Can the Herbicide Dicamba Produce Oxidative Stress in the Native South American fish Jenynsia lineata at Environmentally Relevant Concentrations?

Dicamba (DIC) is one of the most applied auxin herbicides worldwide. Sublethal effects in the South American native fish Jenynsia lineata exposed to DIC concentrations close to environmental concentrations (0.03-30 µg/L) during 48 h were analysed thorough the evaluation of catalase (CAT), glutathione S-transferase (GST), superoxide dismutase (SOD) activities and malondialdehyde (MDA) and H2O2 levels for detecting potential oxidative stress. In gills MDA increased showing oxidative damage probably because of an inefficient antioxidant defense. This response evidenced the important role of gills as an organ of direct contact with waterborne contaminants. In addition, other changes in the biomarkers of oxidative stress were observed such as the inhibition of SOD activities in brain and the inhibition of GST in liver. These results show that short- term exposures to environmentally relevant concentrations of DIC could induce sublethal effects in native fish.

The problem with implementing fish farms in agricultural regions: A trial in a pampean pond highlights potential risks to both human and fish health.

The safety of creating fish farms in agricultural settings was evaluated by growing Piaractus mesopotamicus in a pond, while crops where cultivated in a nearby field under a pesticide application regime typical of the Pampa region. Atrazine, glyphosate and its metabolite, aminomethylphosphonic acid (AMPA), were detected in the water of the pond at concentrations ranging between 92 and 118 µg/L for atrazine, 12 and 221 µg/L for glyphosate and 21 and 117 µg/L for AMPA. Atrazine and malathion were detected in fish muscles at concentrations ranging between 70 and 105 µg/kg for atrazine and 8.6 and 23.7 µg/kg for malathion. Compared to fish raised in a pisciculture, fish from the agricultural pond presented reduced values of pack cell volume, hemoglobin, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration, together with significantly greater cholinesterase activity in both plasma and liver and reduced glutathione-S-transferase activity in the liver. A comet assay also demonstrated that P. mesopotamicus from the agricultural pond presented a significantly greater level of DNA damage in both erythrocytes and gill cells. Overall, the present study demonstrates that pisciculture ponds established in an agricultural setting may receive pesticides applied to nearby cultures and that these pesticides may be taken up by the fish and affect their physiology and health. The accumulation of pesticides residues in fish flesh may also present a risk to human consumers and should be closely controlled.

Evaluación de estrés oxidativo en pacientes con Lupus Eritematoso Sistémico y su posible relación con la exposición ambiental a agroquímicos / Assessment of oxidative stress in patients with Systemic Lupus Erythematosus and its possible relationship with environmental exposure to agrochemicals

Los agroquímicos son un método efectivo para controlar especies perjudiciales a los intereses del hombre, pero aplicados indiscriminadamente provocan diversos impactos a nivel ambiental y en la salud. Uno de los mecanismos más importantes por el cual los agroquímicos se ponen en contacto directo con las poblaciones de zonas periurbanas es mediante la deriva. El Lupus Eritematoso Sistémico (LES) es una enfermedad autoinmune que posee un amplio rango de presentaciones clínicas y severidad. Si bien su etiología es desconocida, se la asocia con diversas causas ambientales dentro de las que podrían estar presentes los agroquímicos. El objetivo de este estudio fue evaluar, el posible daño oxidativo generado por exposición ambiental a mezclas de agroquímicos en pacientes con LES y personas sanas que residen en zonas rurales expuestas a mezclas de plaguicidas y contrastar los resultados con pacientes y personas sanas de zonas urbanas no expuestas. Se evaluaron 44 pacientes con diagnóstico de LES y 58 personas sanas (controles), se utilizaron como marcadores: catalasa (CAT), superóxido dismutasa (SOD), la relación glutation oxidado/reducido (GSH/GSSG) y lipoperoxidación (TBARS). Se encontraron diferencias estadísticamente signifcativas para TBARS y SOD al comparar los resultados del grupo LES urbano con su control y el grupo LES rural con el suyo (p<0,01 en ambos). Al realizar las comparaciones entre LES urbano y LES rural se halló un incremento en TBARS del 18,3% (p=0,014). Esta investigación demuestra la importancia de la utilización de biomarcadores de daño oxidativo en el seguimiento clínico de pacientes con LES, con el fn de establecer pautas de tratamiento adecuadas y considerar la relación entre la exposición ambiental a plaguicidas y el aumento de daño oxidativo en pacientes con LES.

