Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
1.
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
2.
J Environ Manage ; 285: 112029, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33578208

RESUMO

Leachate is difficult to biodegrade, and presents variable physical, chemical and biological characteristics, as well as high toxicological potential for soil, groundwater and water bodies. In this context, untreated leachate toxicity was evaluated through acute and chronic exposures in Eisenia andrei earthworms. Physico-chemical leachate characterizations indicate a complex composition, with high organic matter (COD - 10,634 mg L-1) and ammoniacal nitrogen (2388 mg L-1) concentrations. Metals with carcinogenic potential, such as Cr, As and Pb, were present at 0.60, 0.14 and 0.01 µg L-1, respectively and endocrine disrupting compounds were detected in estradiol equivalents of 660 ± 50 ng L-1. Acute tests with Eisenia andrei indicated an LC50 (72 h) of 1.3 ± 0.1 µL cm-2 in a filter paper contact test and 53.9 ± 1.3 mL kg-1 in natural soil (14 days). The EC50 in a behavioral test was estimated as 31.6 ± 6.8 mL kg-1, indicating an escape effect for concentrations ranging from 35.0 to 70.0 mL kg-1 and habitat loss from 87.5 mL kg-1 of leachate exposure. Chronic exposure (56 days) led to reproduction effects, resulting in a 4-fold decreased cocoon production and 7-fold juvenile decrease. This effect was mainly attributed to the possible presence of endocrine disrupting compounds. An estimated NOAEL of 1.7 mL L-1 and LOAEL of 3.5 mL L-1 were estimated for earthworms exposed to the assessed effluent. Extremely high-risk quotients (RQ ≥ 1) were estimated based on leachate application in irrigation. Thus, adequate municipal solid waste management is paramount, especially with regard to generated by-products, which can result in high toxicological risks for terrestrial organisms.


Assuntos
Oligoquetos , Poluentes do Solo , Poluentes Químicos da Água , Animais , Reprodução , Medição de Risco , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
3.
Ecotoxicol Environ Saf ; 183: 109572, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31442806

RESUMO

The neonicotinoid acetamiprid has been suggested as a worldwide substitute for organophosphates, due to its lower toxicity. The present study assessed several acetamiprid effects on Eisenia andrei earthworms in acute contact (ranging from 1.6 × 10-5 to 0.16 µg cm-2 acetamiprid), behavioral (0.1, 0.5, 1 mg kg-1) and chronic (0.001, 0.01, 0.05 and 0.1 mg kg-1 acetamiprid) assays carried out in natural soil. Reproduction, cytotoxicity (coelomocyte density and viability), immune cell typing (eleocytes and amoebocytes) and antioxidant defense system (glutathione (GSH), catalase (CAT) and glutathione S-transferase (GST)) responses were determined. The LC50 in the acute contact test was calculated as 1.86 × 10-2 µg cm-2. Acetamiprid concentrations of 0.5 and 1 mg kg-1 led to earthworm avoidance responses (NR = 61.09 ±â€¯10.01%) and habitat loss (NR = 78.02 ±â€¯12.03%), respectively. Reproduction was also affected, with a decreased number of cocoons and hatchlings per cocoon observed at 0.05 and 0.1 mg kg-1. Amoebocytes were the predominant immune system cells during the 15th and 30th assay days, while eleocytes were the main cells observed at the 45th day. CAT activities on the 30th and 45th day of exposure were increased at the lowest acetamiprid concentrations (0.001 and 0.01 mg kg-1) and decreased with increasing pesticide concentration (0.05 and 0.1 mg kg-1). Maximum GST activities and GSH levels were noted at 0.01 mg kg-1 acetamiprid. However, increasing concentrations led to GST inhibition, while GSH levels were maintained. A long-term acetamiprid exposure affected earthworm reproduction, behavior and immune and antioxidant systems, which could affect the ecological soil balance and, consequently, the entire food chain.


