Relationship between mercury and selenium concentrations in marine tetrapod livers: a comparative assessment between birds, turtles and odontocetes

Abstract

The issue associated with contamination and availability of mercury has been shown to be very significant for the quality of marine ecosystems and the health of aquatic organisms. This cause-and-effect relationship can be gauged mainly in chain top organisms arising from bioaccumulation by the food web, which in turn tends to relate to the biomagnification of toxic effects. However, researchers noted the absence of clinical signs common in animals exposed to Hg, along with the presence of mercury selenide, and inert and insoluble mercury granules. Thus, it is hypothesized that selenium should be a reducing potential for mercury forms, capable of increasing tolerance to trace elements and restricting the clinical symptoms of mercury (generally, in molar ratios close to 1:1). Thus, this project aims to evaluate and measure the total concentrations of Hg and compare their molar proportions in histopathological samples of birds, turtles, and odontocetes. The samples will be analyzed using the inductively coupled plasma mass spectrometry with, or alternatively, by an atomic fluorescence spectrometry associated with cold vapor. The data to be obtained will be treated statistically, considering interspecific and intraspecific factors, in order to provide information capable of broadening the understanding of the Hg-Se synergy between groups of marine tetrapods in the Santos basin.(AU)