title: Time course of congener uptake and elimination in rats after short-term inhalation exposure to an airborne polychlorinated biphenyl (PCB) mixture.
abstract: Despite the continued presence of PCBs in indoor and ambient air, few studies have investigated the inhalation route of exposure. While dietary exposure has declined, inhalation of the semivolatile, lower-chlorinated PCBs has risen in importance. We measured the uptake, distribution, and time course of elimination of inhaled PCB congeners to characterize the pulmonary route after short-term exposure. Vapor-phase PCBs were generated from Aroclor 1242 to a nose-only exposure system and characterized for congener levels and profiles. Rats were exposed via inhalation acutely (2.4 mg/m3 for 2 h) or subacutely (8.2 mg/m3, 2 hx10 days), after which pulmonary immune responses and PCB tissue levels were measured. Animals acutely exposed were euthanized at 0, 1, 3, 6, and 12 h post exposure to assess the time course of PCB uptake and elimination. Following rapid absorption and distribution, PCBs accumulated in adipose tissue but decayed in other tissues with half-lives increasing in liver (5.6 h)<lung (8.2 h)<brain (8.5 h)<blood (9.7 h). PCB levels were similar in lung, liver, and adipose tissue, lower in brain, and lowest in blood. Inhalation of the airborne PCB mixture contributed significantly to the body burden of lower-chlorinated congeners. Congeners detected in tissue were mostly ortho-substituted ranging from mono- to pentachlorobiphenyls. Selective uptake and elimination led to accumulation of a distinct congener spectrum in tissue. Minimal evidence of toxicity was observed.
authors.affiliation: Interdisciplinary Graduate Program in Human Toxicology, Department of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Hu
authors.forename: Andrea
authors.initials: A
authors.lastname: Adamcakova-Dodd
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Lehmler
authors.forename: Dingfei
authors.initials: D
authors.lastname: Hu
authors.forename: Izabela
authors.initials: I
authors.lastname: Kania-Korwel
authors.forename: Keri C
authors.initials: KC
authors.lastname: Hornbuckle
authors.forename: Peter S
authors.initials: PS
authors.lastname: Thorne
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000818:Animals; D019570:Inhalation Exposure / Q000032:analysis*; D008297:Male; D011078:Polychlorinated Biphenyls / Q000008:administration & dosage* / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014018:Tissue Distribution
chemical_list: D000393:Air Pollutants; D011078:Polychlorinated Biphenyls