Assuntos
Comportamento Animal/efeitos dos fármacos , Neonicotinoides/toxicidade , Oligoquetos/fisiologia , Estresse Oxidativo/efeitos dos fármacos , Poluentes do Solo/toxicidade , Animais , Antioxidantes/metabolismo , Oligoquetos/efeitos dos fármacos , Oxirredução , Reprodução/efeitos dos fármacos
4.
Sci Total Environ ; 915: 170083, 2024 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-38224881

RESUMO

Leachate is a highly complex waste with high toxicological potential that poses a significant threat to the terrestrial environment. Determining leachate physicochemical parameters and identifying xenobiotics alone is, however, not enough to determine the real environmental impacts. In this context, the use of terrestrial model organisms has been highlighted as a tool in ecotoxicological leachate assessments and as a guiding principle in risk assessments. In this context, this review aimed to present the most current state of knowledge concerning leachate toxicity and the bioassays employed in this evaluation concerning terrestrial plants and animals. To this end, a literature search on leachate effects on terrestrial organisms was carried out using ten search terms, in 32 different combinations, at the Web of Science and Scopus databases. A total of 74 eligible articles were selected. The retrieved studies analyzed 42 different plant and animal species and employed nine endpoints, namely phytotoxicity, genotoxicity, bioaccumulation, antioxidant system, cytotoxicity, reproduction, physiological changes, behavior and lethality. A frequent association of toxic leachate effects with metals was observed, mainly Pb, Cd, Cr, Mg, Zn and Cr, which can cause antioxidant system alterations and cyto- and genotoxicity. These elements have also been associated to reproductive effects in earthworms and mice. Specifically concerning plants, most of the retrieved studies employed Allium cepa in toxicity assays, reporting phytotoxic effects frequently associated to metals and soil parameter changes. Animal studies, on the other hand, mostly employed mice and evaluated genotoxicity and antioxidant system effects. Even with the description of toxic leachate effects in both plants and animals, a lack of knowledge is still noted concerning reproductive, physiological, cytotoxic, and behavioral effects in terrestrial species. We, thus, suggest that further studies be carried out on other animals, advancing our understanding on potential environmental leachate effects, also allowing for human health risk assessments.


Assuntos
Resíduos Sólidos , Poluentes Químicos da Água , Humanos , Animais , Camundongos , Resíduos Sólidos/análise , Antioxidantes/farmacologia , Plantas , Cebolas , Metais , Poluentes Químicos da Água/análise
5.
Environ Sci Pollut Res Int ; 31(7): 10737-10749, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38206461

RESUMO

Water body contamination by leachate originated from dumpsites is a concern for municipal solid waste (MSW) management. In this context, this study aimed to evaluate antioxidant system alterations and oxidative and genotoxic effects in Danio rerio (zebrafish) exposed to leachate from a closed dumpsite. Groups comprising 50 fish were exposed (96 h) to different leachate concentrations (5, 15, 30, and 50%) to evaluate effects on liver and brain superoxide dismutase (SOD), catalase (CAT), and glutathione-S-transferase (GST) activities and reduced glutathione (GSH) and metallothionein (MT) concentrations, as well as malondialdehyde (MDA) and protein carbonylation (PTC) levels. Blood genotoxicity was evaluated by the comet assay. The investigated dumpsite leachate pond presented high chloride concentrations (Cl-; 2288.4 ± 69.5 mg L-1) and high electrical conductivity (EC; 8434.0 mS cm-1), indicating the presence of leachate. Concerning Danio rerio exposure, higher SOD (37%), CAT (67%), and GST (39%) activities and higher GSH (57%) concentrations were observed in liver following exposure to 50% leachate, while decreased brain GST (42%) activities and GSH (90%) levels were observed at the same leachate concentration. A significant increase in the olive tail moment (OTM; 280%) indicative of genotoxicity in blood was observed. A principal component analysis indicated that increased enzymatic activities and high levels of both GSH and MT were not sufficient to prevent the accumulation of reactive oxygen species, resulting in PTC and genotoxicity. Therefore, leachate exposure causes sublethal Danio rerio effects, altering the antioxidant system, increasing ROS production, and leading to PTC and genotoxicity. The findings demonstrate the need to further develop sublethal level assessments in zebrafish using leachate from different sources to subsidize risk assessments regarding MSW management.


