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1.
Environ Pollut ; 276: 116759, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33639491

RESUMO

The majority of experimental studies carried out to date, regarding the effects of pollutants on meiofauna have been conducted by means of closed systems, and rarely using open ones. The current work explored the impact of three Polycyclic Aromatic Hydrocarbons (PAHs), anthracene, pyrene and benzo[a]pyrene, applied alone or combined, on meiobenthic nematodes using both systems. The results revealed that single PAHs impacted the nematofauna similarly in closed or open systems with a higher toxicity observed for benzo[a]pyrene. However, the closed microcosms contaminated with PAHs became organically enriched, resulting in more non-selective deposit feeders and omnivores-carnivores. Taxonomic and functional effects related to combinations of PAHs were close to those of individual treatments in closed systems, however, for open ones, the outcomes were different. The caudal morphology influenced the response of taxa during their avoidance/endurance of hydrocarbons in open systems where the effects of PAHs mixtures appeared not only additive but also synergetic. Based on the results of the study, the use of open systems is preferred to closed ones as the research outcomes were more accurate and representing better conditions prevailing in nature.


Assuntos
Nematoides , Hidrocarbonetos Policíclicos Aromáticos , Animais , Antracenos/toxicidade , Benzo(a)pireno/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Pirenos
2.
Environ Pollut ; 277: 116727, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33640809

RESUMO

The response taxonomic and trophic of meiobenthic organisms, especially marine nematodes to polybrominated diphenyl ether (BDE-47) was studied using a community from Bizerte lagoon (Nord-East Tunisia). Four concentrations of BDE-47 [D1 (2.5 µg/kg dw), D2 (25 µg/kg dw), D3 (50 µg/kg dw), and D4 (100 µg/kg dw)] were applied, and responses were determined 30 days after exposure. Species abundance and all univariate indices were significantly affected in all treated microcosms compared to the control. The non-parametric cluster based on species abundance separated the nematode population into two groups: control + all treated microcosms. After grouping nematode species according to their trophic diversity, their abundance showed differential responses. The non-metric multi-dimensional scaling analysis and cumulative k-dominance based on the abundance of trophic groups abundances reflected significant separation between the control microcosm and each treatment condition. The correspondence analysis 2D plot generated from nematode species and trophic groups abundance showed the control microcosm was dominated by microvores, represented by two species of Terschellingia. However, when treated with the highest concentration of BDE-47, the community was occupied by the resistant trophic groups of facultative predators and epigrowth feeders represented by Metoncholaimus pristiurus and Paracomesoma dubium, respectively.


Assuntos
Éteres Difenil Halogenados , Nematoides , Animais , Éteres Difenil Halogenados/toxicidade , Tunísia
3.
Biomarkers ; 26(3): 240-247, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33459570

RESUMO

CONTEXT: The Au-TiO2NPs have a wide range of applications and can easily enter the cells. Due to their properties, they can cause toxicity. OBJECTIVE: It was aimed to test the toxic effects of Au-TiO2 NPs in the brain, heart, kidney and liver of rats in this work. MATERIALS AND METHODS: All used rats in this work were treated using diverse concentrations (doses) of NPs (100 and 200 mg/kg bw) for 21 days. SOD, CAT, AChE activities and MDA, H2O2, NO contents were evaluated in different organs. RESULTS: The Au-TiO2 NPs exposure induced biochemical changes in different organs of rats in view of oxidative stress and neurotoxicity by the alteration of the activity of the enzyme of neurotransmitter (AChE activity). CONCLUSION: The Au-TiO2 NPs have the potential to interact with rat's biochemical status and cause undesirable effects. One of those damaging effects was oxidative stress and neurotoxicity. CLINICAL SIGNIFICANCE: The study signifies the impact of usage of Au-TiO2 NPs in the medical field for further exploration.

