Evaluación ecotóxica y genotóxica de aguas residuales hospitalarias Ecotoxicological and genotoxic evaluation of hospital wastewaters

Los líquidos residuales provenientes de hospitales constituyen un riesgo potencial para los ecosistemas y la salud humana debido a la presencia de compuestos tóxicos y genotóxicos. El objetivo de este trabajo fue analizar la toxicidad y la genotoxicidad de los efluentes provenientes del Hospital de Clínicas José de San Martín (Buenos Aires). Las muestras del efluente se tomaron durante los días y horarios de mayor actividad del hospital y se separaron en dos fracciones: acuosa y orgánica (extractos). Los ensayos de toxicidad se realizaron en la fracción acuosa utilizando dos especies de algas verdes: Pseudokirchneriella subcapitata y Chlorella vulgaris. La genotoxicidad se evaluó en las dos fracciones mediante el ensayo de Salmonella/ microsomas en ausencia y presencia de mezcla S9, utilizando las cepas TA98 y TA100. Veintinueve muestras de un total de 53 muestras analizadas resultaron tóxicas para P. subcapitata (entre 18 y 55 % de inhibición), mientras que sólo 8 muestras lo fueron para C. vulgaris (entre 21 y 50 % de inhibición). Ninguna de las muestras resultó genotóxica para Salmonella, ni en los extractos ni en las fracciones acuosas. De los tres ensayos utilizados, P. subcapitata fue el más sensible, siendo el ensayo más apropiado para el monitoreo de estos efluentes.<br>Wastewaters from hospitals constitute a potential risk to the ecosystems and human health due to the presence of toxic and genotoxic chemical compounds. The objective of this work was to analyze the toxicity and genotoxicity of wastewaters from the "Hospital de Clínicas José de San Martín" (Buenos Aires). Wastewater samples were obtained during the days and hours of major hospital activities and they were separated into two fractions: aqueous and organic (extracts). The toxicity assays were performed for the aqueous fraction using the green algae species: Pseudokirchneriella subcapitata and Chlorella vulgaris. Genotoxicity was assessed for the two fraction samples using the Salmonella/microsome assay in presence and in absence of S9 mix, with the strains TA98 and TA100. Twenty nine of the 53 total analyzed samples were toxic to P. subcapitata (between 18 and 55 % inhibition), whereas only 8 samples were toxic to C. vulgaris (between 21 and 50 % inhibition). None of the samples resulted genotoxic to Salmonella. Of the three tests used, P. subcapitata was the most sensible, resulting in the most suitable species to be used in hospital wastewaters monitoring

Cropping and livestock impacts on surface waters in the Pampas region (Argentina)

The rivers and streams of the cropping and livestock regions of Buenos Aires province (Argentina) contain variable concentrations of pollutants and high concentrations of nutrients that simultaneously affect aquatic ecosystem communities. In the present study, we evaluated the water quality of the Burgos stream and El Tala river (San Pedro, Buenos Aires province) by analyzing chemical contaminants (As, Cu, Pb, Zn, and glyphosate), nutrients (ammonium, nitrate, and phosphate), and algal toxicity bioassays. Surface water was collected at six sampling stations in three months (April and September 2019, and February 2020). By taking into account the percentages of algal growth inhibition (%I), the standard species Raphidocelis subcapitata and a species isolated from the study area, Scendesmus acutus, showed different sensitivities to the water samples, with a maximum %I of 70.64% and 34.62%, respectively. Moreover, algal growth stimulation was observed due to the high nutrient concentrations. A risk quotient (RQ) was applied to evaluate the environmental hazards of the chemical contaminants Cu, Pb, Zn, and glyphosate on the algal populations. According to the RQ values obtained for Pb (1.20 and 3.30) and Zn (1.17 and 2.12), the growth of algal populations could be at risk due to the maximum environmental concentrations measured of Pb (132 µg L-1) and Zn 106 µg L-1). The present study showed the first approach of an environmental risk analysis based on simultaneous determinations of chemical contaminants and laboratory bioassays with algae, using a strain of alga isolated from the aquatic ecosystems studied.The rivers and streams of the cropping and livestock regions of Buenos Aires province (Argentina) contain variable concentrations of pollutants and high concentrations of nutrients that simultaneously affect aquatic ecosystem communities. In the present study, we evaluated the water quality of the Burgos stream and El Tala river (San Pedro, Buenos Aires province) by analyzing chemical contaminants (As, Cu, Pb, Zn, and glyphosate), nutrients (ammonium, nitrate, and phosphate), and algal toxicity bioassays. Surface water was collected at six sampling stations in three months (April and September 2019, and February 2020). By taking into account the percentages of algal growth inhibition (%I), the standard species Raphidocelis subcapitata and a species isolated from the study area, Scendesmus acutus, showed different sensitivities to the water samples, with a maximum %I of 70.64% and 34.62%, respectively. Moreover, algal growth stimulation was observed due to the high nutrient concentrations. A risk quotient (RQ) was applied to evaluate the environmental hazards of the chemical contaminants Cu, Pb, Zn, and glyphosate on the algal populations. According to the RQ values obtained for Pb (1.20 and 3.30) and Zn (1.17 and 2.12), the growth of algal populations could be at risk due to the maximum environmental concentrations measured of Pb (132 μg L-1) and Zn 106 μg L-1). The present study showed the first approach of an environmental risk analysis based on simultaneous determinations of chemical contaminants and laboratory bioassays with algae, using a strain of alga isolated from the aquatic ecosystems studied