Heavy Metals in Glass Beads Used in Pavement Markings
MetadataShow full item record
Pavement markings are vital for safely navigating roadways. The nighttime visibility of pavement markings is enhanced by addition of retroreflective glass beads, most of which are made from recycled glass. Concern has been raised over the presence of heavy metals in glass beads used in pavement markings and their effect on human and environmental health. Based upon the potential risk associated with the presence of arsenic and lead in the glass beads, two Bills are currently being considered before the 112th Congress of the United States of America seeking to set a maximum permissible limit for the amount of arsenic and lead in glass beads used within pavement marking systems on domestic roadways. This study was designed to support legislative decision making by providing data necessary for risk assessment. The experiments carried out provide: an analysis of glass bead metal content and extractability; an evaluation of the relationship between arsenic content of the glass beads and their retroreflective performance; an evaluation of analytical methods used to measure the total bead metal content; and an analysis of samples of glass bead and soil mixture from a glass bead storage site used to determine site-specific metal concentrations in the soil media. Mean arsenic content, measured using the Pacific Northwest National Laboratory's KOH fusion digestion, in all the glass beads examined ranged from 11 ppm to 82 ppm, while mean lead content, measured using KOH fusion digestion, ranged from below quantification limit to 199 ppm. Total metal content measurements indicated a high amount of variability in the glass bead samples; most likely associated with the use of recycled glass feed during manufacturing. The relationship between the retroreflective performance and the arsenic content of the glass beads was analyzed and a weak but positive correlation was observed between the two factors. However, a more detailed study is required to evaluate the relationship between arsenic content and retroreflectivity. Different methods to evaluate the total metal content in glass beads were compared; it is recommended that any analytical method may be used, as long as the standard reference material is reproduced within the range of concentration expected in the glass beads. In the analysis of the field site samples of soil containing glass beads obtained from a glass bead storage and transfer facility, the mass content of beads in the soil varied from a mean of 19% to 78% depending on the location within the facility. However, a detailed analysis with larger number of samples must be performed to evaluate the effect of glass beads on the total arsenic content of the soil.
Glass beads in soil
Leaching of heavy metals
Heavy metal analysis of glass beads
Total metal content
Extractable metal content
Bioavailable metal content
Bioaccessible metal content
SBRC Oral Bioaccessibility Assay
Mangalgiri, Kiranmayi (2012). Heavy Metals in Glass Beads Used in Pavement Markings. Master's thesis, Texas A&M University. Available electronically from
Showing items related by title, author, creator and subject.
Metal specificity and the mechanism of allosteric regulation in metal-sensing metal-responsive transcriptional repressors Staphylococcus aureus CzrA and Mycobacterium tuberculosis NmtR Pennella, Mario Antonio (Texas A&M University, 2005-08-29)The metal-responsive transcriptional repressors of the SmtB/ArsR family repress the expression of their respective operons in the absence of metal and are released from the operator/promoter region when metal ions bind, ...
Ligand Design for Novel Metal-Organic Polyhedra and Metal-Organic Frameworks for Alternative Energy Applications Kuppler, Ryan John (2011-10-21)The primary goal of this research concerns the synthesis of organic ligands in an effort to create metal-organic porous materials for the storage of gas molecules for alternative energy applications as well as other ...
Specific-Heat of the Organic Metal Bis(tetrathiotetracene) Tri-Iodide from 20-K to 100-K, the Vicinity of the Metal-Nonmetal Phase-Transition CORT, B.; Naugle, Donald G. (American Physical Society, 1981)