Pesticide effects on crabs: how environmental concentrations of endosulfan and chlorpyrifos affect embryos.

The objectives of this work were to evaluate the effects of environmentally relevant chlorpyrifos and endosulfan, concentrations in the incubation period, effective hatching and survival of embryos and neonates of the freshwater burrowing crab, Zilchiopsis collastinensis (Decapoda, Trichodactylidae). Both pesticides were prepared from commercial and technical grade products. The exposure to about 100, 200, and 400 ng endosulfan L(-1), and 48, 240, and 1,200 ng chlorpyrifos L(-1) did not cause differences in the incubation period or in effective hatching but decreased survival of neonates, especially in the concentrations prepared from the technical grade product.

Predator-prey imbalances due to a pesticide: density and applicability timing as determining factors for experimental assessments.

Predator-prey relationships are determining factors in sustaining community structure but xenobiotics, including pesticides, have the potential to alter them, causing imbalances at the ecosystem level. Although invertebrate predation on zooplankton is of high importance in shallow lakes, there is still little information regarding disturbances on this trophic interaction. This work assessed the potential effects of a chlorpyrifos-based pesticide (CLP) on the interaction between prawns Macrobrachium borellii and cladocerans Ceriodaphnia dubia, taking into account prey densities, specific time of exposure and contamination level.

Bioaccumulation in freshwater crabs. Endosulfan accumulation in different tissues of Zilchiopsis collastinensis P. (Decapoda: Trichodactylidae).

We examined the bioaccumulation of α- and β-endosulfan and endosulfan sulfate in tissues from the crab Zilchiopsis collastinensis. There was more endosulfan accumulated in the hepatopancreas (from <2 to 467.8 ng g(-1)) than in the gonads (from <2 to 52.