The agrochemicals are an effective method to control harmful species of interests to humans, but when they are applied indiscriminately, they can cause environmental and health damage to people. Systemic Lupus Erythematosus (SLE) is an autoimmune disease that has a wide range of clinical manifestations and severity. While the etiology of SLE is unknown, it is associated with various environmental causes, being one possibility the exposure to agrochemicals. The aim of this study was to evaluate the possible oxidative damage generated by environmental exposure to agrochemical mixtures in SLE patients and healthy people living in rural areas and compare them with patients and healthy people living in urban, unexposed areas. Forty four patients diagnosed with SLE and 58 healthy individuals (controls) were evaluated, using the following markers: Catalase (CAT), superoxide dismutase (SOD), the oxidized/reduced glutathione ratio (GSH / GSSG) and lipid peroxidation (TBARS). Statistically signifcant differences were found in TBARS and SOD by comparing the results of the urban SLE group with its control and rural SLE group with its control (p <0.01 for both cases). When making comparisons between urban SLE group and the rural SLE group, an increase of 18.3% was found in TBARS (p = 0.014). This research demonstrates the importance of using biomarkers of oxidative stress in the clinical monitoring of patients with SLE, in order to establish guidelines for appropriate treatment and consider the relationship between environmental exposure to pesticides and increased oxidative damage in patients with SLE.

Evaluación de genotoxicidad a través de la frecuencia de Micronúcleos en eritrocitos de Piaractus mesopotamicus (pacúes) expuestos in vivo a nanopartículas de plata / Assessment of genotoxicity by Micronucleus frequency in Piaractus mesopotamicus erythrocytes exposed to silver nanoparticles in vivo

El uso creciente de nanomateriales en productos industriales y de consumo ha incrementado la preocupación mundial respecto a sus posibles efectos adversos en los sistemas biológicos. Como consecuencia de la falta de un marco legislativo y la ausencia de un consenso sobre los protocolos experimentales, las investigaciones ecotoxicológicas se llevan a cabo a un ritmo mucho más lento que la producción de nuevas nanopartículas. Por esta razón, existe una necesidad creciente de realizar estudios que aporten conocimiento sobre el riesgo de estos contaminantes emergentes de propiedades únicas. El objetivo del presente trabajo fue evaluar la frecuencia de micronúcleos (FMN) en eritrocitos de ejemplares juveniles de pacú (Piaractus mesopotamicus) expuestos a nanopartículas de plata (Nano-Ag) a las concentraciones de 0 μg·L-1 (control); 2,5 μg·L-1; 10 μg·L-1; y 25 μg·L-1, durante 24 horas. Se observó que la FMN se incrementó significativamente (p<0,01) en la concentración de 25 μg·L-1, mientras que no hubo diferencias significativas entre los grupos expuestos a 2,5 y 10 μg·L-1 y el control. Estos resultados sugieren que los eventos aneugénicos o clastogénicos podrían representar un posible mecanismo de toxicidad de Nano-Ag en esta especie.

The growing use of nanomaterials in consumer and industrial products has aroused global concern about possible adverse effects on biological systems. Due to the lack of a regulation framework and the absence of a consensus on the experimental protocols, ecotoxicological investigations are carried out much slower than the production of new nanoparticles. For this reason, there is a growing need for studies that provide knowledge about the risk of these emerging contaminants of unique properties. The objective of the present study was to evaluate the frequency of micronuclei (FMN) in erythrocytes of juvenile Piaractus mesopotamicus exposed to silver nanoparticles (nano-Ag; Nanotek SA) at concentrations of 0 μg·L-1 (control); 2.5 μg·L-1; 10 μg·L-1; and 25 μg·L-1, for 24 hours (n = 10 per treatment). The FMN show a significant increase (p <0.01) in fish exposed to 25 μg·L-1 of Nano-Ag, while there were no significant differences among the groups exposed to 2.5 and 10 μg·L-1 with the control. These results suggest that the aneugenics or clastogenics events may represent a possible mechanism of toxicity of Nano-Ag in this specie.