[Use of bioindicators for assessing and monitoring pesticides contamination in streams and rivers].

The objective of this article is to present an analysis of the main bioindicators that are currently used to assess the environmental impact of pollution in water resources. The simple quantification of chemicals in the environment is not enough to reveal the real effects of contamination on ecosystems, making necessary the assessment of the biological effects that pollution causes at different hierarchical levels. The bioindicators used in this article on two case studies comprehend different hierarchical levels: in case study 1, three organization levels were utilized: individual, cellular and molecular, to detect the early effects of exposition to environmental pollutants in three hydrographic basins.

Short-term responses to cadmium exposure in the estuarine polychaete Laeonereis acuta (polychaeta, Nereididae): subcellular distribution and oxidative stress generation.

Some effects of cadmium exposure (100 microg/L for 4, 8, 12, and 24 h) on the estuarine polychaete Laeonereis acuta (Nereididae) were evaluated. This polychaete was able to accumulate cadmium in the body, with the metal stored mainly in the cytosolic fraction (>10 kDa). Activity of the antioxidant enzymes superoxide dismutase, glutathione S-transferase, and glutathione reductase (GR) as well as the total oxyradical scavenger capacity, the glutamate cysteine ligase catalytic subunit gene expression, and the metallothionein-like proteins content were not affected by cadmium at any exposure time tested.