oEPA
United States
Environmental Protection
Agency
EPA/600/R 24/020.1 | April 2024 | www.epa.gov/research
Synthetic Turf Field Recycled Tire Crumb
Rubber Research Under the Federal
Research Action Plan
FINAL REPORT PART 2-
EXPOSURE CHARACTERIZATION VOLUME 1
Centers for Computational Toxicology and Exposure, Environmental Measurement and Modeling
Environmental Solutions and Emergency Response, and Public Health and Environmental
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EPA/600/R-24/020.1
April 2024
Synthetic Turf Field Recycled Tire Crumb
Rubber Research Under the Federal
Research Action Plan
Final Report Part 2 -
Exposure Characterization
Volume I
April 16, 2024
By
U.S. Environmental Protection Agency / Office of Research and Development (EPA/ORD)
Centers for Disease Control and Prevention / Agency for Toxic Substances and Disease Registry
(CDC/ATSDR)
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Disclaimer
This document has been reviewed by the U.S. Environmental Protection Agency and the Agency for
Toxic Substances and Disease Registry and approved for release. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use.
Preferred citation: U.S. EPA& CDC/ATSDR. (2024). Synthetic Turf Field Recycled Tire Crumb
Rubber Research Under the Federal Research Action Plan Final Report: Part 2 - Exposure
Characterization (Volumes 1 and2). (EPA/600/R-24/020). U.S. Environmental Protection Agency,
Centers for Disease Control and Prevention/Agency for Toxic Substances and Disease Registry.
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Foreword
The U.S. Environmental Protection Agency (EPA) Office of Research and Development (ORD) and the
Centers for Disease Control and Prevention (CDC) Agency for Toxic Substances and Disease Registry
(ATSDR) have worked collaboratively to complete the research activities on synthetic turf playing fields
under the "Federal Research Action Plan on Recycled Tire Crumb Used on Playing Fields and
Playgrounds" (FRAP). The Agencies have released the research activities' results in two parts. The Part
1 Report (U.S. EPA & CDC/ATSDR, 2019) summarizes the research effort to characterize tire crumb
rubber, which includes characterizing the components of, and emissions from, recycled tire crumb
rubber. The exposure characterization report (Part 2 - this report) summarizes the potential exposures
that may be experienced by users of synthetic turf playing fields with recycled tire crumb rubber infill,
such as how people come in contact with the materials, how often and for how long. It includes the
results from a supplemental biomonitoring study conducted by CDC/ATSDR. This Part 2 exposure
characterization report completes FRAP efforts with respect to playing fields.
The study is not a risk assessment; however, the results of the research described in the FRAP reports
will advance our understanding of exposure to inform the risk assessment process. We anticipate that the
results from this multi-agency research effort will be useful to the public and interested stakeholders to
understand the potential for human exposure to chemicals found in recycled tire crumb rubber used on
synthetic turf fields.
This report has been prepared to communicate to the public the research objectives, methods, results and
findings for the exposure characterization research conducted as part of the Federal Research Action
Plan. The report has undergone independent, external peer review in accordance with EPA and CDC
policies. A response-to-peer review comments document accompanies the release of the Part 2 report.
The mission of the EPA is to protect human health and the environment so that future generations inherit
a cleaner, healthier environment that supports a thriving economy. Science at EPA provides the
foundation for credible decision-making to safeguard human health and ecosystems from environmental
pollutants. ORD is the scientific research arm of EPA, whose leading-edge research helps provide the
solid underpinning of science and technology for the Agency. ORD supports six research programs that
identify the most pressing environmental health research needs with input from EPA offices, partners
and stakeholders.
CDC works 24/7 to protect America from health, safety and security threats, both foreign and in the
United States. ATSDR is a non-regulatory, environmental public health agency that was established by
Congress under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980.
ATSDR protects communities from harmful health effects related to exposure to natural and man-made
hazardous substances by responding to environmental health emergencies; investigating emerging
environmental health threats; conducting research on the health impacts of hazardous waste sites; and
building capabilities of and providing actionable guidance to state and local health partners.
Maureen Gwinn
Principal Deputy Assistant Administrator for Science
EPA Office of Research and Development
Aaron Bernstein
Director
Agency for Toxic Substances and Disease Registry
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Authors, Contributors, and Reviewers
Lead Authors:
Kent Thomas
Elizabeth Irvin
Annette Guiseppi-Elie
Angela Ragin-Wilson
Jose Zambrana, Jr.
U.S. EPA, Office of Research and Development, Center for Public Health
and Environmental Assessment (EPA/ORD/CPHEA)
Centers for Disease Control and Prevention, Agency for Toxic Substances
and Disease Registry (CDC/ATSDR)
U.S. EPA, Office of Research and Development, Immediate Office of the
Assistant Adminstrator (EPA/ORD/IOAA)
Centers for Disease Control and Prevention, Agency for Toxic Substances
and Disease Registry (CDC/ATSDR)
U.S. EPA, Office of Research and Development, Center for
Environmental Measurement and Modeling (EPA/ORD/CEMM)
Collaborating Federal Organizations:
U.S. Consumer Product Safety Commission
U.S. Defense Centers for Public Health-Aberdeen (former U.S. Army Medical Command, Army Public
Health Center)
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Contributing Authors:
Authors
Affiliation
Kelsey Brady, Michael Lewin, Zheng Li, Teresa
Wang
CDC/ATSDR
Nichole Brinkman
EPA/ORD/Center for Environmental Solutions
and Emergency Response (CESER)
Matthew Clifton, Carry Croghan, Kasey
Kovalcik, Georges-Marie Momplaisir, Karen
Oliver, Gene Stroup, Mark Strynar, Xiaoyu Liu,
Brian Schumacher
EPA/ORD/CEMM
Peter Egeghy, Monica Linnenbrink
EPA/ORD/C enter for Computational Toxicology
and Exposure (CCTE)
Marsha Morgan
EPA/ORD/CPHEA
Barbara Jane George, Steven Gardner, Edward
Heithmar, Ashley Jackson, Jianping Xue, Donald
Whitaker, Larissa Hassinger (Student Services
Contractor [SSC], Oak Ridge Associated
Universities [ORAU]), Linda Phillips
Formerly with the U.S. EPA, Office of Research
and Development
Chris Carusiello, Ksenija Janjic
U.S. EPA, Office of Land and Emergency
Management, Office of Resource Conservation
and Recovery (EPA/OLEM/ORCR)
Brandon Law, Aleksandr Stefaniak
CDC, The National Institute for Occupational
Safety and Health (CDC/NIOSH)
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Contributors:
Contributors
Affiliation
Emily Adler, Tyra Barrett, Carol Cusack, Michelle
Dittrich, John Marr, Miranda Mitchell, Christopher
Mugford, Chris Poulet, Nykiconia Preacely, Tara
Serio, Timothy Turner, Aaron Grober, Britnee Bailey,
Julianne Botelho, Antonia Calafat, Joaudimir (Joy)
Castro Georgi, Alfonsina (Sina) De Leon Salazar,
Christopher Hamilton, Rebecca Hunt, Erin (Nikki)
Pittman, Debra Trinidad, Denise Tevis, Hubert
Vesper, Neelam Zahoor, Enada Archibold, Yuesong
Wang, Cynthia D. Ward, Kathleen Caldwell
CDC/ATSDR
Lillian Alston (Senior Environmental Employee
[SEE]), Andrea Clements, Scott Keely, Asja Korajkic,
James McCord, Larry McMillan (SEE), Brian
McMinn, Gary Norris, Margie Vazquez (QA),
Richard Walker (SEE), Alan Williams, Libby Nessley
(QA)
EPA/ORD/CEMM
Elin Ulrich, Ann Richard, Antony Williams
EPA/ORD/CCTE
Christine Alvarez (Quality Assurance [QA]), Maliha
Nash, Holly Ferguson (QA), Emily Snyder
EPA/ORD/CPHEA
Susan Burden, Michelle Henderson (QA), Sania Tong-
Argao (QA)
EPA/ORD/Office of Science Advisor, Policy
& Engagement (OSAPE)
Brittany Stuart (QA), James Noel (QA)
EPA/ORD/Office of Science Information
Management (OSIM)
Marisol Figueroa, Megan Maguire
EPA/ORD/IO A A
Gregory Grissom (ORISE Participant), Jacqueline
McQueen, Fu-Lin Chen, Kathleen Hibbert, Tammy
Jones-Lepp, Myriam Medina-Vera, Sandra Utile-
Okechukwu (ORISE Participant), Kelly Widener, Ron
Williams
Formerly with the U.S. EPA, Office of
Research and Development
Matt Allen, Tamira Cousett, Christopher Fuller,
Denise Popeo-Murphy, Mary Wright, Patrick Lawler,
Guy Fazzio
Jacobs Technology Incorporated (JTI)
Julia Campbell, Justicia Rhodus, Samantha Shattuck
Pegasus Technical Services
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Reviewers:
Reviewers
Affiliation
Eric Hooker
U.S. Consumer Product Safety Commission
Kiran Alapaty, Kevin Oshima
EPA/ORD/CEMM
Geoffrey Braybrooke, Michael R. Bell, Debra C.
Colbeck, Jarod M. Hanson, Sherri L. Hutchens,
Mark S. Johnson, Jeffrey G. Leach, Charles E.
McCannon, Robert L. von Tersch
APHC, now the U.S. Defense Centers for Public
Health-Aberdeen
Bob Thompson
Formerly with the U.S. EPA, Office of Research
and Development
Michael Firestone, Kathleen Schroeder (SEE)
Formerly with the U.S. EPA, Office of the
Administrator, Office of Children's Health
Protection
Nicole Villamizar
EPA/OLEM/ORCR
Marcus Aguilar
U.S. Environmental Protection Agency, Region 9
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Acknowledgments
Contract support to the EPA was provided by Jacobs Technology, Inc under Contract EP-C-15-008, the
Eastern Research Group, Inc. under Contract EP-C-12-029, Oregon State University under Purchase
Order EP-18-Z-000023, and Pegasus Technical Services under Contract EP-C-15-010. Special
acknowledgements are given to Justicia Rhodus of Pegasus Technical Services for technical editing, and
to Attainx, contractor to the EPA for graphics and media support under Contract
68HERH23D0009 G&M. Authors and contributors included student service contractors to EPA Larissa
Hassinger under Contract EP-D-15-003, and Oak Ridge Institute for Science and Education (ORISE)
participants Gregory Grissom, James McCord, and Sandra Utile-Okechukwu under an interagency
agreement with the Department of Energy. Larry McMillan, Lillian Alston and Richard Walker were
supported under the Senior Environmental Employment Program.
Special acknowledgements are given to the external peer reviewers who reviewed the draft report under
contract EP-C-17-017 with the Eastern Research Group, Inc.
• Alesia Ferguson, MPH, Ph.D.: Associate Professor, College of Public Health,
University of Arkansas Medical Sciences
• Panagiotis Georgopoulos, Ph.D.: Professor, School of Public Health, Rutgers University
• Tee L. Guidotti, MD, MPH: Consultant, Occupational and Environmental Health
• Maria Llompart, Ph.D.: Professor, Department of Analytical Chemistry, University of Santiago
de Compostela, Spain
• Martin Reinhard, Ph.D.: Professor Emeritus, Stanford University
• P. Barry Ryan, Ph.D.: Professor, Rollins School of Public Health, Emory University
• Clifford P. Weisel, Ph.D.: Tenured Professor, Environmental and Occupational Health
Sciences Institute (EOHSI), Rutgers University
Special acknowledgements are given to collaborators at the U.S. Consumer Product Safety Commission,
Army Public Health Center (now the Defense Centers for Public Health-Aberdeen), the National
Toxicology Program of the National Institutes of Environmental Health Sciences, and the California
Environmental Protection Agency's Office of Environmental Health Hazard Assessment.
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Table of Contents
Disclaimer i
Foreword ii
Authors, Contributors, and Reviewers iii
Acknowledgments vii
Table of Contents viii
List of Figures xii
List of Tables xvi
Acronyms and Abbreviations xix
Executive Summary xxiv
1.0 Introduction 1
1.1 Background 1
1.2 Report Organization 3
2.0 Summary of Results and Findings 5
2.1 Summary of Research Activities 5
2.2 Exposure Characterization: Overview of Research Approach, Results and Key Findings .... 6
2.2.1 Research Approach 6
2.2.2 Overview of Results and Key Findings 7
2.2.3 In Summary 13
2.3 Detailed Summaries of Research Results 15
2.3.1 Exposure Characterization Pilot Study for Athletes Using Synthetic Turf Fields
with Tire Crumb Rubber Infill 15
2.3.1.1 Participant Recruitment 15
2.3.1.2 Field Measurements 15
2.3.1.3 Personal Measurements 16
2.3.1.4 Activity Data Collection 17
2.3.1.5 Exposure Pathway Modeling 18
2.4 Research Limitations 20
2.4.1 Research Design Constraints 20
2.4.2 Planned Work Not Completed in this Study 21
2.4.3 Multi-source and Pathway Exposure Characterization 21
2.4.4 Other Limitations 21
2.5 Future Research Recommendations 22
2.6 Conclusions 23
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3.0 Exposure Characterization Methods 26
3.1 Overall Research Design 26
3.2 Exposure Measurement Pilot Study Recruiting and Questionnaire Methods 29
3.2.1 Participant Recruiting 29
3.2.2 Field User Questionnaire Administration 30
3.3 Exposure Pilot Study Sample Collection Methods 30
3.3.1 Field Environment Samples 30
3.3.1.1 Field Air Samples 31
3.3.1.2 Field Surface Samples - Surface Wipe and Drag Sled Samples 34
3.3.1.3 Field Dust Samples 37
3.3.2 Personal Samples 38
3.3.2.1 Personal Air Samples 38
3.3.2.2 Dermal Wipe Samples 39
3.3.3 Biological Samples - Pilot-Scale Biomonitoring Study 41
3.3.3.1 Urine Samples 41
3.3.3.2 Blood Samples 41
3.3.4 Field Meta-Data Collection 42
3.4 Sample Analysis Methods 42
3.4.1 Gravimetric Particle Size Analysis 42
3.4.2 Extraction and ICP/MS Metals Analysis 43
3.4.2.1 Field Air Sample and Field Dust Sample Preparation 43
3.4.2.2 Wipe Sample Preparation - Microwave-assisted Extraction 43
3.4.2.3 ICP/MS Analysis 43
3.4.3 TD/GC/TOFMS Analysis of Field Air and Personal Air Samples for VOCs 44
3.4.4 Solvent Extraction and SVOC Analysis 45
3.4.4.1 Air Sample SVOC Extraction 45
3.4.4.2 Field Surface Wipe Sample SVOC Extraction 45
3.4.4.3 Drag Sled Sample SVOC Extraction 46
3.4.4.4 Dermal Wipe Sample SVOC Extraction 46
3.4.4.5 Field Dust Sample SVOC Extraction 47
3.4.4.6 GC/MS/MS Analysis for SVOCs 47
3.4.5 Urine, Blood, and Serum Sample Analysis - Pilot-Scale Biomonitoring Study 47
3.5 Video Activity Assessments for Synthetic Field Users 47
3.5.1 Online Video Assessment (Phase 1) 48
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3.5.1.1 Videos of Selected Athletes from the Internet 48
3.5.1.2 Training Technicians for Video Translation 48
3.5.1.3 Translation of Targeted Micro-activities of Athletes in Publicly-available
Videos 49
3.5.1.4 Quality Control Measures 50
3.5.1.5 Statistical Analysis 50
3.5.2 Exposure Pilot Study Participant Video Assessment (Phase 2) 51
3.5.2.1 Videography of Study Participants 51
3.5.2.2 Training Technicians for Video Translation 51
3.5.2.3 Translation of Targeted Micro-activities of Study Participant Athletes. 52
3.5.2.4 Quantification of the Frequency of Micro-activity Events for Study
Participants 52
3.5.2.5 Quantification of the Intensity and Duration of Activity Levels of Study
Participants 52
3.5.2.6 Quality Control Measures 53
3.5.2.7 Statistical Analysis 53
3.6 Data Processing and Analysis 54
3.6.1 Data Processing 54
3.6.2 Data Analysis 54
4.0 Exposure Characterization Results 56
4.1 Exposure Pilot Study Recruitment 56
4.2 Exposure Pilot Study Field User Questionnaires 56
4.2.1 Demographics 56
4.2.2 Field Contact Frequency and Duration Questions 57
4.2.3 Contact Types and Scenarios per Field Use 59
4.2.4 Activity Intensity 59
4.2.5 Dermal and Non-dietary Ingestion Exposure 60
4.2.6 Tire Crumb, Dirt and Debris in Other Areas 61
4.2.7 Hygiene Practices Post-Field Use 61
4.2.8 General Hygiene Practices 61
4.3 Video Activity Assessments for Field Users 62
4.3.1 Publicly-Available Video Assessment (Phase 1) 62
4.3.1.1 General Descriptive Statistics of Athletes and Fields Observed in
Publicly-Available Videos 62
4.3.1.2 Descriptive Statistics of Micro-activity Events Observed in Publicly-
available Videos 63
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4.3.2 Exposure Pilot Study Participant Video Assessment (Phase 2) 70
4.3.2.1 General Descriptive Statistics of Athletes Videoed in the Exposure Pilot
Study 70
4.3.2.2 Descriptive Statistics of Micro-Activity Events by Athletes Videoed in
the Exposure Pilot Study 71
4.3.2.3 Descriptive Statistics of Activity Intensity and Duration by Athletes
Videoed in the Exposure Pilot Study 74
4.4 Exposure Measurement Pilot Study Meta-Data Summaries 77
4.5 Exposure Pilot Study Measurement Results 82
4.5.1 Field Environment Sample Measurements 83
4.5.1.1 Field Air Samples 83
4.5.1.2 Field Surface Wipe, Drag Sled and Dust Samples 91
4.5.1.3 Comparisons of Tire Crumb Rubber Infill, Field Surface Wipe, Drag
Sled, and Dust Measurement Results 97
4.5.2 Personal Sample Measurements 100
4.5.2.1 Personal Air Samples 100
4.5.2.2 Dermal Wipe Samples 101
4.5.3 Pilot-Scale Biological Sample Measurements Ill
4.5.3.1 Urine and Blood Samples Ill
4.6 Initial Testing of Silicone Wristbands 132
4.6.1 Feasibility Assessment of Wristbands at Synthetic Turf Fields 133
5.0 Assessing Exposure Pathway Modeling 136
5.1 Exposure Pathway Modeling Methods 136
5.1.1 Research Design Summary 136
5.1.2 Synthetic Turf Field User Exposure Estimation Using Existing Measurements... 139
5.1.3 Synthetic Turf Field User Exposure Estimation Using Exposure Pilot Study
Measurements 147
5.1.4 Background Exposure Estimation from Residential and Dietary Sources 148
5.2 Exposure Pathway Modeling Results 152
5.2.1 Synthetic Turf Field User Exposure Estimation Results Using Extant Measurements
152
5.2.2 Synthetic Turf Field User Exposure Estimation Results Using Exposure Pilot Study
Measurements 154
5.2.3 Synthetic Turf Field User Estimated Exposures for Chemicals of Interest by
Exposure Route 154
5.2.3.1 Benzo[a]pyrene Exposure Estimates 155
5.2.3.2 Pyrene Exposure Estimates 156
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5.2.3.3 Benzothiazole Exposure Estimates 157
5.2.3.4 Methyl Isobutyl Ketone Exposure Estimates 158
5.2.3.5 Lead Exposure Estimates 159
5.2.3.6 Zinc Exposure Estimates 160
5.2.4 Background Exposure Estimation Results from Residential and Dietary Sources 161
5.3 Comparison of Synthetic Turf Field User Exposure Estimates Using Extant Data and
Exposure Pilot Study Data 162
5.4 Comparisons Between Synthetic Turf Field and Background Exposure Estimates 163
5.5 Conclusions 167
6.0 References 170
7.0 Appendices 174
List of Figures
Figure ES-1. Pilot exposure characterization research schematic overview xxxi
Figure 2-1. Geometric mean of unadjusted urinary PAH concentrations (ng/L) for exposure pilot study
participants, pre-activity and post-activity, compared to NHANES 2013-2014 weighted and
design-adjusted values for ages 11-21 9
Figure 2-2. Geometric mean of unadjusted 1-hydroxynaphthalene and 2-hydroxynaphthalene
concentrations (|ig/L) for exposure pilot study participants, pre-activity and post-activity,
compared to NHANES 2013-2014 weighted and design-adjusted values for ages 11-21 9
Figure 2-3. Geometric mean of creatinine-adjusted urinary PAH concentrations (ng/g) for exposure pilot
study participants, pre-activity and post-activity, compared to NHANES 2013-2014 weighted
and design-adjusted values for ages 11-21 11
Figure 2-4. Geometric mean of creatinine-adjusted 1-hydroxynaphthalene and 2-hydroxynaphthalene
concentrations (jug/g) for exposure pilot study participants, pre-activity and post-activity,
compared to NHANES 2013-2014 weighted and design-adjusted values for ages 11-21 11
Figure 2-5. Exposure pilot study, pre-activity and post-activity, blood selenium, serum copper, serum
selenium, and serum zinc geometric mean levels compared to NHANES 2013-2014 weighted
and design-adjusted values for ages 11-21 12
Figure 2-6. Exposure pilot study, pre-activity and post-activity, blood cadmium, blood manganese, blood
lead and total blood mercury geometric mean levels compared to NHANES 2013-2014
weighted and design-adjusted values for ages 11-21 12
Figure 3-1. Pilot exposure characterization research schematic overview 27
Figure 3-2. Sample collection locations for field air, surface wipe, drag sled, and dust samples 30
Figure 3-3. Typical field air sampling station setup (photo taken during pre-pilot testing), including
particulate/metal, semivolatile organic compound (SVOc), active volatile organic compound
(VOC), and passive VOC samplers 31
Figure 3-4. Total suspended particulate/metals field air sampling setup, showing deployed A) batteries
and pumps and B) filter-containing sampling heads 32
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Figure 3-5. Volatile organic compound field air sampling setup, showing A) Pump and passive and
active air samplers in deployed configuration, with close-up of B) active Carbopack™ X
fenceline monitor sampler and C) passive Radiello™ sampler 33
Figure 3-6. Semivolatile organic compound field air sampling setup, with A) batteries and pumps and B)
filter-containing sampler. The pump/battery configuration shows duplicate sample collection.