4.
Sci Total Environ ; 770: 145251, 2021 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-33508666

RESUMO

Trophic web structuring in aquatic sediments is dependent on the biological interactions between metazoans and microbial communities. The presence of pollutants in these biotas can therefore impact the meiofauna structure via the modification of the microbial communities. The current study examined in a laboratory bioassay the response of meiobenthic communities, particularly marine nematode taxa from the Bizerte Lagoon to the effect of the most detected polybrominated diphenyl ether in this aquatic environment, BDE-47. Four doses [D1 (2.5 ppb Dry weight (DW)), D2 (25 ppb DW), D3 (50 ppb DW), and D4 (100 ppb DW)] were gradually applied and sediment microcosms were incubated for 30 days in the presence or absence of meiofauna. Our results show that BDE-47-enriched sediments decreased the meiofaunal taxa and bacterial abundance. A lower taxonomic diversity of the nematodes' general structure was observed with all doses used. The numerical analysis of the two dimensional (2D) non-metric multidimensional scaling (nMDS) plots and the evolution of the relative abundances of each functional group of nematode genus assemblages revealed that the abundance of all biological traits was modified. Nevertheless, only three of the functional traits, adult length, feeding group, and amphid shape, showed a clear difference between the control and the treated microcosms. The similarity percentage analysis (SIMPER) revealed that the average dissimilarity between nematode genera communities and biological traits increased with BDE-47-enriched sediments. The nMDS second-stage ordination of inter-matrix rank correlations for matrices including genera and biological traits showed that the amphid shape was the functional trait closest to the generic distribution. Finally, the Principal Component Analysis (PCA) for the nematode biological traits and bacteria indicated a positive correlation of these microbes with the functional groups [1A, Cr, and ef], and a negative correlation only with the "cla"-type tail shape.


Assuntos
Nematoides , Poluentes Químicos da Água , Animais , Bactérias , Sedimentos Geológicos , Éteres Difenil Halogenados/análise , Poluentes Químicos da Água/análise
5.
Aquat Toxicol ; 228: 105632, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33010638

RESUMO

An experiment was carried out using microcosms to evaluate the impact of the fluoroquinolone antibiotic on nematode trophic groups structure and bacterial abundance. Sediment samples were experimentally enriched with four increasing doses of ciprofloxacin [D1 (50 ppm), D2 (100 ppm), D3 (200 ppm) and D4 (500 ppm)] and compared to non-enriched sediments (used as control). Ciprofloxacin changed the trophic composition of nematodes taxa where the relative abundance of microvores (M), epigrowth feeders (EF) and ciliate consumers (CF), raised in a control microcosm, was highly affected and significantly decreased in response to the increasing doses. Nevertheless, the abundance of deposit feeders (DF), optional predators (FP) and exclusive predators (Pr) showed a significant increase. Results from the multivariate analysis showed a clear impact of this antibiotic on nematode trophic assemblages. Microcosms treated with the three highest doses [D2, D3 and D4] were different from the control. The exceptions were those treated with the lowest dose, D1, and which were grouped with the control. The SIMPER analysis results showed that the average dissimilarity continuously increased in the treated microcosms compared to the control. Furthermore, our results have shown that ciprofloxacin also leads to a significant decrease in bacterial density with the highest dose, which could explain the results obtained for nematode trophic groups distribution. Thus, the bacteriophages nematodes only use bacteria as a nutrition source and the lack or presence in small quantity of this food could induce a decrease in their abundance as well as changing of nematodes groups repartition. Our work demonstrates that the nematode responses were dependent on sediment enrichment with ciprofloxacin and opens new perspectives on the potential impact of antibiotics on functional nematode diversity.


Assuntos
Antibacterianos/toxicidade , Organismos Aquáticos/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Ciprofloxacino/toxicidade , Ecossistema , Sedimentos Geológicos/química , Nematoides/fisiologia , Animais , Bactérias/efeitos dos fármacos , Análise por Conglomerados , Geografia , Sedimentos Geológicos/microbiologia , Região do Mediterrâneo , Análise Multivariada , Nematoides/efeitos dos fármacos , Densidade Demográfica , Análise de Componente Principal , Poluentes Químicos da Água/toxicidade
6.
Ecotoxicol Environ Saf ; 205: 111084, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32810644

