Age trends and reproductive transfer of organochlorine compounds in long-finned pilot whales from the Faroe Islands

Total DDT and PCB concentrations were determined in blubber of 130 long-finned pilot whales, Globicephala melas (100 females and 30 males) from the Faroe Islands (northern north-east Atlantic). In males and immature females no relation was observed between age and organochlorine concentrations or the ratio of tDDT (total DDT)/PCB; in contrast, concentrations and ratios in mature females declined with age, which is attributed to reproductive transfer to their offspring during gestation and lactation. Relative abundance of DDE respective to tDDT increased in males and young females and decreased in mature females. Organochlorine transfer to offspring during lactation was found to represent about 60-100% of the mother's body load, while that occurring during gestation was estimated to be much lower, in the range 4-10% of mother's body load. Transfer rates tended to decrease with mother's age and were, consequently, much higher in primiparous females than in those that had already given birth. Transplacental rates were found to be consistent with the ratio between mother's body weight and neonatal body weight.