PCBs and chlorinated pesticides in clinically healthy Tursiops truncatus: Relationships between levels in blubber and blood

A method for estimating organochlorine (OC) levels in blubber from levels found in blood samples could augment health assessment of dolphin populations where blubber sample collection is not possible. To explore the relationship between residue levels in red blood cells and blubber, paired preprandial blubber and blood samples were collected from 16 clinically healthy bottlenose dolphins, Tursiops truncatus. Residue levels were quantified for 10 PCB congeners and 17 chlorinated pesticides using GC/MS. Not all OCs detected in blubber were found in detectable levels in blood. However, significant relationships (p ≤ 0.05) were found for HCB, trans-nonachlor, o,p′-DDD, p,p′-DDD, o,p′-DDE, p,p′-DDE, o,p′-DDT, tDDT, and PCBs 52, 101, 118, 128, 138(+158), 153, 170, and 187. The statistically significant r2 terms ranged from 0.95 (p,p′-DDD) to 0.36 (trans-nonachlor) with a median of 0.64. The slopes of the regression models presented here for these analytes may be useful in estimating population levels of OCs in Tursiops blubber using levels measured in blood samples.