| Summary: | 碩士 === 國立臺灣大學 === 職業醫學與工業衛生研究所 === 88 === The purpose of this study was to determine the bioavailability of ingested lead dust from a lead battery plant and changes in lead isotope composition in the blood. At the same time, this study tries to evaluate the possibility of distinguishing the lead exposure sources by examining isotope ratio changes.
An animal experiment was performed with 5-6 weeks old male Sprague-Dawley rats. The rats of each experiment group were fed the mixture of AIN-76 semipurifed diet with various lead dusts from the assembly line of a lead battery plant. The target doses were 5mg Pb/kg BW/Day and 10 mg Pb/kg BW/Day, respectively, for each type of lead dust which control group were fed with AIN-76 semipurified diet only. Every three animals for a specific lead dust and dose group were sacrificed at the15th, 29th, 43rd, respectively. Blood samples were collected and analyzed for blood lead level and lead isotope composition.
Results of blood lead determination showed that, in addition to the effect of lead dose on the bioavailability, the lead dust species and their particle sizes also had influences on the bioavailability. It was found that the bioavailability of lead dust was inversely associated with particle size, and the lead peroxide dust demonstrated higher bioavailability than the elemental lead powder.
Besides, the results of lead isotope composition analysis showed that Pb206/Pb207 was a sensitive indicator in this study, for lead source identification. According to the results of present study, Pb206/Pb207 ratio is a useful tool to trace the lead dusts to which the workers were exposed. Moreover, with different extents of lead exposure, there were few changes in various lead isotope ratios in blood. If the original isotope ratios of lead dust from the lead battery plant were known, it would be available to use this method to estimate the lead exposure level of the workers in the battery plant, and to set up the priority for working environment improvement.
|
|---|
