotinoids (thiamethoxam, imidacloprid, and clothianidin) were most toxic with LD50 values ranging from 2.88 to 26.35 ng/bee, respectively. Macrocyclic lactones (abamectin and ivermectin) were also highly toxic to O. lignaria with LD50 estimates of 5.51-32.86 ng/bee. Pyrethroids (permethrin and bifenthrin) were relatively less toxic with LD50 values greater than 33 ng/bee. Sensitivity ratios for each pesticide were calculated to relate O. lignaria LD50 values to existing honey bee toxicity data. All three neonicotinoids were more toxic to O. lignaria than A. mellifera, but pyrethroids and abamectin were relatively less toxic. Additionally, three of seven pesticides (43%) resulted in significantly different mass normalized LD50 values for male and female O. lignaria. These results indicate that non-Apis pollinators may be highly susceptible to pesticides originating from beef cattle feed yards, necessitating consideration of more stringent regulatory protections than those based on A. mellifera pesticide sensitivity.


Assuntos
Abelhas/efeitos dos fármacos , Lactonas/toxicidade , Compostos Macrocíclicos/toxicidade , Neonicotinoides/toxicidade , Praguicidas/toxicidade , Piretrinas/toxicidade , Animais , Relação Dose-Resposta a Droga , Feminino , Dose Letal Mediana , Masculino , Modelos Teóricos , Polinização/efeitos dos fármacos , Testes de Toxicidade Aguda
10.
Arch Environ Contam Toxicol ; 80(2): 426-436, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33386940

RESUMO

The Army is replacing traditional munitions with insensitive munitions (IM) resistant to accidental detonation. The aquatic toxicity of 1-methyl-3-nitroguanidine (MeNQ), which is being assessed for potential use in IM formulations, remains largely untested. The present study fills a number of critical data gaps for MeNQ aquatic toxicity by evaluating effects across two vertebrate and five invertebrate species. Specifically, responses in larval Pimephales promelas, Rana pipiens tadpoles, Chironomus dilutus, Lumbriculus variegatus, Hydra littoralis, Hyalella azteca, and Daphnia pulex were assessed in MeNQ exposures across various acute, subchronic, and chronic bioassays. Overall, survival was unaffected in most of the MeNQ exposures where significant lethal effects were only observed in D. pulex, H. littoralis, and C. dilutus and only at concentrations ≥ 2186 mg/L. Significant sublethal effects on growth were observed for C. dilutus at 903 mg/L and H. azteca at 1098 mg/L in 10-d assays. Significantly decreased reproduction was observed at 2775 mg/L for H. azteca in a chronic 35-d assay and at 174 mg/L for D. pulex in the 11-d three-brood assay representing a sublethal effect one order of magnitude more sensitive than the effective lethal concentration for D. pulex (2987 mg/L). Degradation of MeNQ in ultraviolet light (UV) greatly increased toxicity to D. pulex. Specifically, exposure to a MeNQ solution that was completely UV-degraded prior to D. pulex exposures resulted in an 11-d LC50 of 6.1 mg/L and a 50% reduction in reproduction at 3.125 mg/L, based on the original MeNQ parent-compound concentrations.


Assuntos
Guanidinas/toxicidade , Poluentes Químicos da Água/toxicidade , Anfípodes , Animais , Chironomidae , Cyprinidae/crescimento & desenvolvimento , Daphnia/fisiologia , Larva , Dose Letal Mediana , Rana pipiens , Testes de Toxicidade , Raios Ultravioleta , Poluentes Químicos da Água/análise
11.
Ecotoxicol Environ Saf ; 208: 111612, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396132

