title: Repeatability of tibia lead measurement by X-Ray fluorescence in a battery-making workforce.
abstract: The purpose of this study was to remeasure in vivo tibia lead levels in a lead-acid battery manufacturing workforce measured in a previous survey and believed to be unrealistically high. Tibia lead levels were measured by K-shell X-ray fluorescence (XRF) spectroscopy in a stratified random sample (n=40) of the original study group (n=381). The repeat survey showed much lower tibia lead levels (median=54.3 microg lead/g bone mineral, compared to 217.9 microg lead/g bone mineral, n=40). Tibia lead levels were significantly correlated with duration of occupational exposure, zinc protoporphyrin levels, and cumulative blood lead index, but not with current blood lead levels. Thirty-eight of the 40 subjects underwent two consecutive tibia lead measurements to assess the test-retest repeatability of the XRF tibia lead measurement technique. The intraclass correlation coefficient between repeated measurements was 0.926 (P=0.0001). Three measurement pairs differed by more than 20 microg/g. There was no fixed or proportional bias between the two sets of measurements. We conclude that the technique offers a highly repeatable measurement of tibia bone lead. However, care needs to be taken to avoid contamination when performing measurements on active lead workers.
authors.affiliation: Department of Community and Preventive Medicine, The Mount Sinai School of Medicine, New York, New York 10029-6574, USA.
authors.forename: A C
authors.initials: AC
authors.lastname: Todd
authors.forename: R I
authors.initials: RI
authors.lastname: Ehrlich
authors.forename: P
authors.initials: P
authors.lastname: Selby
authors.forename: E
authors.initials: E
authors.lastname: Jordaan
mesh_terms: D000328:Adult; D006801:Humans; D007221:Industry; D007854:Lead / Q000032:analysis*; D008297:Male; D016273:Occupational Exposure; D015203:Reproducibility of Results; D013052:Spectrometry, X-Ray Emission / Q000592:standards*; D013977:Tibia / Q000737:chemistry*
chemical_list: D007854:Lead