Metal and metalloid concentration, distribution and accumulation in embryonic tissues of the batoid Sympterygia acuta

A few studies have assessed the environmental contamination in elasmobranch embryos, remarkably oviparous species. In this study, we evaluated the concentration of 10 metals and As in embryos of the critically endangered Bignose Fanskate Sympterygia acuta, and the distribution and accumulation pattern of these elements in embryonic tissues. Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn concentrations were determined in egg capsules, homogenized embryos, and yolk sac, through Inductively Coupled Plasma Mass Spectrometry, and data was analyzed through univariate multiple comparisons, Principal Component Analysis and generalized linear models. Overall, Al was the highest non-essential element present in the matrixes analyzed. All nonessential metals showed similar distribution patterns with embryos and egg capsules presenting relatively higher concentrations. By contrast, other elements, such as Fe and Zn were found in embryos and yolk sac, indicating a potential maternal input. Arsenic also followed this pattern. Ni, and Cu, to a lesser extent, were detected at higher levels in egg capsules, suggesting the potential selectivity of this structure in oviparous elasmobranchs - a hypothesis that needs further studies. Only Fe concentrations were related to embryo length, suggesting a biodilution of this element throughout the embryonic development. Further studies assessing the implications of such exposure are necessary for the future monitoring of this critically endangered species.