RESUMO

A microcosm experiment was conducted to evaluate the impacts of the fluoroquinolone antibiotic ciprofloxacin on meiobenthic taxa abundance, nematode genus structure, and functional trait parameters. Sediment samples were experimentally enriched with four different doses of ciprofloxacin [D1 (50 ppm Dry weight 'DW'), D2 (100 ppm DW), D3 (200 ppm DW), and D4 (500 ppm DW)] and were then compared with non-enriched sediments (controls). After one month of exposure, the data showed that ciprofloxacin had altered the meiofaunal taxa abundance. A change in the structure of nematofaunal genera was observed, particularly with the highest dose (D4), which was characterized by the lowest taxonomic diversity. The SIMPER analysis revealed that the average dissimilarity between nematode communities increased with increasing doses of ciprofloxacin. Two dimensional (2D) non-metric multidimensional scaling (nMDS) plots and relative abundances of functional groups of nematode genus assemblages revealed that all functional trait abundances were affected, particularly with the highest dose. However, only the amphid shape and feeding group functions showed a clear distribution separation between the control and ciprofloxacin treatments. The nMDS second-stage ordination of inter-matrix rank correlations for matrices including genus and functional traits showed that the tail shape was the closest functional trait to the generic distribution. Thus, only the curves of cumulative dominance related to the tail shape mirrored discernibly the sedimentary concentrations in ciprofloxacin.


Assuntos
Antibacterianos , Ciprofloxacino , Nematoides , Animais , Sedimentos Geológicos/química , Análise Multivariada
7.
Mar Pollut Bull ; 157: 111375, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32658716

RESUMO

At the end of March 2020, ivermectin was confirmed as a drug for COVID-19 treatment. A significant amount of ivermectin could deposit into sediments of the semi-closed Mediterranean Sea, where three European COVID-19 epicenters are located: Italy, Spain, and France. Meiobenthic nematodes were exposed to three ivermectin doses (1.8 ng.g-1, 9 ng.g-1, and 18 ng.g-1) for 10 days. Ivermectin caused a great reduction in abundance. However, the diversity indices decreased only at high doses. Ivermectin disadvantaged the 1B-Cr-Id functional type (non-selective deposit feeders and nematodes with circular or indistinct amphids) and benefited the 2A-REL-Sp type (epistrate feeders and nematodes with rounded or elongated loop amphids). Thus, Trophic Diversity and Amphideal Diversity index values increased with sedimentary ivermectin enrichment. Large amphideal foveas were more efficient for 2A-REL-Sp nematodes to avoid ivermectin. The responses of the functional type 2A-REL-Sp and corresponding taxa predict post-COVID-19 environmental concerns and the bioaccumulation of ivermectin in seafoods.


Assuntos
Antivirais/toxicidade , Infecções por Coronavirus , Ivermectina , Nematoides , Pandemias , Pneumonia Viral , Animais , Betacoronavirus , Infecções por Coronavirus/tratamento farmacológico , França , Humanos , Itália , Ivermectina/toxicidade , Mar Mediterrâneo , Espanha
8.
Pestic Biochem Physiol ; 165: 104463, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32359554

RESUMO

Cypermethrin (Cyp) is a kind of pyrethroids compound that is broadly used against different species of insects and pests. Cyp can also elicit a range of neurotoxic, immunotoxic, genotoxic and reproductive toxic effects on various experimental organisms. The aim of this study was to evaluate the protective effects of Hibiscus sabdariffa against the toxicity damage induced by Cyp exposure. The Hibiscus sabdariffa calyxes extract was given to mice (200-500 mg/kg bw). The mice, which were treated with Cyp and Hibiscus sabdariffa, were divided into six groups of six mice each. Groups I, IV and VI were used as control and groups II CYP control (20 mg/kg body weight)., groups III and V were treated with Hibiscus sabdariffa extract (200 and 500 mg/kg body weight) plus (20 mg/kg body weight) for 21 days Furthermore, HPLC was used to identify the compound fraction. This result showed Cyp -induced biochemical changes in all organs of mice. Cyp caused decreased CAT activity, inhibition of AChE activity and increased the levels of H2O2 and MDA in brain, heart, liver and kidney. Hibiscus sabdariffa exhibited antioxidant effect and significantly attenuated the neurotoxicity of Cyp. Hibiscus sabdariffa exhibits neuroprotective effects and can be an effective and novel alternative approach to reduce the risk caused by pyrethroid compound.


