U.S. Department of Transportation
Federal Highway Administration
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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
REPORT |
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
Notice
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1. Report No. FHWA-HRT-14-021 |
2. Government Accession No.
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3. Recipient’s Catalog No.
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4. Title and Subtitle Screening Level Assessment of Arsenic and Lead Concentrations in Glass Beads Used in Pavement Markings |
5. Report Date January 2014 |
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6. Performing Organization Code: |
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7. Author(s) Bryan Boulanger, Paul Carlson, Harry Fatkin, and Aditya Raut-Desai |
8. Performing Organization Report No. |
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9. Performing Organization Name and Address Texas A&M Transportation Institute The Texas A&M University System College Station, Texas 77843-3135 |
10. Work Unit No. TRAIS |
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11. Contract or Grant No. DTFH68-09-E-00105 |
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12. Sponsoring Agency Name and Address Office of Infrastructure Research & Development Federal Highway Administration 6300 Georgetown Pike McLean, VA 22101-2296 |
13. Type of Report and Period Covered Final Report |
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14. Sponsoring Agency Code
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15. Supplementary Notes Projects were performed
with the cooperation and participation of the Environmental Protection Agency
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16. Abstract Retroreflective
glass beads used in pavement markings are a critical component of highway
safety. Glass beads meeting American Association of State Highway and
Transportation Officials (AASHTO) M247 specifications are the current
industry standard. AASHTO M247 glass beads are fabricated using reclaimed
glass cullet, offering cost effective performance while beneficially reusing
sources of industrial and commercial waste glass. However, reclaimed glass
cullet may contain elevated levels of arsenic and lead that can be passed
through to the final product. Concern regarding the presence of arsenic and
lead in retroreflective glass bead products within the U.S. marketplace
resulted in recently adopted legislation that sets a 200 part-per-million
(ppm = This research developed a preliminary understanding of the risk associated with the presence of arsenic and lead in glass beads used in pavement marking systems to support decisionmaking. Researchers tested 15 samples of commercially available glass beads in current use on U.S. roadways from State transportation department stockpiles. The mean total concentration observed in the sampled beads across replicates was 71 ppm arsenic and 54 ppm lead. Extractable and bioaccessible arsenic levels in the beads were below instrument detection limits, and extractable and bioaccessible levels of lead in the beads were present at less than 3.6 ppm as a maximum mean value. Based on laboratory-generated characterization data, field investigations, available literature data, and the developed model, reasonably conservative screening levels for arsenic and lead in glass beads were determined to be 220 ppm and 580 ppm, respectively. Lead and arsenic levels observed in glass bead samples provided by State transportation departments were within the determined screening limits, indicating that currently available products pose minimal health risk while meeting retroreflective performance criteria. |
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17. Key Words Pavement markings, glass beads, health, human health, environment, risk assessment, arsenic, lead, retroreflectivity, extractable, bioaccessible |
18. Distribution Statement No restrictions. This document is available to the public through the National Technical Information Service, Springfield, VA 22161. |
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19. Security Classif. (of this report) Unclassified |
20. Security Classif. (of this page) Unclassified |
21. No. of Pages 92 |
22. Price
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Form DOT F 1700.7 (8-72) Reproduction of completed page authorized
Assessment of Arsenic and Lead Content in Commercially Available Glass Beads
Relationship Between Retroreflectivity and Total Arsenic Content
Method for Determining Total Arsenic and Lead in Glass Bead Samples
Method for Determining Extractable Arsenic and Lead in Glass Bead Samples.
Method for Determining Bioaccessible Arsenic and Lead in Glass Bead Samples.
Method Comparison for Analysis of Total Arsenic and Lead Analysis in Glass Beads
Retroreflectivity Measurements
Arsenic Speciation Determination
Estimation of Glass Bead Mass in Site Soil Samples
Analysis of Total Metals in Respirable Fraction of Soil Samples
Bioaccessible Arsenic and Lead
Comparison of Total Metal Content in Glass Beads Evaluated from Different Methods
Parameter Data Available for Development of the Modeling Method
Receptor-Specific Exposure Parameters
Contaminant and Site-Specific Exposure Parameters
Bead-Specific Exposure Parameters
Concentration of Metals in Glass Beads and Leaching Potential
Figure 3. Equation. Formula for determining sample size.