RESUMO

Water quality standards are essential for regulation of contaminants in marine environment. Seawater quality criteria (SWQC) for arsenic (As), cadmium (Cd) and lead (Pb) have not been developed for India. The aim of this study is to derive the SWQC for the metals based on Species Sensitivity Distribution (SSD). Eight species of sensitive marine organisms belonging to five phyla were assessed for their sensitivity to toxicity of As, Cd and Pb. Median effective concentrations (EC50) and Median Lethal Concentrations (LC50) were derived from the acute toxicity bio-assays. No Observed Effect Concentrations (NOEC), Lowest Observed Effect Concentrations (LOEC) and chronic values were derived from chronic toxicity bio-assays. Diatoms were more sensitive to As with 96 h EC50 of 0.1 mg/l and copepods were more sensitive to Cd and Pb with 96 h EC50 of 0.019 mg/l and 0.05 mg/l respectively. Estimated NOECs ranged from 4.87 to 21.55 µg/l of As, 1.0 to 120 µg/l of Cd and 5.67 to 91.67 µg/l of Pb. Similarly, chronic values (µg/l) were in the range of 6.71-26.1, 1.38-170, and 7.67-91.67 of As, Cd and Pb respectively. The Criterion Maximum Concentration (CMC), Criterion Continuous Concentration (CCC) and Predicted No Effect Concentration (PNEC) values were prescribed as SWQC. The CMC (µg/l) of 19, 1.7 and 17 for As, Cd, and Pb were derived respectively for acute exposure during accidental marine outfalls. The CCC (µg/l) for As was 4.6, 1.1 for Cd and 5.9 for Pb are recommended as SWQC for protection of 95% of marine organisms. PNEC (µg/l) of 3.8 for As, 0.92 for Cd and 4.3 for Pb are suggested for highly disturbed ecosystems, shell fishing and mariculture uses of water bodies. These values are recommended as a baseline for site specific water quality criteria for the coastal waters of the country.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Arsênico/toxicidade , Cádmio/toxicidade , Chumbo/toxicidade , Água do Mar/química , Poluentes Químicos da Água/toxicidade , Qualidade da Água/normas , Animais , Arsênico/análise , Cádmio/análise , Copépodes/efeitos dos fármacos , Diatomáceas/efeitos dos fármacos , Ecossistema , Índia , Chumbo/análise , Dose Letal Mediana , Especificidade da Espécie , Poluentes Químicos da Água/análise
12.
Ecotoxicol Environ Saf ; 207: 111305, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32942101

RESUMO

Poultry litter is one of the main sources of fluoroquinolones (FQs) in agricultural soils. In this study, our main goal was to investigate FQ-contaminated poultry litter effects on Eisenia andrei earthworms. To achieve this, acute and chronic tests covered several endpoints, such as avoidance, biomass, lethality, reproduction and changes to immune cells. FQs (enrofloxacin and ciprofloxacin) were determined in a poultry litter sample through high performance liquid chromatography with a fluorescence detector. The avoidance test indicates that poultry litter strongly repels earthworms, even at the lowest concentration (50 g kg-1). In the acute test, the lethal concentration of poultry litter to 50% of the earthworms (LC50), was estimated at 28.5 g kg-1 and a significant biomass loss (p < 0.05) occurred at 40 g kg-1. In the chronic test, a significant reproduction effect was observed at 20 g kg-1. Cell typing, density and feasibility indicated significant effects ranging from 5 to 20 g kg-1. A high risk quotient was estimated based on recommended poultry litter applications in field studies. Although FQ contamination in poultry litter and soils has been widely reported in previous studies, this is, to the best of our knowledge, the first toxicological assessment concerning earthworms exposed to FQ-contaminated poultry litter.