34
Figure 3-7. Field surface wipe sampling for metals analysis 35
Figure 3-8. Field surface wipe sampling for semivolatile organic compound analysis 36
Figure 3-9. Drag sled sampling for semivolatile organic compound analysis 37
Figure 3-10. Dust sampling for metals and semivolatile organic compound analysis using a sieve
method 38
Figure 3-11. Personal air passive sampling for volatile organic compounds, showing A) placement on the
participant's pinnie and B) a close-up of the air sampler 39
Figure 3-12. Dermal sampling on A) hand and B) arm 40
Figure 3-13. Paper template for tallying the selected micro-activity events of an athlete 50
Figure 3-14. Paper template for tallying the intensity and duration of selected activity levels of an athlete.
53
Figure 4-1. Box-and-whisker plots of athlete micro-activity events per hour observed on publicly-
available video (Phase 1), by age group and sport 64
Figure 4-2. Micro-activity events per hour for all athletes (children and adults) observed on publicly-
available video (Phase 1), by sport 65
Figure 4-3. Micro-activity events per hour for adults observed on publicly-available video (Phase 1), by
sport 67
Figure 4-4. Micro-activity events per hour for children observed on publicly-available video (Phase 1),
by sport 68
Figure 4-5. Hand-to-mouth and hand-to-turf events per hour for athletes observed on publicly-available
video (Phase 1), by glove use and by glove use and sport 69
Figure 4-6. Hand-to-mouth and object-to-mouth events per hour of athletes observed on publicly-
available video (Phase 1), by mouthguard use and by mouthguard use and sport 70
Figure 4-7. Box-and-whisker plots of the micro-activity events per hour by athletes in Exposure Pilot
Study videos (Phase 2), by age group and sport type 72
Figure 4-8. Box-and-whisker plots of the mean amount of time all athletes spent (seconds/hour) at the
three different activity levels in Exposure Pilot Study videos (Phase 2) 75
Figure 4-9. The proportion of time athletes in Exposure Pilot Study videos (Phase 2) spent participating at
the three different activity levels in one hour, by sport 76
Figure 4-10. The proportion of time athletes in Exposure Pilot Study videos (Phase 2) spent participating
at the three different activity levels, by gender 76
Figure 4-11. Sample collection locations of field air, field wipe, drag sled, and dust samples. Collection
locations for air samplers was dependent on wind direction 82
Figure 4-12. Concentrations of cobalt, lead, and zinc in air samples collected next to fields and at upwind
background sample collection locations 86
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Figure 4-13. Concentrations of several SVOCs in air samples collected next to fields and at upwind
background sample collection locations 88
Figure 4-14. Concentrations of methyl isobutyl ketone, benzothiazole, benzene, and styrene in air
samples collected next to fields and at upwind background sample collection locations 91
Figure 4-15. Distributions of hand, arm and leg dermal measurement results for cobalt, lead and zinc. 105
Figure 4-16. Distributions of dermal measurement results for fluoranthene, the sum of 15 PAHs,
benzothiazole, and di-n-octyl phthalate Ill
Figure 4-17. Exposure pilot study pre- and post-activity differences in creatinine- adjusted 1-
hydroxynaphthalene measurements (jug/g), by participant 115
Figure 4-18. Exposure pilot study pre- and post-activity differences in creatinine- adjusted 1-
hydroxyphenanthrene measurements (ng/g), by participant 115
Figure 4-19. Exposure pilot study pre- and post-activity differences in creatinine- adjusted 1-
hydroxypyrene measurements (ng/g), by participant 116
Figure 4-20. Exposure pilot study pre- and post-activity differences in creatinine- adjusted 2- & 3-
hydroxyphenanthrene measurements (ng/g), by participant 116
Figure 4-21. Exposure pilot study pre- and post-activity differences in creatinine-adjusted 2-
hydroxyfluorene measurements (ng/g), by participant 117
Figure 4-22. Exposure pilot study pre- and post-activity differences in creatinine-adjusted 2-
hydroxynaphthalene measurements (jug/g), by participant 117
Figure 4-23. Exposure pilot study pre- and post-activity differences in creatinine-adjusted 3-
hydroxyfluorene measurements (ng/g), by participant 118
Figure 4-24. Exposure pilot study pre-activity and post-activity creatinine-adjusted urinary PAH
geometric means compared to NHANES (2013-2014) geometric mean values for ages 11 to
21 122
Figure 4-25. Exposure pilot study pre- and post-activity differences in blood cadmium measurements
(|ig/L), by participant 125
Figure 4-26. Exposure pilot study pre- and post-activity differences plots in blood manganese
measurements (|ig/L), by participant 125
Figure 4-27. Exposure pilot study pre- and post-activity differences in blood lead measurements (|ig/dL),
by participant 126
Figure 4-28. Exposure pilot study pre- and post-activity differences in blood selenium measurements
(|ig/L), by participant 126
Figure 4-29. Exposure pilot study pre- and post-activity differences in serum copper measurements
(|ig/dL), by participant 127
Figure 4-30. Exposure pilot study pre- and post-activity differences in serum selenium measurements
(|ig/L), by participant 127
Figure 4-31. Exposure pilot study pre- and post-activity differences in serum zinc measurements (|ig/dL),
by participant 128
Figure 4-32. Exposure pilot study pre- and post-activity differences in total blood mercury measurements
(|ig/L), by participant 128
Figure 4-33. Exposure pilot study pre-activity and post-activity blood cadmium, blood manganese, blood
lead and total blood mercury geometric mean levels compared to NHANES (2013-2014)
xiv
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weighted and design-adjusted values for Ages 11-21 131
Figure 4-34. Exposure pilot study pre-activity and post-activity blood selenium, serum copper, serum
selenium and serum zinc geometric mean levels compared to NHANES (2013-2014)
weighted and design-adjusted values for ages 11-21 132
Figure 5-1. Process for generating pathway-specific exposure estimates using both existing data (on left)
and new data from this exposure pilot study (on right) 138
Figure 5-2. Diagram of exposure pathway modeling, showing possible media for each route-specific
exposure estimate 139
Figure 5-3. Process flowchart of the commands used in Excel to calculate the geometric standard
deviation 140
Figure 5-4. Benzo[a]pyrene daily dose calculated for three age groups, by route of exposure, using extant
data 155
Figure 5-5. Benzo[a]pyrene daily dose calculated for three age groups, by route of exposure, using
exposure pilot study data 155
Figure 5-6. Pyrene daily dose calculated for three age groups, by route of exposure, using extant data. 156
Figure 5-7. Pyrene daily dose calculated for three age groups, across by route of exposure, using
exposure pilot study data 156
Figure 5-8. Benzothiazole daily dose calculated for three age groups, by route of exposure, using extant
data 157
Figure 5-9. Benzothiazole daily dose calculated for three age groups, by route of exposure, using
exposure pilot study data 157
Figure 5-10. Methyl isobutyl ketone inhalation daily dose calculated for three age groups, using extant
data 158
Figure 5-11. Methyl isobutyl ketone inhalation daily dose calculated for three age groups, using exposure
pilot study data 158
Figure 5-12. Lead daily dose calculated for three age groups, by route of exposure, using extant data. 159
Figure 5-13. Lead daily dose calculated for three age groups, by route of exposure, using exposure pilot
study data 159
Figure 5-14. Zinc daily dose calculated for three age groups, by route of exposure, using extant data.. 160
Figure 5-15. Zinc daily dose calculated for three age groups, by route of exposure, using exposure pilot
study data 160
Figure 5-16. Total estimated benzo[a]pyrene background (residential/dietary) and synthetic turf field
daily dose rate comparison across all pathways, by age group 164
Figure 5-17. Total estimated pyrene background (residential/dietary) and synthetic turf field daily dose
rate comparison across all pathways, by age group 165
Figure 5-18. Total estimated lead background (residential/dietary) and synthetic turf field daily dose rate
comparison across all pathways, by age group 165
Figure 5-19. Total estimated zinc background (residential/dietary) and synthetic turf field daily dose rate
comparison across all pathways, by age group 166
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List of Tables
Table 2-1. Topic Area and Specific Activities Described in This Report 5
Table 3-1. Exposure Characterization Research Areas and Specific Research Activities 28
Table 3-2. TD/GC/TOFMS Parameters for VOC Field Exposure Sample Analysis 45
Table 3-3. Number of Subjects Selected for Assessment by Sport from Publicly-available Videos 48
Table 3-4. Number of Exposure Study Participant Athletes Videotaped by Sport 51
Table 4-1. Exposure Pilot Study Participant Recruitment and Participation Types 56
Table 4-2. Age and Gender of Questionnaire Participants 57
Table 4-3. How Long Questionnaire Participants Have Been Coming to the Facility for All Combined
Age Groups 57
Table 4-4. Number of Days per Week Questionnaire Participants Typically Spent on the Synthetic Turf
Fields at this Facility, by Season 57
Table 4-5. Number of Hours per Day Questionnaire Participants Typically Spent on the Synthetic Turf
Fields at this Facility, by Season 58
Table 4-6. Longest Period of Time Questionnaire Participants Spent on Synthetic Turf Fields in a Single
Day 58
Table 4-7. How Often Questionnaire Participants Played on Synthetic Turf Fields and Grass Fields in the
Past Year and Past Five Years 58
Table 4-8. Types and Frequency of Questionnaire Participant Contact with Synthetic Turf Fields in
Spring and Summer 59
Table 4-9. Intensity of Activity Engaged in by Questionnaire Participants When Using Synthetic Turf
Fields 59
Table 4-10. Frequency of Different Activities Performed by Questionnaire Participants on Synthetic Turf
Fields 60
Table 4-11. Clothing Worn by Questionnaire Participants, by Season 60
Table 4-12. Frequency of Questionnaire Participants Noticing Tire Crumb Rubber, Dirt or Debris After
Using Facility 61
Table 4-13. Frequency of Hygiene Practices by Questionnaire Participants, Post-field Use 61
Table 4-14. How Many Times per Day Questionnaire Participants Generally Wash Their Hands 62
Table 4-15. How Often Questionnaire Participants Generally Shower or Bathe per Week 62
Table 4-16. General Characteristics of the Athletes and Fields They Were Observed Playing on in
Publicly-available Videos (Phase 1) 62
Table 4-17. One-way ANOVA Results for Select Micro-activity Events Performed per Hour by Athletes
(Children and Adults) Observed on Publicly-available Video (Phase 1), by Sport 65
Table 4-18. ANOVA Results for Select Micro-activity Events per Hour for Adults Observed on Publicly-
available Video (Phase 1), by Type of Sport 66
Table 4-19. ANOVA Results for Select Micro-activity Events per Hour for Children Observed on
Publicly-available Video (Phase 1), by Sport 67
Table 4-20. General Characteristics of the Athletes Observed Playing Soccer and Football in Exposure
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Pilot Study Videos (Phase 2) 71
Table 4-21. Welch's t-test Results for Micro-activity Events Per Hour by Athletes in Exposure Pilot
Study Videos (Phase 2), by Sport 73
Table 4-22. Welch's t-test Results for Hand-to-mouth and Hand-to-turf Events per Hour by Athletes in
Exposure Pilot Study Videos (Phase 2), by Glove Use 73
Table 4-23. Welch's t-test Results for Hand-to-mouth and Object-to-mouth Events per Hour by Athletes
in Exposure Pilot Study Videos (Phase 2), by Mouthguard Usage 74
Table 4-24. Welch's t-test Results for the Mean Amount of Time Athletes in Exposure Pilot Study
Videos (Phase 2) Spent (Seconds/hour) in the Three Different Activity Levels, by Sport 75
Table 4-25. Welch's t-test Results for the Mean Amount of Time Athletes in Exposure Pilot Study
Videos (Phase 2) Spent (Seconds/hour) at the Three Different Activity Levels, by Gender.. 76
Table 4-26. Exposure Pilot Study Field Measurement Overview 77
Table 4-27. Field Conditions and Overall Activities During Time Periods When Personal Exposure
Measurement Sample Collection Activities Were Performed at Synthetic Turf Fields 79
Table 4-28. Summaries of Observed Participant Clothing and Safety Equipment in Exposure Pilot Study
80
Table 4-29. Summaries of Observed Participant Activities in Exposure Pilot Study 81
Table 4-30. Types and Numbers of Samples and Quality Control Samples for the Exposure Pilot Study 83
Table 4-31. Exposure Pilot Study Field Air Sampling Total Suspended Particulate (TSP) Measurements
84
Table 4-32. Exposure Pilot Study Field Air Sampling Metals Measurements 85
Table 4-33. Exposure Pilot Study Field Air Sampling SVOC Measurements 87
Table 4-34. Exposure Pilot Study Field Air Sampling VOC Measurements 89
Table 4-35. Exposure Pilot Study Field Dust Sampling Metals Measurements 92
Table 4-36. Exposure Pilot Study Field Surface Wipe Sampling Metals Measurements 93
Table 4-37. Exposure Pilot Study Field Dust Sampling SVOC Measurements 93
Table 4-38. Exposure Pilot Study Field Surface Wipe Sampling SVOC Measurements 95
Table 4-39. Exposure Pilot Study Field Drag Sled Sampling SVOC Measurements 96
Table 4-40. Comparison of Average Tire Crumb Rubber Infill, Field Dust, and Field Surface Wipe Metal
Measurement Results from the Three Exposure Pilot Study Fields 98
Table 4-41. Comparison of Average Tire Crumb Rubber Infill, Field Dust, Field Wipe, and Drag Sled
SVOC Measurement Results from the Three Exposure Pilot Study Fields 99
Table 4-42. Exposure Pilot Study Participant Dermal Wipe Measurement Results for Selected Metals 102
Table 4-43. Exposure Pilot Study Dermal Wipe Measurement Results for Select SVOCs 106
Table 4-44. Exposure Pilot Study Pre- and Post-Activity Creatinine-Adjusted Urinary PAH
Measurements 112
Table 4-45. Exposure Pilot Study Pre- and Post-Activity Creatinine-Adjusted Urinary PAH
Measurements, by Sport 113
Table 4-46. Exposure Pilot Study Pre- and Post-Activity Specific-Gravity-Adjusted Urinary PAH
Measurements, by Sport 114
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Table 4-47. Statistical Analysis of Differences in Exposure Pilot Study Pre- and Post-Activity Creatinine-
Adjusted Urinary PAH Measurements 119
Table 4-48. Statistical Analysis of Differences in Exposure Pilot Study Pre- and Post-Activity Creatine-
Adjusted Urinary PAH Measurements, by Sport 120
Table 4-49. NHANES Weighted and Design-Adjusted Urinary PAH Values (2013-2014) for Ages 11 to
21 121
Table 4-50. Exposure Pilot Study Pre- and Post-Activity Blood and Serum Metal Measurements 123
Table 4-51. Exposure Pilot Study Pre- and Post-Activity Blood and Serum Metal Measurements, by Sport
124
Table 4-52. Statistical Analysis of Differences in Exposure Pilot Study Pre- and Post-Activity Whole
Blood Metals and Serum Metals Measurements 129
Table 4-53. Statistical Analysis of Differences in Exposure Pilot Study Pre- and Post-Activity Whole
Blood Metals and Serum Metals Measurements, by Sport 130
Table 4-54. NHANES Weighted and Design-Adjusted Blood and Serum Metal Values (2013-2014) for
Ages 11 to 21 131
Table 5-1. Select Physico-chemical Properties of Chemicals Used in Exposure Pathway Modeling in this
Study 137
Table 5-2. Weighted Arithmetic Means for Chemicals of Interest in Exposure Pathway Modeling 141
Table 5-3. Weighted Geometric Means for Chemicals of Interest in Exposure Pathway Modeling 141
Table 5-4. Upper Confidence Limits (UCLs) for Chemicals of Interest in Exposure Pathway Modeling
142
Table 5-5. Age Ranges from the EPA Exposure Factors Handbook 142
Table 5-6. Exposure Scenarios from Several Studies, Including this Exposure Pilot Study 143
Table 5-7. Exposure Parameters for Extant Data 144
Table 5-8. Parameter Input Value Comparisons Among Select Studies 146
Table 5-9. Mean Concentrations and Estimated Total Dermal Loads of Chemical Substances Measured in
the Exposure Pilot Study 148
Table 5-10. Exposure Parameters for Residential and Dietary Estimates 149
Table 5-11. Residential and Dietary Concentrations Reported in the Literature for Chemicals of Interest
150
Table 5-12. Data Availability by Chemical and Medium 150
Table 5-13. Estimated Exposure Results Using Extant Measurements, by Exposure Pathway 153
Table 5-14. Estimated Exposure Results Using Exposure Pilot Study Measurements, by Exposure
Pathway 154
Table 5-15. Estimated Residential Plus Dietary Daily Dose for Chemicals of Interest, by Age Group .. 161
Table 5-16. Total Estimated Daily Dose Across all Pathways by Age Group 164
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Acronyms and Abbreviations
ACGIH
American Conference of Governmental Industrial Hygienists
ACH
Air change per hour
AIC
Akaike information criterion
ANOVA
Analysis of variance
APHC
U.S. Army Public Health Center
API
Analytical profile index
ASTM
American Society for Testing and Materials
AT SDR
Agency for Toxic Substances and Disease Registry
BLP
Bacteria-like particles
BSD
Backscattered electron detector
BTEX
Benzene, toluene, ethylbenzene, xylenes
°C
Degrees Celsius
CalEPA
California Environmental Protection Agency
CalOSHA
California Division of Occupational Safety and Health
CAS
Chemical Abstracts Service
CCTE
Center for Computational Toxicology and Exposure
CDC
Centers for Disease Control and Prevention
CFU
Colony forming units
CICAD
Concise International Chemical Assessment Documents
cm
Centimeter
CEMM
Center for Environmental Measurement and Modeling
CESER
Center for Environmental Solutions and Emergency Response
COC
Chain of custody
CP
Carcinogenic potency
CPHEA
Center for Public Health and Environmental Assessment
CPSC
Consumer Product Safety Commission
CVAA
Cold vapor atomic absorption
DAD
Diode array detector
DBA + ICDP
Sum of Dibenz[a,h]anthracene and Indeno(l,2,3-cd)pyrene
ddPCR
Droplet digital polymerase chain reaction
DNA
Deoxyribonucleic acid
DNPH
Dinitrophenyl hydrazine
dNTP
Deoxyribonucleotide triphosphate
dsDNA
Double-stranded DNA
DSSTox
EPA's Distributed Structure-Searchable Toxicity Database
EI
Electron impact
EOHSI
Environmental and Occupational Health Sciences Institute
EPA
U.S. Environmental Protection Agency
EPMA
Electron probe microanalysis
ESI
Electrospray ionization
eV
Electronvolt
FLM
Fence line monitor
FRAP
Federal Research Action Plan on Recycled Tire Crumb Used on Playing Fields and Playgrounds
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g Gram
GC/MS Gas chromatography/mass spectrometry
GC/TOFMS Gas chromatography/time-of-flight mass spectrometry
GS/MS/MS Gas chromatography/tandem mass spectrometry
h Hour
HDPE High density polyethylene
HEAST Health Effects Assessment Summary Table
HPLC High performance liquid chromatography
HR-ICPMS High resolution magnetic sector inductively coupled plasma mass spectrometer
HS High-sensitivity
Hz Hertz
IAC Internal amplification control
IARC International Agency for Research on Cancer
ICP/AES Inductively coupled plasma-atomic emission spectrometry
ICP/MS Inductively coupled plasma/mass spectrometry
ICR Information Collection Request
in Inch
10AA Immediate Office of the Assistant Administrator
IPCS WHO International Programme on Chemical Safety
IRB Institutional Review Board
IRIS U.S. EPA Integrated Risk Information System
IS Internal standard
ISO International Standards Organization
IUR Inhalation unit risk
JTI Jacobs Technology, Inc.
kg Kilogram
kV Kilovolt
L Liter
LC/MS Liquid chromatography/mass spectrometry
LC/TOFMS Liquid chromatography/time-of-flight mass spectrometry
LOD Limit of detection
LOQ Limit of quantitation
lpm Liters per minute
LRGA Literature Review and Data Gaps Analysis
mg Milligram
m/z Mass-to-charge ratio
MADL Maximum allowable dose levels
Max Maximum
mecA Gene for methicillin resistance
MFE Molecular feature extraction
min Minute
Min Minimum
mL Milliliter
mm Millimeter
mM Millimolar
Mohm Megaohm
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mol
Mole
MQL
Minimum quantifiable limit
MRL
Minimum risk level
MRM
Multiple reaction monitoring
MRSA
Methicillin-resistant Staphylococcus aureus
MSD
Mass selective detector
N/A
Not applicable/Not available
NAM
New approach methods
ng
Nanogram
NIEHS
National Institutes of Environmental Health Sciences
NIOSH
National Institute for Occupational Safety and Health
NIST
National Institute of Standards and Technology
nM
Nanomolar
NR
Not reported
NSRL
No significant risk level
ns
Nanosecond
NTP
National Toxicology Program
OCHP
U.S. EPA Office of Children's Health Protection
OEHHA
California Office of Environmental Health Hazard Assessment
OEM
Original equipment manufacturer
OLEM
U.S. EPA Office of Land and Emergency Management
OMB
U.S. Office of Management and Budget
ORAU
Oak Ridge Associated Universities
ORCR
U.S. EPA Office of Resource Conservation and Recovery
ORD
U.S. EPA Office of Research and Development
ORISE
Oak Ridge Institute for Science and Education
OSAPE
Office of Science Advisor, Policy and Engagement
OSF
Oral slope factor
OSHA
Occupational Safety and Health Administration
OTU
Operational taxonomic unit
PAH
Polyaromatic hydrocarbon
PCDL
Personal compound database list
PCR
Polymerase chain reaction
PEL
Permissible exposure limit
pM
Picomolar
ppbv
Parts per billion by volume
ppm
Parts per million
PPRTV
Provisional peer-reviewed toxicity value
PSA
Particle size analysis
psi
Pounds per square inch
PUF
Polyurethane foam
QA
Quality assurance
QC
Quality control
REL
Recommended exposure limit/Reference exposure levels
RF
Radio frequency
RfC
Reference concentration
-------
RfD Reference dose
RH Relative humidity
RIVM Netherlands National Institute for Public Health and the Environment
RNA Ribonucleic acid
RPM Revolutions per minute
rRNA Ribosomal ribonucleic acid
%RSD Percent relative standard deviation
s Second
SBR Styrene-butadiene rubber
SD Standard deviation
SEE Senior Environmental Employee
SEM Scanning electron microscopy
SF Slope factor
SOP Standard operating procedure
SSC Student Services Contractor
STEL Short term exposure limit
Suml5PAH Sum of 15 of the 16 EPA 'priority' PAHs
SumBTEX Sum of benzene, toluene, ethylbenzene, m/p-xylene, and o-xylene
SVOC Semi-volatile organic compound
S-W Shapiro-Wilk
TCR Tire crumb rubber
TD Thermal desorption
TIC Total ion current
TIFF Tagged image file format
TLV Threshold limit value
TOFMS Time-of-flight mass spectrometry
TPE Thermoplastic elastomers
TSA Technical systems audit
TSP Total suspended solids
TWA Time weighted average
jam Micrometer
|iL Microliter
UR Unit risk
U.S. United States of America
U.S. EPA United States Environmental Protection Agency
UV Ultraviolet spectrometry
VID Video identification number
V Volt
VOC Volatile organic compound
W Watt
WHO World Health Organization
XRF X-ray fluorescence spectrometry
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Executive Summary
The goal of the research under the Federal Research Action Plan on Recycled Tire Crumb Used on
Playing Fields and Playgrounds (FRAP) is to characterize potential human exposures to the
substances associated with recycled tire crumb rubber used on synthetic turffields. Results of the
effort are being reported in two parts. Part 1 communicates the research objectives, methods, results,
andfindings for the tire crumb rubber characterization research (i. e., what is in the material?). Part 2
(this document) characterizes potential human exposures to the chemicals found in the tire crumb
rubber material while using synthetic turffields. Neither Part 1 nor Part 2 of this study, separately or
combined, constitutes an assessment of the risks associated with playing on synthetic turffields with
recycled tire crumb rubber infill. The results of the research described in both Part 1 and Part 2 of the
final report can be used to inform risk assessments.