Assuntos
Hibiscus , Piretrinas , Animais , Peróxido de Hidrogênio , Camundongos , Estresse Oxidativo , Extratos Vegetais
9.
Environ Technol ; : 1-12, 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32149584

RESUMO

The phosphate fertilizer and phosphoric acid industries increase phosphogypsum levels in the aquatic environment leading to various disturbing effects. In the present work, we investigated the bio-uptake of heavy metals following the exposure of Ruditapes decussatus to three concentrations of phosphogypsum, 10, 20 and 40 g kg-1, under laboratory conditions. The amounts of Zn, Cd and Pb in several organs of the clam Ruditapes decussatus was determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). Phosphogypsum acts on the behaviour of R. decussatus by increasing filtration rates. The most treatments showed significantly higher metal concentration in all tissues than the controls. Excavation behaviour was altered in treated bivalves compared to controls. The filtration rate (FR) of clams was significantly affected by exposure to phosphogypsum. Indeed, FR increased in clams exposed to phosphogypsum. Phosphogypsum has decreased SOD, CAT and MDA activities in the gills, digestive gland, gonad and muscles according to the concentration indicating a defense against oxidative stress. AChE was significantly inhibited in clams from all the sampling sites compared to controls. The considered parameters could be useful biomarkers for the evaluation of phosphogypsum toxicity in threatened biota. This study was conducted as part of a further investigation into the use of a comprehensive approach combining chemical and biological parameters to assess the health status of the Gabes gulf population. It provides the first database referring to phosphogypsum contamination and its biological effect in this ecosystem. The present study fills in a needed gap in the literature.

10.
Environ Pollut ; 262: 114350, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32197121

RESUMO

A laboratory bioassay was conducted to investigate the ecotoxicity of a chromium-enriched superfood, Spirulina platensis, on the meiofauna collected from the Ghar El Melh lagoon, Tunisia. After 1 month of exposure, the abundances of meiobenthic taxa and the taxonomic and morpho-functional diversity of nematodes showed significant differences between the Spirulina and Spirulina + chromium groups. The nematodes were more tolerant of all types of stressors compared to harpacticoids, polychaetes, and oligochaetes, and the lowest taxonomic and morpho-functional diversity of nematodes was observed in the highest sedimentary concentration of S. platensis (50% DW). The mixed treatments may have been richer in micro-habitats and subject to low selective pressure, thereby hosting nematodes with a wide range of adaptations. The responses of the nematode species differed depending on their functional traits. Spirulina enriched with chromium induced two responses for the same feeding group: high toxicity for Daptonema fallax and low toxicity for two Theristus species (T. flevensis and T. modicus). The ecotoxicity of the Spirulina/chromium mixtures were lower than that of Spirulina alone, suggesting mutual neutralization between these two elements. The association between functional traits and taxonomic diversity showed that the effects of the mixtures were not additive and that one of the stressors camouflaged the effect of the other. Our findings should encourage the commercialization of chromium-enriched S. platensis owing to its lower ecotoxicity than Spirulina alone.


Assuntos
Nematoides , Spirulina , Animais , Cromo , Ecossistema , Tunísia
11.
Artigo em Inglês | MEDLINE | ID: mdl-32150949

RESUMO

This study evaluated the engagement of staff regarding infectious healthcare waste management, in two case-study universities in Tunisia. Using a questionnaire survey, it was found that the most significant reported factors that influenced engagement were the availability of technical sheets and posters, training and education programs, and the age range of the staff. While there was some accordance with the Tunisian Decree application n° 2008-2745 of July 28th, 2008, as well as international guidelines and best practice (e.g. the use of color coded bins, waste management teams, and infection control measures), there were also limitations in the provision of training. This limitation in training and, to a lesser extent, awareness impacted on the beliefs about infectious healthcare waste management of staff and their practices. Recommendations for addressing these issues are suggested.