Assuntos
Fluoroquinolonas/toxicidade , Oligoquetos/efeitos dos fármacos , Aves Domésticas , Poluentes do Solo/toxicidade , Solo/química , Resíduos Sólidos/análise , Agricultura , Animais , Biomassa , Fluoroquinolonas/análise , Dose Letal Mediana , Oligoquetos/crescimento & desenvolvimento , Reprodução/efeitos da radiação , Poluentes do Solo/análise , Testes de Toxicidade Aguda , Testes de Toxicidade Crônica
13.
Aquat Toxicol ; 230: 105693, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33310671

RESUMO

Sea dumping of chemical warfare (CW) took place worldwide during the 20th century. Submerged CW included metal bombs and casings that have been exposed for 50-100 years of corrosion and are now known to be leaking. Therefore, the arsenic-based chemical warfare agents (CWAs), pose a potential threat to the marine ecosystems. The aim of this research was to support a need for real-data measurements for accurate risk assessments and categorization of threats originating from submerged CWAs. This has been achieved by providing a broad insight into arsenic-based CWAs acute toxicity in aquatic ecosystems. Standard tests were performed to provide a solid foundation for acute aquatic toxicity threshold estimations of CWA: Lewisite, Adamsite, Clark I, phenyldichloroarsine (PDCA), CWA-related compounds: TPA, arsenic trichloride and four arsenic-based CWA degradation products. Despite their low solubility, during the 48 h exposure, all CWA caused highly negative effects on Daphnia magna. PDCA was very toxic with 48 h D. magna LC50 at 0.36 µg × L-1 and Lewisite with EC50 at 3.2 µg × L-1. Concentrations at which no immobilization effects were observed were slightly above the analytical Limits of Detection (LOD) and Quantification (LOQ). More water-soluble CWA degradation products showed no effects at concentrations up to 100 mg × L-1.


Assuntos
Arsênico/toxicidade , Substâncias para a Guerra Química/toxicidade , Daphnia/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Arsênico/análise , Arsenicais/análise , Substâncias para a Guerra Química/análise , Cloretos/análise , Ecossistema , Dose Letal Mediana , Limite de Detecção , Água do Mar/química , Testes de Toxicidade Aguda , Poluentes Químicos da Água/análise
14.
Chemosphere ; 266: 129235, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33316472

RESUMO

The use of nanoparticles in consumer products is currently on the rise, so it is important to have reliable methods to predict any associated toxicity effects. Traditional in vitro assays fail to mimic true physiological responses of living organisms against nanoparticles whereas murine in vivo models are costly and ethically controversial. For these reasons, this study aimed to evaluate the efficacy of Galleria mellonella as an alternative, non-rodent in vivo model for examining nanoparticle toxicity. Silver, selenium, and functionalized gold nanoparticles were synthesized, and their toxicity was assessed in G. mellonella larvae. The degree of acute toxicity effects caused by each type of NP was efficiently detected by an array of indicators within the larvae: LD50 calculation, hemocyte proliferation, NP distribution, behavioral changes, and histological alterations. G. mellonella larvae are proposed as a nanotoxicological model that can be used as a bridge between in vitro and in vivo murine assays in order to obtain better predictions of NP toxicity.


Assuntos
Nanopartículas Metálicas , Mariposas , Animais , Ouro , Larva , Dose Letal Mediana , Nanopartículas Metálicas/toxicidade , Camundongos
15.
Sci Total Environ ; 758: 144025, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33333299

