Ecological impacts of pesticides on Astyanax jacuhiensis (Characiformes: Characidae) from the Uruguay river, Brazil.

Brazilian freshwater ecosystems are continuously exposed to pesticides and domestic sewage. The Uruguay River was chosen for this study because of its international importance, as it flows through Brazil, Argentina, and Uruguay. It receives contaminants such as pesticides and domestic residues. Thus, the aim of this study to assess the accumulation of pesticides in muscle of the fish Astyanax jacuhiensis, its biochemical responses, and the presence of pesticides in water. In total, seven pesticides were registered in water from both river sites. Eight pesticides were detected in fish muscle. The biochemical responses showed that brain lipid peroxidation (LPO) and protein carbonyl (PC) in A. jacuhiensis were higher in the summer. Muscle showed the highest LPO levels in the spring and the highest PC in the summer. Liver LPO and PC levels were higher in the spring and summer. In the gills, the PC was higher in the spring and the LPO in the spring and winter. In the brain and in the gills, glutathione-S-transferase activity was high in the summer and autumn. Catalase activity was lower during the winter and spring. Non-protein thiol (NPSH) levels were lower in the brain in the winter and spring. Muscle tissue showed lower NPSH in the winter (site 1). Liver NPSH showed increased levels in liver in the spring and winter (site 2). The biochemical results clearly is related to pesticides and/or to the presence of other contaminants in the water such as metals or domestic sewage. The accumulation of pesticides in fish muscle added evidence that pesticides have been used in the area surrounding the Uruguay River. In conclusion, the biomarkers assayed in the present study could be used in future investigations considering other sampling sites along Uruguay River.

Biochemical Responses in Freshwater Fish Exposed to Insecticide Propoxur.

Although designed to control pests selectively, there is some evidence that environmental contamination by pesticides increases risks for humans and wildlife. In the present study, we evaluated biomarkers of oxidative stress in Astyanax jacuhiensis exposed to (5, 15 and 30 µg L-1) of carbamate Propoxur (PPX) for 96 h. Glutathione S-transferase (GST) in liver and gills showed reduced activity in all PPX concentrations tested. Acetylcholinesterase (AChE) activities reduced in brain and muscle at concentrations 15 and 30 µg L-1 of PPX. Lipid peroxidation (LPO) and hydrogen peroxide (HP) had no significant differences. In the brain, protein carbonyl (PC) increased in all groups treated with PPX. Although PPX is a selective pesticide, it causes oxidative damage and enzyme alteration in fish. This study pointed out some biomarkers that could be used to assess effects of environmentally relevant concentrations of pesticides, and infer about studies using fish as bioindicator.

Effects of prenatal and postnatal exposure to a low dose of bisphenol A on behavior and memory in rats.

Endocrine disruptors (EDs) are increasingly common chemicals in the environment. Bisphenol A (BPA), used to manufacture polycarbonate plastics, is an ED recognized for its estrogenic, anti-estrogenic, and anti-androgenic effects. Behavior is considered a vital characteristic for an animal's life cycle. This study evaluated the effect of exposure to low doses of BPA during pregnancy and/or lactation on several aspects of rat behavior, including memory, locomotion, and the exploratory instinct. Pups at 16 weeks of age (females and males) were divided into groups according to the mother's exposure to BPA (40µg/kg/day): CON (vehicle only); PRE (during pregnancy); LAC (during lactation); PRE-LAC (during both pregnancy and lactation). In the PRE-LAC group, exposure to BPA impaired both short-term (STM) and long-term memory (LTM) in inhibitory avoidance and the object recognition task, and also affected locomotor activity and spatial memory. Some sex-specific behavioral characteristics disappeared in the LAC group. Sex-specific memory and behavior impairment were caused by BPA exposure during brain organogenesis and differentiation.