Development and verification of a toxicokinetic model of polychlorinated biphenyl elimination in persons working in a contaminated building.
BACKGROUND
Polychlorinated biphenyls are toxic and slowly degrading substances that have been in widespread industrial use in the 1960s and 1970s. Despite a worldwide reduction, environmental exposure remains an issue; the assessment of an individual's level of exposure at a given time in retrospect requires valid toxicokinetic modeling of the different PCB congeners.


OBJECTIVE
To develop and verify a toxicokinetic model of the in vivo-degradation of PCB 28 and 52 in adult humans.


METHODS
The plasma concentrations of PCB congeners were measured in 583 persons working in a contaminated building for an average of 14.7+/-9.6 years. The values were adapted to a simple pharmacokinetic model (yt = y0 x (1 - e(-kt))); the steady state concentration y0 was estimated based on the median values of persons working exposed more than 10 years.


RESULTS
The steady state concentration of PCB 28 was 0.10 microg/l, that of PCB 52 0.02 microg/l. The half-life of the congeners was estimated based on a logarithmic regression analysis according to the model mentioned above; it was 2.18 (95% CI: 1.91-2.54) years for PCB 28 and 3.95 (95% CI: 3.55-4.45) years for PCB 52, respectively. Stepwise elimination of persons with very long employment duration did not reduce the estimated half-life.


CONCLUSIONS
The estimated half-life is higher than previously published data especially for PCB 52. Possible reasons and implications of this finding are discussed.
Broding
Horst Christoph
HC
Institute and Outpatient Clinic of Occupational-, Social and Environmental Medicine, Friedrich-Alexander-Universität Erlangen-Nuremberg, Schillerstrasse 25/29, 91054 Erlangen, Germany. broding@rzmail.uni-erlangen.de
Schettgen
Thomas
T
Göen
Thomas
T
Angerer
Jürgen
J
Drexler
Hans
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D000395:Air Pollutants, Occupational / Q000097:blood / Q000493:pharmacokinetics*; D016902:Air Pollution, Indoor / Q000032:analysis*; D002849:Chromatography, Gas; D003627:Data Interpretation, Statistical; D005260:Female; D006207:Half-Life; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011078:Polychlorinated Biphenyls / Q000097:blood / Q000493:pharmacokinetics*; D017132:Workplace / Q000592:standards*
D000395:Air Pollutants, Occupational; D011078:Polychlorinated Biphenyls