Hydroxylated and methyl sulfone PCBmetabolites in adipose and whole blood of polar bear (Ursus maritimus) from East Greenland

Persistent methyl sulfone (MeSO ) and hydroxylated (HO–) polychlorinated biphenyl (PCB) metabolites have y2 emerged as important classes of environmental contaminants in vertebrate, aquatic biota and humans. In the present study, PCB, MeSO2–PCB and HO–PCB concentrations and congener patterns were determined in the whole blood and adipose tissue of male (ns7) and female (ns12) polar bears (Ursus maritimus) of random age (3–25 years of age), and collected in 1999–2001 from the IttoqqortoormiityScoresby Sound area in central East Greenland. There was no significant difference (P-0.05) between males and females with respect to PCBor PCB metabolite concentrations in either tissue. The mean sum (S) PCBconcentrations were 7020"3366 ngyg lipid weight (lw) (range 2708–18148 ngyg lw) and 46.1"44.6 ngyg wet weight (ww) (range 12.6–204.2 ngyg ww) in adipose and blood, respectively. The mean S-HO–PCBconcentration in whole blood was 182.3"72.1 ngyg ww (range 93.8– 382.1 ngyg ww). The mean S-HO–PCBto S-PCBconcentration ratios in whole blood were 4.59"3.58 (range 1.03–11.88) and 8.30"5.56 (range 2.16–19.47) in females and males, respectively, which are the highest ratios reported so far for polar bears from any population, or for any free-ranging animal. S-HO–PCBconcentrations were greater than all other major classes of organochlorines (i.e. S-PCBs, S-MeSO2–PCBs, S-chlordanes (CHLs), S-hexachlorocyclohexanes (HCHs) and S-chlorobenzenes (CBzs). The mean S-MeSO2–PCBconcentrations were 699"836 ngyg lw (range 127–3920 ngyg lw) and 10.9"9.6 ngyg ww (range 4.3–52.1 ngyg ww) in the adipose and blood, respectively. Regardless of age and sex, in both adipose and whole blood the MeSO2–PCBcongener pattern was dominated by 39- and 49-MeSO2–CB101 and -CB87, and 4-MeSO2–CB149 (approx. 70% of the S-MeSO2–PCBs). Minor differences in the MeSO2–PCBcongener pattern were observed between blood and adipose, which suggests the possible influence of metabolite structure on mobilization andyor deposition to the adipose tissue. Sixteen HO–PCBcongeners and one di-HO–PCBcongener were identified, and five HO–PCB isomers and one di- HO–PCBisomer were detected. However, congener patterns were dominated by 49-OH–CB120, 4-HO–CB146y3- HO–CB153, 4-OH–CB187, 49-HO–CB172, 4-HO–CB193 and 4,49-di-HO–CB202 ()10 ngyg ww). HO–PCB congener patterns in whole blood were not significantly different (P-0.05) between males and females. Other chlorinated phenolic contaminants, pentachlorophenol (0.3"0.3 ngyg ww) and 4-HO-heptachlorostyrene (7.5"2.9 ngyg ww) were also detected in blood. To our knowledge, this is to first report comparing PCBs, MeSO2–PCBs and HO–PCBs in whole blood and adipose tissue in a free-ranging wildlife species. HO–PCBs and MeSO2–PCBs are both important circulating contaminants in polar bears from this eastern Greenland population. Given the known toxicities of PCBmetabolites, this population of polar bear may be experiencing health risks due to exposure to a complex loading of organohalogen contaminants that include HO–PCBand MeSO2–PCB metabolites.