Assuntos
Eliminação de Resíduos de Serviços de Saúde , Política Organizacional , Gerenciamento de Resíduos , Fatores Etários , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Eliminação de Resíduos de Serviços de Saúde/estatística & dados numéricos , Inquéritos e Questionários , Tunísia , Gerenciamento de Resíduos/estatística & dados numéricos , Engajamento no Trabalho
12.
Environ Pollut ; 252(Pt A): 644-656, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31185353

RESUMO

Bacterial communities inhabiting sediments in coastal areas endure the effect of strong anthropogenic pressure characterized by the presence of multiple contaminants. Understanding the effect of pollutants on the organization of bacterial communities is of paramount importance in order to unravel bacterial assemblages colonizing specific ecological niches. Here, chemical and molecular approaches were combined to investigate the bacterial communities inhabiting the sediments of the Ichkeul Lake/Bizerte Lagoon, a hydrological system under anthropogenic pressure. Although the microbial community of the Ichkeul Lake sediment was different to that of the Bizerte Lagoon, common bacterial genera were identified suggesting a lake-lagoon continuum probably due to the hydrology of the system exchanging waters according to the season. These genera represent bacterial "generalists" maintaining probably general biogeochemical functions. Linear discriminant analysis effect size (LEfSe) showed significant differential abundance distribution of bacterial genera according to the habitat, the pollution type and level. Further, correlation analyses identified specific bacterial genera which abundance was linked with pesticides concentrations in the lake, while in the lagoon the abundance of specific bacterial genera was found linked with the concentrations of PAHs (Polycyclic aromatic hydrocarbons) and organic forms of Sn. As well, bacterial genera which abundance was not correlated with the concentrations of pollutants were identified in both lake and lagoon. These findings represent valuable information, pointing out specific bacterial genera associated with pollutants, which represent assets for developing bacterial tools for the implementation, the management, and monitoring of bioremediation processes to mitigate the effect of pollutants in aquatic ecosystems.


Assuntos
Lagos/microbiologia , Microbiologia da Água , Poluição da Água/análise , Bactérias , Biodegradação Ambiental , Ecossistema , Sedimentos Geológicos/química , Hidrologia , Lagos/química , Praguicidas/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Tunísia
13.
Biomarkers ; 23(6): 580-588, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29633866

RESUMO

CONTEXT: Nanoparticles may cause adverse environmental effects but there is limited information on their interactions with marine organisms. OBJECTIVE: Our aim was to examine the effects of triangular gold nanoparticles (Tr-Au NPs) on the clam, Ruditapes decussatus. MATERIALS AND METHODS: Clams were exposed to Tr-Au1 = 5 µg/L and Tr-Au2 = 10 µg/L for 2 and 7 days. Effects on shell structure were investigated. Superoxide dismutase (SOD), catalase (CAT), glutathione transferase (GST) activities, protein carbonyl levels and malondialdehyde content were used to assess biochemical status. RESULTS: Transmission electron microscopy (TEM) and electron dispersive X-ray microanalysis (EDX) showed that Tr-Au NPs modified shell structure and morphology. Tr-Au NPs size increased forming aggregate particles. Tr-Au NPs increased SOD, CAT and GST activities in gill and digestive gland in a concentration- and time-dependent manner indicating defence against oxidative stress. Enhanced lipid peroxidation and protein carbonyl levels confirmed oxidative stress. CONCLUSION: Tr-Au NPs cause oxidative stress and affect shell structure of clams. These findings may have relevance to other marine species.


Assuntos
Exoesqueleto/metabolismo , Bivalves/anatomia & histologia , Enzimas/metabolismo , Ouro/química , Nanopartículas Metálicas/química , Exoesqueleto/efeitos dos fármacos , Exoesqueleto/ultraestrutura , Animais , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Bivalves/efeitos dos fármacos , Bivalves/metabolismo , Catalase/metabolismo , Microanálise por Sonda Eletrônica , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Glutationa Peroxidase/metabolismo , Glutationa Transferase/metabolismo , Ouro/administração & dosagem , Malondialdeído/metabolismo , Nanopartículas Metálicas/administração & dosagem , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Transmissão , Superóxido Dismutase/metabolismo
14.
Biomarkers ; 23(2): 167-173, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29017403

