PM06 Emerging Pollutants
Exhibit Hall
8:00 AM - Monday
(PM063) Hydroxylated PCBs in precipitation and surface waters of Southern Ontario.
Darling, Colin1, Alaee, Mehran1, Campbell, Linda1, 2, Pacepavicius, Grazina1, Ueno, Daisuke1, Muir, Derek1, 1 National Water Research Institute, Burlington, Ontario, Canada2 Queen's University, Kingston, Ontario, Canada
ABSTRACT- Hydroxylated PCBs (OH-PCBs) have the potential to disrupt the mammalian thyroid system, and are therefore of significant interest environmentally. OH-PCBs may be formed within biota via cytochrome P450 mediated oxidation. They may also be formed abiotically in the atmosphere or in surface water through the reaction of PCBs with OH radicals. There are 837 possible mono-hydroxylated PCB congeners, with only 47 of these congeners commercially available as standards. The necessity of monitoring OH-PCBs in varied biotic and abiotic compartments, combined with the scarcity of accessible standards, presents some analytical challenges. OH-PCBs can be extracted from water and snow samples using XAD resin, with subsequent pH adjustments to extract and separate the PCBs from the OH-PCBs, followed by cleanup steps. Water samples were taken in southern Ontario from the Detroit River, Hamilton Harbour, and Toronto Harbour. Snow samples were collected from various sites in southern Ontario, melted, and pumped through the XAD resin columns. OH-PCBs are typically present in environmental matrices at pg/g or pg/L levels, and thus we have found high resolution mass spectrometry using an electron ionization source provides a clearer and more complete characterization of all OH-PCB homolog groups. Both matrices displayed a large number of OH-PCBs ranging from mono- to hexa-chlorinated congeners, many of which could not be specifically identified using the available standards, although they were quantified indirectly using response factors. We are investigating the feasibility of tentatively identifying unknown congeners using retention indices.
Key words: snow, OH-PCBs, surface water