In the United States, synthetic turf fields are used at municipal and
county parks; schools, colleges, and universities; professional
sports stadiums and practice fields; and military installations. The
fields are designed to simulate the experience of practicing and
playing on grass fields.1 First introduced in the 1960s, synthetic
turf fields have evolved over time from first-generation systems
made of tightly curled nylon fibers to third-generation systems
typically made of polyethylene yarn fibers. These third-generation
systems typically use small pieces of recycled tires, referred to as
"recycled tire crumb rubber" (or simply "tire crumb rubber"), to
fill the space between the polyethylene yarn fibers. The recycled
tire crumb rubber (sometimes mixed with sand or other raw
materials) is added for ballast, support for the synthetic grass
blades, and as cushioning for field users. Third-generation
synthetic turf field systems are widely used today. There are
between 18,000 and 19,000 synthetic turf fields in the United
States, with 1,200 - 1,500 new installations each year, about half
of which are replacements.2 It is estimated that millions of people use and/or work at these fields.
Some parents, athletes, schools, and communities have raised concerns about the use of recycled tire
crumb rubber on synthetic turf fields. To help address these concerns, the Centers for Disease Control
and Prevention/Agency for Toxic Substances and Disease Registry (CDC/ATSDR) and the U.S.
Environmental Protection Agency (EPA), in collaboration with the Consumer Product Safety
Commission (CPSC), launched a multi-agency research effort in February 2016.
This multi-agency research effort, known as the Federal Research Action Plan on Recycled Tire Crumb
Used on Playing Fields and Playgrounds (FRAP)3, is focused on assessing potential human exposure,
1 More information on the intended uses of synthetic turf can be found at:
https://www.SYntheticturfcouncil.org/page/About Synthetic Turf.
2 Personal communication with the Synthetic Turf Council.
3 The multi-agency research effort, called the Federal Research Action Plan on Recycled Tire Crumb Used on Playing Fields
and Playgrounds (FRAP), was launched in February 2016. Prior to initiating the study, federal researchers developed a
research protocol. Collections Related to Synthetic Turf Fields with Crumb Rubber Infill, that describes the study's
objectives, research design, methods, data analysis techniques and quality assurance/quality control (QA/QC) measures.
These documents are available at: http://www.epa. gov/TireCrumb. CPSC is conducting the work on playgrounds and results
[
KEY RESEARCH ACTIVITIES
DISCUSSED IN PART 2
• Collect human activity data using
video and questionnaires.
• Pilot study collection of air, dermal
wipe, and biomarker samples from
people using synthetic turf fields.
• Pilot study collection of air, surface
wipe, and dust samples from fields.
• Conduct an exposure modeling
assessment.
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which includes conducting research activities to characterize the chemicals associated with recycled tire
crumb rubber and to identify the ways in which people may be exposed to those chemicals based on
their activities on synthetic turf fields. Also, the FRAP includes characterizing emissions and
bioaccessibility to differentiate what is present in the recycled tire crumb rubber from what people may
actually be exposed to from recycled tire crumb rubber.
The research laid out in the FRAP is not intended to be a risk assessment. Like other studies, this
research has limitations, and risks cannot be inferred from the information and conclusions found in this
study. Prior to initiating the FRAP, most studies examining these potential risks have been considered
inconclusive or otherwise incomplete. Based upon available literature, this research effort represents the
largest tire crumb rubber study conducted in the United States. The information and results from the
effort will fill specific data gaps about the potential for human exposure to chemical constituents
associated with recycled tire crumb rubber used in synthetic turf fields.
A status report was previously released describing FRAP
activities as of December 2016 (EPA600/R-16/364,
available at: http://www.epa.gov/TireCrumb). The status
report included a summary of stakeholder outreach, an
overview of the tire crumb rubber manufacturing industry,
progress on the research activities, and the final peer-
reviewed literature review/gaps analysis (LRGA) white
paper. The results of the research activities under the FRAP
are being documented in two parts. The previously released
Part 1 Report (EPA600/R-19/051, available at:
http://www.epa.gov/TireCrumb) documents the tire crumb
characterization activities and results. This Part 2 report
documents the results from the pilot exposure
characterization research study conducted by EPA and
CDC/ATSDR and includes the supplemental biomonitoring
study conducted by CDC/ATSDR (Appendix A). Part 2 also
includes future research recommendations that could
provide additional insights into potential exposures to
recycled tire crumb rubber used on synthetic turf fields.
This Executive Summary provides a synopsis of the
exposure characterization research (Part 2 of the study).
Section 1 of this report provides introductory information;
Section 2 provides a more complete technical summary of
these activities and the study's key findings; Sections 3 and
4 describe the methods and contain detailed results for the
exposure characterization activities; and Section 5 provides
information on exposure pathway modeling assessment. Results from the supplemental biomonitoring
study, quality control/quality assurance assessments, and information about methods are provided in the
Appendices (Volume 2 of this report).
from that effort will be reported separately. While artificial turf is also used at residences, that turf does not typically include
tire crumb rubber; as a result, the use of artificial turf at residences is not part of the FRAP study.
RECAP: RECYCLED TIRE CRUMB
RUBBER CHARACTERIZATION
• As expected, a range of metals,
semivolatile organic compounds
(SVOCs), volatile organic compounds
(VOCs) and bacteria were measured in
and on recycled tire crumb rubber infill.
• Many chemicals were found at similar
concentrations in other studies of
recycled tire crumb rubber, where
comparable data are available.
• Emissions of most SVOCs and many
VOCs were low when tested at 25 °C,
while emissions were higher for some,
but not all at 60 °C.
• The amount of metals released into
simulated biological fluids was low, on
average about 3% in gastric fluid and
less than 1% in saliva and sweat plus
sebum.
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Exposure Characterization
A small-scale pilot study was conducted to better understand the ways in which people may be exposed
to chemicals associated with recycled tire crumb rubber (Figure ES-1). As part of the pilot study, human
activity data were collected using video and questionnaires. Personal air and dermal wipe samples were
collected from 25 people participating in soccer or football practices at synthetic turf fields. Surface
wipe, air, and dust samples were also collected from fields. The analyses of these samples provided
additional data for assessing inhalation exposures and new data for better understanding exposures
through dermal and ingestion pathways. Technical details are provided in Section 4, which contains
detailed assessment results for the exposure characterization.
While the results from these studies are not generalizable to all other situations and activities, our field
and dermal measurements (while limited) indicate that people can be exposed to chemicals associated
with recycled tire crumb rubber infill material when they use synthetic turf fields. A range of chemicals
associated with recycled tire crumb rubber was found in air, field surface, field dust, and in dermal
exposure media collected from the participants, including metals and organic chemicals.
For many analytes measured during active play at the outdoor fields, next-to-field concentrations in air
did not differ from background samples. Other chemicals, such as methyl isobutyl ketone,
benzothiazole, 4-tertbutyl phenol, and several PAHs, were somewhat higher. Exposures may be higher
for people using indoor synthetic turf fields than outdoor fields. Many chemicals were measured in next-
to-field air samples at the indoor field at higher concentrations compared to those at the two outdoor
fields. This aligns with findings from the Tire Crumb Characterization Part 1 report where most organic
compounds were found in tire crumb rubber at higher levels at indoor fields compared to outdoor fields,
and higher emissions from tire crumb rubber were observed for most organic chemicals at indoor fields
compared to outdoor fields. Results from the personal air sampling for volatile organic chemicals
(VOCs) are not available, as the method was not successful.
In the biomarker measurements, of the 25 participants, 14 provided urine samples and 13 provided blood
samples. Participants providing blood and urine were 11-21 years old. The participants provided blood
and urine samples before and after practice on synthetic turf fields with tire crumb rubber infill. The
blood samples collected before and after practice, and the serum derived from the blood, were analyzed
for metals. An increase in metal concentration was not observed after practice. However, blood selenium
levels, both pre- and post-activity, were higher than the geometric mean for participants aged 11 - 21 in
the 2013-2014 National Health and Nutrition Examination Survey (CDC NHANES 2013 - 2014).
Selenium was not found above detection limits in tire crumb and other field environment matrices. With
the exception of blood selenium, body burden levels of metals in these study participants were consistent
with those found for the general population (CDC NHANES 2013 -2014, participants aged 11-21).
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AIR SAMPLING FINDINGS
• Potential for overall exposures is
expected to be low.
• For many analytes measured during
active play at the outdoor fields,
next-to-field concentrations in the air
did not differ from background
samples.
• Other chemicals, such as methyl
isobutyl ketone, 4-tertbutyl phenol,
benzothiazole and several PAHs,
were somewhat higher.
• Many chemicals were measured in
air samples at the indoor field at
higher concentrations compared to
those at the two outdoor fields.
Urine samples were analyzed for seven polycyclic aromatic
hydrocarbon (PAH) metabolites. The unadjusted urinary PAH
metabolite concentrations were significantly higher post-
activity compared to pre-activity, and all of the unadjusted
post-activity PAH metabolite concentrations were higher than
those found in the general population (NHANES 2013-2014,
participants aged 11-21), with the exception of 1-
hydroxypyrene. The creatinine-adjusted urinary PAH
metabolites showed no difference in concentration in samples
collected before and after practice, with the exception of 2-
hydroxynaphthalene. When comparing creatinine adjusted
pre- and post- activity concentrations, there was a significant
increase post activity (34%) for 2-hydroxynaphthalene. For
specific gravity-adjusted metabolite concentrations, all post-
activity concentrations were statistically higher than pre-
activity concentrations, and all differences were statistically
significant using the signed-rank test. The creatinine adjusted
2-hydroxynaphthalene concentration was higher pre- and
post-activity when compared to the general US population
(CDC
NHANES 2013-2014, participants aged 11-21).
However, only low levels of the parent compound,
naphthalene, were found in the tire crumb rubber,
field air, dust, field wipe, and dermal wipe
samples. It is important to note that the
biomonitoring study that was conducted as part of
the exposure measurement study was a pilot-scale
effort with several limitations. The sample size was
very small (n=14) and individuals who participated
in the pilot-scale biomonitoring study were
recruited at only two outdoor fields.
A supplemental biomonitoring study was
conducted to expand the pilot-scale study results
using a larger sample size (Appendix A). Among
161 participants, 82% (n=132) played on synthetic
turf with tire crumb rubber infill, and the remaining
18% (n=29) played on natural grass. 25% (n=41)
played on an indoor synthetic turf field, and 75%
(n=120) played on outdoor fields where synthetic
turf and natural grass fields were co-located.
Recycled tire crumb rubber infill field users and
natural grass field users experienced similar
differences in pre- and post-activity PAH
concentrations, including for 2-
hy droxy naphthal ene.
PILOT BIOMONITORING STUDY
FINDINGS
• An increase in metal concentrations in blood
samples was not observed after practice.
• However, blood selenium levels, both pre- and
post-activity, were higher than the geometric
mean for participants aged 11 - 21 in the 2013-
2014 National Health and Nutrition Examination
Survey (CDC NHANES 2013 - 2014). Selenium was
not found above detection limits in tire crumb
and other field environment matrices.
• With the exception of blood selenium, body
burden levels of metals in these study
participants were consistent with those found for
the general population (CDC NHANES 2013 -
2014, participants aged 11-21).
• In comparing pre- and post-activity creatinine-
adjusted measurements for these PAH
metabolites in urine, there was no significant
difference in pre- and post-activity
concentrations, except for 2-hydroxynaphthalene.
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SUPPLEMENTAL BIOMONITORING
STUDY FINDINGS
An exposure pathway modeling assessment was
included in this exposure characterization study to
complement the measurement activities and evaluate
the availability and robustness of data needed to
support modeling. Modeling was conducted for
athletes using synthetic turf fields with recycled tire
crumb rubber infill, using extant exposure information
(from previous synthetic turf field studies) and then
updated with information collected in this exposure
characterization study. The estimation used six (6)
chemicals (pyrene, benzo[a]pyrene, benzothiazole,
methyl isobutyl ketone, lead, and zinc), chosen to
provide a range of physical and chemical properties
for which data were available. In general, estimated
daily exposures were <5 x 10"5 mg/kg-day for most chemicals and pathways, with inhalation being the
dominant pathway for more volatile chemicals and ingestion being dominant for metals and less volatile
chemicals. While the data collected from the exposure characterization study improved the estimates,
the results still carry a degree of uncertainty associated with limited data for factors like ingestion rates
and dermal adhesion values for tire crumb rubber and field dust, along with airborne particle sizes.
Exposures at synthetic turf fields should also be considered in context, since the chemicals in recycled
tire crumb rubber are present in other products and/or environmental media that people use or contact.
To provide this context, exposure from other typical sources (such as, residential and dietary
"background") were compared to those of field users. Residential (i.e., exposures expected through
typical residential media, such as indoor air and dust) plus dietary 'background' exposures were
estimated for a subset of four chemicals associated with tire crumb rubber (pyrene, benzo[a]pyrene, zinc
and lead) for which data are available. Modeled estimates for this limited set of PAHs and metals
expected in recycled tire crumb suggest that synthetic turf field users may have pyrene and
benzo[a]pyrene exposures similar to, or somewhat lower than, typical background exposures. Exposures
to zinc and lead are expected to be substantially lower than background. Data are sparse for estimating
background exposures for many of the chemicals associated with tire crumb rubber for comparison with
synthetic turf field user exposure estimates. Such estimates also carry a degree of uncertainty due to
limited numbers of studies.
• Pre- and post-activity differences in urinary
PAH concentrations were not associated with
field type (synthetic turf fields with tire
crumb rubber infill vs natural grass fields).
• Except for 2-hydroxynaphthalene, pre-
activity PAH concentrations were lower than
those in the U.S. population (NHANES 2015-
2016).
xxviii
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Conclusions
In general, the findings from the entire playing fields portion of the FRAP activities (both the Tire
Crumb Characterization Part 1 and the Tire Crumb Exposure Characterization Part 2 combined) support
the conclusion that although chemicals are present (as expected) in the tire crumb rubber and exposures
can occur, they are likely limited; for example:
• Generally, only small amounts of most organic chemicals are released from tire crumb rubber
into the air through emissions. For many analytes measured during active play at the outdoor
fields, next-to-field concentrations in air were not different than background samples while
others were somewhat higher.
• For metals, only small fractions are released from tire crumb rubber into simulated biological
fluids (average mean about 3% for gastric fluid and <1% for saliva and sweat plus sebum)
compared to a default assumption of 100% bioaccessibility.
• In the biomonitoring pilot study, concentrations for metals measured in blood were similar to
those in the general population.
• No differences in PAH metabolites in urine were observed in the supplemental biomonitoring
study between study participants using natural grass fields and those on synthetic turf fields with
tire crumb rubber infill.
Risk is a function of both hazard (toxicity) and exposure. Understanding what is present in the material
(Part 1 Report) and how individuals are potentially exposed (Part 2 Report) is critical to understanding
potential risk. It is important to note that the study activities completed as part of this multi-agency
research effort were not designed, and are not sufficient by themselves, to directly answer questions
about potential health risks. Other studies may aid in this regard. The FRAP supports the findings of
limited exposure, as reported in studies from RIVM and ECHA as well as the chemical assessments
from the NTP 4 More specifically:
• The Netherlands National Institute for Health and Environment (RIVM) released a December
2016 report, updated in March 2017, titled "Evaluation of health risks of playing sports on
synthetic turf pitches with rubber granulate" (RIVM, 2017). The RIVM collected rubber infill
from 100 synthetic turf fields and performed analyses for selected chemicals of interest.
Exposure estimates were performed for five exposure scenarios using assumed exposure
parameters for different ages and player categories. Exposure estimates and toxicological
information were used to evaluate potential health risks. RIVM reported: "The results of this
research indicate that playing sports on these fields is safe. The risk to health from playing
sports on these synthetic turf fields is virtually negligible. While rubber granulate contains
harmfid substances, these substances are only releasedfrom the rubber granulate in very small
quantities after ingestion, contact with the skin or evaporation in hot weather. RIVM
recommends adjusting the standardfor rubber granulate to one that is closer to the standard
applicable to consumer products. "
4 Other research studies by the California Office of Environmental Health Hazard Assessment (OEHHA) will provide tire
crumb rubber characterization data for additional fields in California. They will also characterize additional synthetic turf
field component materials and particles in the air above the synthetic fields as a result of simulated activities and measure the
bioaccessibility of inorganic and organic chemicals from tire crumb rubber.
xxix
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The European Chemicals Agency (ECHA) released a report in February 2017 titled "Annex XV
Report; An Evaluation of the Possible Health Risks of Recycled Rubber Granules Used as Infill
in Synthetic Turf Sports Fields" (ECHA, 2017). ECHA evaluated human health risks for
chemicals found in tire crumb rubber used on outdoor and indoor synthetic turf football (soccer)
fields. ECHA compiled information for PAHs,
metals, phthalates, VOCs, and SVOCs primarily
from European studies. ECHA then created
several exposure scenarios for children, adults,
and workers installing or maintaining fields, and
estimated inhalation, dermal, and ingestion
exposures. Conclusions from the ECHA
reported: "ECHA has found no reason to advise
people against playing sports on synthetic turf
containing recycled rubber granules as infill
material. This advice is based on ECHA's
evaluation that there is a very low level of
concern from exposure to substances found in
the granules. This is based on the current
evidence available. However, due to the
uncertainties, ECHA makes several
recommendations to ensure that any remaining
concerns are eliminated. "
The National Toxicology Program (NTP, 2019)
has conducted chemical assessments and short-
term toxicity studies on the recycled tire crumb
rubber material itself, not specific chemical
constituents found in the material. Findings
from the NTP research included: "There was no
evidence of toxicity in mice from ingestion of
crumb rubber. Analysis of the animals' blood
and urine showed that internal levels of crumb
rubber chemicals were very low. No health
problems were observed. For tests using human
cells, NTP found that crumb rubber, under
certain experimental conditions such as high
heat, leached chemicals, some of which caused
cell death. The NTP studies did not assess
individual chemicals of crumb rubber, although
they did confirm that it contains many
substances, such as polycyclic aromatic
hydrocarbons (PAHs), metals, plasticizers, such
as phthalates, and bisphenol A (BPA). "
OVERALL CONCLUSIONS FOR THE
PLAYING FIELDS STUDY
> In general, the findings from the FRAP
activities on playing fields (Parts 1 and 2
combined) support the conclusion that
although chemicals are present (as
expected) in the tire crumb rubber and
exposures can occur, they are likely limited;
for example:
- Generally, only small amounts of most
organic chemicals are released into the air
through emissions. For many analytes
measured during active play at the
outdoor fields, next-to-field
concentrations in air were not different
than background samples while others
were somewhat higher.
- For metals, only small fractions (average
mean about 3% for gastric fluid and <1%
for saliva and sweat plus sebum) are
released from tire crumb rubber into
simulated biological fluids compared to a
default assumption of 100%
bioaccessibility.
- In the biomonitoring pilot study,
concentrations for metals measured in
blood were similar to those in the general
population.
- In the supplemental biomonitoring study,
no differences in PAH metabolites in urine
were observed between study
participants using natural grass fields and
those using synthetic turf fields with tire
crumb rubber infill.
Overall, we anticipate that the results from this multi-
agency research effort will be useful to the public and
interested stakeholders for understanding the potential for human exposure to chemicals associated with
recycled tire crumb rubber infill material used on synthetic turf fields.
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Synthetic Field User Activity Information Collection
Extant Publidv Available Video
60 Hours publicly available video
AdultSt child activity categories
3 Sports
Questionnaire Data Collection
32 adultand child participants
3 facilities
3 Age/a ctivity groups
Video Activity Data Collection
17 adultand child participants
3 facilities
2 Sports
Synthetic Turf Field User Exposure Measurement Pilot Study
Exposure Data Collection
Up to 25 adultand child participants
At 3 facilities
3 Age/activity groups
Personal Samples
AirVOC samples (25)
Derma! metals sampies (75)
Derma] SVOC samples (75)
Biological Samples
Urine sampies pre-activity (14)
Urine samples post-activity (14)
Blood andserum pre-activity(13)
Blood andserum post-activity(11)
Facility Samples
AirVOC samples (9)
Air particle/meta ls samples (9)
AirSVOC samples(9)
Surface wipe metals samples (9)
Surface wipe SVOC samples (9)
Surface dragsled SVOC samples (9)
Dust metalssamples(3)
Dust SVOC samples (3)
Meta Data Collection
Meteorological information
Pa rti ci p a nt a ctivity i nf ormati on
Overall activity information
Field facility information
Exposure Pathway Modeling Assessment
Using Extant Measurement Data
Using Data from This Studv
Residential + Dietarv Comparison
6 Selected chemicals
6 Selected chemicals
4 Selected chemicals
Adult & child scenarios
Adult& child scenarios
Adult& child scenarios
Inhalation pathway
Inhalation pathway
Inhalation pathway
ingestion pathway
Ingestion pathway
Ingestion pathway
Dermal pathway
Dermal pathway
Dermal pathway
Figure ES-1. Pilot exposure characterization research schematic overview.
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1.0 Introduction
1.1 Background
While research efforts have tended to focus on characterizing tire crumb rubber constituents and
environmental concentrations of related chemicals, less research has been performed to examine human
exposures and potential risks to people using synthetic turf fields and playgrounds. With respect to
exposure characterization, human exposure measurement data for synthetic turf field users are limited.
