Taxonomic and non-taxonomic responses of benthic macroinvertebrates to metal toxicity in tropical reservoirs. The case of Cantareira Complex, São Paulo, Brazil.

Benthic macroinvertebrates are organisms that are recognized as water quality bio-indicators. A wide variety of indices and metrics have been shown to respond to a variety of anthropogenic impacts, usually under a general condition of environmental impairment. The absence of a clear distinction in the relations between specific pollutants and biotic variables is very common and can lead to biased interpretation of biomonitoring.

Spatial distribution, bioavailability, and toxicity of metals in surface sediments of tropical reservoirs, Brazil.

Depending on the environmental conditions, surface sediments can retain all the contaminants present and provide a record of the anthropic activities affecting the aquatic environment. In order to analyze the impacts on reservoirs, surface sediments were collected in three characteristic regions (riverine, transitional, and limnetic zones) of seven reservoirs in São Paulo State, Brazil. Analyses were made of grain size, organic matter (OM), total phosphorus (TP), and total nitrogen (TN).

Lethal and sublethal effects of metal-polluted sediments on Chironomus sancticaroli Strixino and Strixino, 1981.

The Cantareira Complex is one of the most important water supplies of the metropolitan region of São Paulo, Brazil. Previously, it was demonstrated that the sediments in this complex were polluted with metals and that Paiva Castro Reservoir-the last reservoir in the sequence, which receives water from the five previous reservoirs-was the reservoir with the greatest concentration of pollutants. Based on field data, it was noticed that copper concentrations in sediments were related to morphological alterations in chironomids.

Metals and limnological variables in an urban reservoir: compartmentalization and identification of potential impacted areas.

Reservoirs in urban areas are used for different purposes and are liable to different types of pressures that can cause the loss of chemical and biological quality, hence diminishing their ecological, economic, and cultural benefits. Here, a study of surface water heterogeneity was undertaken at the Guarapiranga urban reservoir (São Paulo, Brazil) in order to improve understanding of the structure and functioning of these ecosystems. Sampling was performed during the dry and rainy seasons at 33 sites.