Figure 4. Equation. Formula to calculate total metals content.
Figure 5. Equation. Formula to calculate extractable metals content of glass beads.
Figure 7. Equation. Formula to calculate total mass of glass beads in a representative sample.
Figure 8. Equation. Formula to calculate the percentage of glass beads within a site soil sample.
Figure 11. Photo. Application of glass beads to long line markings.
Figure 12. Photo. Close-up of glass bead application to long lines.
Figure 13. Diagram. Conceptual site exposure model for pavement-marking beads.
Figure 14. Equation. Formula to calculate intake of metals due to incidental ingestion.
Figure 15. Equation. Formula to calculate exposure concentrations for inhalation of metals.
Figure 17. Equation. Formula to calculate ILCR for direct contact through ingestion.
Figure 18. Equation. Formula to calculate ILCR for inhalation exposures.
Figure 19. Equation. Formula to calculate CSL for protection of human health.
Figure 20. Equation. Formula to calculate HQ for direct contact.
Figure 21. Equation. Formula to calculate HQ for inhalation.
Figure 22. Equation. Formula to calculate NCSL.
Figure 23. Equation. Formula to calculate GW SL.
Table 2. Intra-method comparison for total arsenic and lead in the 15 glass bead samples
Table 3. Arsenic speciation in leachate water in contact with beads
Table 5. Screening levels for arsenic and lead from each scenario
Table 6. MDL and PQL for arsenic and lead for total, extractable and bioaccessible metals
Table 8. Total arsenic and lead content (ppm) in SRM
Table 10. Comparison of arsenic content (ppm) in glass beads from intra-method evaluation
Table 11. Comparison of lead content (ppm) in glass beads from intra-method evaluation.
Table 17. Bead workflow elements and release potential
Table 18. Exposure parameters for glass bead assessment due to direct exposures.
Table 19. Calculation of particulate emission factor
Table 21. Toxicity data for glass bead assessment
Table 22. Estimates of bead loading to soil per year
Table 23. Estimated glass bead application and loss rate for line applications.
Table 24. Summary of statistics for bead analysis
Table 25. Summary of TTI/TAMU leaching studies for arsenic—December 2012
Table 26. Summary of TTI/TAMU leaching studies for lead—December 2012
Table 27. Summary of glass bead risks for arsenic
Table 28. Estimated groundwater risk for arsenic
Table 29. Summary of glass bead screening levels for arsenic
AAS Atomic Absorption Spectroscopy
AASHTO American Association of State Highway and Transportation Officials
ACS American Chemical Society
AGBMA American Glass Bead Manufacturing Association
ALM Adult Lead Model
ATSDR Agency for Toxic Substances and Disease Registry
ATV All-Terrain Vehicle
BDL Below the Detection Limit
BQL Below the Quantitation Limit
CFR Code of Federal Regulations
CSEM Conceptual Site Exposure Model
CSL Cancer Screening Level
DAF Dilution-Attenuation Factor
DI Deionized
EPA Environmental Protection Agency
FDOT Florida Department of Transportation
FHWA Federal Highway Association
FP-XRF Field-Portable XRF
GW SL Groundwater Screening Level
HI Hazard Index
HPLC High Performance Liquid Chromatography
HQ Hazard Quotient
ICP-MS Inductively Coupled Plasma-Mass Spectrometry
IEUBK Integrated Exposure Uptake Biokinetic Model
ILCR Incremental Lifetime Cancer Risk
KOH Potassium Hydroxide
MAP-21 Moving Ahead for Progress in the 21st Century Act
MDL Method Detection Limit
NCSL Non-Carcinogenic Screening Level
NIST National Institute of Standards and Technology
NJIT/RU New Jersey Institute of Technology/Rowan University
NRMRL National Risk Management Research Laboratory
PEF Particulate Emission Factor
PNNL Pacific Northwest National Laboratory
PQL Practical Quantitation Limit
QA/QC Quality Assurance/Quality Control
RSL Regional Screening Level
SRM Standard Reference Material
TAMU Texas A&M University
TFHRC Turner-Fairbanks Highway Research Center
TTI Texas A&M Transportation Institute
UCL95% 95-Percent Upper Confidence Limit
XRF X-Ray Fluorescence