RESUMO

CONTEXT: Cypermethrin (CYP) is a synthetic pyrethroid insecticide used worldwide in agriculture, home pest control. The toxicity of CYP is well studied in many organisms. OBJECTIVE: The aim of present study was to investigate the protective effect of Zizyphus lotus (Zizyp) fruit against neurotoxicity and oxidative stress induced by CYP in mice. MATERIALS AND METHODS: Mice were divided into four groups of six each: groups I and II were used as control and CYP control (20 mg/kg body weight). While, groups III was orally treated with Zizyphus lotus fruit (5 g/kg body weight) plus CYP (20 mg/kg body weight) for 18 days. Furthermore, HPLC-ESI-MS-MS (Q-Tof) and GC-MS were used to identify the compounds fraction. RESULTS: Antioxidant enzyme catalase (CAT), neurotoxicity enzyme acetylcholinesterase (AChE) activities and hydrogen peroxide (H2O2), malondialdehyde (MDA) levels were determined in the liver, kidney and heart. CYP caused decreased CAT activity, inhibition of AChE activity and increased the levels of H2O2 and MDA in heart, liver and kidney. CONCLUSION: Our results indicate that Zizyp fruit is markedly effective in protecting mice against CYP-induced biochemical changes. This protection may be due to its antioxidant property and scavenging ability against active free radicals.


Assuntos
Frutas/química , Síndromes Neurotóxicas/prevenção & controle , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/farmacologia , Ziziphus/química , Animais , Catalase/metabolismo , Coração/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/patologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Masculino , Malondialdeído/metabolismo , Camundongos , Miocárdio/metabolismo , Miocárdio/patologia , Fármacos Neuroprotetores/farmacologia , Síndromes Neurotóxicas/etiologia , Fitoterapia/métodos , Piretrinas/toxicidade
15.
Mar Pollut Bull ; 123(1-2): 329-338, 2017 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-28918983

RESUMO

Analyses of organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and butyl tins (BuSn) were conducted on sediments from Ichkeul Lake-Bizerte Lagoon watershed (Tunisia). A total of 59 compounds (16 PAHs, 12 PCBs, 22 OCPs and 9 BuSn) were measured in 40 surface sediment samples collected during two campaigns. High concentrations of total PAHs were identified in the lagoon ranging from 122 to 19600ng·g-1. Several OCPs, including endrin, dieldrin, and lindane (Hexachlorocyclohexane or HCH or BHC) were found in high concentrations in Ichkeul Lake, ranging from 28 to 2012ngg-1. PAHs and OCPs varied seasonally, in response to the complex hydrology of the watershed. The concentrations of total PCBs ranged between 0.04 and 10.653ngg-1 and suggests low total PCBs sediment contamination, when compared to most international criteria. Total BuSn concentrations range between 67 and 526ng·g-1, which are relatively low when compared to most international criteria and ecological risk assessments. This is the first study of organic contamination in Ichkeul Lake (RAMSAR and UNESCO World Heritage site).


Assuntos
Sedimentos Geológicos/análise , Lagos/análise , Poluentes Químicos da Água/análise , Dieldrin/análise , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Hexaclorocicloexano/análise , Hidrocarbonetos Clorados/análise , Lagos/química , Praguicidas/análise , Bifenilos Policlorados/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Água do Mar/análise , Tunísia
16.
Environ Sci Process Impacts ; 18(7): 832-43, 2016 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-27285609