Assuntos
Perciformes , Poluentes Químicos da Água , Animais , Antioxidantes/metabolismo , Peixe-Zebra/metabolismo , Estresse Oxidativo , Poluentes Químicos da Água/toxicidade , Catalase/metabolismo , Dano ao DNA , Superóxido Dismutase/metabolismo , Perciformes/metabolismo , Cloretos
6.
Biol Trace Elem Res ; 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38773036

RESUMO

A mining tailing dam rupture in Brazil in November 2015 released millions of tons of mining waste into the Rio Doce ecosystem, leading to long-term aquatic ecosystem impacts. Although multiple lines of evidence indicate tailings associations with potentially toxic elements in estuarine sediments and biological impact and bioaccumulation pathways in fishes, the extent of contamination in base benthic species is still largely unknown. Moreover, Rare Earth Elements (REE) have not received any attention in this regard. This study assessed REE in fiddler crabs (Minuca rapax) sampled from the Rio Doce estuary in 2017, nearly 2 years after the disaster. The ΣREE in crab hepatopancreas and muscle were high (327.83 mg kg-1 w.w. and 33.84 mg kg-1 w.w., respectively, compared to other assessments in crabs, indicating a preference for REE bioaccumulation in the hepatopancreas compared to muscle. Neodimium, La, and Ce were detected at the highest concentrations. The REE from the Rio Doce Basin were, thus, transported and deposited in the estuary with the mine tailings slurry, leading to bioaccumulation in crabs. This may lead to trophic effects and other ecological impacts not readily measured by typical impact assessment studies, revealing an invisible and not typically acknowledged damage to the Rio Doce estuary.

7.
Environ Pollut ; 345: 123497, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38331242

RESUMO

Mining is of great relevance to the global economy, but its activities are challenging due to socio-environmental impacts. In January 2019, an iron ore tailings dam collapsed in Brumadinho (Minas Gerais, Brazil) releasing 12 × 106 m3 of tailings, causing human losses and devastation around 3.13 × 106 m2 of a watershed. In this context, the present study aimed to investigate the potential toxic effects of tailings from the collapsed dam using earthworms Eisenia andrei as a model organism for terrestrial environments. An extensive set of tests was performed, including behavioral (avoidance), acute (mortality and biomass) and chronic tests, such as biomass, reproduction and cytotoxicity (viability and cell density and change in coelomocyte pattern). The physical-chemical characterization revealed a higher density of the tailings in relation to the control soil, which can result in physical changes, such as soil compaction and surface sealing. Aluminum, Ca, Fe, Hg, Mg, Mn, K, Na and P registered higher concentrations in the tailings compared to the control soil, while Total Nitrogen, Total Organic Carbon and Organic Matter were higher in the natural soil. Based on the avoidance test, an EC50 of 27.18 ± 2.83% was estimated. No lethality was observed in the acute exposure, nor variations in biomass in the acute and chronic assays. However, there was a tendency to reduce the number of juveniles in relation to cocoons in the proportions of 3125; 12.5 and 25%. Significant changes in viability, cell density and pattern of amebocytes and eleocytes were observed up to the 35th day of exposure. A multi-biomarker approach (Integrated Biological Response version 2) indicated concentration-dependent effects and attenuation of cellular changes over time. These are the first results of chronic effects on earthworms exposed to tailings from the B1 dam. Despite being conclusive, we highlight the possible heterogeneity of the tailings and the necessary care in extrapolating the results.


Assuntos
Desastres , Oligoquetos , Poluentes do Solo , Animais , Humanos , Solo/química , Mineração , Biomarcadores/metabolismo , Brasil , Poluentes do Solo/análise
8.
Mol Cell Endocrinol ; 564: 111883, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36736881

RESUMO

This study investigated the mechanism of action of clotrimazole (CTZ) and its adverse effects in a model of endometriosis. After autologous endometrial implantation, 18 rats were randomized into two treatment groups: 200 mg/kg CTZ or vehicle for 15 consecutive days. The lesion growth, implant size, glandular atrophy, nitric oxide (NO) serum levels, number of macrophage cells and inducible nitric oxide synthase (iNOS) immunoreactivity were significantly reduced in the CTZ group compared with the control. CTZ (p < 0.05) reduced the lipid peroxidation and protein carbonylation levels in the liver but did not alter the superoxide dismutase (SOD), glutathione (GSH) or glutathione S-transferase (GST) levels in the brain; however, the drug significantly reduced SOD activity and enhanced GST activity in the liver. These results suggest that CTZ interferes with reactive nitrogen species production by downregulating iNOS expression and thus enhances the antioxidant system to promote atrophy and regression of endometriotic lesions, without adverse effects on the brain and/or liver.