RESUMO

This study evaluated low salinity effect on acute Hg toxicity and bioconcentration capacity in L. vannamei juveniles (8.4 ± 0.7 g), because this species is frequently exposed to hypo-osmotic environments in its natural habitat, and in farming ponds. Hg LC50 values were 1723, 1272, 983 and 536 µg L-1 at salinity of 5 ppt (parts per thousand); 2203, 1740, 1340 and 873 µg L-1 at 10 ppt; and 7013, 5693, 1759 and 1534 µg L-1 at 25 ppt for 24, 48, 72 and 96 h, respectively. After 96 h, acute Hg toxicity in shrimp was significantly higher in salinity of 5 ppt than in 25 ppt; likewise, Hg bioconcentration in shrimp exposed to different Hg treatments was statistically greater in salinity of 5 ppt than in 25 ppt. The chemical speciation calculated in experimental waters suggested that neutral chemical Hg species (HgCl2 and HgClOH) were the most bioavailable because their fractions (51-62%) increased when salinity decreased. Therefore, the inverse relationship between Hg toxicity and salinity was due to osmotic stress and the neutral chemical Hg species fractions that increased at lower salinities. Hg bioconcentration factors indicated that the higher Hg waterborne concentrations were the most saturated uptake and storage mechanisms in shrimp. Thus, Hg concentrations in organisms did not increase in proportion to waterborne Hg concentrations in the three salinities. These results support the hypothesis of an effect of low salinity on Hg toxicity and bioconcentration capacity in L. vannamei. The safe Hg concentrations 5.4, 8.7 and 15.3 µg L-1 were proposed for shrimp exposed to salinity of 5, 10 and 25 ppt, respectively. This information allows recognizing risky environments for both wild and cultured healthy growth of these shrimp, which can help decision makers on coastal management and shrimp pond managers to have better water quality.


Assuntos
Mercúrio , Penaeidae , Animais , Bioacumulação , Dose Letal Mediana , Mercúrio/toxicidade , Salinidade
16.
Aquat Toxicol ; 231: 105715, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33341507

RESUMO

This study was conceptualized in order to assess the 96-h LC50 of bifenthrin (BF) in O. niloticus and also to measure the biochemical, behavioral, and molecular responses of the fish suchronically exposed to a sub-lethal concentration of the insecticide. The role of Petroselinum crispum essential oil (PEO) supplementation in mitigating the resulted neurotoxic insult was also investigated. The acute toxicity study revealed that the 96-h LC50 of BF is 6.81 µg/L, and varying degrees of behavioral changes were recorded in a dose-dependent manner. The subchronic study revealed reduction of dissolved oxygen and increased ammonia in aquaria of BF-exposed fish. Clinical signs revealed high degree of discomfort and aggressiveness together with reductions in survival rate and body weight gain. The levels of monoamines in brain, and GABA and amino acids in serum were reduced, together with decreased activities of Na+/K+-ATPase and acetylcholine esterases (AchE). The activities of antioxidant enzymes were also diminshed in the brain while oxdative damage and DNA breaks were elevated. Myeloperoxidase (MPO) activity in serum increased with overexpression of the pro-inflammatory cytokines in the brain tissue. BF also upregulated the expression of brain-stress related genes HSP70, Caspase-3 and P53. Supplemention of PEO to BF markedly abrogated the toxic impacts of the insecticide, specially at the high level. These findings demonstrate neuroprotective, antioxidant, genoprotective, anti-inflammatory and antiapoptic effects of PEO in BF-intoxicated fish. Based on these mechanistic insights of PEO, we recommend its use as an invaluable supplement in the fish feed.


Assuntos
Encéfalo/patologia , Ciclídeos/fisiologia , Suplementos Nutricionais , Inflamação/patologia , Óleos Voláteis/farmacologia , Petroselinum/química , Piretrinas/toxicidade , Acetilcolinesterase/metabolismo , Aminoácidos/metabolismo , Animais , Antioxidantes/metabolismo , Comportamento Animal , Biomarcadores/metabolismo , Encéfalo/efeitos dos fármacos , Ciclídeos/crescimento & desenvolvimento , Citocinas/metabolismo , Dano ao DNA , Regulação da Expressão Gênica/efeitos dos fármacos , Inseticidas/metabolismo , Dose Letal Mediana , Neurotoxinas/toxicidade , Neurotransmissores/metabolismo , Estresse Oxidativo/efeitos dos fármacos , ATPase Trocadora de Sódio-Potássio/metabolismo , Análise de Sobrevida , Poluentes Químicos da Água/toxicidade , Qualidade da Água , Ácido gama-Aminobutírico/metabolismo
17.
Ecotoxicol Environ Saf ; 209: 111764, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33310535