RESUMO

A mesocosm experiment was conducted to evaluate the effects of Irgarol on nematode diversity, composition and trophic structure. Sediment samples were experimentally contaminated using four increasing Irgarol concentrations [I1 (11.5 ng g(-1)), I2 (35 ng g(-1)), I3 (105 ng g(-1)) and I4 (315 ng g(-1))] and compared to non-contaminated sediments (controls). Nematode diversity as the number of nematodes species (S) and species richness (d) was significantly lower in all Irgarol treatments than in the controls while the evenness (J') increased significantly in I4 treated mesocosms. The nematode species composition significantly changed following Irgarol concentrations. Paracomesoma dubiun and Terschellingia longicaudata appeared as "tolerant" species to the highest Irgarol concentration. Additionally, Chromadorina germanica and Microlaimus cyatholaimoides appeared as "opportunistic" species. In contrast, Daptonema normandicum seemed to be a "sensitive" species to Irgarol contamination. Irgarol modified also the nematode trophic structure where the relative abundance of deposit feeders decreased significantly in all the treatments compared to control mesocosms and optional predators decreased only in treated mesocosms with I3. Epigrowth feeders increased significantly in treated mesocosms with I3 and I4 and the microvores increased with I1 and decreased with I4. The relative abundance of ciliate consumers appeared unaffected by the presence of Irgarol contamination. Our results open new perspectives on the potential impact of antifouling booster biocide Irgarol 1051 on nematode biodiversity and functional diversity as trophic structures.


Assuntos
Desinfetantes/análise , Desinfetantes/toxicidade , Nematoides/efeitos dos fármacos , Triazinas/análise , Triazinas/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Animais , Relação Dose-Resposta a Droga
17.
Ecotoxicology ; 25(6): 1160-9, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27230096

RESUMO

Trophic structure of free living nematode from Bizerte lagoon was tested by a microcosmic study after 30 days of exposure with 5 increasing doses of pharmaceutical penicillin G (D1: 3 mg L(-1), D2: 30 mg L(-1), D3: 300 mg L(-1), D4: 600 mg L(-1), D5: 700 mg L(-1)). Results showed significant differences between nematode assemblages from undisturbed controls and those from penicillin G treatments. Selective deposit-feeders (1A) or nonselective deposit-feeders (1B), very abundant in the control microcosm, were significantly affected and their dominance declined significantly. Epistrate feeders (2A) were significantly gradual increase for all microcosms treated with penicillin G, appeared to be more tolerant to the antibiotic and to take advantage of the growing scarcity of other trophic groups. Compared to the control microcosms, omnivorous-carnivorous (2B) was found to be higher in all treated microcosms, with the exception of those treated with D5. Trophic index (Σθ(2)) was significantly reduced in all microcosms treated whereas trophic ratio 1B/2A appears to be insignificant.


Assuntos
Antibacterianos/toxicidade , Nematoides/fisiologia , Penicilina G/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Relação Dose-Resposta a Droga , Cadeia Alimentar , Sedimentos Geológicos/química , Nematoides/efeitos dos fármacos , Testes de Toxicidade
18.
Pestic Biochem Physiol ; 129: 83-88, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27017886

RESUMO

Synthetic pyrethroids are a family of chiral pesticides with a large number of stereoisomers. Cypermethrin (CYP) is used in a variety of agricultural crops, but also has public health and veterinary uses. In this work, the freshwater mussel (Unio gibbus) was chosen to evaluate the stereoselectivity of CYP through the use of gas chromatography with mass-spectrometry. The effects of CYP on mussels were examined by measuring neurotoxicity and oxidative stress biomarkers during its uptake. The investigation was performed under laboratory conditions using nominal CYP concentrations C1=100 µg/L and C2=150 µg/L over 96 h. Preferential bioaccumulation of cis-CYP isomers was observed. Furthermore, enantiomeric characterization revealed enantioselective accumulation, most probably related to mussel metabolism. Antioxidant enzyme activities (superoxide dismutase (SOD), and catalase (CAT)), and levels of reduced glutathione (GSH) and malondialdehyde (MDA) were determined in digestive gland after 4 days of exposure. CYP significantly inhibited acetylcholine esterase activity, by 51% and 57%, respectively, in mussels treated with 100 and 150 µg/L doses. The highest and lowest CYP concentrations elicited an increase of 67 and 63%, respectively, in SOD activity compared to the controls, while CAT activity was increased by 65 and 73%. A statistically significant decrease in GSH levels (40%) was observed only with the highest CYP concentration tested (150 µg/L). In addition, lipid peroxidation was significantly higher (67%) than in controls. These results provided information on CYP-enantioselective uptake and potential biomarkers that could be effectively applied for the biomonitoring of freshwater ecosystem.


