Metal and Metalloid Concentrations in Domestic and Imported Glass Beads Used for Highway Marking

摘要

Glass beads are used in road markings to obtain retroreflectivity and recently have received attention due to thenpresence of arsenic (As), lead (Pb), and antimony (Sb). In this study, six domestic (U.S.-manufactured) and 12nimported batches of glass beads were analyzed for total metal and metalloid concentrations using field-portablenX-ray fluorescence. For domestic batches, average concentrations of 8 mg/kg for As, 23 mg/kg for Pb, andn55 mg/kg for Sb were observed. On the other hand, the imported batches were found to have averages ofn485 mg/kg for As, 97mg/kg for Pb, and 106 mg/kg for Sb. Samples from batches followed Gaussian distributions;nhowever, variability in concentrations within the imported batches was significant with errors rangingnfrom 18% to 22% for As, 50% to 83% for Pb, and 13% to 16% for Sb. Based on these results, additional studies arenwarranted to evaluate the potential for leaching of metals.