RESUMO

The negative effect of insecticides on bees has been reported as one of the factors associated with the decline in population of these pollinators. Thus, the aim of this study was to evaluate the response of the stingless bee Nannotrigona aff. testaceicornis (Lepeletier, 1836) to a promising source of new insecticide molecules obtained from Lippia sidoides (rosemary pepper) essential oil (EO) and its major compounds (thymol, ρ-cymene, and (E)-caryophyllene), comparing them to commercial insecticides (organosynthetic: imidacloprid, deltamethrin and semisynthetic: spinetoram). For this, stingless bees were exposed by contact with these compounds to evaluate the lethal and sublethal (locomotion and flight orientation) toxicity. The L. sidoides EO and its major compounds have low lethal toxicity to forager worker bees (N. aff. testaceicornis). The organosynthetics imidacloprid (LD50 =0.00146 µgbee-1) and deltamethrin (LD50 =0.0096 µg bee-1) were about 209,589 and 31,875 times more toxic, respectively, than the least toxic natural compound, (E)-caryophyllene (LD50 =306 µgbee-1). Locomotion ability and flight orientation were little affected by spinetoram and by L. sidoides EO and its major compounds, however, were greatly reduced by the imidacloprid and deltamethrin insecticides. Besides shows low lethal and sublethal toxicity, the bioinsecticides were also avoided by the forager bees. Individuals treated with the L. sidoides EO and thymol were avoided by the untreated bees. Therefore, the natural products studied here were promising due to their recognized effectiveness against pest insects and greater safety to bees N. aff. testaceicornis.


Assuntos
Abelhas/fisiologia , Inseticidas , Óleos Voláteis , Animais , Laboratórios , Dose Letal Mediana , Locomoção , Macrolídeos , Neonicotinoides , Nitrilos , Nitrocompostos , Polinização , Piretrinas
18.
J Ethnopharmacol ; 265: 113142, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32697959

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: The leaf of Sarcocephalus latifolius is known to be used traditionally by the Fulanis in Nigeria to deworm animals. As helminthosis remains a major constraint to profitable livestock production worldwide, a precarious situation aggravated by the advent of resistant parasites, the discovery of new anthelmintics is a priority, necessitating exploration of medicinal plants for their anthelmintic principles. AIM OF THE STUDY: To identify and characterise compounds with anthelmintic activity from the leaf of Sarcocephalus latifolius. MATERIALS AND METHODS: Powdered S. latifolius leaves were extracted by successive maceration with n-hexane, chloroform and acetone. The dried extracts were evaluated for anthelmintic activity against Haemonchus placei adult worms, and the most active extract was subjected to bioassay-guided chromatographic separations. The isolated compounds were evaluated for cytotoxicity against the mammalian HeLa and MC3T3-E1 cell lines, using alamar blue and CellTitreGloTM to quantify cell viability. LC50 values were computed from the in vitro anthelmintic activity data by fitting to a non-linear regression equation (variable slope). Isolated compounds were characterized using spectroscopic and mass spectrometric analyses. RESULTS: Anthelmintic activity LC50 values for n-hexane, chloroform and acetone extracts were 47.85, 35.76 and 5.72 (mg/mL), respectively. Chromatographic separation of acetone extract afforded two bioactive epimers, identified as vincosamide (LC50 14.7 mg/mL) and strictosamide (LC50 12.8 mg/mL). Cytotoxicity evaluation showed that, below 200 µg/mL (400 µM), neither compound was toxic to the HeLa or MC3T3-E1 cells. CONCLUSION: Vincosamide and strictosamide could serve as novel scaffolds for the development of anthelmintic derivatives with improved potency and helminth selectivity.


