Comparison of Lead Concentration in Human Deciduous and Permanent Teeth in Urban and Rural Reigns in Zanjan

Background and Lead is a heavy metal، which has been replaced by calcium hydroxyapatite in tooth enamel. It is considered as an index of pollution assessment. Zanjan province is potential area for lead element accumulation. This study aimed at comparing the amount of lead in human deciduous and permanent teeth in order to evaluate and determine the risk of lead pollution in urban and rural regions in Zanjan (North West of Iran). The samples were 95 deciduous and permanent teeth which were randomly collected from urban and rural regions in Zanjan. After primary preparation and acidic digestion، the lead content was measured in samples using ICP-OES. The mean concentrations of lead in deciduous and permanent teeth in rural regions were 36. 78 and 45. 81 μgg-1، respectively and in urban regions they were 54. 44 and 75. 10 μgg-1، respectively. Significant differences was observed in lead content of deciduous teeth in urban and rural regions (P<0. 05). Also، the concentration of lead in permanent teeth in urban regions was 1. 5 times higher than that of the rural regions. Lead content was significantly higher in permanent teeth compared to that of the deciduous teeth. In studied areas، lead concentrations of permanent teeth increased significantly with age. Teeth are the best bioindicators for determining the concentration of heavy metals. This study demonstrated that lead concentration in teeth depended on sex، age، and place of residency. According to the results، in both regions the lead concentration in samples of female teeth was less than that of male subjects. We found higher level of lead contamination in urban areas compared to rural areas.