Comet assay in Aegla platensis (Decapoda: Anomura) using a non-lethal hemolymph field sampling for in situ monitoring of freshwater genotoxicity.

This study aimed to apply the comet assay on Aegla platensis crabs as a suitable non-destructive approach for in situ monitoring of freshwater genotoxicity. Animals were captured during four sampling periods in a stream under minor anthropogenic impacts in Southern Brazil. Crabs were captured with a hand net, then the hemolymph samples were collected, and the animals were released into the stream after a 20-min recovery time. Hemolymph samples were transported to the laboratory and used to perform the alkaline comet assay. Results showed an intermediate level in the DNA damage index (range 107.3-165.0 arbitrary unit). No significant differences were observed among the different sampling periods. Hemolymph was successfully used as a non-lethal source of biological samples, and the comet assay using A. platensis proved to be a feasible approach for genotoxicity studies.

Treated tannery effluent and its impact on the receiving stream water: physicochemical characterization and cytogenotoxic evaluation using the Allium cepa test.

Tanneries are considered some of the most polluting industries due to the heavy use of toxic compounds, most of which are released into water bodies, thus exerting adverse effects on aquatic biota. However, the effects on organisms of treated effluents when released into the natural environment are rarely evaluated. This study aims to assess the physicochemical parameters of a tannery effluent after treatment (TE) at a Common Effluent Treatment Plant as well as the water of the receiving stream and to evaluate cytogenotoxic effects in Allium cepa. Three sampling sites (A: TE discharge point; B: 100 m downstream from site A along the receiving stream; C: 100 m upstream from site A along the stream) were selected. Onion bulbs were exposed to TE (100%, 80%, 60% v/v), water samples from sites B and C, and tap water for 72 h. Chromosomal aberration and mitotic index were analyzed on the root cells of A. cepa. The TE was above the standard limits for ammoniacal nitrogen, COD, and total nitrogen. No cytogenotoxicity was observed in A. cepa exposed to samples from sites A and C. However, the stream water sampled downstream from the TE discharge site significantly reduced the mitotic index, indicating a cytotoxic effect. Therefore, this demonstrates the effects of interactions between the receiving water and the complex chemical mixtures in the TE. The findings thus showed that the toxicity assessment of treated effluents along with the receiving water body would provide valuable and more realistic information about the joint toxicity of chemical pollutants in aquatic environments.

DNA Damage in Wistar Rats Exposed to Organophosphate Pesticide Fenthion.

In the last several decades, exposure to pesticides has become a concern to environmental and human health. Many pesticides are environmentally persistent and are characterized by varying degrees of toxicity and adverse effects, including DNA damage. The present study was undertaken to evaluate the genotoxic potential of organophosphate pesticide fenthion in Wistar rats, as assessed by the comet assay. Adult male Wistar rats were treated with a solution of fenthion at a concentration of 40 mg/kg/day, administered intraperitoneally for 18 consecutive days. Rats were killed 24 hours after the last pesticide administration, and the comet assay was performed in peripheral blood cells. The comet assay results revealed that the damage index (19.29 ± 3.59 vs. 7.80 ± 2.25) and the damage frequency (17.00 ± 3.46 vs. 7.5 ± 2.46) found in fenthion-treated rats were significantly higher than those found in the control group (p = 0.001 and p = 0.0006, respectively). The results show that fenthion affects the DNA integrity of rat cells and may induce DNA damage in exposed organisms.

Potencial mutagênico do fungicida Mancozebe em Astyanax jacuhiensis (Teleostei: Characidae) / Mutagenic potential of the fungicide Mancozeb in Astyanax jacuhiensis (Teleostei: Characidae)

O Mancozebe é um fungicida etilenobisditiocarbamato (EBDC) amplamente utilizado, cujos efeitos tóxicos já foram estudados em diversas espécies. No entanto, até o momento nenhum estudo avaliou o potencial mutagênico deste agrotóxico em peixes. Os efeitos mutagênicos de uma exposição aguda (120 h) a quatro diferentes concentrações (0,3 mg/L, 0,7 mg/L, 1,5mg/L e 2,5 mg/L) de uma formulação comercial à base de Mancozebe foram avaliados através do teste do micronúcleo (MN) e da ocorrência de anormalidades nucleares (AN) nos eritrócitos da espécie Astyanax jacuhiensis. Para a determinação das freqüências de MN e AN, foram analisadas 2000 células por animal. Os resultados não demonstraram diferenças significativas (P≥0,05) na freqüência de micronúcleos e anormalidades nucleares entre o grupo controle e os quatro tratamentos à base de Mancozebe, indicando que este fungicida não apresenta evidências de genotoxicidade em peixes da espécie Astyanax jacuhiensis, quando expostos às concentrações testadas neste trabalho.

Mancozeb, a widely used ethylenebisdithiocarbamate (EBDC) fungicide, has been studied for its toxic effects on several species. However, no study has evaluated the genotoxic potential of this agrochemical in fish. Therefore, the mutagenic effects of an acute exposure (120 h) in aquarium to four different concentrations (0,3 mg/L, 0,7 mg/L, 1,5mg/L and 2,5 mg/L) of a Mancozeb commercial formulation were evaluated using the micronucleus (MN) test and the analysis of nuclear abnormalities (NA) in Astyanax jacuhiensis erythrocytes. To determine the frequencies of MN and NA, 2000 cells per fish were evaluated. The results showed no significant differences (P≥0.05) in the micronuclei and nuclear abnormalities frequencies between the control group and the four groups treated with Mancozeb, indicating that this fungicide does not present evidence for genotoxicity on Astyanax jacuhiensis, when exposed to the concentrations tested in this work.