Assuntos
Clotrimazol , Endometriose , Feminino , Humanos , Ratos , Animais , Óxido Nítrico Sintase Tipo II/metabolismo , Clotrimazol/farmacologia , Estresse Oxidativo , Antioxidantes/metabolismo , Glutationa/metabolismo , Superóxido Dismutase/metabolismo , Peroxidação de Lipídeos , Óxido Nítrico/metabolismo , Biomarcadores/metabolismo
9.
Environ Pollut ; 287: 117351, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34000669

RESUMO

It is estimated that approximately 0.4% of the total leachate produced in a landfill is destined for treatment plants, while the rest can reach the soil and groundwater. In this context, this study aimed to perform leachate toxicity evaluations through immune system cytotoxic assessments, genotoxic (comet assay) appraisals and antioxidant system (superoxide dismutase - SOD; catalase - CAT, glutathione-S-transferase - GST; reduced glutathione - GSH and metallothionein - MT) evaluations in Eisenia andrei earthworms exposed to a Brazilian leachate for 77 days. The leachate sample contained high organic matter (COD - 10,630 mg L-1) and ammoniacal nitrogen (2398 mg L-1), as well as several metals, including Ca, Cr, Fe, Mg, Ni and Zn. Leachate exposure resulted in SOD activity alterations and increased CAT activity and MT levels. Decreased GST activity and GSH levels were also observed. Antioxidant system alterations due to leachate exposure led to increased malondialdehyde levels as a result of lipid peroxidation after the 77 day-exposure. An inflammatory process was also observed in exposed earthworms, evidenced by increased amoebocyte density, and DNA damage was also noted. This study demonstrates for the first time that sublethal effect assessments in leachate-exposed earthworms comprise an important tool for solid waste management.


Assuntos
Oligoquetos , Poluentes do Solo , Poluentes Químicos da Água , Animais , Antioxidantes , Catalase/metabolismo , Dano ao DNA , Malondialdeído , Oligoquetos/metabolismo , Estresse Oxidativo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Superóxido Dismutase/metabolismo , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
10.
Environ Pollut ; 267: 115570, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32916435

RESUMO

Triclocarban (TCC) is a contaminant of emerging concern widely applied as an antimicrobial in personal care products and introduced into the terrestrial environment through the application of biosolids (i.e., treated sewage sludge) in agriculture. Displaying the potential to bioaccumulate in the food chain and a high half-life in the soil, the presence of this compound in the environment may lead to potential ecological risks. In this context, TCC toxicity assessments in Eisenia andrei earthworms were carried out through acute, avoidance and chronic tests following cytotoxicity, antioxidant system, i.e. acatalase (CAT), glutathione-S-transferase (GST), glutathione (GSH), lipid peroxidation (LPO), and DNA damage (comet assay) evaluations. An LC50 of 3.3 ± 1.6 mg cm-2 in the acute contact test and an EC50 of 1.92 ± 0.31 mg kg-1 in the avoidance test during 72 h and 48 h, respectively, were obtained. The behavioral test indicates earthworm avoidance from 15.0 mg kg-1 of TCC. During chronic soil exposure, a 44% reduction in earthworm cell viability was observed after 14 days of exposure to 10 mg kg-1 TCC, while an increase in the percentage of amoebocyte cells also ocurred. Chronic exposure to TCC led to reduced CAT and GST activities, decreased GSH levels and increased LPO in exposed organisms. DNA damage was observed after 45 days from a 1 mg kg-1 dose of TCC. Therefore, TCC exhibits toxicological potential to Eisenia andrei earthworms, mainly during long-term exposures. This study provides mechanistic earthworm information towards understanding the environmental and human health implications of TCC exposure and draws attention to correct biosolid management.


Assuntos
Oligoquetos , Poluentes do Solo , Animais , Carbanilidas , Dano ao DNA , Humanos , Estresse Oxidativo , Poluentes do Solo/toxicidade
11.
Tese em Português | ARCA | ID: arc-59037

