PRELIMINARY ASSESSMENT OF TRACE METALS IN TEETH OF COMMERSON'S DOLPHINS (CEPHALORHYNCHUS C. COMMERSONII) FROM TIERRA DEL FUEGO, ARGENTINA

CÁCERES SAEZ, I.; PEREZ CATÁN, S.; DELLABIANCA, N.; CAPPOZZO, L.; GOODALL, R.N.P.

Cartagena de las Indias

Congreso; IV Congreso Colombiano de Zoología; 2014

Asociación Colombiana de Zoología

Calcified tissues, such as teeth, are good indicators of environmental exposure to trace elements. Museum specimens are often an important source of biological material for species and historical analyses for environmental studies. Depending on the treatment and storage of specimens and teeth, the latter have been found to provide an adequate matrix for elemental analysis. Graphite Furnace Atomic Absorption Spectrometry (GFAAS-) was used to assess essential (Cr) and non-essential (Ni, Cd and Pb) trace elements concentrations in teeth of Commerson?s dolphins from subantarctic waters of the southwestern South Atlantic Ocean. The Commerson?s dolphin (Cephalorhynchus c. commersonii) is endemic to South America (40ºS - 56ºS) and is affected by incidental catch in southern Patagonia and Tierra del Fuego island. Specimens were collected during the last four decades and provided by the Goodall collection at the Museo Acatushún de Aves y Mamíferos Marinos Australes, TdF, Arg. We studied 33 individuals: 9 females, 21 males and 3 of unknown sex. Ages, ranging between 0 - 17 years were estimated by counting growth layer groups (GLGs) in dentine. Elemental concentrations determined (expressed in dry weight, DW) were as follows: Cr 0.380.52; Ni 1.150.38 µg g-1 DW; Cd 0.110.11 µg g-1 DW and Pb 1.611.84 µg g-1 DW The data obtained are compared with those sparsely reported for other oceans, yet Pb concentrations ranged in the same order of magnitude as those found in teeth of small cetaceans (Delphinus delphis, Phocoena phocoena and Stenella coeruleoalba) from Mediterranean waters. In particular, mean Pb in teeth of Commerson?s dolphins examined was above the permissible limit of Pb for food at 0.05 µg g−1 WW (WHO, 1971) and the permissible limit of Pb in fish at 0.05 µg g−1 (FAO, 1983). A larger number of specimens should be analyzed to substantiate this trend. Lead analysis in teeth should provide information on long-term trends of bioaccumulation throughout the life of a cetacean. This study is the first assessment of toxic elements in teeth small cetacean species from the southern South Atlantic Ocean. In addition, it contributes with basic information for future nutritional and environmental monitoring research for subantarctic species and marine ecosystems.