Evaluation of transgenerational effects caused by metals as environmental pollutants in Daphnia magna

Abstract

The present study aimed to evaluate the acute and chronic toxicity of environmentally relevant concentrations of metals (Mn, Al, Fe, and Pb) in Daphnia magna and the generational transposition of reproductive and morphological damages. The effective concentration for 10% of the organisms from each metal was obtained by the acute toxicity test (96 hours); then, another five concentrations lower than this one were defined for the chronic experimentation (21 days), in which the number of neonates generated by each individual was checked daily. At the end of the exposition, the lengths and number of morphological damages were recorded in each adult daphnid. During this, the molt generated on the 14th and 21st days were collected and cultivated for posterior evaluation of the same parameters. Alterations in the reproductive performance were observed in the organisms exposed to manganese and aluminum (4.0 and 0.5 mg L⁻¹, respectively). Organisms exposed to aluminum (0.05 mg L⁻¹) and iron (0.27 mg L⁻¹) showed a reduction in body length. It is also noteworthy that the molt of these adults and their respective offspring also presented reproductive alterations, especially the molt from the 14th day of lead exposure (0.02 mg L⁻¹) and the 21st day of manganese exposure (4.0 mg L⁻¹). Such effects allow us to conclude that environments polluted by metals can reduce the ability of the species to maintain themselves in the ecosystem. In addition, there is a need to increase the control and monitoring of metals, such as aluminum, which present risks even in low concentrations.