have shown that triclosan inhibits various biotransformation enzymes, including SULT

and UDP-glucuronosyltransferases (UGT) (Wang et al., 2004).

 The fact that 3-OH-B[a]P, triclosan, OHMXC, 4'-OH-PCB79, 4'-OH-PCBl59 and

4'-OH-PCBl165 have not been reported as environmental contaminants in polar bears to

date may be due to non-significant levels in the Arctic environment or efficient

metabolism via, for example, sulfonation. On the other hand, the presence of PCP and,

particularly, high amounts of TCPM in these Arctic carnivores, may indicate poor

sulfonation of these substrates. The polychlorobiphenylols 4'-OH-PCBl59 and 4'-OH-

PCBl165 are of interest since though they have not been detected in polar bears, they are

structurally similar to 4'-OH-PCBl72, one of the major OH-PCBs found in polar bear

plasma (Sandau et al., 2000). It is thus possible that these compounds are sulfonated with

similar efficiencies. The other major Phase II biotransformation pathway for the above-

mentioned compounds is glucuronidation. Polar bear liver efficiently glucuronidated 3-

OH-B[a]P and several OH-PCBs (Sacco and James 2004).

 Hypothesis

 Sulfonation occurring in polar bear liver is an inefficient route of detoxification for

a structurally diverse group of environmental contaminants.

 Methodology

 Unlabeled PAPS was purchased from the Dayton Research Institute (Dayton, OH).

Uridine 5' -diphosphoglucuronic acid (UDPGA) was obtained from Sigma (St.Louis,

MO). Radiolabeled [35S]PAPS (1.82 or 3.56 Ci/mmol) was obtained from Perkin-Elmer

Life Sciences, Inc. (Boston, MA). The benzo[a]pyrene metabolites 3-OH-B[a]P, B[a]P-3-

O-sulfate and B [a]P-3-O-glucuronide were supplied by the Midwest Research Institute

(Kansas City, MO), through contact with the Chemical Carcinogen Reference Standard