title: A rapid analytical method to quantify complex organohalogen contaminant mixtures in large samples of high lipid mammalian tissues.
abstract: In vitro investigations of the health impact of individual chemical compounds have traditionally been used in risk assessments. However, humans and wildlife are exposed to a plethora of potentially harmful chemicals, including organohalogen contaminants (OHCs). An alternative exposure approach to individual or simple mixtures of synthetic OHCs is to isolate the complex mixture present in free-ranging wildlife, often non-destructively sampled from lipid rich adipose. High concentration stock volumes required for in vitro investigations do, however, pose a great analytical challenge to extract sufficient amounts of complex OHC cocktails. Here we describe a novel method to easily, rapidly and efficiently extract an environmentally accumulated and therefore relevant contaminant cocktail from large (10-50 g) marine mammal blubber samples. We demonstrate that lipid freeze-filtration with acetonitrile removes up to 97% of blubber lipids, with minimal effect on the efficiency of OHC recovery. Sample extracts after freeze-filtration were further processed to remove residual trace lipids via high-pressure gel permeation chromatography and solid phase extraction. Average recoveries of OHCs from triplicate analysis of killer whale (Orcinus orca), polar bear (Ursus maritimus) and pilot whale (Globicephala spp.) blubber standard reference material (NIST SRM-1945) ranged from 68 to 80%, 54-92% and 58-145%, respectively, for13C-enriched internal standards of six polychlorinated biphenyl congeners, 16 organochlorine pesticides and four brominated flame retardants. This approach to rapidly generate OHC mixtures shows great potential for experimental exposures using complex contaminant mixtures, research or monitoring driven contaminant quantification in biological samples, as well as the untargeted identification of emerging contaminants.
authors.affiliation: Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000, Roskilde, Denmark.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Desforges
authors.affiliation: Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000, Roskilde, Denmark.
authors.forename: Igor
authors.initials: I
authors.lastname: Eulaers
authors.affiliation: Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, ON, K1A 0H3, Canada.
authors.forename: Luke
authors.initials: L
authors.lastname: Periard
authors.affiliation: Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000, Roskilde, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Sonne
authors.affiliation: Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000, Roskilde, Denmark.
authors.forename: Rune
authors.initials: R
authors.lastname: Dietz
authors.affiliation: Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, ON, K1A 0H3, Canada. Electronic address: robert.letcher@canada.ca.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Letcher
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry*; D000818:Animals; D002623:Chemistry Techniques, Analytical / Q000379:methods; D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000032:analysis*; D005411:Flame Retardants / Q000032:analysis; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D008055:Lipids / Q000302:isolation & purification; D008322:Mammals; D010575:Pesticides / Q000032:analysis; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D001503:Ursidae; D050685:Whale, Killer
chemical_list: D004785:Environmental Pollutants; D005411:Flame Retardants; D006843:Hydrocarbons, Chlorinated; D008055:Lipids; D010575:Pesticides; D011078:Polychlorinated Biphenyls
keywords: Flame retardants; Freeze-lipid filtration; Marine mammal; Mixture toxicology; Polychlorinated biphenyls; Realistic exposure