RESUMO

O lixiviado de resídios sólidos é um efluente de composição complexa, capaz de contaminar solos e águas superficiais e subterrâneas, criando uma grande zona de contaminação ao redor dos lixões. Portanto, avaliações ecotoxicológicas com organismos vivos são relevantes para investigar os reais efeitos do lixiviado. O objetivo do estudo foi avaliar os efeitos ecotoxicológicos do lixiviado de lixão em organismos aquático e terrestre. Para isso, foi realizada uma revisão crítica dos efeitos do lixiviado em organismos terrestres, utilizando as bases de busca Web of Science e Scopus a fim de encontrar as lacunas presentes na literatura. Além disso, peixes Danio rerio e minhocas Eisenia andei foram utilizados para a análises de biomarcadores do sistema antioxidante e, de efeito oxidativo. Por fim, foi feita a avaliação da genotoxicidade em peixes e da citotoxicidade em minhocas. Durante a revisão, foi observado o uso de 15 espécies e oito endpoints do lixiviado em organismos terrestres. Os artigos selecionados apontaram os metais como principais responsáveis pelos efeitos adveros. As amostras coletadas no lixão apresentam altos níveis de cloreto (1.885 ­ 4.101 mg L-1 ) e de condutividade elétrica (6.495 ­ 10.452 mS cm-1 ). Sete gêneros de fungos filamentosos e/ou leveduriformes foram identificados, incluindo o fungo patogênico Candida krusei. Foi determinado um fator alto (CF>6) de contaminação por metais no solo para os elementos Br, Se e I. A exposição de Danio rerio ao lixiviado modulou o sistema antioxidante do fígado, aumentando os níveis de SOD (37 %), CAT (67 %), GST (39 %) e GSH (57 %) em 50 % de lixiviado, e no cérebro com a redução de GST (42 %) e de GSH (90 %) na mesma concentração. No sangue, houve o aumento do dano ao DNA. As análises mostraram que o sistema antioxidante não foi capaz de impedir o acúmulo de espécies reativas de oxigênio (EROs), levando a carbonilação de proteínas (PTC). Em minhocas, o lixiviado gerou efeito de fuga em concentrações até 50 % e atração acima de 50 %. A citotoxicidde foi observada com a redução da densidade e viabilidade celular. O lixiviado aumentou os níveis de SOD (6 %), CAT (35 %), GST (70 %), GSH (37 %) e MT (67 %). Não foram observados efeitos oxidativos, mostrando que o sistema antioxidante combateu o acúmulo de EROs. De forma inédita, foi realizada uma avaliação ecotoxicológica do lixiviado em organismos aquático e terrestre, utilizando endpoints de cito- e genotoxicidade, e avaliação no sistema antioxidante. Contudo, devido a lacuna ainda presente na literatura sobre os efeitos subletais do lixiviado em organismos aquáticos e terrestes, e diante dos resultados cito- e genotóxicos, e alterações no sistema antioxidante, presente trabalho sugere que novos estudos sejam feitos para que os efeitos do lixiviado em organismos vivos sejam completamente entendidos.


Assuntos
Descargas a Céu Aberto , Toxicidade , Peixe-Zebra , Metais , Ambiente Marinho , Líquido Percolado , Revisão
15.
Tese em Português | ARCA | ID: arc-34248

RESUMO

O lixiviado é um efluente de difícil biodegradação com características físicas, químicas e biológicas variáveis com elevado potencial de causar a contaminação do solo, das águas subterrâneas e dos corpos hídricos. Com base nisso, quando se busca avaliar os seus impactos no meio ambiente, faz-se necessário o uso de indicadores que permitam medir a ação destes sobre organismos vivos. No presente trabalho, buscou-se avaliar a toxicidade do lixiviado não tratado por meio de exposições agudas e crônicas, utilizando biomarcadores de estresse oxidativo, citotoxicidade e genotoxicidade em minhocas da espécie Eisenia andrei. Os ensaios ecotoxicológicos agudos mostraram CL50 de 2,3 mL cm-2 em teste de contato e 77,8 mL kg-1 em solo natural, durante 72 h e 14 dias, respectivamente. Foi observado, também, efeito de fuga dos organismos em concentrações acima de 37,5 mL kg-1 . O ensaio crônico apontou efeito na reprodução, reduzindo a produção de casulos e impedindo o desenvolvimento de indivíduos recém-nascidos com o aumento das concentrações de lixiviado. A exposição prolongada ao lixiviado foi citotóxica, com redução da viabilidade e a densidade celular, principalmente na concentração de 10,5 mL kg-1 . Os biomarcadores de estresse oxidativo, evidenciaram efeito oxidante proveniente da exposição ao lixiviado. Os agentes antioxidantes catalase (CAT) e metalotioneína (MT) foram induzidos, ou seja, aumentaram sua atividade e concentração com o aumento da exposição, a partir de 35 dias de exposição. Por outro lado, houve redução da atividade e concentração de glutationa-Stransferase (GST) e glutationa reduzida (GSH), respectivamente. Foi observado um aumento da concentração de malondialdeído (MDA) ao final de 77 dias de exposição, evidenciando a lipoperoxidação causada por lesões oxidativas. Por meio do ensaio cometa, foi observado efeito genotóxico dose-dependente a partir dos primeiros 7 dias de exposição em ensaio crônico. A análise de componentes principais (ACP) mostrou correlação entre os agentes antioxidantes e o efeito genotóxico, assim como entre a genotoxicidade e citotoxicidade, mostrando que sistema de defesa a contaminantes exógenos funciona de forma conjunta a fim de manter a homeostase celular. Conclui-se que o lixiviado de aterro de resíduos sólidos mostrou ser tóxico para a espécie Eisenia andrei em exposição aguda e crônica gerando efeitos citotóxicos, genotóxicos e de estresse oxidativo. No mesmo sentido, a análise de efeitos subletais mostrou ser eficaz na determinação de efeitos tóxicos precoces ao lixiviado nos organismos testados.


