A concha do mexilhão Perna Perna: presença de impurezas e espessura em diferentes condições ambientais.

The study evaluates and compares the environmental influences (river inputs and wave exposure) on the presence of Fe(III) and Mn(II) and thickness of the shell of Perna perna mussel. The following hypotheses are raised: i) shells from areas with greater influence of rivers have higher concentrations of Fe(III) and Mn(II); and ii) shells from areas with greater wave exposure are thicker. The first hypothesis was confirmed, and the highest concentration of both elements were registered in shells from Atafona, area located near the mouth of the Paraíba do Sul River. The second hypothesis was not confirmed. The mean shell thickness values were higher in Búzios, which is classified as an area without wave exposure. This result can be explained by the high availability of CO32- for coastal waters in this area. The P. perna mussel is a sessile filter with wide distribution along the Brazilian coast, and the results suggests that its natural banks can serve as sentinels for environmental characterization and monitoring. [ABSTRACT FROM AUTHOR]