There are significant data gaps in human activity parameters for various synthetic turf field activities,
and this information is essential for estimating exposures and evaluating risks from contact with tire
crumb rubber constituents. While the potential for inhalation exposures has been characterized for some
constituents, there is far less information for characterizing dermal and ingestion exposures. Improved
exposure factor information is needed to estimate and model exposures from the inhalation, dermal, and
ingestion pathways. There are also significant limitations in the methods that have been developed and
used to characterize human exposure from activities on synthetic turf fields. These include challenges
collecting relevant surface, dust, and personal air samples; limited measurements of dermal exposures;
and limited collection of urine or blood samples, which could be used for measuring biomarkers of
exposure to chemicals in crumb rubber infill.
To support the Federal Research Action Plan on Recycled Tire Crumb Used on Playing Fields and
Playgrounds (FRAP), a Research Protocol was developed (U.S. EPA and CDC/ATSDR, 2016). Some
elements of the research design outlined in the Research Protocol were intended to fill these knowledge
gaps and address the limitations of prior studies. The data collection components of the tire crumb
rubber exposure study went through the Office of Management and Budget (OMB) Information
Collection Request (ICR) review process. On August 5, 2016, the U.S. Environmental Protection
Agency (EPA), Centers for Disease Control and Prevention/Agency for Toxic Substances and Disease
Registry (CDC/ATSDR), and Consumer Product Safety Commission (CPSC) received final approval to
begin the research. The results of the FRAP research described in the Part 1 Report (U.S. EPA &
CDC/ATSDR, 2019) and this Part 2 Report can be useful for improving exposure and risk assessment
and for designing and conducting larger scale exposure and biomonitoring studies.
Scientists identified various exposure scenarios (i.e., ways in which people may be exposed to tire
crumb rubber infill based on their activities on synthetic turf fields) and then designed and conducted a
pilot-scale exposure study. As defined in the Research Protocol (U.S. EPA and CDC/ATSDR, 2016),
there were two primary aims or objectives for the exposure characterization research:
Aim 1: Collect human activity data for synthetic turf field users that will reduce the reliance of
default exposure factor assumptions in exposure and risk assessment; and,
Aim 2: Conduct an exposure measurement sub-study for people using synthetic turf fields with
tire crumb rubber infill, in what are likely to be among the higher exposure scenarios to improve
understanding of potential exposures, particularly for the dermal and ingestion exposure
pathways.
To meet the first objective, researchers used questionnaires to collect information from adults and youth
(or the parents of youth) who use synthetic turf fields with crumb rubber infill. Video data collection
was used for a subset of these participants while they engaged in activity on synthetic fields to obtain
objective information about important dermal and ingestion contact rates. In addition, extant
videography of individuals engaged in activities on synthetic turf fields was acquired to provide
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additional data on contact rates for a wider group of people and activities that could not be captured
otherwise just using the questionnaires. The human activity information provided data for the parameters
used in characterizing and modeling exposures associated with the use of synthetic turf fields and
improves upon the information currently available in the literature for the dermal and ingestion exposure
pathways.
To meet the second objective, a pilot-scale human exposure measurement sub-study was implemented to
further develop and deploy appropriate sample collection methods and generate data to better understand
potential exposures that may occur when individuals frequently use synthetic turf fields. A subset of the
participants that provided questionnaire responses were asked to participate in the exposure
measurement pilot study based on their field usage. Field use scenarios anticipated to be among those
with relatively high potential exposures due to frequency and duration of time spent on the field and the
potential for contact with synthetic field materials were the focus of the study. A set of personal,
biological, and field environmental samples was collected around a sport or training activity performed
on a participating synthetic turf field. Personal and environmental samples were analyzed for metals,
volatile organic compounds (VOCs), and semi-volatile organic compounds (SVOCs). For the
biomonitoring pilot, blood and urine samples collected before and after participant practice sessions
were analyzed for selected metal and polycyclic aromatic hydrocarbon (PAH) metabolites, respectively.
Following the pilot-scale biomonitoring effort, ATSDR designed and conducted a supplemental
biomonitoring study measuring PAH urinary metabolites for a larger number of synthetic field users and
included athletes playing on natural grass fields for comparison (Appendix A).
Researchers utilized information from the literature and data collected in this study to conduct exposure
pathway modeling on six selected chemicals for athletes using synthetic turf fields with tire crumb
rubber infill. This effort aimed to elucidate which exposure pathways are likely to be the biggest
contributors to total exposure for different types of tire crumb rubber constituents; explore whether data
produced in this study can improve our exposure estimates, particularly for the dermal and ingestion
pathways; assess the availability, robustness, and adequacy of tire crumb and exposure measurement
data, and data for exposure model parameters in the context of accuracy and uncertainty for exposure
estimation; and prepare examples of modeled estimates of background exposures from residential and
dietary sources for comparison with exposure estimates for synthetic turf field users.
The study was performed in accordance with all required human subjects reviews and protections
specified in the Code of Federal Regulations (45 CFR 46 for the U.S. Department of Health and Human
Services [HHS]; 40 CFR 26 for the EPA) and in other applicable policies on human subjects at the EPA
and CDC/ATSDR. Prior to the recruitment and collection of data, the study protocol was submitted to
the CDC Human Research Protection Office. The study protocol was reviewed and approved by the
CDC Institutional Review Board (CDC IRB), and then the EPA Human Subjects Research Review
Official (HSRRO). Information and details on the consenting process, forms, and protocols was
previously published (U.S. EPA and CDC/ATSDR, 2016). On August 2, 2017, the OMB approved the
Information Collection Request that enabled EPA and CDC/ATSDR to conduct the field work
associated with the exposure characterization research (OMB Control Number 0923-0058); the field
work was concluded in Fall 2017. Following a delay due to the COVID-19 pandemic, the supplemental
biomonitoring study was conducted in 2022.
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1.2 Report Organization
This report is organized into two volumes - Volume I contains the body of the report and Volume II
contains the appendices. Volume I consists of five sections:
• Section 1 provides a short introduction to the exposure characterization portion of the
federal research action plan.
• Section 2 provides a summary of the research results and main conclusions from the
exposure characterization study, along with important limitations.
• Section 3 provides detailed methods for the exposure characterization.
• Section 4 provides detailed assessment results for the exposure characterization.
• Section 5 contains the results of exposure pathway modeling and modeling approach
assessments.
• Section 6 contains the references.
Volume II of this report consists of eight appendices:
• Appendix A describes the methods and results for the supplemental biomonitoring study.
• Appendix B contains the Quality Assurance/Quality Control section.
• Appendices C contains the standard operating procedures (SOPs) used for the exposure
characterization studies.
• Appendix D contains the facility user study questionnaires.
• Appendix E contains the exposure characterization meta-data collection forms.
• Appendix F contains the blood metals and serum metals analysis protocols.
• Appendix G contains the results from the video activity data.
• Appendix H contains the feasibility assessment for silicone wristband passive samplers
at synthetic turf fields.
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2.0 Summary of Results and Findings
This section provides both an overview and detailed summary of the results of individual components of
this research study, specifically focusing on the exposure characterization and the associated findings
based on those results. A discussion of the findings is provided along with limitations and
recommendations for next steps.
Technical details of the methods and detailed research results are provided in subsequent sections (3-5)
and their associated appendices. Quality assurance and quality control results can be found in Appendix
B. The research standard operating procedures (SOPs) are provided in Appendix C.
2.1 Summary of Research Activities
The federal research described in this report provides new and additional data needed for improved
exposure estimation for athletes using synthetic turf fields with recycled tire crumb rubber infill.
Specific activities undertaken and described in this report are summarized in Table 2-1.
Table 2-1. Topic Area and Specific Activities Described in This Report
Topic Area
Activities
Exposure Characterization Pilot
Study for Youth and Adult
Athletes Using Synthetic Turf
Fields with Tire Crumb Rubber
Infill
Recruiting youth and adult participants for sample and data collection around their
usual sport activities at svnthetic turf fields
Using questionnaire data collection to obtain data for field use duration and
frequency of use, activity patterns on fields, and hygiene to improve exposure
scenario development and exposure modeling for youth and adult athletes using
synthetic turf fields
Using extant video data and participant video data collection approaches to provide
data for contact types and frequencies, and activity levels for improving exposure
modeling for youth and adult athletes using synthetic turf fields
Performing measurements to provide additional data on particles, metals, SVOCs
and VOCs in the air at synthetic turf fields during periods of activity on the field
and during warm to hot ambient air conditions for assessing exposure through the
inhalation pathways
Developing methods and providing initial data on inorganic and organic chemicals
on field surfaces, in field dust, and on athlete skin needed to better understand and
estimate both child and adult exposures, particularly for the dermal and ingestion
exposure pathways
Developing, applying and assessing methods and approaches for personal air
sample collection
For the pilot-scale biomonitoring effort, collecting and analyzing blood and urine
samples for measurement of selected metals and PAH biomarkers before and after
the monitored participant sport activities at synthetic turf fields
Assessing silicone wristbands as potential sampling devices for future use in field
air and personal sampling assessments of exposure at synthetic turf fields
Applying and assessing exposure pathway models to examine differences in
exposure levels across pathways, and to identify where lack of data (or lack of
robust data) may be limiting accuracy and/or resulting in potentially large
uncertainties in exposure estimation for synthetic turf field users
Supplemental Biomonitoring
Study
Expanding upon the FRAP's pilot-scale effort by including a larger sample size of
synthetic turf with recycled tire crumb rubber infill users and a comparison group
of natural grass field users
Examining potential associations with pre- and post-activity urinary PAH
biomarker concerntrations with field type
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Topic Area
Activities
Comparing study participants' urinary PAH concentrations to those found in the
noninstitutionalized general U.S. population
2.2 Exposure Characterization: Overview of Research Approach, Results and Key
Findings
2.2.1 Research Approach
The exposure characterization study was a pilot-scale effort to: (a) collect information on human activity
for synthetic turf field users that may affect exposures to tire crumb rubber and its constituents; and (b)
implement a human exposure measurement study to further develop and test appropriate sample
collection methods and to generate data for improved exposure characterization, including exposures
from dermal and ingestion pathways.
For the human activity data collection, questionnaires were administered to adults and youth (or the
parents of children) who participated in athletic activities on synthetic turf fields with tire crumb rubber
infill. Information was collected to help better understand the frequency and duration of play on
synthetic fields, the variety of activities performed, and specific activity and hygiene factors that might
influence contact with field materials and chemical exposures. Video data were also collected on a
subset of participants performing physical activity on synthetic turf fields. In addition, publicly-available
videos of users engaged in activities on synthetic turf fields were used to provide objective assessment
of contact rates and types that are difficult to capture consistently using questionnaires.
A subset of participants providing questionnaire responses also participated in an exposure measurement
study. A set of personal, biological and field environmental samples were collected around a sport
practice activity performed on synthetic turf fields. Personal (air and dermal wipe) samples and
environmental samples were analyzed for metal, VOC and SVOC analytes. Urine and blood samples
were also collected from a subset of participants as part of pilot exposure characterization research
activities. Exposure pathway models were constructed and assessed for select chemicals and exposure
scenarios, first using existing measurement data from other studies and then again with data from this
study.
Participants for the exposure characterization pilot study were adult and youth soccer or American
football (hereafter described only as football) players (> 7 years of age) recruited from sport teams
practicing at several of the synthetic turf fields sampled in the tire crumb rubber characterization study.
Thirty-two (32) athletes from two outdoor fields and one indoor field participated in the questionnaire
component of the exposure characterization pilot study, and 25 of those 32 participated in the exposure
measurements activities. Seventeen (17) of the 25 exposure measurement study participants took part in
the video data collection. For the pilot-scale biomonitoring portion, 14 of the 25 provided urine samples,
and 13 of the 25 provided blood samples.5 Seven of the exposure characterization pilot study
participants were between seven to 10 years of age, 18 participants were ages 11 to 17 years of age, and
seven were adults (18+). Additional activity information was obtained from 34 publicly-available videos
of 60 athletes (adults and youth) engaged in soccer, football, and field hockey sports.
5 See Appendix A for the supplemental biomonitoring study.
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2.2.2 Overview of Results and Key Findings
Human activity data were collected using both video and questionnaire approaches to gain more
information about the ways people use and come into contact with synthetic turf fields and tire crumb
rubber infill. Video data analysis provided objective data for important exposure factors, including hand-
to-mouth, object-to-mouth, hand-to-turf, and body-to-turf contact rates. Children and adults were found
to have similar contact rate frequencies. Some types of exposure contacts were observed more
frequently for football players compared to soccer players, such as object-to-mouth contact due to the
use of mouth guards. Previous exposure evaluations had not been performed for football player exposure
scenarios on synthetic turf with tire crumb rubber infill.
Study participants reported via the questionnaires that they engaged in athletic activities through most
seasons at both synthetic turf fields and at grass fields. Physical contact with synthetic turf was
frequently reported by participants. Participants also frequently reported finding tire crumb rubber on
their bodies and in their cars and homes after playing on synthetic turf fields with recycled tire crumb
rubber infill. There were no consistent exposure patterns across age groups, except older participants
were more likely to report finding tire crumb rubber on their bodies. Note that the questionnaire did not
include questions about potential exposures before participants came to a synthetic turf field. The data
from the questionnaires helped inform our knowledge of factors that may affect exposure to recycled tire
crumb rubber infill used on synthetic turf fields, and the questionnaire developed and used in this pilot
effort can help in the design of activity data collection approaches in larger future studies.
Air samples were collected for VOC, SVOC, metal and total suspended particulate (TSP) analysis at
three synthetic turf fields during warm to hot weather, while athletic teams practiced. For many analytes
at the outdoor fields, next-to-field concentrations were not different than background samples;
exceptions included methyl isobutyl ketone, 4-tert-octylphenol, benzothiazole and several PAHs, for
which next-to-field measurements for most were modestly above background levels. Air concentrations
of many analytes were higher in the indoor field facility compared to background levels.
To assess the potential availability of residues and dust for exposures, SVOCs and metals were analyzed
in field dust samples and field surface wet wipe samples, and SVOCs were also analyzed in field surface
drag sled samples. Field dust was obtained by placing infill from the synthetic turf field surface into a
sieve and collecting particles <150 |im for analysis. On average, SVOCs were present in field dust at
concentrations similar to, but lower than, those measured in the tire crumb rubber infill. Zinc and cobalt,
two tire crumb rubber metal constituents, were measured in field dust at lower levels than in tire crumb
rubber. Other metals, such as lead, were present in field dust at levels higher than those measured in the
tire crumb rubber, suggesting potential sources other than the rubber. Given the small particle sizes, field
dust may be an important medium for inhalation, dermal and ingestion exposures. SVOCs were
measured at low levels in field wipe and drag sled samples, with average transferable levels generally
below 0.2 ng/cm2. Many metals were measured in field surface wipes at average values below 2 ng/cm2,
while zinc and metals typically found in soil were measured at higher levels.
Personal dermal wipe sample collection was performed for youth and adult participants. SVOCs and
metals were analyzed using wet wipes that were applied to the hand, arm, and leg of study participants
following their usual athletic practice sessions on synthetic turf fields. All metals except selenium were
found at measurable levels in dermal wipe samples. Many metals were measured in dermal wipe
samples at median values below 1 ng/cm2, while zinc and other metals typically found in soil were
7
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measured at 4.1 to 140 ng/cm2. About half of the SVOCs were measured in dermal wipe samples at
levels above the method detection limit. Most SVOCs had median values below 0.2 ng/cm2, with up to
0.21 ng/cm2 for 4-tert-octylphenol, 0.69 ng/cm2 for n-hexadecane, and several phthalates with median
levels up to 7.0 ng/cm2. The phthalates may have been present from other sources in addition to, or
instead of, field materials. Few clear differences in dermal levels were observed between age groups or
between football and soccer groups. The dermal measurements have limitations (e.g., samples were
collected only post-activity, sampling efficiency is uncertain), but provide information that can be used
in exposure models to avoid highly uncertain transfer rate estimates for dermal exposures.
Collecting personal air samples for research participants engaged in active athletic activities is
challenging. The concentration of analytes of interest are generally low, the activity durations are short,
and player safety must be a priority in collecting samples, particularly for children. In this study, a small,
passive VOC air sampler with high effective sampling rates was attached to the upper backs of a
practice jersey worn by each study participants during their usual athletic practice sessions on synthetic
turf fields. When collecting air samples from the football players, one sampler was destroyed and
another damaged during vigorous tackling activities; all other samples were successfully collected. The
samplers did not perform as desired, however, with inconsistent effective sampling rates measured in
testing based on both laboratory chamber and field conditions, and low recoveries of the two highest
concentration analytes, benzothiazole and methyl isobutyl ketone. Additional research would be
required to determine if any personal air sampling devices can be successfully used in research studies
with youth participants. It may be necessary to limit personal air sampling to adult volunteers willing to
wear more bulky samplers with pumps and certain types of activities.
A total of 14 individuals, aged 11-21, consented to participate in the pilot-scale biomonitoring portion
of the exposure measurement study. For the biomarker measurements pilot-scale biomonitoring study,
blood and urine samples were collected from study participants before and after their sports activities on
the field. Of the 25 exposure measurement study participants, 14 provided urine samples and 13
provided blood samples. The participants providing blood and urine samples were 11-21 years old.
The urine samples were analyzed for seven PAH metabolites, and the blood and serum samples were
analyzed for metals. The laboratory analyses were performed by the CDC's National Center for
Environmental Health Division of Laboratory Sciences. For the pilot-scale study, significant differences
in mean concentrations were observed when comparing pre- and post-activity levels for the unadjusted
PAH metabolites. For the unadjusted concentrations, the post-activity geometric mean was significantly
higher (p-value < 0.05) for all urinary PAH metabolites than the pre-activity geometric mean (Figures 2-
1 and 2-2). For example, the unadjusted post-activity geometric mean for 2-hydroxynaphthalene
(geometric mean= 18.6 |ig/L; 95% CI: 12.6 - 27.4) is significantly greater than the unadjusted pre-
activity geometric mean (geometric mean= 7.69 |ig/L; 95% CI: 4.61 - 12.8). When compared with PAH
analytes reported in NHANES 2013-2014 (CDC 2013-2014) for participants aged 11 to 21, the
geometric mean for all unadjusted urinary PAH metabolites post-activity was higher than the NHANES
geometric mean, with the exception of 1-hydroxypyrene.
8
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ill ill ill ill ill
1-PHE (ng/L) 1-PYR (ng/L) 2 & 3-PHE (ng/L) 2-FLU (ng/L) 3-FLU (ng/L)
¦ Pre-activity ¦ Post-activity BNHANES
Figure 2-1. Geometric mean of unadjusted urinary PAH concentrations (ng/L) for
exposure pilot study participants, pre-activity and post-activity, compared to NHANES
2013-2014 weighted and design-adjusted values for ages 11-21. [PAH = polycyclic
aromatic hydrocarbon; NHANES = National Health and Nutrition Examination Survey; 1-PHE =
1 -Hydroxyphenanthrene; 1-PYR = 1-Hydroxypyrene; 2 & 3-PHE = 2- & 3-Hydroxyphenanthrene;
2-FLU = 2-Hydroxyfluorene; 3-FLU = 3-Hydroxyfluorene]
25
1-NAP (ng/L) 2-NAP (ng/L)
¦ Pre-activity ¦ Post-activity BNHANES
Figure 2-2. Geometric mean of unadjusted 1-hydroxynaphthalene and 2-hydroxynaphthalene
concentrations (jug/L) for exposure pilot study participants, pre-activity and post-activity,
compared to NHANES 2013-2014 weighted and design-adjusted values for ages 11-21.
[NHANES = National Health and Nutrition Examination Survey; 1-NAP = 1 -Hydroxynaphthlaene; 2-NAP =
2-Hydroxynaphthlaene]
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350
300
250
200
150
100
50
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The NHANES urinary PAH metabolite concentrations adjusted for creatinine and the creatinine-
adjusted concentrations pre- and post-activity were compared. In comparing pre- and post-activity
creatinine-adjusted measurements for these PAH metabolites in urine, most results were similar. There
was no significant difference in pre- and post-activity concentrations, except for 2-hydroxynaphthalene.
For 2-hydroxynaphthalene, there was a statistically significant increase in the post-activity mean
concentrations when compared to the pre-activity mean concentrations (p-value = 0.041). The difference
was greater for football players (p-value = 0.016). When compared with PAH analytes reported in
NHANES 2013-2014 for participants aged 11 to 21, the synthetic turf field user group had similar mean
concentrations of PAH analytes (Figure 2-3). The measured NHANES geometric means were similar,
except for 1-hydroxypyrene, 2-hydroxynaphthalene, and 3-hydroxyfluorene (Figures 2-3 and 2-4). The
NHANES geometric mean for both 1-hydroxypyrene and 3-hydroxyfluorene was greater than the pre-
and post-activity geometric mean for this study. The NHANES geometric mean for 2-
hydroxynaphthalene was less than the pre- and post-activity geometric means for this study. It should be
noted that field measurements of naphthalene (a parent compound to 2-hydroxynaphthalene) in tire
crumb rubber infill, field air, field dust, field wipe and drag sled samples were all low, and only 17% of
the dermal wipe (personal) naphthalene measurements were above the quantifiable limit for football
players. In addition, napthalene was 4 to over 100 times lower than phenanthrene and pyrene in these
media, yet metabolites of these PAHs were lower than their NHANES values. Specific gravity
measurements were also performed, and the PAH concentrations were adjusted. Specific gravity (SG)
adjusted pre- and post-activity PAH concentrations in urine were compared. Post-activity concentrations
were statistically higher than pre-activity concentrations for all metabolites, and all differences were
statistically significant using the signed-rank test. Median differences were larger for soccer players than
for football players. Comparing this result to the same analysis of creatinine-adjusted concentrations
shows how the choice of urine-dilution method can profoundly affect study conclusions. Because SG-
adjusted concentrations were only collected in the 2007-2008 NHANES cycle, and because PAH
concentrations have changed over time, a comparison to study concentrations would not be meaningful.
CDC/ATSDR conducted a supplemental biomonitoring study which elucidated the findings of the pilot
biomonitoring efforts; results for the supplemental biomonitoring study can be found in Appendix A.