Assuntos
Ecotoxicologia , Líquido Percolado , Oligoquetos , Estresse Oxidativo , Genotoxicidade , Resíduos Sólidos
16.
Rio de Janeiro; s.n; 2019. 105 p. ilus, graf, tab.
Tese em Português | ENSP, FIOCRUZ | ID: ens-37009

RESUMO

O lixiviado é um efluente de difícil biodegradação com características físicas, quí-micas e biológicas variáveis com elevado potencial de causar a contaminação do solo, das águas subterrâneas e dos corpos hídricos. Com base nisso, quando se busca avaliar os seus impactos no meio ambiente, faz-se necessário o uso de indicadores que permitam medir a ação destes sobre organismos vivos. No presente trabalho, buscou-se avaliar a toxicidade do lixiviado não tratado por meio de exposições agudas e crônicas, utilizando biomarcado-res de estresse oxidativo, citotoxicidade e genotoxicidade em minhocas da espécie Eisenia andrei. Os ensaios ecotoxicológicos agudos mostraram CL50 de 2,3 mL cm-2 em teste de contato e 77,8 mL kg-1 em solo natural, durante 72 h e 14 dias, respectivamente. Foi obser-vado, também, efeito de fuga dos organismos em concentrações acima de 37,5 mL kg-1. O ensaio crônico apontou efeito na reprodução, reduzindo a produção de casulos e impedindo o desenvolvimento de indivíduos recém-nascidos com o aumento das concentrações de lixiviado. A exposição prolongada ao lixiviado foi citotóxica, com redução da viabilidade e a densidade celular, principalmente na concentração de 10,5 mL kg-1. Os biomarcadores de estresse oxidativo, evidenciaram efeito oxidante proveniente da exposição ao lixiviado. Os agentes antioxidantes catalase (CAT) e metalotioneína (MT) foram induzidos, ou seja, au-mentaram sua atividade e concentração com o aumento da exposição, a partir de 35 dias de exposição. Por outro lado, houve redução da atividade e concentração de glutationa-S-transferase (GST) e glutationa reduzida (GSH), respectivamente.(AU)


Foi observado um au-mento da concentração de malondialdeído (MDA) ao final de 77 dias de exposição, evi-denciando a lipoperoxidação causada por lesões oxidativas. Por meio do ensaio cometa, foi observado efeito genotóxico dose-dependente a partir dos primeiros 7 dias de exposição em ensaio crônico. A análise de componentes principais (ACP) mostrou correlação entre os agentes antioxidantes e o efeito genotóxico, assim como entre a genotoxicidade e citotoxi-cidade, mostrando que sistema de defesa a contaminantes exógenos funciona de forma conjunta a fim de manter a homeostase celular. Conclui-se que o lixiviado de aterro de re-síduos sólidos mostrou ser tóxico para a espécie Eisenia andrei em exposição aguda e crô-nica gerando efeitos citotóxicos, genotóxicos e de estresse oxidativo. No mesmo sentido, a análise de efeitos subletais mostrou ser eficaz na determinação de efeitos tóxicos precoces ao lixiviado nos organismos testados.(AU)


Assuntos
Animais , Ecotoxicologia , Líquido Percolado , Oligoquetos , Estresse Oxidativo , Genotoxicidade , Resíduos Sólidos , Estudos Epidemiológicos , Indicadores de Contaminação , Poluentes Ambientais , Ensaios Clínicos como Assunto
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA