PARENT SESSION
80 - Biomonitoring and Assessment
8:00 AM to 6:30 PM, Wednesday, 15 May 2002
Exhibition Area

(80-07) First evidence of organochlorines in blubber samples of delphins from Golfo Dulce, Costa Rica.

Cubero-Pardo, Priscilla¹, Forestell, Paul², Ruepert, Clemens³, Rodríguez-Fonseca, Javier¹, Crespo-Varela, María Luisa¹, Montenegro-Hidalgo, Victor¹, Albertazzi, Federico⁴, de Voogt, Pim^*,5, ¹ Centro de Proyección del Ambiento Marino, San José, Costa Rica² Pschbiology Program, Southampton College, New York, USA³ Instituto Regional de Estudios en Sustancias Tóxicas IRET, Heredia, Costa Rica⁴ Centro de Investigaciones en Biologia Celular y Molecular, San José, Costa Rica⁵ Environmental & Toxicological Chemistry, Amsterdam, The Netherlands

ABSTRACT- While in Northwestern Europe a decline in organochlorine concentrations has become visible in marine mammals, there has been a strong increase in the last 10 years in other parts of the world. For the Eastern Tropical Pacific there is a great lack of information. Golfo Dulce is a ′tropical fjord′ on the Pacific coast of Costa Rica. In recent years it has been determined that different kinds and levels of chemical pollution are present in the gulf, mainly carried along by rivers. The gulf currently supports resident or seasonal populations of at least three species of cetaceans: Tursiops truncatus (Bottlenose dolphin, bufeo), Stenella attenuata (Spotted dolphin, delfin manchado) and Megaptera novaeangliae (humpback whale, ballena jorobada), and five other species have been reported. This study is the first to assess the extent of organochlorine accumulation in the two most common species of dolphins in the area. Levels of organochlorines have not been presented before for Spotted dolphins. Skin biopts were obtained from four specimen by non destuctive cross-bow sampling. Total levels of PCBs amount to 200-250 g/kg wet tissue (1500-1800 g/kg lipid wt.) in Spotted dolphins and 1500-1800 g/kg wet tissue (6400-8200 g/kg lipid wt.) in Bottlenose dolphins. Differences between male and female species appear to be minor, confirming that the female species have not yet reached a reproductive age. The levels found in Bottlenose dolphins in the present study are in the low range of data reported in the literature for this species, confirming the relatively pristine status of the area. Levels of DDE in Spotted dolphin amount to 260-340 g/kg (wet weight), and DDT levels range from < lod − 60 g/kg. DDE and DDT levels in Bottlenose dolphin range from 1000-1200, and 150-250 g/kg, respectively. The ratios of DDT/DDE do not indicate a recent use of DDT in the area.

Key words: organochlorines, pcb, dolphins, Costa Rica