Trace Metal (Cr, Ni, Cd and Pb) Concentrations in Teeth of Commerson?s Dolphins Cephalorhynchus commersonii

NATALIA A. DELLABIANCA; H. LUIS CAPPOZZO; IRIS CÁCERES-SÁEZ; CAROLINA LOCH; SOLEDAD PEREZ-CATAN; R. NATALIE P. GOODALL

Valparaiso

Congreso; XI Congreso de la Sociedad Latinoamericana de Especialistas en Mamíferos Acuáticos; 2016

SOLAMAC & Universidad de Valparaiso

Calcified tissues such as teeth, and bones, are metabolically inert structures that preserve into the organism the chemical variations related to the environment. Moreover, mammal teeth constitute a preserved material in which, for example, temporal trends of trace elements and toxic metals can be measured. As a preliminary study to investigate the trace metal accumulation, we used entire dry teeth (DW) of caught Commerson?s dolphins (C. commersonii) from Subantarctic waters of Tierra del Fuego, Argentina. Total concentrations of Cr, Ni, Cd and Pb were determined by Graphite Furnace Atomic Absorption Spectrometry. Teeth were collected from 42 specimens (9 females, 30 males and 3 unknown sex) belonging to the RNP Goodall collection at Museo Acatushún, Tierra del Fuego, Arg. throughout decades (1975-2011). The ages were estimated by counting growth layer groups (GLGs) in dentine and range between 0 - 17 years. Statistical analyses were applied to evaluate differences between sex and sexual maturity of individuals, for this purpose animals were grouped as mature and immature (>6 and ≤5 years old, respectively). Chromium and Cd were not detectable and below the detection limit in 43% and 9.5% of the samples analyzed; respectively. The mean value of Cr was 0.13 µg gr-1 DW and for Cd was 0.61 µg gr-1 DW. Lead and Ni concentrations were the highest among metals analyzed, and range in values from 0.11 to 4.1 µg gr-1 and 0.67 to 5.1 µg gr-1; respectively. We found similar levels between sexes for all elements. Mature animals showed mean highest concentrations in comparison to those immature individuals for elements, such as Pb, Ni and Cd, however no statistical differences were detected. An age-related accumulation trend needs to be confirmed more larger number of specimens under analyses. Our study adds with novel information of trace metal contents in calcified tissue of small cetaceans. To point out, the trace elements levels of animal teeth may be useful as complementary information about the exposure of the individuals and the conditions of ocean environmental.