Can a low concentration of an organophosphate insecticide cause negative effects on an aquatic macrophyte? : Exposure of <i>Potamogeton pusillus</i> at environmentally relevant chlorpyrifos concentrations

The contamination of the aquatic environments with organophosphorus pesticides may affect non-target organisms. The aim of this study was to evaluate the toxic effects of the insecticide chlorpyrifos (CPF) at environmental concentrations on the freshwater macrophyte Potamogeton pusillus belonging to a genus of worldwide distribution. For this purpose, individuals were exposed from 3.5 to 94.5 ng of CPF L-1 for 96 h. A battery of biochemical responses including bioaccumulation, defense and damage biomarkers were measured in leaf, stem and root. Even when CPF was not detected in the macrophyte tissues, our results showed that this insecticide promotes oxidative stress and biomolecule damages in P. pusillus after acute exposure. Significant response of biomarkers was observed from the lowest tested concentration (3.5 ng CPF L-1). Oxidative stress was evidenced by increased lipid peroxidation and antioxidant enzymatic activation, including changes in superoxide dismutase, guaiacol peroxidase and glutathione peroxidase activities, especially in leaf. Also, a significant decrease in chlorophyll a and b contents was observed mainly in leaf. Finally, with some selected biomarkers, an Integrated Biomarker Response index was calculated showing a dose–response relationship with CPF exposure. Previous studies reported that herbicides and organophosphorus pesticides are responsible for several effects on photosynthetic systems but at higher exposure concentrations than the tested in this study. These results draw attention to the need for more studies in toxic effects of insecticides on aquatic macrophytes, at low concentrations and different biological levels, since the protection guidelines would not be preserving these species.Facultad de Ciencias ExactasCentro de Investigaciones del Medioambient

A multi-biomarker approach to assess the sublethal effects of settleable atmospheric particulate matter from an industrial area on Nile tilapia (Oreochromis niloticus)

Iron and steel industries discharge a large amount of atmospheric particulate matter (PM) containing metals and metallic nanoparticles (NPs) that contaminate not only the air, but also settle into the aquatic environments. However, the effects of settleable atmospheric particulate matter (SePM) on aquatic fauna are still poorly understood. This study aimed to evaluate the sublethal effects of a short-term exposure to a realistic concentration of SePM on Nile tilapia (Oreochromis niloticus) using a multi-biomarker approach: relative ventricular mass (RVM) and heart function, blood oxidative stress, stress indicators, hemoglobin concentration, metallic NPs internalization, and metal bioaccumulation. Exposed fish exhibited reduced hemoglobin content and elevated plasma cortisol and glucose levels, reflecting stressed states. Furthermore, SePM caused blood oxidative stress increasing lipid and protein oxidation, decreasing glutathione levels, and inhibiting superoxide and glutathione reductase activities. SePM exposure also increased RVM and improved cardiac performance, increasing myocardial contractile force and rates of contraction and relaxation. In the heart tissue there was a significant accumulation of Fe > Zn > > Cr > Cu > Rb > Ni > V > Mn > Se > Mo > As. On the other hand, in the erythrocytes there was significant accumulation of Sn > Zn > > Cr > Ti > Mn = Ni > Nb > As > Bi. The highest bioaccumulation factors were found for Cr, Zn and Ni in both tissues. NPs (Ti, Sn, Al, Fe, Cu, Si, Zn) were also detected in ventricular myocardium of fish exposed and nanocrystallographic analysis revealed a predominance of anatase phase of TiO2-NP, which is regarded to be more cytotoxic. The association between blood oxidative stress and energy expenditure to sustain increased cardiac pumping capacity under stress condition suggests that SePM has negative impacts on fish physiological performance, threatening their survival, growth rate and/or population establishment.Fil: Adorno, Henrique Aio. Universidade Federal do São Carlos; BrasilFil: Souza, Iara da Costa. Universidade Federal do São Carlos; BrasilFil: Monferrán, Magdalena Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Wunderlin, Daniel Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Fernandes, Marisa Narciso. Universidade Federal do São Carlos; BrasilFil: Monteiro, Diana Amaral. Universidade Federal do São Carlos; Brasi

MTs in Palaemonetes argentinus as potential biomarkers of zinc contamination in freshwaters

Aquatic invertebrates take up and accumulate essential and non-essential trace metals even when both are likely to be poisonous. In order to study the potential of the metallothioneins (MTs) as biomarkers of metal contamination in native shrimp Palaemonetes argentinus, organisms have been exposed at 0, 5, 50 and 500 μg L-1 of zinc for 96 h. Moreover, accumulation and subcellular distribution of this essential metal were evaluated. A significant Zn accumulation was observed in different body sections. Higher Zn levels occurred in cephalothorax compared to abdomen, especially at the highest exposure concentration (500 μg Zn L-1). A clear differential subcellular metal distribution between cephalothorax and abdomen was also observed. In cephalothorax Zn was similarly distributed between the soluble and insoluble fractions; while in abdomen, when total Zn increased, insoluble metal augmented more markedly than the soluble one. Cytosolic Zn levels increased more in cephalothorax than in abdomen of shrimps exposed to 500 μg Zn L-1 when compared to control. Finally, a significant induction of MTs was observed in cephalothorax at 500 μg Zn L-1. A potential role for MTs as biomarkers in P. argentinus should be further studied to enhance the sensitivity of the response, although it is likely that MTs play a key role in metal detoxification since the increase of these proteins is linked to metal challenge.Fil: Bertrand, Lidwina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Monferran, Magdalena Victoria. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Métais, Isabelle. Université Catholique de l'Ouest; FranciaFil: Mouneyrac, Catherine. Université Catholique de l'Ouest; FranciaFil: Amé, María Valeria. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentin