CHAPTER 3
 SULFONATION OF XENOBIOTICS BY POLAR BEAR LIVER

 The lipophilicity and inherent chemical stability of persistent organic pollutants

(POPs) renders them excellent candidates for absorption through biological membranes

as well as accumulation in both organisms and their environment. Many POPs have been

shown to biomagnify in food webs to potentially toxic levels in top predators such as the

polar bear (Grsus maritimus), whose diet mainly consists of ringed seal (Phoca hispida)

blubber (Kucklick et al., 2002).

 Since the sulfonation of xenobiotics has never been studied in the polar bear, the

obj ective of this study was to investigate the efficiency of this route of detoxification on a

select group of known environmental pollutants: 4'-hydroxy-3,3',4,5 '-

tetrachlorobiphenyl (4'OH-PCB79), 4'-hydroxy-2,3,3 ',4,5,5 '-hexachlorobiphenyl (4'-

OH-PCBl159), 4'-hydroxy-2,3,3 ',5,5 ',6-hexachlorobiphenyl (4'-OH-PCBl165),

pentachlorophenol (PCP), tris(4-chlorophenyl)-methanol (TCPM), 2-(4-methoxyphenyl)-

2-(4-hydroxyphenyl)- 1,1,1 -trichloroethane (OHMXC), 3 -hydroxybenzo(a)pyrene (3-OH-

B [a]P), triclosan (2,4,4'-trichloro-2 '-hydroxydiphenyl ether) (Figure 3-1). The OH-PCBs

were named as PCB metabolites, according to the convention suggested by Maervoet et

al. (2004).

 Polychlorinated biphenylols (OH-PCBs), major biotransformation products of

PCBs (James, 2001), have been shown to be present in relatively high concentrations in

polar bears (Sandau and Norstrom 1998; Sandau et al., 2000). The abundance of these

hydroxylated metabolites may be due to CYP induction (Letcher et al., 1996), inefficient