Enantiomer‐specific biomagnification of α‐Hexachlorocyclohexane and selected chiral chlordane‐related compounds within an arctic marine food web

• Published in: Environmental Toxicology and Chemistry
• Main Authors: Hoekstra, Paul F., Hara, Todd M. O, Karlsson, Heidi, Solomon, Keith R., Muir, Derek C. G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2003
• Subjects: Health, Toxicology and Mutagenesis; Environmental Chemistry; Arctic; Arctic cod; Balaena mysticetus; Beluga; Beluga*; Boreogadus saida; bowhead whale; Chukchi; Delphinapterus leucas; Erignathus barbatus; Phoca hispida; Salvelinus alpinus; Zooplankton
• Online Access: http://dx.doi.org/10.1897/02-459; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1897%2F02-459; https://setac.onlinelibrary.wiley.com/doi/pdf/10.1897/02-459

Abstract Concentrations of achiral and chiral organochlorine contaminants (OCs), including hexachlorocyclohexane isomers (HCH), chlordane congeners ( cis ‐ and trans ‐chlordane, cis ‐ and trans ‐nonachlor, MC5, MC7, and U82), and related metabolites (oxychlordane [OXY] and heptachlor exo ‐epoxide [HEPX]), were quantified in seawater (100 L; n = 6) and biota from the coastal Beaufort–Chukchi Seas food web near Barrow (AK, USA). The biota included zooplankton ( Calanus spp.; n = 5), fish species such as arctic cod ( Boreogadus saida; n = 10), arctic char ( Salvelinus alpinus; n = 3), and marine mammals including bowhead whales ( Balaena mysticetus liver: n = 23; blubber: n = 40), beluga whales ( Delphinapterus leucas blubber: n = 20), ringed seals ( Phoca hispida blubber: n = 20), and bearded seals ( Erignathus barbatus blubber: n = 7). The food web magnification factors (FWMFs) for HCHs and chlordane compounds ranged from 0.5 (γ‐HCH) to 6.5 (HEPX) and were expected based on known recalcitrance and biotransformation of OCs. The enantiomer fractions (EFs) of all chiral OCs were near racemic (EF = 0.50) in seawater, zooplankton, and all fish analyzed. In contrast, the EFs for most OCs analyzed were nonracemic (EF ≠ 0.50) in the marine mammals blubber (range: 0.09–0.79) because of enantiomer‐specific biotransformation and (or) accumulation. However, EF values were not significantly correlated with isotopically determined trophic level. The EFs for all chiral OCs (except α‐HCH) in bowhead whale liver closely approximated the values in zooplankton, suggesting that the accumulation of chiral OCs from prey into this cetacean is not enantiomer specific. However, the modification of EFs from bowhead liver to blubber suggests that this species has the ability to enantioselectively biotransform and accumulate several chiral OC compounds.