title: Blood and exhaled air can be used for biomonitoring of hydrofluorocarbon exposure.
abstract: Various hydrofluorocarbons (HFCs) have replaced the ozone-depleting chlorofluorocarbons and hydrochlorofluorocarbons during the last decades. The objective of this study was to examine the usefulness of blood and breath for exposure biomonitoring of HFCs. We compared data on blood and exhaled air from a series of experiments where healthy volunteers were exposed to vapors of four commonly used HFCs; 1,1-difluoroethane, 1,1,1-trifluoroethane, 1,1,1,2-tetrafluoroethane, and 1,1,1,3,3-pentafluoropropane. All four HFCs had similar toxicokinetic profiles in blood with a rapid initial increase and an apparent steady-state reached within a few minutes. For all HFCs, the inhalation uptake during exposure was low (less than 6%), most of which was exhaled post-exposure. No metabolism could be detected and only minor amounts were excreted unchanged in urine. The observed time courses in blood and breath were well described by physiologically-based pharmacokinetic (PBPK) modeling. Simulations of 8-h exposures show that the HFC levels in both blood and breath drop rapidly during the first minutes post-exposure, whereafter the decline is considerably slower and mainly reflects washout from fat tissues. We conclude that blood and exhaled air can be used for biological exposure monitoring. Samples should not be taken immediately at the end of shift but rather 20-30 min later.
authors.affiliation: Work Environment Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77, Stockholm, Sweden. Electronic address: Lena.Ernstgard@ki.se.
authors.forename: Lena
authors.initials: L
authors.lastname: Ernstgård
authors.affiliation: Work Environment Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77, Stockholm, Sweden. Electronic address: Bengt.Sjogren@ki.se.
authors.forename: Bengt
authors.initials: B
authors.lastname: Sjögren
authors.affiliation: Work Environment Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77, Stockholm, Sweden. Electronic address: Sara.Gunnare@sll.se.
authors.forename: Sara
authors.initials: S
authors.lastname: Gunnare
authors.affiliation: Work Environment Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77, Stockholm, Sweden. Electronic address: Gunnar.Johanson@ki.se.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Johanson
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics*; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D001944:Breath Tests; D003198:Computer Simulation; D004784:Environmental Monitoring / Q000379:methods*; D045853:Exhalation; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D006845:Hydrocarbons, Fluorinated / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics*; D019570:Inhalation Exposure; D008297:Male; D008954:Models, Biological; D014018:Tissue Distribution; D055815:Young Adult; D004980:Ethane / Q000031:analogs & derivatives; D005466:Fluorocarbons
chemical_list: D000393:Air Pollutants; D015415:Biomarkers; D006845:Hydrocarbons, Fluorinated; C059268:1,1-difluoroethane; C104768:1,1,1-trifluoroethane; C063006:norflurane; D004980:Ethane; D005466:Fluorocarbons; C403631:1,1,1,3,3-pentafluoropropane
keywords: Difluoroethane (HFC152a); Pentafluoropropane (HFC245fa); Tetrafluoroethane (HFC134a); Trifluoroethane (HFC143a)