The concentrations of metals in whole blood and serum were compared in samples collected from study
participants pre- and post-activity. Significant differences were not observed in the means and geometric
means between the pre- and post-activity samples for football or soccer players. When compared with
blood and serum metal concentrations reported in NHANES 2013-2014, participants aged 11 to 21, the
geometric mean concentrations for whole metals in blood and serum for the synthetic turf field users
were similar, with the exception of blood selenium (Figures 2-5 and 2-6). The pre-activity and post-
activity geometric mean concentrations for blood selenium were greater than the NHANES geometric
mean. However, selenium was below the detection limits in the tire crumb rubber analyses, field air,
field wipe, field dust, and dermal wipe samples. Selenium was also measured in serum. Serum selenium
geometric mean concentrations reported in NHANES 2013-2014 were similar to the mean
concentrations measured for the study participants.
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200
180
160
140
120
100
80
60
40
20
0
iJ
1-PHE (ng/g) 1-PYR (ng/g) 2 & 3-PHE (ng/g) 2-FLU (ng/g)
¦ Pre-activity ¦ Post-activity ¦NHANES
3-FLU (ng/g)
Figure 2-3. Geometric mean of creatinine-adjusted urinary PAH concentrations (ng/g) for exposure
pilot study participants, pre-activity and post-activity, compared to NHANES 2013-2014 weighted
and design-adjusted values for ages 11-21. [PAH = polycyclic aromatic hydrocarbon; NHANES = National
Health and Nutrition Examination Survey; 1-PHE = 1 -Hydroxyphenanthrene; 1-PYR = 1-Hydroxypyrene; 2 & 3-PHE =
2- & 3-Hydroxyphenanthrene; 2-FLU = 2-Hydroxyfluorene; 3-FLU = 3-Hydroxyfluorene]
Figure 2-4. Geometric mean of creatinine-adjusted 1-hydroxynaphthalene and 2-hydroxynaphthalene
concentrations (jug/g) for exposure pilot study participants, pre-activity and post-activity, compared
to NHANES 2013-2014 weighted and design-adjusted values for ages 11-21. [NHANES = National
Health and Nutrition Examination Survey; 1-NAP = 1-Hydroxynaphthlaene; 2-NAP = 2-Hydroxynaphthlaene].
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250
Blood selenium (pg/L) Serum Copper (pg/dL) Serum Selenium (pg/L) Serum Zinc (pg/dL)
¦ Pre-activity ¦ Post-activity BNHANES
Figure 2-5. Exposure pilot study, pre-activity and post-activity, blood selenium, serum
copper, serum selenium, and serum zinc geometric mean levels compared to NHANES 2013-2014
weighted and design-adjusted values for ages 11-21. [NHANES = National Health and Nutrition
Examination Survey]
10.5
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9.5
9
8.5
8
7.5
7
6.5
6
5.5
5
4.5
4
3.5
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2.5
2
1.5
1
0.5
0
Blood cadmium (pg/L) Blood manganese (pg/L) Blood lead (pg/dL)
Blood mercury, total
(Pg/L)
I Pre-activity ¦ Post-activity BNHANES
Figure 2-6. Exposure pilot study, pre-activity and post-activity, blood cadmium, blood
manganese, blood lead and total blood mercury geometric mean levels compared to NHANES
2013-2014 weighted and design-adjusted values for ages 11-21. [NHANES = National
Health and Nutrition Examination Survey]
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As a complement to exposure measurements, modeling can provide information on potential exposures.
Exposure pathway modeling for athletes using synthetic turf fields with reeve) ed tire crumb rubber infill
was performed. By way of example, six chemical substances (pyrene, benzo[a]pyrene, benzothiazole,
methyl isobutyl ketone, lead and zinc) were evaluated using data available from the literature and
supplemented with data collected in this study. In general, estimated daily exposures were < 5 x 10"5
mg/kg-d for most chemicals and pathways. Inhalation was the most dominant pathway for the more
volatile chemicals, with inhalation exposure estimates reaching up to 5 x 10"3 mg/kg-d for methyl
isobutyl ketone at indoor fields. Ingestion was estimated to be the most dominant pathway for metals
and less volatile chemicals. Ingestion estimates for zinc were as high as 5 x 10"3 mg/kg-d when estimates
were made using existing measurement data, and 2 x 10"4 mg/kg-d when using data from this study.
To provide context, exposure from other typical sources (such as residential and dietary "background")
were compared to those of field users. Residential (e.g., indoor air and dust) plus dietary 'background'
exposures were estimated for four chemicals associated with tire crumb rubber. For pyrene and
benzo[a]pyrene, residential plus dietary exposure estimates were 1.5 to 3 times higher than average
exposures estimated for synthetic field users using data generated in this study. For zinc and lead,
residential plus dietary exposure estimates were over 100 times higher than average exposures estimated
for synthetic field users based on data produced in this study and over 10 times higher than estimates
using literature results to model exposures for synthetic turf field users. When using literature data and
different model parameters, synthetic turf field users were estimated to have at most 1.5 times higher
pyrene exposures than those from residential plus dietary background. However, there is likely
considerable uncertainty in these exposure estimates.
2.2.3 In Summary
• Pilot study measurements were made in air, surface wipe, dust and dermal media for a
wide range of chemicals for 25 participants participating in soccer or football practices at
synthetic turf fields. The measurements provided additional data for assessing inhalation
exposures and new data for better understanding exposures through dermal and ingestion
pathways. Many of the chemicals that were associated with tire crumb rubber were found
in the environmental or dermal samples. Most SVOCs were found at low concentrations
in the field wipe and drag sled samples, and many SVOCs had a high percentage of
dermal wipe measurements below quantifiable limits. In air samples collected next to
outdoor fields with active play, several chemicals were measured at levels modestly
above background air concentrations, while many chemicals were not found above
background levels. Higher levels of many chemicals were measured in the air at the
indoor field compared to the levels at the outdoor fields or in the background air samples.
• This study has provided important new and additional information about chemicals in tire
crumb rubber and the ways field users may come into contact with this material and its
chemicals; however, the magnitude of potential exposures is still somewhat uncertain, in
part due to incomplete information regarding the amounts of field dust that adhere to the
skin of synthetic turf field users and the amounts of dust and tire crumb rubber ingested.
• When compared with NHANES 2013-2014 data for individuals age 11-21, the geometric
mean concentrations of metals in blood and serum were similar, with the exception of
blood selenium. The unadjusted urinary PAH metabolite concentrations were higher post-
activity than pre-activity and higher post-activity than concentrations reported for
individuals age 11-21 in NHANES 2013-2014. When adjusted for creatinine, urinary
PAH metabolite concentrations showed no difference in concentrations pre- and post-
activity, with the exception of 2-hydroxynaphthalene. However, generally low
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concentrations of naphthalene were found in the tire crumb rubber, field measurement,
and dermal wipe samples. Specific gravity was not collected in the 2013-2014 NHANES
cycle. Comparing our SG results to the 2007-2008 NHANES cycle could be
inappropriate due to changes in PAH levels over time.
Modeled estimates suggest that synthetic turf field users may have pyrene and
benzo[a]pyrene exposures similar to or somewhat lower than estimated background
exposures, and exposures to zinc and lead that are substantially lower than background.
Taking into account the pilot nature of this study and related uncertainties, neither of
these observations on their own can provide definitive answers that exposures may be
low; together they are consistent with results of recent studies.
Video data analysis approaches were tested and, along with questionnaires, applied in this
pilot study. These video and questionnaire approaches were found to be effective for
generating information on human activity patterns of youth and adult synthetic turf field
users that may affect their exposures to tire crumb rubber and its constituents. This
information can be used to further develop and improve exposure scenario generation and
exposure modeling; however, more data are needed for a wider range of on-field
activities and for athletes with higher field contact rates. Most assessments to date have
been performed for soccer player scenarios; data produced in this study suggests football
players may have higher frequencies of certain types of contacts that may increase
exposure. An increase in blood metal concentration was not observed after practice.
Blood selenium levels, both pre- and post-activity, were higher than the geometric mean
for participants aged 11 - 21 in the 2013-2014 National Health and Nutrition
Examination Survey (CDC NHANES 2013 - 2014). However, selenium was not found
above detection limits in tire crumb and other field environment matrices.
With the exception of blood selenium, body burden levels of metals in these study
participants were consistent with those found for the general population (CDC NHANES
2013 -2014, participants aged 11-21).
Significant differences in mean concentrations were observed when comparing pre- and
post-activity levels for the unadjusted urinary PAH metabolites.
In comparing pre- and post-activity creatinine-adjusted measurements for these
PAH metabolites in urine, there was no significant difference in pre- and post-
activity concentrations, except for 2-hydroxynaphthalene.
When compared with PAH analytes reported in NHANES 2013-2014 for participants
aged 11 to 21, the geometric mean for all unadjusted urinary PAH metabolites post-
activity was higher than the NHANES geometric mean, with the exception of 1-
hydroxypyrene. The geometric mean for creatinine-adjusted urinary PAH metabolites
was similar to the NHANES geometric mean, with the exception of 1-hydroxypyrene and
3-hydroxyfluorene which had higher geometric means in NHANES.
The supplemental biomonitoring study (Part 2 Report Appendix A) further elucidates
the initial pilot findings. In general, no differences in PAH metabolites in urine were
observed between study participants using grass and synthetic turf fields with tire crumb
rubber infill in the supplemental biomonitoring stud
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2.3 Detailed Summaries of Research Results
2.3.1 Exposure Characterization Pilot Study for Athletes Using Synthetic Turf Fields
with Tire Crumb Rubber Infill
2.3.1.1 Participant Recruitment
Children and adults participating on sports teams that practiced on community synthetic turf fields that
participated in the tire crumb rubber characterization study were recruited to participate in the
questionnaire, exposure measurement, and video activity components of the exposure characterization
pilot study.
• In-person recruitment was conducted Monday through Thursday immediately prior to,
during, and after field activities.
• Recruited participants included 32 for the questionnaire component, 25 for the exposure
measurements sub-study, and 17 for the video activity. For the biomonitoring pilot study,
fourteen participants provided urine samples and 13 participants provided blood
samples.6
• Participants were a variety of ages; specifically, seven participants were between seven to
less than 11 years of age, 18 participants were ages 11 to less than 18 years of age, and
seven were adults (18+).
• Participants were recruited and sampling was conducted during two sport activities,
football and soccer practice sessions.
2.3.1.2 Field Measurements
• Air samples were collected for VOC, SVOC, metal, and total suspended particulate
analysis at three synthetic turf fields (i.e., two outdoors fields and one indoor field)
during warm to hot weather during athletic team practices. For many analytes at the
outdoor fields, next-to-field concentrations were not different than background ambient
air samples; exceptions included next-to-field levels of methyl isobutyl ketone, 4-tert-
octylphenol, benzothiazole, and several PAHs. For most of these analytes, differences at
outdoor fields between next-to-field and background levels were modest. It is not clear
how well air samples collected next to the field represent personal inhalation exposures,
however, collecting accurate breathing zone air samples for the wide range of chemicals
present in tire crumb rubber is a challenge.
• Air concentrations of many VOC, SVOC and metal analytes associated with tire crumb
rubber were higher in the indoor field facility compared to outdoor fields and background
levels.
• On average, SVOCs were present in field dust at concentrations similar to, but somewhat
lower than, those measured in the tire crumb rubber infill. It is not clear whether the
amounts of SVOCs in field dust were lower than the amounts in the tire crumb rubber or
were a result of relatively low extraction efficiencies from the dust. Zinc and cobalt were
measured in dust at somewhat lower levels than in tire crumb rubber. Other metals, such
as lead, were present in dust at levels higher than those measured in the tire crumb
rubber.
6 See Appendix A for the supplemental biomonitoring study.
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• SVOCs were measured at low levels in field wipe and drag sled samples, with average
transferrable levels generally below 0.2 ng/cm2.
• Many metals were measured in field surface wipes at average values below 2 ng/cm2,
while zinc and metals typically found in soil were measured at higher levels. Zinc in tire
crumb rubber likely contributed to the levels measured in the field surface wipes.
2.3.1.3 Personal Measurements
• Personal dermal wipe sample collection was performed for exposure measurement sub-
study participants. SVOCs and metals were analyzed using wet wipes collected from the
hand, arm, and leg of study participants following their usual athletic practice sessions on
synthetic turf fields. (Pre-practice dermal samples were not collected due to time and
participant availability constraints).
• All metals except selenium were found at measurable levels in the dermal wipes. Many
metals were measured in dermal wipes at median values below 1 ng/cm2, while zinc and
other metals typically found in soil were measured at 4.1 to 140 ng/cm2.
• About half of the SVOCs were measured in dermal wipe samples at levels above the
method detection limit. Most SVOCs had median values below 0.2 ng/cm2, with up to
0.21 ng/cm2 for 4-tert-octylphenol, 0.69 ng/cm2 for n-hexadecane, and several phthalates
with median levels up to 7.0 ng/cm2. The phthalates may have been present from other
sources in addition to or instead of field materials.
• Few clear differences in dermal levels for the different analytes were observed between
age groups or between football and soccer groups.
• In this study, a small passive VOC air sampler with high effective sampling rates was
attached to the upper backs of each study participants during their usual athletic practice
sessions on synthetic turf fields. For the football players, one sampler was destroyed and
another damaged during vigorous tackling activities. Otherwise, all remaining samples
were successfully collected.
• The personal air samplers did not provide usable measurement results. Inconsistent
effective sampling rates were measured under laboratory chamber and field conditions,
and low recoveries were observed for the two highest concentration analytes,
benzothiazole and methyl isobutyl ketone.
• For the pilot-scale biomonitoring study, all unadjusted urine PAHs showed PAH
metabolites were higher after practice, and the after practice geometric means were
greater than the NHANES 2013-2014 geometric mean for the same age group. For the
creatinine-adjusted urinary PAH metabolite concentrations, no difference in
concentration was observed before or after practice on a synthetic turf field with tire
crumb rubber infill, except for 2-hydroxynaphthalene. Both the pre-activity and post-
activity geometric mean for 2-hydroxynaphthalene was greater than the NHANES 2013-
2014 geometric mean for the same age group.
• For specific gravity-adjusted metabolite concentrations, all post-activity concentrations
were statistically higher than pre-activity concentrations, and all differences were
statistically significant using the signed-rank test.
• The whole blood and serum metals results showed no significant difference in
concentrations before or after practice on a synthetic turf field with tire crumb rubber
infill. A majority of the pre- and post-activity geometric mean concentrations were
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similar to NHANES 2013-2014 geometric mean concentrations for the same age group,
with exception of selenium. Selenium concentrations were slightly higher in the pilot
study participants than the NHANES comparison group. It is important to note that the
biomonitoring study that was conducted as part of the exposure measurement study was a
pilot-scale effort with several limitations. The sample size was very small (n=14) and
individuals who participated in the pilot-scale biomonitoring study were recruited at only
two outdoor fields. A larger sample size was needed in order to confirm the pilot-scale
study results. See Appendix A for the report of the supplemental biomonitoring study.
2.3.1.4 Activity Data Collection
Participant Questionnaires - Questionnaires were administered to 32 participants - adults (age 18+),
youth (11 to 18 years of age), and the parents of children (7 to 10 years of age) - to obtain information
on the frequency, duration, and activities performed on various types of fields, along with other
information on hygiene and activities that may affect exposures to tire crumb rubber and associated
chemicals.
• A majority of participants reported playing on synthetic turf fields at least once a week in
the past year (63%) and past five years (56%). A majority also reported playing on
natural grass fields at least once a week in the past year (59%) and past five years (56%).
• For all participants, diving, falling, sitting, and drinking on turf fields were commonly
reported, especially in the summer.
• Commonly reported activities occurring on synthetic turf fields every time or often
included drinking (81% of participants), hands touching the turf (78% of participants),
and body parts (other than hands) touching turf (75% of participants).
• A majority of participants reported finding tire crumb rubber, dirt or debris every time or
often on their body (66% of participants), in their car (75% of participants), or at home
(59%) of participants) after using a synthetic turf field.
Video Data Collection and Analysis - Video recordings were used to generate objective information on
exposure-related micro-activity events for youth and adult athletes participating in sports activities on
athletic fields. Two approaches were applied, using existing, publicly-available videos and videos
recorded for a subset of exposure characterization pilot study participants.
• Publicly-available videos of 30 youth and 30 adults participating in soccer, football, or
field hockey allowed generation of frequency counts for hand-to-mouth, object-to-mouth,
hand-to-turf, and body-to-turf events.
• In data from the publicly-available videos, there were no significant differences in the
frequency of youth and adult micro-activity events. There were significantly higher hand-
to-mouth, object-to-mouth, hand-to-turf, and body-to-turf events for football players
compared to soccer and field hockey players, however.
• Video recording and activity analysis was performed for 17 youth and adult participants
engaging in soccer or football practice sessions during the exposure characterization pilot
study. Micro-activity frequencies and information on physical activity levels and physical
activity duration was captured from the videos.
• Because of the use of mouth guards, football players had a four-fold higher frequency of
object-to-mouth events than soccer players in the exposure pilot study videos, and they
had a two-fold higher frequency of body-to-turf events. Soccer players had significantly
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higher average duration in the high physical activity category, while football players had
significantly higher average duration in the resting category during practice sessions.
• These types of contact frequency and physical activity level information, when combined
with questionnaire data on duration and frequency of field uses, could be used in future
work to refine exposure scenarios and improve exposure models for synthetic field users.
2.3.1.5 Exposure Pathway Modeling
Exposure pathway modeling for athletes using synthetic turf fields with tire crumb rubber infill was
performed using data available from the literature and supplemented with data collected in this study.
The primary purposes of this modeling exercise were to:
• Elucidate which exposure pathways are likely to be the biggest contributors to total
exposure for different types of tire crumb rubber constituents.
• Explore whether data produced in the federal study can improve our exposure
estimations, particularly for the dermal and ingestion pathways.
• Assess the availability, robustness and adequacy of tire crumb rubber data, exposure
measurement data and the data needed for exposure model parameters to determine the
accuracy and uncertainties in exposure estimations for athletes using synthetic turf fields.
• Prepare modeled estimates of background exposures from residential and dietary sources
for comparison with exposure estimates for synthetic turf field users.
Six chemical substances associated with synthetic turf fields and tire crumb rubber were selected for
exposure pathway modeling. They were selected based on the availability of previous measurement data
and represent a range of physical and chemical properties. Adult and child pathway-specific exposure
estimates were calculated for each of the six chemical substances and were compared to identify the
predominant pathway for each chemical substance.
• Pathway algorithms were first run using previously-reported measurement values.
• In general, chemicals of like or similar classifications (i.e., VOCs/SVOCs, metals)
followed the same pattern of exposure for each age group.
• Ingestion of tire crumb rubber appears to be the most significant pathway of exposure for
the PAHs pyrene and benzo[a]pyrene, and exposure decreases with age due to an
assumed decrease in tire crumb rubber ingestion with age.
• Exposure to metals, namely lead and zinc, is highest in the 6 to 10 age range, with a
predominant route of ingestion. The results show a significant decrease in exposure in the
other age groups due to an assumed decrease in tire crumb rubber ingestion.
• The main exposure pathway for benzothiazole and methyl isobutyl ketone appears to be
inhalation, with much higher inhalation exposures at indoor fields than outdoor fields;
however, this is based only on a very small number of indoor field air measurements.
• Dermal exposures are estimated to be lower than ingestion exposures for the metals and
PAHs and much lower than the inhalation exposures for benzothiazole. However, there
are large uncertainties in the model adherence and dermal absorption parameters.
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Using tire crumb rubber, metals bioaccessibility, field environment measurement data, and exposure
measurement data from this tire crumb rubber and exposure characterization study (including
measurements in field dust and in dermal wipes), the exposure pathway models were re-run. Dermal
wipe measurements from the exposure pilot study provided the ability to calculate the amount of
chemical directly in contact with the exposed skin, avoiding more uncertain adherence assumptions.
Field dust measurements were used in place of those for the tire crumb rubber, as these measurements
were likely more relevant for the ingestion pathway. Field air measurements from the exposure pilot
study were used for the inhalation pathway.
• Similar exposure pathway patterns were seen using the exposure pilot study data and the
extant data. The assumed amounts of tire crumb rubber ingested were the key drivers for
age-related differences.
• Ingestion estimates were slightly lower using the exposure pilot study data, based on
slightly lower metal and PAH levels in field dust compared to tire crumb rubber.
• There are no objective data for assessing tire crumb rubber or field dust ingestion
amounts for synthetic field turf scenarios, resulting in highly-uncertain ingestion
exposure estimates.
• Dermal exposure estimates using dermal measurements from the exposure pilot study
were lower than those estimated from extant data and an assumed adherence factor.
Metals estimates were also lower when using the lower absorption values applied from
the bioaccessibility measurements from this study.
Estimates of 'background' exposures from residential and dietary sources were compared to modeled
estimates for synthetic turf field users for benzo[a]pyrene, pyrene, lead and zinc as an example of how
this type of comparison might be approached. Modeling 'background' exposures may also inform
approaches for estimating total exposures that synthetic turf field users may experience from all sources.
Total exposure estimates would best be performed over an appropriate time interval, for example over a
year, rather than the comparison of daily exposures that was performed here.
• Benzo[a]pyrene and pyrene exposures estimated from residential plus dietary sources
were estimated to be 1.5 to 3 times higher than modeled exposure estimates for synthetic
turf field users based on data produced in this study.
• When using literature results for synthetic turf fields and somewhat different model
parameters, benzo[a]pyrene exposures from residential plus dietary sources were similar
to those for synthetic turf field users. Pyrene exposures were at most 1.5 times higher for
synthetic turf field users using literature data compared to residential plus dietary sources.
• Lead and zinc exposures estimated from residential plus dietary sources were estimated
to be over 100 times higher than modeled exposure estimates for synthetic turf field users
based on data produced in this exposure pilot study, and over 10 times higher than
estimates using extant data from the literature to model exposures for synthetic turf field
users.
Based on these modeling exercises, we report the following observations regarding the adequacy of the
data for exposure estimation for athletes using synthetic turf fields:
• The data are not adequate to support probabilistic exposure modeling approaches. For
many chemicals found to be associated with tire crumb rubber infill on synthetic turf
fields, there is a lack of robust data for many exposure media, including air (particularly
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in athlete breathing zones for particulate matter), field surfaces and field dust, and dermal
residue loadings. This lack of robust data likely results in increased uncertainty in
exposure estimation.
• Current exposure estimates are somewhat limited by the lack of exposure scenarios that
more fully account for actual activity levels and types and frequencies of contact, and
their differences among sport types (e.g., football vs. soccer) and specific positions that
may involve higher rates of contact with turf materials (e.g., soccer goalies and football
running backs).
• More information on activity patterns and micro-activity events related to exposures were
collected in this study. This information can be used to help fill gaps in some exposure
parameters and perhaps allow improved exposure estimates across age groups and sports
through development of more detailed exposure pathway algorithms.
