Resumen Se evaluó la actividad genotóxica de varias concentraciones del herbicida marvel (0.76 μg/1 ml, 7.68 μg/1 ml, 76.8 μg/1 ml, 768 μg/1 ml) en linfocitos humanos y de ratones cepa Balb/c y eritrocitos de tilapia (Oreochromis niloticus). Se expusieron a cada una de las concentraciones durante 6 h y luego se evaluó daño genético mediante el ensayo cometa. Todas las concentraciones probadas indujeron un daño genético significativo en comparación con el control negativo (p < 0.01). No hubo diferencias entre las células sanguíneas de los organismos estudiados. La longitud de la cola y el momento de la cola aumentaron a partir de 0.76 μg/1 ml, esta es la concentración más baja reportada capaz de producir daño genético. Los datos sugieren que las diferencias reportadas con respecto a la genotoxicidad de marvel y sus ingredientes activos se deben a las marcadas diferencias entre las concentraciones estudiadas y los adyuvantes presentes en las formulaciones comerciales.

Abstract The genotoxic activity of various concentrations of the marvel herbicide (0.76 μg/1 ml, 7.68 μg/1 ml, 76.8 μg/1 ml, 768 μg/1 ml) was evaluated in lymphocytes of humans and in Balb/c strain mice, as well as in erythrocytes of tilapia (Oreochromis niloticus). They were exposed to each of the concentrations for 6 h, and then genetic damage was evaluated using the comet assay. All concentrations tested induced significant genetic damage compared to the negative control (p < 0.01). On the other hand, there were no differences between the blood cells of the organisms studied. Tail length and tail moment increased starting from 0.76 μg/1 ml concentration, which is the lowest concentration reported to cause any genetic damage. Data suggest that the reported differences regarding the genotoxicity of marvel and its active ingredients are due to the marked differences between the concentrations studied and the adjuvants present in the commercial formulations.

POPs are a group of chemicals with genotoxic capacity, found as contaminants in many water bodies. Given the high chemical pollution of Chapala Lake (including POPs), consumption of this water poses a genotoxic risk for people in the Guadalajara metropolitan area. Concentrations of POPs were quantified in water from Chapala Lake, Sayula Lake and in the liver of Goodea atripinnis on two seasons of the year: the dry and rainy seasons of 2006. Chromatographic analysis of the water showed very low concentrations of POPs and variations from one season to another. The increase of methoxychlor, 2,4 D and DDT is notable, indicating that they are dragged into the water bodies during the rainy season. POPs were detected in the liver of fish from both lakes; however, 2,4 D in the liver of fish from Chapala (0.02 ppm) is 10 times as concentrated as in Sayula (0.002 ppm). The evaluation of genetic damage by alkaline comet assay in hepatocytes during the dry season showed significant genetic damage (p < 0.01) in fish from the two reservoirs, probably due to 2,4 D. In the rainy season there was a significant difference (p < 0.01) in the case of Sayula but not for Chapala. Genetic damage in Sayula can be attributed to other substances with a mutagenic capacity different to that of POPs.

Los COP's son un grupo de sustancias químicas con capacidad genotóxica, correspondiente a contaminantes en muchos cuerpos de agua. Dada la alta contaminación química del Lago de Chapala, México (incluyendo compuestos orgánico-persistentes), el consumo de estas aguas, representa un riesgo mutagénico/genotóxico para los habitantes de la Zona Metropolitana de Guadalajara. En este estudio se cuantificaron las concentraciones de COP's del agua del Lago de Chapala y Laguna de Sayula y también del hígado de peces Goodea atripinnis, en dos épocas del año: sequía y lluvias del 2006. El análisis cromatográfico del agua de ambos embalses mostró muy bajas concentraciones de COP's y variación en ambas temporadas. Durante la época de lluvia destacó el incremento de metoxicloro, 2,4 D y DDT lo que indica que estos compuestos son arrastrados hasta los cuerpos de agua durante esta temporada. En el hígado de peces de ambos lagos se detectaron COP's, sin embargo, el valor de 2,4 D en los organismos de Chapala fue 10 veces más concentrado (0.02 ppm) en comparación con los de Sayula (0.002 ppm). La evaluación de daño genético a través de la prueba del cometa alcalino en hepatocitos durante la época de secas, mostró daño genético significativo (p < 0.01) en los peces de ambos embalses, debido probablemente al 2,4 D. En la época de lluvias se encontró daño genético significativo (p < 0.01) en peces de Sayula pero no para peces de Chapala. El daño genético encontrado en organismos provenientes de Sayula se atribuyó a otras sustancias con capacidad mutagénica diferentes a los COP's.

There is considerable controversy with regard to the genotoxicity of glyphosate, with some reports stating that this compound is non-toxic for fish, birds and mammals. In this work, we used the comet assay to examine the genotoxicity of glyphosate isopropylamine (0.7, 7, 70 and 700 µM) in human lymphocytes, erythrocytes of Oreochromis niloticus and staminal nuclei of Tradescantia (4430) in vitro and in vivo. Cells, nuclei and fish that had and had not been exposed to 5 mM N-nitrosodiethylamine (NDEA) were used as positive and negative controls, respectively. Significant (p < 0.01) genetic damage was observed in vivo and in vitro in all cell types and organisms tested. Human lymphocytes and Tradescantia hairs showed lower genetic damage in vivo compared to in vitro, possibly because of efficient metabolization of the herbicide. In O. niloticus erythrocytes, significant (p < 0.001) genotoxicity was observed at > 7 µM, whereas in vitro, glyphosphate was genotoxic in human lymphocytes and Tradescantia hairs at > 0.7 µM. These results indicate that glyphosate is genotoxic in the cells and organisms studied at concentrations of 0.7-7 µM.

Glyphosate is noted for being non-toxic in fishes, birds and mammals (including humans). Nevertheless, the degree of genotoxicity is seriously controversial. In this work, various concentrations of a glyphosate isopropylamine salt were tested using two methods of genotoxicity assaying, viz., the pink mutation assay with Tradescantia (4430) and the comet assay with nuclei from staminal cells of the same plant. Staminal nuclei were studied in two different forms, namely nuclei from exposed plants, and nuclei exposed directly. Using the pink mutation assay, isopropylamine induced a total or partial loss of color in staminal cells, a fundamental criterion utilized in this test. Consequently, its use is not recommended when studying genotoxicity with agents that produce pallid staminal cells. The comet assay system detected statistically significant (p < 0.01) genotoxic activity by isopropylamine, when compared to the negative control in both the nuclei of treated plants and directly treated nuclei, but only the treated nuclei showed a dose-dependent increase. Average migration in the nuclei of treated plants increased, when compared to that in treated nuclei. This was probably due, either to the permanence of isopropylamine in inflorescences, or to the presence of secondary metabolites. In conclusion, isopropylamine possesses strong genotoxic activity, but its detection can vary depending on the test systems used.