Using multibiomarker approach as a tool to improve the management plan for a Private Reserve of Natural Heritage (RPPN).

This study aimed to monitor an aquatic ecosystem during two different periods (dry and rainy season) on a protected area located inside a sugarcane farm, using the fish Astyanax sp. as bioindicator. An integrated approach was adopted by combining the responses of well-known biomarkers: acetylcholinesterase, lipid peroxidation (LPO), catalase (CAT), glutathione S-transferase (GST), micronucleus test, and liver histopathology. The activity of enzymes CAT and GST was increased after the rainy season. This can be explained mainly by the intensification of rain density, which drags substances into the streams, especially pesticides applied on agriculture. LPO and micronucleus test also suggested some effects of contamination in the surrounding area during this season. The results have supported a discussion about the effectiveness of protected areas in agricultural regions, emphasizing the biomonitoring as a tool for improving management plans in protected areas.

Insecticides biomarker responses on a freshwater fish Corydoras paleatus (Pisces: Callichthyidae).

This study was undertaken to investigate the effects of sublethal concentration of three different classes of insecticides (carbamate, organophosphate, and pyrethroid compounds) on the freshwater fish Corydoras paleatus. For this purpose, fish were exposed for 96 hours to commercial pesticides. Different biomarkers were analyzed as levels of lipid peroxidation (LPO), piscine micronucleus test, and enzymatic activities of catalase (CAT), glutathione S-transferase (GST), and acetylcholinesterase (AChE). The brain AChE was inhibited with carbaryl and methyl parathion, but no inhibition was observed with deltamethrin. The insecticides did not cause oxidative stress or genotoxic effects at the tested concentrations. Further studies are needed to elucidate the biotransformation of Corydoras paleatus insecticides and a possible resistance mechanism.

Sublethal effects of waterborne herbicides in tropical freshwater fish.

The study evaluated the sublethal effects of the herbicides glyphosate (Roundup) and diuron (Hexaron) and the mixture of them, used extremely in agriculture, through biomarkers in fish. The glutathione S-transferase activity increased (74%) and catalase activity decreased (37%) at the higher exposure concentration of Hexaron in comparison to the control group, suggesting an activation of this metabolism route. Membrane damage was observed at the higher exposure of Roundup and in the mixture group compared to the control group, which can be related to the nuclear alterations observed in these exposed groups. The cholinesterase activity was also inhibited (37%) in mixture group compared to the control group and no gill morphology damage was found. The results suggested a potential synergic effect in some analysed parameters.

Low concentrations of cylindrospermopsin induce increases of reactive oxygen species levels, metabolism and proliferation in human hepatoma cells (HepG2).

Human hepatoma cells (HepG2) were exposed to purified cylindrospermopsin (CYN), a potent toxicant for eukaryotic cells produced by several cyanobacteria. CYN was not toxic at concentrations up to 10 µgl(-1), leading to increased viability and metabolism in cells cultured with 10% fetal bovine serum (FBS). Reduction of FBS concentration to 2% and induction of cytochrome P450 (CYP) isoforms were performed in order to make xenobiotic-metabolizing capacity of HepG2 cells closest to that of 'normal' cells. HepG2 cells proliferated less after CYPs-induction, and this induction has lead to similar results of non-induced cells, except for few individual parameters such lipid peroxidation. Foremost, low concentrations of CYN (below or equal 10 µgl(-1)) have induced HepG2 cells proliferation and metabolism increase, which was not expected.

Resíduos de pesticidas em alimentos / Pesticide residues in food

Este trabalho teve como objetivos comparar os níveis de resíduos de pesticidas encontrados em alimentos investigados pelo Programa de Análise de Resíduos de Pesticidas em Alimentos da Agência Nacional de Vigilância Sanitária (PARA/ANVISA) e avaliar o possível risco tóxico da sua ingestão. Para tanto, foram comparados os dados dos relatórios do PARA de 2001 e 2003, quando 2647 amostras de nove culturas de hortaliças e frutas foram analisadas. Calculou-se o risco tóxico da ingestão desses resíduos pela população utilizando dados do limite máximo de resíduo para cada pesticida e do consumo alimentar. Também determinou-se o número de pesticidas que ultrapassaram o limite máximo de resíduos (LMR) permitido e pesticidas encontrados em culturas cujo uso não é permitido. Os resultados indicaram que não houve modificações significativas no número de resíduos encontrados nas duas avaliações efetuadas pelo PARA entre os anos de 2001 e 2003. Dentre as 2.647 amostras analisadas foram detectados resíduos de 2.256 pesticidas, sendo 68 por cento envolvendo o uso regular e 32 por cento o uso irregular (não-autorizado 89 por cento e uso acima do LMR 11 por cento). Dezenove pesticidas apresentaram risco tóxico para a população na avaliação do relatório de 2001 e 16 no relatório de 2003. Esses dados permitem concluir que alimentos com resíduos de pesticidas não deveriam apresentar risco para a população, exigindo melhoria na fiscalização do uso de pesticidas na agricultura.