Assuntos
Bivalves/metabolismo , Piretrinas/metabolismo , Animais , Sistema Enzimático do Citocromo P-450/metabolismo , Água Doce , Estereoisomerismo
19.
Environ Sci Pollut Res Int ; 23(8): 7712-21, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26746401

RESUMO

The biocide Irgarol 1051 has been reported to have negative effects on a large number of living components including non-target organisms, but information on its impact on the marine meiofauna and benthic prokaryotes is completely lacking. Here, we report the results of long-term experimental studies in which we determined the effects of increasing Irgarol concentrations (from 11.5 to 315 ng g(-1) sediment dry weight) on meiofauna and benthic prokaryotes. We found that this biocide had a significant impact on meiofauna abundance, even at the lowest concentrations, causing a drastic decline in the abundance of nematodes (the dominant meiofaunal taxon) and an increase of the relative importance of oligochaetes. Even if no direct effects of Irgarol were found on prokaryotic abundance and biomass, the molecular fingerprinting analyses (automated ribosomal intergenic spacer analysis) showed that the prokaryotic diversity was significantly altered by the biocide. The results of the present study indicate that Irgarol 1051 in marine sediments has a significant impact on the smallest eukaryotic and microbial components also at very low concentrations (ca 12 ng g(-1)).


Assuntos
Desinfetantes/toxicidade , Sedimentos Geológicos , Nematoides/efeitos dos fármacos , Células Procarióticas/efeitos dos fármacos , Triazinas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Tunísia
20.
Environ Sci Pollut Res Int ; 23(1): 36-48, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26165992

RESUMO

This study aimed to identify the most commonly used agricultural pesticides around Ichkeul Lake-Bizerta Lagoon watershed. First survey of pesticide use on agricultural watershed was performed with farmers, Regional Commissioner for Agricultural Development, and pesticide dealers. Then, sediment contamination by pesticides and response of benthic communities (bacteria and free-living marine nematode) were investigated. The analysis of 22 active organochlorine pesticides in sediments was performed according to quick, easy, cheap, effective, rugged, and safe (QuEChERS) method, biodiversity of indigenous bacterial community sediment was determined by terminal restriction fragment length polymorphism (T-RFLP), and free-living marine nematodes were counted. The results of the field survey showed that iodosulfuron, mesosulfuron, 2,4-dichlorophenoxyacetic acid (2,4 D), glyphosate, and fenoxaprops were the most used herbicides, tebuconazole and epoxiconazole the most used fungicides, and deltamethrin the most used insecticide. Sixteen organochlorine pesticide compounds among the 22 examined were detected in sediments up to 2 ppm in Ichkeul Lake, endrin, dieldrin, and hexachlorocyclohexane being the most detected molecules. The most pesticide-contaminated site in the lake presented the higher density of nematode, but when considering all sites, no clear correlation with organochlorine pesticide (OCP) content could be established. The bacterial community structure in the most contaminated site in the lake was characterized by the terminal restriction fragments (T-RFs) 97, 146, 258, 285, and 335 while the most contaminated site in the lagoon was characterized by the T-RFs 54, 263, 315, 403, and 428. Interestingly, T-RFs 38 and 143 were found in the most contaminated sites of both lake and lagoon ecosystems, indicating that they were resistant to OCPs and able to cope with environmental fluctuation of salinity. In contrast, the T-RFs 63, 100, 118, and 381 in the lake and the T-RFs 40, 60, 80, 158, 300, 321, and 357 in the lagoon were sensitive to OCPs. This study highlighted that the intensive use of pesticides in agriculture, through transfer to aquatic ecosystem, may disturb the benthic ecosystem functioning of the protected area. The free-living marine nematodes and bacterial communities represent useful proxy to follow the ecosystem health and its capacity of resilience.


Assuntos
Bactérias/efeitos dos fármacos , Lagos , Nematoides/efeitos dos fármacos , Praguicidas , Poluentes Químicos da Água , Ácido 2,4-Diclorofenoxiacético , Agricultura , Animais , Dieldrin , Ecossistema , Hidrocarbonetos Clorados/análise , Inseticidas/análise , Lagos/química , Praguicidas/análise , Tunísia , Poluentes Químicos da Água/análise
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