Xin Hu1, Andrea Adamcakova-Dodd2, Peter S Thorne3. 1. Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA 52242, USA. Electronic address: xin-hu@uiowa.edu. 2. Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA 52242, USA. Electronic address: andrea-a-dodd@uiowa.edu. 3. Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA 52242, USA. Electronic address: peter-thorne@uiowa.edu.
Abstract
BACKGROUND: The production ban of polychlorinated biphenyl (PCB) technical mixtures has left the erroneous impression that PCBs exist only as legacy pollutants. Some lower-chlorinated PCBs are still being produced and contaminate both indoor and ambient air. OBJECTIVES: To inform PCB risk assessment, we characterized lung uptake, distribution, metabolism and excretion of PCB11 as a signature compound for these airborne non-legacy PCBs. METHODS: After delivering [(14)C]PCB11 to the lungs of male rats, radioactivity in 34 major tissues and 5 digestive matter compartments was measured at 12, 25, 50, 100, 200 and 720min postexposure, during which time the excreta and exhaled air were also collected. [(14)C]PCB11 and metabolites in lung, liver, blood, digestive matter, urine, feces, and adipose tissues were extracted separately to establish the metabolic profile of the disposition. RESULTS: [(14)C]PCB11 was distributed rapidly to all tissues after 99.8% pulmonary uptake and quickly underwent extensive metabolism. The major tissue deposition of [(14)C]PCB11 and metabolites translocated from liver, blood and muscle to skin and adipose tissue 200min postexposure, while over 50% of administered dose was discharged via urine and feces within 12h. Elimination of the [(14)C]PCB11 and metabolites consisted of an initial fast phase (t½=9-33min) and a slower clearance phase to low concentrations. Phase II metabolites dominated in liver blood and excreta after 25min postexposure. CONCLUSIONS: This study shows that PCB11 is completely absorbed after inhalation exposure and is rapidly eliminated from most tissues. Phase II metabolites dominated with a slower elimination rate than the PCB11 or phase I metabolites and thus can best serve as urine biomarkers of exposure.
BACKGROUND: The production ban of polychlorinated biphenyl (PCB) technical mixtures has left the erroneous impression that PCBs exist only as legacy pollutants. Some lower-chlorinated PCBs are still being produced and contaminate both indoor and ambient air. OBJECTIVES: To inform PCB risk assessment, we characterized lung uptake, distribution, metabolism and excretion of PCB11 as a signature compound for these airborne non-legacy PCBs. METHODS: After delivering [(14)C]PCB11 to the lungs of male rats, radioactivity in 34 major tissues and 5 digestive matter compartments was measured at 12, 25, 50, 100, 200 and 720min postexposure, during which time the excreta and exhaled air were also collected. [(14)C]PCB11 and metabolites in lung, liver, blood, digestive matter, urine, feces, and adipose tissues were extracted separately to establish the metabolic profile of the disposition. RESULTS:[(14)C]PCB11 was distributed rapidly to all tissues after 99.8% pulmonary uptake and quickly underwent extensive metabolism. The major tissue deposition of [(14)C]PCB11 and metabolites translocated from liver, blood and muscle to skin and adipose tissue 200min postexposure, while over 50% of administered dose was discharged via urine and feces within 12h. Elimination of the [(14)C]PCB11 and metabolites consisted of an initial fast phase (t½=9-33min) and a slower clearance phase to low concentrations. Phase II metabolites dominated in liver blood and excreta after 25min postexposure. CONCLUSIONS: This study shows that PCB11 is completely absorbed after inhalation exposure and is rapidly eliminated from most tissues. Phase II metabolites dominated with a slower elimination rate than the PCB11 or phase I metabolites and thus can best serve as urine biomarkers of exposure.
Authors: Monika A Roy; Karilyn E Sant; Olivia L Venezia; Alix B Shipman; Stephen D McCormick; Panithi Saktrakulkla; Keri C Hornbuckle; Alicia R Timme-Laragy Journal: Environ Pollut Date: 2019-08-06 Impact factor: 8.071
Authors: Fabian A Grimm; Xianran He; Lynn M Teesch; Hans-Joachim Lehmler; Larry W Robertson; Michael W Duffel Journal: Environ Sci Technol Date: 2015-06-18 Impact factor: 9.028
Authors: Eric A Rodriguez; Brigitte C Vanle; Jonathan A Doorn; Hans-Joachim Lehmler; Larry W Robertson; Michael W Duffel Journal: Environ Toxicol Pharmacol Date: 2018-06-26 Impact factor: 4.860