Assuntos
Anti-Helmínticos/farmacologia , Alcaloides Indólicos/farmacologia , Rubiaceae/química , Alcaloides de Vinca/farmacologia , Células 3T3 , Animais , Anti-Helmínticos/isolamento & purificação , Anti-Helmínticos/toxicidade , Haemonchus/efeitos dos fármacos , Células HeLa , Humanos , Alcaloides Indólicos/isolamento & purificação , Alcaloides Indólicos/toxicidade , Dose Letal Mediana , Camundongos , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Extratos Vegetais/toxicidade , Folhas de Planta , Alcaloides de Vinca/isolamento & purificação , Alcaloides de Vinca/toxicidade
19.
Chemosphere ; 262: 127805, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32750593

RESUMO

The present study assessed the individual and combined toxicity effects of Ag- and TiO2- nanoparticles (NPs) on Ag bioaccumulation, oxidative stress, and gill histopathology in common carp as an aquatic animal model. The 96-h acute toxicity tests showed that TiO2NPs enhanced the toxicity of AgNPs deducted from the decreased LC50 in co-exposure to these NPs. Chronic toxicity tests included a 10-day exposure and a 10-day recovery period. In most cases, histological damages were more severe in co-exposure to Ag- and TiO2- NPs compared with the individual AgNPs however, they were reduced in some cases and also after the recovery period. In co-exposure to Ag- and TiO2- NPs, the Ag bioaccumulation was decreased in the gills but increased in the liver and intestine compared with the singular exposure. After the recovery period, Ag bioaccumulation decreased especially in the liver. Decreased levels of antioxidant enzymes were observed in the AgNPs exposed groups, which were partially alleviated by TiO2NPs. The reduction of condition factor (CF) and hepatosomatic index (HSI) and a severe decrease of weight gain (WG) were observed in co-exposure to Ag- and TiO2- NPs. After the recovery period, the CF and HSI increased but the WG decreased less compared with the exposure period. The present results emphasize the importance of considering the co-existence and interaction of NPs in realizing their bioavailability and toxicity in aquatic environments.


Assuntos
Carpas/fisiologia , Nanopartículas Metálicas/toxicidade , Titânio/química , Poluentes Químicos da Água/toxicidade , Animais , Antioxidantes/metabolismo , Brânquias , Dose Letal Mediana , Fígado/metabolismo , Nanopartículas/toxicidade , Estresse Oxidativo , Prata/toxicidade
20.
Ecotoxicol Environ Saf ; 207: 111278, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32979841

RESUMO

Information on soil antimony (Sb) toxicity to earthworm Eisenia fetida (Savingy) is limited. This ecotoxicology study was designed to quantify the soil Sb toxicity to earthworm E. fetida before and after aging process, establishing dose-effect relationship between Sb content and mortality. Results of the avoidance test and acute test showed that the values of net avoidance response, escape rate and mortality were generally decreased in aged treatment compared to that in fresh treatment, respectively from 93.33% to 66.67%, 36.67% to 13.33% and 100% to 53.33% (15 d) taking TL800 (treatment level of 800 mg/kg) for example, meanwhile the values of median lethal content (LC50) at 72 h, 7 d and 15 d were respectively increased from 355.27 mg/kg to 2324.55 mg/kg, 322.19 mg/kg and 1743.19 mg/kg and 282.74 mg/kg to 745.94 mg/kg, indicating that aging process could reduce the Sb acute toxicity to earthworm. According to a three-step sequential extraction procedure, the bioavailable Sb ranged from 24.45% to 43.24% and 16.97% to 27.70% in fresh treatment and aged treatment, respectively, and the mortality of earthworm for 24 h decreased with the decrease of the content of mild acid-soluble antimony (which decreased averagely from 23.09% to 14.00%), which was more suited to assess Sb toxicity. This is the first report that confirms the toxicity of soil Sb to earthworm E. fetida as well as the considering of aging process and speciation.


Assuntos
Antimônio/toxicidade , Oligoquetos/fisiologia , Poluentes do Solo/toxicidade , Animais , Ecotoxicologia/métodos , Dose Letal Mediana , Solo , Poluentes do Solo/análise
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