U.S. Department of Transportation
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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
|This report is an archived publication and may contain dated technical, contact, and link information|
|Publication Number: FHWA-HRT-14-021 Date: January 2014|
Publication Number: FHWA-HRT-14-021
Date: January 2014
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This report provides results of an assessment of the potential risk to human health posed by occupational and residential exposure to arsenic and lead concentrations found in glass beads used in pavement markings. The study used glass beads from samples of inventories from 15 State transportation departments to ascertain minimum screening levels based on both carcinogenic and noncarcinogenic effects, with the lower value selected as the final recommended screening level. The recommended screening levels were determined to be 220 ppm for arsenic, based on the child resident scenario, and 580 ppm for lead, based on the worker scenario. These determined screening levels are greater than the maximum content of 200 ppm for arsenic and 200 ppm for lead in glass beads prescribed in MAP-21 (the Moving Ahead for Progress in the 21st Century Act); therefore, the values specified in the existing legislation are considered protective of health based on currently available data.
The report is divided into three sections. The first section provides a detailed characterization of arsenic and lead concentrations in commercially available glass beads in current use on U.S. roadways, including the total, extractable, and bioaccessible arsenic and lead content in glass bead samples provided by State transportation departments. The second section describes the modeling methodology used to estimate the potential for adverse human health effects associated with arsenic and lead in glass beads used in pavement markings. The third section provides the human health screening levels for arsenic and lead in glass beads that are considered protective of human health. The results of the screening level assessment indicate that currently available products pose minimal health risk to humans while meeting retroreflective performance criteria.
Monique R. Evans
Director, Office of Safety
Research and Development
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