• There are limited or no data for some of the important parameters needed to estimate
exposures for athletes using synthetic turf fields with tire crumb rubber infill. The lack of
parameter data leads to applications of assumed values or values applied from non-
equivalent scenarios, both of which can lead to considerable uncertainties in exposure
estimates. In some cases, conservative parameter values have been applied in order to
inform conservative and protective assessments, but that could lead to exposure over-
estimation. For example, RIVM applied a conservative tire crumb rubber ingestion rate of
0.2 g/event, which is higher than the 24-hour soil and dust ingestion values ranging from
0.01 to 0.06 g/day commonly used for residential exposure estimation. RIVM and ECHA
also applied a conservative soil/dust dermal adherence factor of 0.001 g/cm2, which is
higher than reported amounts measured for residential or other relevant scenarios. In
other cases, important exposure mechanisms may not be correctly accounted for, that
could lead to exposure under-estimation. For example, the amount of airborne tire crumb
rubber fine particles could be higher in the direct breathing zones of some athletes than
existing measurements suggest, potentially resulting in an underestimation of inhalation
exposures.
• There are a large number of chemical substances associated with tire crumb rubber infill
that have not been included in most exposure assessments. Lack of certainty in the
identification of many of these chemicals and lack of quantitative measurements inhibits
a more complete cumulative exposure assessment.
• Data are likely to be sparse for estimating background exposures for many chemicals
associated with tire crumb rubber for comparison with estimates for synthetic turf field
users and for preparing total exposure estimates combining field-related and background
exposures.
2.4 Research Limitations
2.4.1 Research Design Constraints
The exposure characterization pilot study was not based on a representative sampling design and is
underpowered for assessing differences among potential exposure factors. However, the exposure
characterization study was intended as a pilot-scale effort to further develop measures and approaches
suitable for providing relevant exposure information in larger studies. Another design constraint was a
decision to focus characterization research on the recycled tire crumb rubber infill and not to include
other synthetic turf field materials (e.g., synthetic grass blades and backing material) due to the
expanded scope that would be needed for a high-quality characterization of all these materials. In
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regards to the biomonitoring pilot study, design limitations did not allow for control of exposures that
occur from off-field activities and/or exposures when urine, blood and dermal wipe sampling take place.
Therefore, relating these exposures to measures of exposure from tire crumb fields includes a degree of
uncertainty.
2.4.2 Planned Work Not Completed in this Study
Not all research goals for this study were completely met. Exposure pilot study goals included collecting
samples at six synthetic turf fields, administering questionnaires to 60 participants, and performing
personal exposure measurements of 45 participants. Only three fields were sampled, 32 participants
completed questionnaires, and 25 participants underwent personal exposure measurements. Timing
issues as to when fields and/or athletes could be available and study-specific deadlines were the primary
reasons for not fully meeting the intended sample size for the exposure pilot study. No full-time soccer
goalies or football running backs, athletes that may have higher field contact rates, participated in the
measurement study.
2.4.3 Multi-source and Pathway Exposure Characterization
People are exposed to many of the chemicals of interest at synthetic turf fields (e.g., metals, PAHs,
phthalates, VOCs, and SVOCs) from other sources and environmental media, including ambient and
indoor air, soil, house dust, food, and water. Synthetic turf field users may have more specific exposures
to other types of chemicals used in tire manufacturing (e.g., rubber vulcanization agents or accelerators,
antioxidants) that are not typically found in the general environment. However, people are likely
exposed to tire wear particles in the environment, as well. Additionally, many rubber products are used
in buildings and transportation systems. In any risk assessment or epidemiological investigation, it
would be important to try to understand the relative exposures from all sources and pathways, including
synthetic turf fields. This study provides examples of how multi-source and multi-pathway comparative
modeling assessments might be performed for chemicals with sufficient data. Expanding this work to
other chemicals and scenarios was beyond the scope and timeframe for this research.
Exposure pathway modeling was performed for several chemicals associated with tire crumb rubber to
assess potential exposures for adult and youth athletes using synthetic turf fields, to better understand
which exposure pathways might be the most important, and to assess the extent and quality of
information needed for successful modeling. Ideally, probabilistic modeling approaches would have
been used to develop distributions of exposure estimates. However, only point estimates of exposure
were developed through modeling in this study due to the sparseness of data for several important
exposure media and exposure parameters. Limitations in available data and exposure parameter values
for synthetic turf field exposure scenarios result in uncertainties in the accuracy of the point estimates.
The ability to interpret modeled exposures for exposure and risk assessments is limited by the lack of a
more complete understanding of the distribution of exposures for people using synthetic turf fields with
tire crumb rubber infill.
2.4.4 Other Limitations
The research described in this report was exclusively aimed at synthetic turf fields with recycled tire
crumb rubber infill. While it may be desirable for reasons noted below to include other types of fields, it
was beyond the scope of this study to investigate other types of fields (e.g., natural grass, synthetic fields
with natural product infill, or synthetic fields with ethylene propylene diene terpolymer [EPDM] or
thermoplastic elastomer [TPE] infill). It was also beyond the scope of this study to evaluate the use of
recycled tire crumb rubber as a soil amendment or natural grass top dressing. While there is concern
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about chemical exposures resulting from the use of recycled tire and other materials in synthetic fields, it
is important to recognize that some of the chemicals are present in other types of fields, including
natural grass fields. For example, metals (including lead) and PAHs (including benzo[a]pyrene) of
concern at synthetic turf fields with tire crumb rubber infill are also often found in surface soil in the
United States and may be present at natural grass playing fields. Insecticides and herbicides may be used
on some natural grass fields, leading to exposures that may not be experienced by synthetic turf field
users. Because many recreational and sports field users usually spend time on both natural grass and
synthetic fields (either concurrently or during different life stages), characterization of chemical and
microbiological agents at all relevant field types and an understanding of relative exposures across the
different field types would be needed for risk assessment and epidemiological investigations.
The study did not address potential heat exposure and injury concerns for athletes on synthetic turf
fields. In the dermal measurements performed as part of the exposure characterization study, it would
have been ideal to collect both pre- and post-activity samples; however, given the time and complexity
for collecting wipe samples and the participant time needed, we judged the participant burden too large
in the current assessment and prioritized the pre-activity time available with participants towards urine
and blood sample collection for the pilot-scale biomonitoring study.7
2.5 Future Research Recommendations
While this study added considerable new information for better understanding tire crumb rubber to
inform exposures to chemical substances associated with tire crumb rubber material and microbes at
synthetic turf fields, additional research could be performed to further inform and improve future
exposure and risk assessments.
• Given the complex nature of tire crumb, it is not unexpected that many chemicals were
observed during characterization testing. The ability to resolve which, if any, of those that
were tentatively identified are relevant for further evaluation is further complicated by the
potential dearth of toxicity information. Approaches for whole material toxicity testing,
such as those used by the National Toxicology Program, could be further developed and
applied for assessing potential effects of the material.
• Results in this study and other studies suggest that exposures to chemicals associated
with recycled tire crumb rubber infill are likely to be higher for users of indoor synthetic
turf fields as compared to users of outdoor fields. Exposures at indoor facilities may
represent the highest exposure scenarios, based on the higher levels of many organic
chemicals observed in indoor tire crumb rubber infill (in the absence of weathering and
other mechanisms thought to lower the concentration of these chemicals over time) and
reduced ventilation rates, which can lead to higher air concentrations. Future studies
might be directed at collection of more air and exposure measurements at indoor
facilities.
• Exposure modeling approaches have been applied in other studies for exposure
estimation and were examined in this study for the inhalation, dermal and ingestion
exposure pathways. There is a lack of parameter value data for some key model
parameters for synthetic field users, however. For example, the amounts of tire crumb
rubber and field dust that adhere to the skin and the amounts of tire crumb rubber and
field dust that are ingested are not currently available. Future work could be aimed at
7 See Appendix A for the supplemental biomonitoring study.
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improving exposure pathway models and cumulative exposure assessment methods for
synthetic turf field exposure scenarios.
• The exposure pilot study provided field and personal measurement results for a small
number of youth and adults engaged in athletic activities at synthetic turf fields. Building
off methods developed and tested in this and other studies, future larger studies could be
performed to collect additional exposure measurement data. Research aimed at certain
sports positions (e.g., soccer goalies and football running backs) and indoor turf field
users could provide insight into exposures for some of the athletes potentially facing the
greatest exposures. More studies could also be performed for young child bystanders and
field installation and maintenance workers.
• Sample collection methods and questionnaire data collection methods applied in this
study could be considered for use in future epidemiological investigations, should it be
determined that such investigations are warranted.
2.6 Conclusions
This part of the Tire Crumb Research Study report communicates the research objectives, methods,
results and findings for the exposure characterization and fill specific gaps about potential human
exposures to the chemicals found in the tire crumb rubber material while using synthetic turf fields. A
range of chemicals was found in air, field surface, field dust, and in dermal exposure media, including
metals and organic chemicals. Exposures may be higher for people using indoor synthetic turf fields
than outdoor fields.
In general, the findings from the entire synthetic turf field portion of the FRAP activities (both the Tire
Crumb Characterization Part 1 and the Tire Crumb Exposure Characterization Part 2 combined) support
the conclusion that although chemicals are present (as expected) in the tire crumb rubber and exposures
can occur, they are likely limited; for example:
• Generally, only small amounts of most organic chemicals are released from tire crumb rubber
into the air through emissions. For many analytes measured during active play at the outdoor
fields, next-to-field concentrations in air were not different than background samples while
others were somewhat higher.
• For metals, only small fractions are released from tire crumb rubber into simulated biological
fluids (average mean about 3% for gastric fluid and <1% for saliva and sweat plus sebum)
compared to a default assumption of 100% bioaccessibility.
• In the biomonitoring pilot study, concentrations for metals measured in blood were similar to
those in the general population.
• No differences in PAH metabolites in urine were observed in the supplemental biomonitoring
study between study participants using natural grass and those on synthetic turf fields with tire
crumb rubber infill.
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Risk is a function of both hazard (toxicity) and exposure. Understanding what is present in the material
(Part 1 Report) and how individuals are potentially exposed (Part 2 Report) is critical to understanding
potential risk. It is important to note that the study activities completed as part of this multi-agency
research effort were not designed, and are not sufficient by themselves, to directly answer questions
about potential health risks. Other studies may aid in this regard.
Overall, we anticipate that the results from this multi-agency research effort will be useful to the public
and interested stakeholders for understanding the potential for human exposure to chemicals associated
with recycled tire crumb rubber infill material used on synthetic turf fields.
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3.0 Exposure Characterization Methods
3.1 Overall Research Design
As described in the Federal Research Action Plan (U.S. EPA, CDC/ATSDR, and CPSC, 2016a) and in
the Research Protocol, Collections Related to Synthetic Turf Fields with Crumb Rubber Infill (U.S. EPA
and CDC/ATSDR, 2016), this portion of the research was a pilot-scale effort aimed at providing
information and data for characterizing exposures to chemical constituents for users of synthetic turf
fields with tire crumb rubber infill. A goal was to recruit participants from among those thought to be in
one or more higher-exposure scenarios based on the frequency and duration of synthetic turf field use, as
well as specific activities that may be involved in higher levels of contact with synthetic turf field
materials including tire crumb rubber. There were two primary components in the exposure
characterization research: a) information collection from synthetic turf field users on human activity
parameters that may affect potential exposures to tire crumb rubber constituents, and b) human exposure
measurement study to further develop and deploy appropriate sample collection methods and to generate
data for improved exposure characterization. A schematic outline of the tire crumb rubber
characterization research, as implemented, is shown in Figure 3-1.
Several different age groups were included in the exposure characterization pilot study, including adults
(>18 years old), adolescents (13 to 17 years old), youth (10 to 12 years old), and children (7 to 9 years
old). The research design goals included recruitment and participation via questionnaire, exposure
measurement, and videographic data collections.
Human activity data collection included the use of questionnaires administered to adult and adolescent
(or the parents of youth and child) study participants who used synthetic turf fields with tire crumb
rubber infill and videography of users engaged in activities on synthetic turf fields. Information was
collected to provide data about relevant parameters for characterizing and improved modeling of
exposures associated with the use of synthetic turf fields. In addition to answering the questionnaire,
video data collection was performed for a subset of participants during a physical activity on a synthetic
turf field to provide information about exposure-related contact rates and activity levels. Publicly-
available videography of users engaged in activities on synthetic fields was also used to provide
objective assessment of contact rates and activity types, which are difficult to capture consistently using
questionnaires. A subset of the participants that provided questionnaire responses were asked to
participate in an exposure measurement pilot study.
Exposure measurement activities included sample collection and analysis and metadata collection to
help inform exposure measurement interpretation. As part of a pilot-scale biomonitoring study, a set of
personal, biological, and field environment samples were collected around a sport or training activity
performed on a synthetic turf field.8 Personal and environmental samples were analyzed for the metal,
VOC, and SVOC analytes described in Tables 3-1 through 3-3.
8 See Appendix A for the supplemental biomonitoring study.
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The exposure characterization research activities are summarized in Table 3-1.
Synthetic
Field User Activity information Collection
Extant Publicly Available Video
60 Hours publicly available video
Adult & chiid activity categories
3 Sports
Questionnaire Data Collection
32 adultand child participants
3 facilities
3 Age/activity groups
Video Activity Data Collection
17 adultand child participants
3 facilities
2 Sports
Synthetic Turf Field User Exposure Measurement Pilot Study
Exposure Data Collection
Up to 25 adultand child participants
At 3 facilities
3 Age/activity groups
PersonalSamples Biological Samples
AirVOC sa m p les (2 5) U rine sampies pre-acti vity(14)
Dermal metals samples (75) Urine samples post-activity (14)
Derma! SVOC samples (75)
Blood and serum pre-activity (13)
Blood and serum post-activity (11)
Meta Data Collection
Meteorological information
Pa rtici p a nt a ctivity i nf ormati on
Overa 11 a cti vity i nform ati on
Field facility information
Exposure Pathway Modeling Assessment
Using Extant Measurement Data
Using Data from This Study
Residential + Dietary Comparison
6 Selected chemicals
6 Selected chemicals
4 Selected chemicals
Adult & child scenarios
Adult & child scenarios
Adult & child scenarios
Inhalation pathway
Inhalation pathway
Inhalation pathway
Ingestion pathway
Ingestion pathway
ingestion pathway
Dermal pathway
Dermal pathway
Dermal pathway
Figure 3-1. Pilot exposure characterization research schematic overview.
27
Facility Samples
AirVOC samples (9)
Air particle/metals samples (9)
AirSVOC samples (9)
Surface wipe metalssamples (9)
Surface wipe SVOC samples (9)
Surface dragsied SVOC samples (9)
Dust metals samples (3)
Dust SVOC samples (3)
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Table 3-1. Exposure Characterization Research Areas and Specific Research Activities
Research Area
Research Activities
Exposure Characterization Pilot
Study for Youth and Adults
Athletes Using Synthetic Turf
Fields with Tire Crumb Rubber
Infill
Recruiting youth and adult participants for sample and data collection around
their usual sport activities at synthetic turf fields
Using questionnaire data collection to obtain data for field use duration and
frequency of use, activity patterns on fields, and hygiene to improve exposure
scenario development and exposure modeling for youth and adult athletes using
synthetic turf fields
Using video data from online sources and participant video data collection
approaches to provide data for contact types and frequencies, and activity levels
for improving exposure modeling for youth and adult athletes using synthetic
turf fields
Performing measurements to provide additional data on particles, metals,
SVOCs, and VOCs in the air at synthetic turf fields during periods of activity on
the field and during warm to hot ambient air conditions for assessing exposure
through the inhalation pathway
Developing methods and providing data on inorganic and organic chemicals on
field surfaces, in field dust, and on athlete skin to better understand and estimate
both child and adult exposures, particularly for the dermal and ingestion
exposure pathways
Developing, applying, and assessing methods and approaches for personal air
sample collection
As part of a pilot-scale biomonitoring study, collecting and analyzing blood and
urine samples for measurement of selected metals and PAH biomarkers before
and after the monitored participant sport activities at synthetic turf fields
Assessing silicone wristbands as potential sampling devices for future use in
field air and personal sampling assessments of exposure at synthetic turf fields
Applying and assessing exposure pathway models to examine differences in
exposure levels across pathways, and to identify where lack of data (or lack of
robust data) may be limiting accuracy and/or resulting in potentially large
uncertainties in exposure estimation for synthetic turf field users (see section 5)
Supplemental Biomonitoring Study
Expanding upon the FRAP's pilot-scale effort by including a larger sample size
of synthetic turf with recycled tire crumb rubber infill users and a comparison
group of natural grass field users
Examining potential assocaitions with pre- and post-activity urinary PAH
biomarker concerntrations with field type
Comparing study participants' urinary PAH concentrations to those found in the
noninstitutionalized general U.S. population
A pre-pilot test of sample collection and videography standard operating procedures (SOPs) and the
overall plan for sample collection at synthetic turf fields was conducted in June 2017. Based on this
testing, the SOPs and overall sampling plan were modified prior to initiating the exposure
characterization sampling in September 2017; exposure characterization SOPs are provided in Appendix
C. Many of the modifications that were made were aimed at reducing sample deployment and collection
times at fields because a) the amount of time available at a field before and after the monitored
participant activities was likely to be limited in some settings, and b) the time to interact with
participants for multiple sample/data collection procedures before and after their monitored activity was
likely to be highly constrained. These anticipated time constraints were, in fact, realized during the
research study, and the focus on time efficiency in sampling methods and strategies was essential.
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Exposure pathway modeling was performed for adult and child athletes using synthetic turf fields with
tire crumb rubber infill, first using data available from the literature and then again with data collected in
this study. Six chemicals associated with synthetic turf fields and tire crumb rubber were selected for
exposure pathway modeling. They were selected to provide a range of physical and chemical properties
and because of the availability of previous measurement data. Adult and child pathway-specific
exposure estimates were calculated for each of the six chemical substances and were compared to
identify the predominant pathway for each chemical substance. Subsequent to the modeling of tire
crumb-related exposures using previously existing and newly acquired measurement data, daily intakes
of four of the chemicals were also estimated using available dietary and residential "background"
concentrations to provide perspective on the relative magnitude of the crumb-related exposure estimates.
3.2 Exposure Measurement Pilot Study Recruiting and Questionnaire Methods
3.2.1 Participant Recruiting
Recruitment for the exposure characterization pilot study was initiated August 28, 2017 and ended on
October 4, 2017. Researchers aimed to recruit and obtain consent from 60 participants for the exposure
characterization study and 45 participants for the exposure measurements sub-study, including 24
participants to be videotaped during play/athletics. The goal was to have participants from six fields,
including at least one field in each of the four U.S. census regions; however, if the researchers were
unable to obtain that geographic distribution, no geographic restrictions would be placed on participant
recruitment. The target population for the exposure characterization study and exposure measurements
sub-study was defined as children and adults (> 7 years of age) who played sports on community
synthetic turf fields with tire crumb rubber infill in the previous year. There were no restrictions on time
of play in the previous year or type of sport (e.g., baseball). Researchers aimed to have a variety of
athletes consent to participate in the studies, including: professional athletes, college athletes (>18),
adolescents (ages 13-17), youth (ages 10-12), and children (ages 7-9).
Initially, the research team reached out to synthetic turf fields who participated in the tire crumb
characterization study and who consented to allow for recruitment of players at their facilities. Due to
scheduling issues and other factors, only three fields in two U.S. census regions were available for
participant recruitment during the study time frame, specifically one indoor field and two outdoor fields.
The research team received practice schedule information prior to the field visits and reached out to
sports organizations scheduled for field use during the planned recruitment and sampling weeks to
discuss the project and provide outreach materials.
Recruitment was conducted Monday through Thursday, immediately prior to, during, and after field
activities. Prior to practice, research team members endeavored to meet and discuss the project with
team coaches; however, this was not always possible. Researchers approached either players (>18) or
their parents/guardians (<18) to determine interest in participating in the study. At the time of initial
contact, researchers provided a fact sheet and, if requested, a copy of the consent forms. If
parents/guardians or players were interested in participating, an eligibility screening questionnaire was
administered. Once eligibility was confirmed, parents/guardians or the participant were given a consent
form. If desired, the research team reviewed the consent form with the individual and answered any
questions. Participants were given the option to consent to the following study schemes: 1. Field use
questionnaire only; 2. Field use questionnaire and exposure measurements sub-study; or 3. Field use
questionnaire, exposure measurements sub-study, and videography. For the pilot-scale biomonitoring
study, participants were also allowed to decline collection of biological samples. Signed consent was
obtained from adult participants and from parents or guardians of participants <18 years of age;
participants <18 years of age were required to provide signed assent forms, as well.
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3.2.2 Field User Questionnaire Administration
After confirming eligibility to participate in the interview and receiving signed consent/assent forms,
exposure study participants were given contact information and an appointment time for the
questionnaire to be administered (usually before or after field activities). The questionnaire was
administered by a research team member in person at the sampled facility site and lasted approximately
30 minutes. For participants younger than 13 years of age (i.e., youth and children), the questionnaire
was administered to a parent or guardian, as outlined in the protocol. Slightly different questionnaire
versions were used for administration directly to a participant and administration to a participant parent
or guardian; the questionnaires are available in Appendix D. Double data entry occurred, as a hard copy
of the questionnaire was used at the facility and later entered into an Epi Info™ 7.2 database (CDC,
2017). After completion of the questionnaire, the participant was given contact information for any
further questions, as well as a token of appreciation.
3.3 Exposure Pilot Study Sample Collection Methods
3.3.1 Field Environment Samples
Researchers collected field environment samples that included field and off-field (background) air
samples, field surface wipe samples, drag sled samples, and dust samples. Researchers used specified
sampling locations for rectangular (soccer and football) synthetic turf fields (Figure 3-2), although air
sampling locations varied with wind direction. Standard operating procedures were prepared for each
sample collection method; the SOPs are provided in Appendix C. Air samples were collected during the
time periods in which participant athletic activities occurred. Field surface wipe, drag sled, and dust
sample collections were performed at these fields when there were no athletic activities on the field.
Target analytes for metals, VOCs, and SVOCs were the same as those described in Tables 3-1, 3-2, and
3-3 in the Tire Crumb Characterization Report (U.S. EPA & CDC/ATSDR, 2019); however, mercury
was not included as a target analyte for field environment samples.
Air
Sampling
Station
Air
Sampling
Station
Surface Wipe, Drag Sled,
and Dust Sampling Areas
Off-Field Air
Sampling
Station
(Background)
Figure 3-2. Sample collection locations for field air, surface wipe, drag sled, and dust samples.
Collection locations for air samplers were dependent on wind direction.
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3.3.1.1 Field Air Samples
Field air samples were collected while participants engaged in athletic activities on synthetic turf fields.
Samples were collected for particulate, metals, VOC and SVOC analysis. A total of three air samples
were collected simultaneously at each synthetic turf field (Figure 3-2). Air samples were collected from
two points at each synthetic field, preferably downwind and as close as possible to where activities
occurred without posing an obstruction or safety hazard. A third sample was collected upwind and at a
sufficient distance from the field to represent background. In the case of indoor fields, the background
sample was collected outside of the facility building and in an upwind direction. Air sampler inlets were
located 1 meter above the field or ground surface. Figure 3-3 shows the co-located particulate/metals,
VOC, and SVOC air samplers deployed at a soccer field. It was anticipated that sample collection
durations would be approximately two to three hours in order to represent an exposure period that
included participant time spent at the field prior to an athletic activity, during the athletic activity period
(ranging up to two hours), and a short time spent at the field following the athletic activity. The actual
sampling period reflected the duration of the monitored participants' activity at the synthetic turf field.
Figure 3-3. Typical field air sampling station setup (photo taken during pre-pilot
testing), including particulate/metal, semivolatile organic compound (SVOc), active
volatile organic compound (VOC), and passive VOC samplers.
This configuration shows duplicate sample collection for each sample type.
Field Air Samples for Particulates and Metals - Air samples were collected for total suspended
particulate (TSP) and metals analysis. A typical TSP/metals field air sampling set up is shown in Figure
3-4.
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Figure 3-4. Total suspended particulate/metals field air sampling setup, showing deployed
A) batteries and pumps and B) filter-containing sampling heads. This configuration shows
duplicate sample collection.
Samples for TSP and metals analysis were collected at a nominal flow rate of 20 L/min using metered,
direct current-supplied AirChek™ HV30 active samplers (SKC, Inc., Eighty Four, PA, USA), without
size-selective impactor inlets, to enable mass loading on pre-weighed 37-mm Pallflex Teflo membrane
disk filters (Pall Corporation, Port Washington, NY, USA). Sampler flow rates were measured and
recorded, along with the start and stop times at the beginning and completion of the sampling period. At
the conclusion of the sampling event, filter samples were recovered and returned to the laboratory under
ambient temperatures.
Field Air Samples for VOCs - Two types of VOC air sampling methods were employed at the synthetic
turf fields. The first sampling approach employed Radiello™ passive/diffusive samplers containing
Carbopack™ X sorbent, (Sigma-Aldrich, Saint Louis, MO, USA). The Radiello™ samplers were
selected due to their relatively high effective sampling rates, which was anticipated to provide improved
limits of detection for short duration sampling events. The on-field use of the Radiello™ passive
samplers was performed to provide comparability to the personal sample collection approach (also using
Radiello™ samplers) and to reduce the amount of equipment and set-up time for sample collection. The
second sampling approach employed an active pumping system and Carbopack™ X fenceline monitor
(FLM) tubes (Sigma-Aldrich, Saint Louis, MO, USA). This active VOC sampler was used to help better
understand the performance of the Radiello ™ samplers and to provide measurements using a more
standard approach. A typical set up for passive and active sampling of field air for VOCs is shown in
Figure 3-5.
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Figure 3-5. Volatile organic compound field air sampling setup, showing A) Pump
and passive and active air samplers in deployed configuration, with close-up of B)
active Carbopack™X fenceline monitor sampler and C) passive Radiello™ sampler.
Active sampler flow rates were measured and recorded at the start and completion of the sampling
period. Passive samplers were removed from their storage containers to start sampling and returned to
the storage containers immediately at the end of the sampling period. All sampling start and stop times
were recorded. At the conclusion of the sampling event, filter samples were recovered, stored in sealed
transportation containers, and returned to the laboratory. Following receipt at the laboratory, samples
were stored at 6 °C until analysis.
Field Air Samples for SVOCs - SVOCs include many chemical analytes, with large ranges of vapor
pressures and physical and chemical properties. Some SVOCs with higher vapor pressures are found
primarily in the vapor phase in air, while SVOCs with lower vapor pressures are typically found on
airborne particles. In this study, air samples were collected for SVOC analysis without a size-selective
particle inlet to allow both vapor- and particle-phase SVOCs to be collected simultaneously. Separate
particle- and gas-phase air concentrations were not measured. A medium-volume sample collection rate
(20 L/min) was selected, instead of a high-volume collection rate, due to the need for portability (i.e., the
ability to be deployed around the country), the need to minimize the footprint of equipment next to fields
with sports activities, the limited time available for setting up and taking down equipment, and the
uncertainty surrounding the availability of electrical power needed for high-volume sampling.
Calculations made from previously reported field measurements suggested that approximately 3- to 5-m3
samples would provide adequate detection limits for important tire crumb constituents, such as pyrene
and benzothiazole.
Samples were collected on solvent pre-cleaned open-cell 22-mm * 7.6-cm polyurethane foam (PUF)
filters placed in clean 30-mm >< 70-mm tubes. The typical equipment used for field air sampling for
SVOCs is shown in Figure 3-6.
Samples were collected at a nominal flow rate of 20 L/min using metered, direct-current-supplied
AirChek™ HV30 active samplers (SKC, Inc., Eighty Four, PA, USA). Sampler flow rates were
measured and recorded, along with the start and stop times at the beginning and completion of the
sampling period. At the conclusion of the sampling event, filter samples were recovered, stored in a
cooler with ice packs, and returned to the laboratory on frozen ice packs. Following receipt at the
laboratory, samples were stored at -20 °C until extraction.
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Figure 3-6. Semivolatile organic compound field air sampling setup, with A) batteries and pumps and
B) filter-containing sampler. The pump/battery configuration shows duplicate sample collection.
3.3.1.2 Field Surface Samples - Surface Wipe and Drag Sled Samples
Field surface samples were collected for metals analysis using a water-wetted wipe and for SVOC
analysis using two methods - an isopropanol-wetted wipe and a drag sled. Samples were collected from
the field at times when it was safe to do so without posing an obstruction or safety hazard for any
activities occurring on the field. Sample collection time was not critical for these samples; the samples
were collected at a convenient time during the overall exposure measurement activities at each field.
Field surface wipe samples and drag sled samples were collected at each field (Figure 3-2, locations SI,
S2 and S5),
Surface Wipe Samples for Metals - Surface wipe samples for metals analysis were collected at synthetic
turf field sites using a GhostWipe wet (water) wipe (Environmental Express, Inc., Catalogue No.
SC4210, Charleston, SC, USA) conforming to American Society for Testing and Materials (ASTM)
El 792 (ASTM International 2016a) specifications. A total of three surface wipe samples were collected
at each field (Figure 3-2, locations SI, S2 and S5). No background (off-field) surface wipe sample were
collected.
Samples were collected following ASTM E1728 (ASTM International 2016b), a standard wet-wipe
method for collecting dust from indoor floor surfaces using water as the wetting agent. A 30-cm x 30-
cm (approximately 1 -ft2) template was placed on the surface of the field. Using clean, powderless nitrile
gloves, the field sampling technician removed the wet wipe from the foil packet (Figure 3-7A). Using
one side of the wipe, the turf surface was wiped in a S- or Z-shaped pattern within the template area
(Figure 3-7B). After folding the wipe in half to get a fresh wipe surface, the area was wiped again in a S-
or Z-shaped pattern perpendicular to the first wipe pattern (Figure 3-7C). The wipe was then folded in
half again and the edges near the interior portion of the template were wiped. Plastic forceps were used
to remove full-size tire crumb rubber infill granules, synthetic grass blades, and other large debris or
litter from the wipe (Figure 3-7D). The wipe was then folded and placed in a pre-cleaned 50-mL
polyethylene tube (Environmental Express, Inc., Catalogue No. SC475, Charleston, SC, USA) for
storage. The tube was tightly capped and transported at ambient temperature or lower to the laboratory.
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Figure 3-7. Field surface wipe sampling for metals analysis. Blades and debris
were removed from samples prior to placing wipes in storage tubes.
Surface Wipe Samples for SVOCs - Wetted surface wipe samples for SVOC analysis were collected at
synthetic turf field sites using a 10.2-cm at 10.2-cm Texwipe® TX304 cotton wipe (Texwipe,
Kernersville, NC, USA) that was cleaned by pre-extraction, using a series of solvents including acetone
and hexane, prior to use. A total of three SVOC surface wipe samples were collected at each field
(Figure 3-2, locations SI, S2 and S5). SVOC surface wipe samples were collected from a different area
at these locations than that used for metals surface wipe sample collection. No background (off-field)
surface wipe samples were collected.
Using clean Silver Shield® gloves (Siebe North, Inc., North Charleston, SC, USA), the field sampling
technician removed the cotton wipe, which had been pre-wetted in the laboratory with 3 mL of 1:1
deionized water:isopropanol, from its glass storage jar (Figure 3-8A). (Note: Silver Shield® gloves were
used after tests showed potential contamination of wipe material with phthalates, when nitrile gloves
were used). A 30-cm * ;30-cm (approximately 1 -ft2) template was placed on the surface of the field.
Using one side of the wipe, the turf surface was wiped in a S- or Z-shaped pattern within the template
area (Figure 3-8B). After folding the wipe in half to get a fresh wipe surface, the area was wiped again
in a S- or Z-shaped pattern perpendicular to the first wipe pattern. The wipe was then folded in half
again and the edges near the interior portion of the template were wiped. Stainless steel forceps were
used to remove full size tire crumb rubber infill granules, synthetic grass blades, and other large debris
or litter from the wipe (Figure 3-8C, D). The wipe was then folded and placed in a pre-cleaned 60-mL
amber wide-mouth glass jar. The bottle was tightly capped and transported on frozen ice packs to the
laboratory, where the samples were placed in a freezer at -20 °C.
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Figure 3-8. Field surface wipe sampling for semivolatile organic compound
analysis. Blades and debris were removed from samples prior to placing wipes
in storage jars. (Note: This figure shows the use of nitrile gloves. Silver Shield®
gloves were worn during actual sample collections to reduce phthalate contamination
of samples. Also, amber glass jars were used during study.)
Surface Drag Sled Samples for SVOCs - Surface drag sled samples for SVOC analysis were collected at
synthetic turf field sites using a dry 30.5 cm » 30.5 cm Texwipe® TX312 cotton wipe (Texwipe,
Kernersville, NC, USA) that was cleaned by pre-extraction, using a series of solvents including acetone
and hexane, prior to use. The drag sled method provided a standardized approach for collecting
dislodgeable residues from field surfaces in a way that might mimic potential transfers to field users'
skin or clothing. The drag sled method was also likely to be less susceptible to operator variability with
regard to applied pressure. A total of three SVOC drag sled samples were collected at each field (Figure
3-2, locations SI, S2 and S5). Drag sled samples were collected from a different area at these locations
than that used for metals and SVOC wipe sample collection. No background (off-field) drag sled
samples were collected.
Using clean, Silver Shield® gloves (Siebe North, Inc., North Charleston, SC, USA), the field sampling
technician removed the dry cotton wipe from its storage container and clamped it to a custom-built wipe
sampling drag sled device. The device had a 10-kg aluminum block, 25.4 cm x 25.4 cm x 5.1 cm in size,
with clamps on two sides for securing the wipe, and an attached handle for pushing the device. The wipe
was secured so that the 645-cm2 bottom face of the block was completely covered by the wipe. Using a
tape measure, a 5-m >< l-m (5-m2) area was marked on the synthetic turf field (Figure 3-9A). Starting in
one corner, the sled was pushed down and back over the same area. The sled was then moved over one
sled width, and the next pass was made to push the sled down and back over the length of the tape
measure (Figure 3-9B). This was repeated so that the entire 5-m2 sampling area was wiped with a down
and back pass. Large tire crumb granules were removed with stainless steel forceps from the wipe face
that contacted the field, and synthetic grass blades, and other large debris or litter on the sides of the
wipe that did not contact the field were removed to the extent possible (Figure 3-9C, D). The wipe was
then folded and placed in a clean 500-mL amber wide-mouth glass storage bottle with a Teflon™-lined
36
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cap. The bottle was tightly capped and transported on frozen ice packs to the laboratory, where the
samples were placed in a freezer at -20 °C.
Figure 3-9. Drag sled sampling for semivolatile organic compound analysis.
3.3.1.3 Field Dust Samples
Dermal contact, inhalation, and ingestion of dust at synthetic turf fields may represent important
pathways of exposure to chemicals associated with tire crumb rubber, other synthetic field materials, and
environmental dust deposited on the field. Although dust may be an important synthetic turf field
medium for all three exposure pathways, there are no standard methods for collecting dust from
synthetic turf fields with tire crumb rubber infill. Several vacuum methods that have been previously
used for dust collection in residential environments were tested. However, problems were encountered
with each of these methods, (e.g., entrainment of tire crumb rubber granules, excessive moisture
removal, collection of sand material from deep layers, and collection of organic materials and debris),
which precluded their use in this study. Based on experience gained during the particle size analyses
conducted as part of the tire crumb rubber characterization, a sieving method was tested for obtaining
sufficient dust for metals and SVOC analyses. The sieving method was judged to be successful and was
applied in the exposure measurement study to collect dust at the study fields.
Dust samples for SVOCs and metals analysis were collected at synthetic turf fields by on-field sieving
of bulk dust collected as a composite from three locations on the field, using a 120 mesh (150-jiM)
stainless steel sieve. Samples were collected at locations SI, S2 and S5 (Figure 3-2) by successive
collection and sieving of tire crumb rubber at each location. Plastic spatulas were used to collect tire
crumb rubber from the top approximately 3 cm of the field (Figure 3-10A). The sieve was filled
approximately half-full at each location (Figure 3-10B); this is approximately 600 mL (or approximately
340 g) of tire crumb rubber. The total amount sieved at each field was approximately 1800 mL (or
approximately 1020 g). The sieve lid was placed on the sieve, and vigorous shaking was performed for
at least 3 minutes (Figure 3-10C). After sieving at each of the three locations, the combined dust was
brushed through a clean funnel and into a pre-cleaned 50-mL polyethylene tube for metals analysis. The
37
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amount of dust collected was visually compared to tubes containing 200, 300, and 400 mg of house dust
to ensure a sufficient amount was collected for metals analysis. The sample collection and sieving
process was then repeated, with the dust deposited into pre-cleaned 40-mL amber glass vials for SVOC
analysis. The amount of dust collected was visually compared to tubes containing 200, 300, and 400 mg
of house dust to ensure a sufficient amount was collected for SVOC analysis. SVOC dust samples were
placed into a cooler with frozen ice packs at the field, stored cold, and shipped to the laboratory on
frozen ice packs. SVOC dust samples were stored at -20 °C once at the laboratory. Metals dust samples
were stored and shipped along with the SVOC dust samples. No background (off-field) dust samples
were collected.
Figure 3-10. Dust sampling for metals and semivolatile organic compound analysis
using a sieve method. (Note: This figure shows the use of a glass bottle. Dust was
placed in a pre-cleaned 50-mL polyethylene tube for metals analysis and in a pre-
cleaned 40-mL amber glass vial for SVOC analysis.)
3.3.2 Personal Samples
Personal sampling included collection of air samples and dermal (skin) wipe samples for exposure
characterization study participants.
3.3.2.1 Personal Air Samples
Personal sampling for VOCs was performed using Radiello™ passive/diffusive samplers containing
Carbopack™ X sorbent (Sigma-Aldrich, Saint Louis, MO, USA) attached to participants engaged in a
sports activity on a synthetic turf field with tire cmmb rubber infill. It was anticipated that sample
collection durations would be approximately two to three hours in order to represent an exposure period
that included participant time spent at the field prior to an athletic activity, during the athletic activity
period (ranging up to two hours), and a short time spent at the field following the athletic activity. The
actual sampling time reflected the duration of the monitored participant's activity at the synthetic turf
field.
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Passive samplers were removed from their storage containers to start sampling and were returned to the
storage containers as soon as possible after the end of the sampling period. The samplers were attached
to the back upper part of a pinnie that participants wore during their activity (Figure 3-11). This position,
although not directly in the breathing zone, was selected to minimize interference with participant
activities and potential for damage during contact with other athletes or the ground. The sample holder
was attached to the pinnie at three points including the top clip and two Velcro fasteners at the bottom
corners. All pinnies were laundered prior to initial participant use and between uses. All sampling start
and stop times were recorded. At the conclusion of the sampling event, passi ve samples were recovered,
stored in sealed transportation containers, and returned to the laboratory. Following receipt at the
laboratory, samples were stored at -20 °C until analysis.
Figure 3-11. Personal air passive sampling for volatile organic compounds, showing
A) placement on the participant's pinnie and B) a close-up of the air sampler. (Note:
This figure is a demonstration, showing sampler placement on a person that was not a
study participant).
3.3.2.2 Dermal Wipe Samples
Dermal Wipe Samples for Metals Analysis - Three dermal wipe samples were collected for metals
analysis from each participant in the exposure characterization study, following an on-field sports
activity. One wipe sample was collected from the participant's hand, the second wipe sample was
collected from a defined area of the forearm, and the third wipe sample was collected from the leg
(either calf or thigh depending on which area had more exposed skin area during the sports activity);
dermal samples for metals analysis were all collected from the left side of the participant's body. All
dermal wipe samples for metal analysis were collected using a GhostWipe wet (water) wipe
(Environmental Express, Inc., Catalogue No. SC4210, Charleston, SC, USA) conforming to ASTM
El792 (ASTM International 2016a) specifications. (Note: This is the same wipe material used for
collecting field surface wipe samples for metals analysis.) When sampling of the hand, arm, or leg was
complete, the wipe was folded with the exposed (contacted) surface on the inside and placed into a pre-
cleaned 50-mL polyethylene tube (Environmental Express, Inc., Catalogue No. SC475, Charleston, SC,
USA) for storage and shipment to the laboratory.
Using clean, powderless nitrile gloves, the field sampling technician removed a Ghost Wipe wet wipe
from the foil packet and unfolded the wipe to its full dimensions. With moderately-firm pressure, the
technician wiped the participant's left hand with the wipe, including the back, front, and sides of the
hand, fingers, and thumb (Figure 3-12A). The wipe was folded with the exposed (contacted) surface on
the inside and placed into a pre-cleaned 50-mL polyethylene tube. The tube was tightly capped and
transported at ambient temperature or lower to the laboratory.
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Figure 3-12. Dermal sampling on A) hand and B) arm. Leg sampling not shown.
(Note: This figure is a demonstration showing dermal wipe sampling on a person
that was not a research study participant. In this study, dermal sampling for metals
was performed on the left hand, arm, and leg and dermal sampling for SVOCs was
performed on the right hand, arm, and leg; right hand and arm shown in figure.).
Using a fresh pair of clean, powderless nitrile gloves, the field sampling technician removed a Ghost
Wipe wet wipe from the foil packet, unfolded the wipe to its full dimensions, and folded it into quarters.
With moderately-firm pressure, the field technician wiped the bottom side of the participant's left
forearm over a 112-cm2 area designated using a pre-cleaned rectangular Teflon™ template (Figure 4-
12B). The wipe was folded again, with the exposed (contacted) surface now on the inside. The forearm
skin was wiped a second time over the same 112-cm2 area. The wipe was folded with the exposed
(contacted) surface on the inside and placed into a pre-cleaned 50-mL polyethylene tube. The tube was
tightly capped and transported at ambient temperature or lower to the laboratory.
Using a fresh pair of clean, powderless nitrile gloves, the field sampling technician removed a Ghost
Wipe wet wipe from the foil packet, unfolded the wipe to its full dimensions, then folded it into quarters.
With moderately-firm pressure, the field technician wiped the outer facing side of the participant's left
calf or lower thigh (whichever had more exposed skin) over a 112-cm2 area designated using a pre-
cleaned rectangular Teflon™ template. The wipe was folded again, with the exposed (contacted) surface
now on the inside. The leg skin was wiped a second time over the same 112-cm2 area. The wipe was
folded with the exposed (contacted) surface on the inside and placed into a pre-cleaned 50-mL
polyethylene tube for storage. The tube was tightly capped and transported at ambient temperature or
lower to the laboratory.
Dermal Wipe Samples for SVOC, Analysis - Three derm al wipe samples were collected for SVOC
analysis from each participant in the exposure characterization study, following an on-field sports
activity. One wipe sample was collected from the participant's hand, the second wipe sample was
collected from a defined area of the forearm, and the third sample was collected from the leg (either calf
or thigh depending on which are had more exposed skin area during the sports activity); dermal samples
for SVOC analysis were collected from the right side of the participant's body. All dermal wipe samples
for SVOC analysis were collected using a wetted (1:1 water:isopropanol) 10.2-cm >< 10.2-cm cotton
Twill wipe (Texwipe, Kernersville, NC, USA). (Note: This is the same wipe material that was used for
collecting field surface wipe samples for SVOC analysis.) Using clean, Silver Shield® gloves (Siebe
North, Inc. North Charleston, SC, USA), the field sampling technician removed the pre-wetted (1:1
water:isopropanol) wipe from its glass storage jar and unfolded it to its full dimensions. With
moderately-firm pressure, the field technician wiped the participant's right hand with the wipe,
including the back, front, and sides of the hand, fingers, and thumb (Figure 3-12A). The wipe was folded
with the exposed (contacted) surface on the inside and placed back into the glass storage jar. The jar was
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tightly capped and transported on frozen ice packs to the laboratory, where the samples were placed in a
freezer at -20 °C.
Using clean, Silver Shield® gloves, the field sampling technician removed the wetted (1:1
water:isopropanol) wipe from its glass storage jar, unfolded it to its full dimensions, then folded it into
quarters. With moderately-firm pressure, the field technician wiped the bottom side of the participant's
right forearm over a 112-cm2 area designated using a pre-cleaned rectangular Teflon™ template (Figure
3-12B). The wipe was folded again, with the exposed (contacted) surface now on the inside. The same
112-cm2 area of the bottom side of the right forearm was wiped a second time. The wipe was then folded
with the exposed (contacted) surface on the inside and placed back into the glass storage jar. The jar was
tightly capped and transported on frozen ice packs to the laboratory, where the samples were placed in a
freezer at -20 °C.
Using clean, Silver Shield® gloves, the field sampling technician removed the wetted (1:1 water:
isopropanol) wipe from its glass storage jar, unfolded it to its full dimensions, then folded it into
quarters. With moderately-firm pressure, the field technician wiped the outer facing side of the right calf
or lower thigh (whichever had more exposed skin) over a 112-cm2 area designated using a pre-cleaned
rectangular Teflon™ template. The wipe was folded again, with the exposed (contacted) surface now on
the inside. The outer facing side of the right calf or lower thigh was wiped a second time over the same
112-cm2 area. The wipe was then folded with the exposed (contacted) surface on the inside and placed
back into the glass storage jar. The jar was tightly capped and transported on frozen ice packs to the
laboratory, where the samples were placed in a freezer at -20 °C.
3.3.3 Biological Samples - Pilot-Scale Biomonitoring Study
Two types of biological samples were collected in the pilot-scale biomonitoring portion of the exposure
characterization study - urine samples and blood samples. Study participants could decline collection of
biological samples, if they wished.
3.3.3.1 Urine Samples
Each participant who consented to provide urine samples was provided a sealed, sterile urine collection
cup prior to field activity. The participant was informed to (1) not open the container until specimen
collection and (2) to not touch the inside of the collection cup. Immediately upon collection, each
container was placed in a biohazard bag and placed on dry ice. A second urine sample was collected
from the same study participants post-activity, using the same sampling procedure. All specimens were
shipped the next morning on dry ice to the National Center for Environmental Health (NCEH) Division
of Laboratory Sciences.
3.3.3.2 Blood Samples
Blood Collection Procedure - Blood draws were performed on each consented participant both pre-
activity and post-activity. Prior to field activity, each participant was administered a safety questionnaire
to confirm it was acceptable to administer the blood draw. A tourniquet was applied to the upper arm
and a vein was selected for venipuncture. The area selected for venipuncture was cleaned with an
alcohol pad and allowed to air dry. For children and youth, a 23-gauge (23G) butterfly needle was used
for blood collection; for adolescents and adults, a 21G butterfly needle was used. After the vein was
punctured, blood was collected in a 7-mL blue top tube, followed by a 4-mL ethylenediaminetetraacetic
acid (EDTA) purple-top tube for children and youth or a 6-mL EDTA purple-top tube for adolescents
and adults. The EDTA purple-top tube was inverted a minimum of eight times prior to placement in a
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cooler with four freezer packs. After all tubes were filled for a participant, and the last tube had been
removed from the needle holder, the needle was removed and pressure was applied with a gauze pad to
the venipuncture site. The EDTA purple-top tubes were placed in a cushioned box, which was put into a
biohazard bag and set in a cooler with a minimum of four freezer packs. The samples were shipped the
next morning to the NCEH Division of Laboratory Sciences.
Serum Processing Procedure - Blue-top tubes filled during blood collection were placed upright and
allowed to clot at room temperature for a minimum of 30 minutes and a maximum of 1 hour. After
allowing time for the blood to clot, each tube was placed in a Hettich® EBA-20 centrifuge (Hettich
Instrument, LP, Beverly, MA, USA) set at 2400 RPM for 15 minutes. After centrifugation, a minimum
of 1 mL of serum was transferred from the blue-top tube to a 2-mL Nalgene™ cryovial. The cryovials
were immediately placed into a cooler with dry ice. All serum samples were shipped the next morning
on dry ice to the NCEH Division of Laboratory Sciences.
3.3.4 Field Meta-Data Collection
Metadata collection was designed to record field and activity information that might be informative for
exposure study measurement interpretation, such as:
• ambient and field temperatures, which may be related to emissions of some chemicals
from tire crumb rubber;
• overall levels of activity on the field, which may influence the amount of particulate
suspended over the field;
• participant activity levels and durations, which may be related to contact with field
materials and environmental media; and
• activities or the built environment around the field, which may contribute to non-field
related chemicals being collected on air samplers.
Several data collection forms (Appendix E) were designed and filled out for each field and each
participant activity to record metadata that might aid in improved understanding of exposure study
results. Air temperature, field surface temperature, and wind speed and direction were measured at the
beginning, middle, and end of the exposure measurement period at each field and recorded. Air
temperatures and wind speeds were measured at a height of 1 meter above the field. Activity and facility
information was collected using structured forms to record important information about overall activities
at the field, participant-specific activities, and field and field operation conditions during the
measurement period.
3.4 Sample Analysis Methods
3.4.1 Gravimetric Particle Size Analysis
Gravimetric particle analysis was performed on the field air samples collected for TSP and metals
analysis, following at least 24-hrs equilibration in an environmental weighing chamber operating under
EPA's Federal Reference Method (FRM) guidelines (U.S. EPA, 2017) on the EPA-Research Triangle
Park (RTP) campus. The 37-mm Pallflex Teflo membrane disk filters were weighed to get the loaded
(field-based) mass. This mass was compared to the original (tare) weights of the filters. After correcting
for field blank mass change, the resulting mass difference was then used to estimate the mass density
(|ig/m3) of the suspended aerosol. The gravimetric procedure required repeated weighing of each filter
42
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sample until the obtained mass was within the required 5 |ig reweigh threshold. All reported values
reflect gravimetric analyses meeting both the original and final (loaded) weighing requirements.
3.4.2 Extraction and ICP/MS Metals Analysis
3.4.2.1 Field Air Sample and Field Dust Sample Preparation
Metals from particulate matter collected on Teflo membrane disk filters and field dust samples were
extracted for high resolution inductively coupled plasma mass spectrometer (HR-ICPMS) analysis. Air
filters were carefully placed in acid-cleaned 50-mL polypropylene conical tubes, the surface was
covered with 200 |iL of ethanol to aid solubility, and then approximately 25 mL of a mixture of 2%
nitric acid and 0.5% hydrochloric acid (by volume) was added to ensure the filter was completely
submerged. For the dust samples, approximately 20-60 mg of field dust and approximately 25 mL of the
2% nitric acid and 0.5% hydrochloric acid mixture was placed in an acid-cleaned 50-mL polypropylene
conical tube. Mass was recorded at each step. Next, the tubes were placed in a 70 °C water bath,
sonicated for 30 minutes, and left to sit for 3 hours. After the 3-hr leach step, tubes were removed and
left to sit at lab temperature for 10 days. Dust samples were then filtered into acid-cleaned 15-mL
polypropylene tubes using 0.2-|im ion chromatography (IC) Millex®-LG 25-mm syringe filters
(Millipore Sigma, Burlington, MA, USA).
In order to estimate the metal leaching efficiency of the field dust samples, National Institute of
Standards and Technology (NIST, Gaithersburg, MD, USA) Standard Reference Material (SRM®)
1648a, Urban Particulate Matter, was used as a spiked sample surrogate. It is important to note that the
collected field dust and the SRM® have many differences, including but not limited to, morphology,
particle size, and chemical structure. However, the SRM® is a good indicator of the leaching method
precision.
3.4.2.2 Wipe Sample Preparation - Microwave-assisted Extraction
A microwave-assisted extraction procedure was used to prepare wipe samples for elemental analysis.
The entire wipe sample was placed into a 100-mL XP-1500 Plus microwave digestion vessel with
TFM® liner (CEM Corporation, Matthews, NC, USA), and 9 mL of nitric acid and 3 mL of
hydrochloric acid were added to the vessel. The vessel contents were gently swirled and then allowed to
rest in a fume hood until the wipe was completely dissolved. The closed microwave digestion vessel was
then transferred into a MARS-5 microwave system fitted with a ESP-1500 Plus pressure sensor and
RTP-300 Plus fiber optic temperature sensor (temperature range -40-250 °C; CEM Corporation,
Matthews, NC, USA), where the digestion/extraction was performed at 200 °C.
3.4.2.3 ICP/MS Analysis
Quantitative elemental concentration measurements were carried out using an Element 2™ HR-ICPMS
(Thermo Finnigan, Bremen, Germany). The sample introduction system consisted of in-line
standardization prior to the PFA micro nebulizer, cyclonic quartz spray chamber, and platinum sampler
and skimmer cones. All sample handling and analysis were performed in an Internal Organization for
Standardization (ISO) Class 5 Clean Room (ISO 2015). The multi-element instrument method utilized
all three resolution modes. Instrument settings and method parameters are the same as those previously
shown in Table 3-7 in the Tire Crumb Characterization Report (U.S. EPA & CDC/ATSDR, 2019).
External calibrations were performed with multi-element calibration standards (High-Purity Standards,
Charleston, SC, USA). Initial calibration accuracy was performed using a secondary source multi -
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element standard (SCP Science, Champlain, NY, USA), NIST SRM® 1643f (NIST, Gaithersburg, MD,
USA), analysis of the calibration blank, and analysis of the diluent, if necessary. Continuing calibration
verification (CCV), continuing blank checks, and re-sampled duplicates were analyzed to verify
accuracy and precision during the analytical sequences. Minimum reportable limits (MRL) were
determined for each sample matrix based on a statistical representation of the continuing blank checks
(10*standard deviation). The reportable limit for selenium was set at the lowest calibration standard,
based on observed mass spectral peak shapes at the target isotope ranges.
Sample matrices that were assumed to be high in total dissolved solids (e.g., GhostWipes and field dust)
were gravimetrically-diluted by two factors (1:10 and 1:100) prior to analysis. The particulate matter
from the field air samples (i.e., the Teflo membrane disk filters) was not diluted. Final acid content in
the diluted samples was approximately 2% nitric acid and 0.5% hydrochloric acid (v/v). When a sample
was analyzed at each of the dilution factors, the 100-fold (1:100) diluted sample was used for reporting
the medium-resolution elements, which were higher in concentration.
3.4.3 TD/GC/TOFMS Analysis of Field Air and Personal Air Samples for VOCs
Carbopack™ X FLM and Radiello™ sorbent tube samples were received from the field and refrigerated
at 6 °C. The samples were removed from the refrigerator and allowed to come to room temperature prior
to analysis. Samples were analyzed using a Unity 2™ Ultra 50:50™ thermal desorption (TD) system
(Markes International, Inc., Gold River, CA, USA) interfaced to an Agilent 7890B gas chromatograph
equipped with an Rxi-ms column (60 m x 0.32mm, 1 |im; Agilent Technologies, Santa Clara, CA, USA)
and Markes International BenchTOF™ Select MSD System (Markes International, Inc., Gold River,
CA, USA). The instrument was tuned using the AutoOpt function and was calibrated using an internal
standard method with concentrations of target compounds in the nominal range of 0-50 ppbv per
compound. Internal standards were manually loaded on all tubes analyzed, including calibration tube,
QC samples, and field samples. The actual mass loading (in ng/tube) depends on the molecular weight
of the individual compound and the loaded volume of gaseous calibration standard. For example, mass
loadings in the nominal range of 0 to 160 ng/tube benzene and 0 to 260 ng/tube benzothiazole for the
calibration curve. Calibration checks were run using a low-level standard between every 11 samples.
The VOC target compounds determined using the TD/GC/TOFMS system are listed in Table 3-2 (with
exception of formaldehyde, which was not analyzed in the exposure pilot study), and the
TD/GC/TOFMS instrument operating parameters are shown in Table 3-2.
MSD ChemStation Enhanced Data Analysis Software (Version E.02.02.1431, Agilent Technologies,
Santa Clara, CA, USA) was used for peak identification/integration and combination of individual files
into a database. This database was exported to Microsoft® Excel (Office 365, Microsoft Corporation,
Redmond, WA, USA) for final data reduction. Quantitation was performed using quadratic curves
generated from the relative response ratios and concentration ratios of internal standards and calibration
standards. Inherent artifacts of target compounds found on Carbopack™ X sorbent (e.g., benzene) were
addressed through the use of blank corrected calibration curves. Results were reported as ng/tube. In
order to determine ng/L or |ig/m3, the total pumped volume for Carbopack™ X FLM actively-collected
samples was used. For Carbopack™ X Radiello™ diffusively-collected samples, an effective sampling
or uptake rate was used.
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Table 3-2. TD/GC/TOFMS Parameters for VOC Field Exposure Sample Analysis8
System Component
Parameter
Value
Thermal Desorption System
Trap
TO-15/TO-17 air toxics focusing trap
Thermal Desorption System
Split Flows
Inlet split - none; Outlet split - 25:1
Gas Chromatograph
Column Flow
1.5 mL/min
Gas Chromatograph
Temperature Program
Initial: Set point 30 °C, hold for 2 min
Ramp 1: Rate 3 °C/min to set point 69 °C, hold 0 min
Ramp 2: Rate 4 °C/min to set point 141 °C, hold 0 min
Ramp 3: Rate 40 °C/min to set point 240 °C, hold 3.52 min
Mass Selective Detector
Mass Range
Mass range: 35-350 mass to charge ratio (m/z)
Mass Selective Detector
Data Rate
3 Hertz (Hz)
Mass Selective Detector
Transfer Line Temperature
250 °C;
Mass Selective Detector
Ion Source Temperature
280 °C
Mass Selective Detector
Voltage
Ionization Voltage = 70 electronvolt (eV); Filament
voltage = 1.6 volt (V)
Mass Selective Detector
Filament Drops
None
a Thermal desorption/liquid chromatography/time-of-flight mass spectrometry (TD/LC/TOFMS) was conducted using a Unity
2™ Ultra 50:50™ Thermal Desorption (TD) system interfaced to an Agilent 7890B gas chromatograph equipped with an
Rxi-ms column (60 m x 0.32mm, 1 |im) and Markes International BenchTOF™ Select Mass Selective Detector System.
VOC = Volatile organic compound
3.4.4 Solvent Extraction and SVOC Analysis
3.4.4.1 Air Sample SVOC Extraction
The glass-lined sample cartridges containing the PUF plugs were stored in a freezer at approximately -
20 °C until removed for extraction. For each sample, a 250-mL narrow-mouth glass collection bottle was
labelled and fitted with a glass funnel. After the samples had warmed to room temperature, they were
removed from the bag and foil and the PUF plug was transferred to an appropriately-labelled, clean 60-
mL glass jar using stainless steel forceps. The glass-lined sampling cartridge that contained the PUF
plug was rinsed into the corresponding collection bottle with 5 mL of 1:1 acetone:hexane. Internal
standard solution (100 |iL) was then added to each sample. Eachjar was filled with 50 mL of 1:1
acetone:hexane and sealed with a PTFE-lined cap. The jars were placed in an ultrasonic cleaner with
water level well below the level of the jar cap. The ultrasonic cleaner was then turned on for 15 minutes.
Sample jars were removed from the cleaner and the extracts were transferred through funnels into the
corresponding collection bottles. The funnels were rinsed with 1:1 acetone:hexane from a wash bottle
after the extracts were added. The solvent addition, extraction and transfer was repeated two more times.
The extracts in the bottles were then evaporated to 2-5 mL, using a parallel evaporator. The
concentrated extracts were then transferred to a 15-mL graduated glass tube, along with two 2-mL 1:1
acetone:hexane rinses of the collection bottle, prior to concentration to a final volume of 1 mL under
nitrogen. The extracts were then transferred to autosampler vials for analysis.
3.4.4.2 Field Surface Wipe Sample SVOC Extraction
The sample jars containing the field surface wipe samples collected for SVOC analysis were stored in a
freezer at approximately -20 °C until removed for extraction. An effort was made to remove all synthetic
grass from the wipes before extraction. For each sample, a 250-mL narrow-mouth glass collection bottle
was labelled and fitted with a glass funnel. After the samples had warmed to room temperature, internal
standard solution (100 |iL) was added to each sample. After addition of internal standard, eachjar was
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filled with 50 mL of 1:1 acetone:hexane and sealed with a PTFE-lined cap. The jars were placed in an
ultrasonic cleaner with water level well below the level of the jar cap. The ultrasonic cleaner was then
turned on for 15 min. Sample jars were removed from the cleaner and the extracts were transferred
through funnels into the corresponding collection bottles. The funnels were rinsed with 1:1
acetone:hexane from a wash bottle, after the extracts were added. The solvent addition, extraction and
transfer was repeated two more times. The extracts in the bottles were then evaporated to 2-5 mL using
a parallel evaporator. The concentrated extracts were transferred to a 15-mL graduated glass tube, along
with two 2-mL 1:1 acetone:hexane rinses of the collection bottle, prior to concentration to a final
volume of 1 mL under nitrogen. The extracts were then transferred into autosampler vials, through 0.2-
|im PTFE syringe filters, in preparation for GC/MS/MS analysis.
3.4.4.3 Drag Sled Sample SVOC Extraction
The sample jars containing the drag sled samples collected for SVOC analysis were stored in a freezer at
approximately -20 °C until removed for extraction. An effort was made to remove all synthetic grass
from the wipes before extraction, and the two side sections were left on the wipes. For each sample, a 1-
L boiling flask was labelled and fitted with a glass funnel. After the samples had warmed to room
temperature, internal standard solution (100 |iL) was added to each sample. Then each jar was filled
with 300 mL of 1:1 acetone:hexane and sealed with a PTFE-lined cap. The jars were placed in an
ultrasonic cleaner with water level well below the level of the jar cap. The ultrasonic cleaner was then
turned on for 15 min. Sample jars were removed from the cleaner and the extracts were transferred
through funnels into the corresponding boiling flasks. The funnels were rinsed with 1:1 acetone:hexane
from a wash bottle, after the extracts were added. The solvent addition, extraction and transfer was
repeated two more times. The extracts in the boiling flasks were then evaporated to 2-5 mL using rotary
evaporators. The concentrated extracts were transferred to a 15-mL graduated glass tube, along with two
2-mL 1:1 acetone :hexane rinses of the boiling flasks, prior to concentration to a final volume of 1 mL
under nitrogen. The extracts were then transferred into autosampler vials, through 0.2-|im PTFE syringe
filters, in preparation for GC/MS/MS analysis.
3.4.4.4 Dermal Wipe Sample SVOC Extraction
The sample jars containing the dermal wipe samples collected for SVOC analysis were stored in a
freezer at approximately -20 °C until removed for extraction. For each sample, a 250-mL narrow-mouth
glass collection bottle was labelled, fitted with a glass funnel with glass wool, and filled with
approximately 10 g of anhydrous sodium sulfate (Na2S04). After the samples had warmed to room
temperature, internal standard solution (100 |iL) was added to each sample. Then each jar was filled
with 50 mL of 1:1 acetone:hexane and sealed with a PTFE-lined cap. The jars were placed in an
ultrasonic cleaner with the water level well below the level of the jar cap. The ultrasonic cleaner was
then turned on for 15 min. Sample jars were removed from the cleaner and the extracts were transferred
through funnels into the corresponding collection bottles through the funnels containing Na2S04 for
removal of residual water used along with isopropanol for sampling. The funnels were rinsed with 1:1
acetone:hexane from a wash bottle, after the extracts were added. The solvent addition, extraction and
transfer was repeated two more times. The extracts in the bottles were then evaporated to 2-5 mL using a
parallel evaporator. The concentrated extracts were transferred to a 15-mL graduated glass tube, along
with two 2-mL 1:1 acetone:hexane rinses of the collection bottle, prior to concentration to a final
volume of 1 mL under nitrogen. The extracts were then transferred into autosampler vials, through 0.2-
|im PTFE syringe filters, in preparation for GC/MS/MS analysis.
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3.4.4.5 Field Dust Sample SVOC Extraction
The vials containing the field dust samples for SVOC analysis were stored in a freezer at approximately
-20 °C until removed for extraction. The samples were allowed to warm to room temperature before
weighing 100 mg of dust into a 50-mL polypropylene centrifuge tube. Internal standard solution (100
|iL) was added to each tube, along with a ceramic homogenizer. A 10-mL volume of 1:1 acetone:hexane
was then added to each sample tube. The tubes were capped and vortex-mixed for 1 min, allowed to sit
for 2 min, then vortex-mixed for one additional minute. The tubes were then centrifuged at 4,000 RPM
for 5 min. The solvent layer was removed and transferred to a 15-mL vial. A 1-mL aliquot of the extract
was transferred to an autosampler vial for GC/MS/MS analysis. The extracts were then transferred into
autosampler vials, through 0.2-|im PTFE syringe filters, in preparation for GC/MS/MS analysis.
3.4.4.6 GC/MS/MS Analysis for SVOCs
Field air and surface sample extracts were analyzed using an Agilent Model 7890 gas chromatograph
equipped with a VF-5ms column (30 m x 0.25 mm, 0.25 |im) and a Model 7010 triple quadrupole mass
spectrometer (Agilent Technologies, Santa Clara, CA, USA). The GC/MS/MS parameters previously
shown in Table 3-8 in the Tire Crumb Characterization Report (U.S. EPA & CDC/ATSDR, 2019) were
used for data acquisition. The instrument was standardized using High Sensitivity Electron Impact (EI)
Autotune and was calibrated for target analytes in the range of 0.1 ng/mL to 500 ng/mL. Calibration
checks were run using a mid-level standard between every 10 samples. Quantitation was performed
using linear regression curves generated from the responses and nominal concentrations of calibration
standard solutions. Data were processed using Agilent MassHunter Workstation Quantitative Analysis
for QQQ (Version B.07.01, Agilent Technologies, Santa Clara, CA, USA) and were exported to
Microsoft® Excel (Office 365, Microsoft Corporation, Redmond, WA, USA) for further data reduction.
3.4.5 Urine, Blood, and Serum Sample Analysis - Pilot-Scale Blomonltorlng Study
For blood and serum samples collected as part of the pilot-scale biomonitoring study, venipunctures
were performed on-site at a designated area, and blood samples collected by a trained phlebotomist from
participants. Sample collection protocols indicate a blood draw of 6 mL for serum metals and 5 mL for
blood metals (total of 11 mL); the maximum blood draw per participants did not exceed 25 mL. Serum
samples were collected via centrifugation. Per NCEH Division of Laboratory Sciences' sample
collection protocols, blood samples were shipped on freezer packs, and serum samples were shipped on
dry ice. Blood and serum samples were analyzed for metals via inductively coupled plasma dynamic
reaction cell mass spectrometry (ICP-DRC-MS) (Appendix F).
For urine specimens, participants were provided with a sealed sterile urine collection cup to collect the
urine samples on-site in facility restrooms. Samples were shipped on dry ice to the NCEH Division of
Laboratory Sciences. Urine samples were analyzed for polyaromatic hydrocarbon (PAH) metabolites
and creatinine; PAH metabolites were quantified using online solid phase extraction high performance
liquid chromatography/tandem mass spectrometry (SPE-HPLC-MS/MS) (Wang et al., 2017). All
urinary PAH metabolites were adjusted for creatinine to account for urinary dilution.
3.5 Video Activity Assessments for Synthetic Field Users
In early 2017, a novel videography collection method using online sources was developed to quantify
the frequency of select micro-activities (i.e., hand-to-mouth, object-to-mouth, hand-to-turf, and body-to-
turf contact) of 60 athletes playing soccer, field hockey, or football on (natural or synthetic turf) fields,
as seen on publicly-available videos downloaded from the internet. The adapted video translation part of
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this method was then slightly modified and used to quantify the frequencies of these four micro-
activities for 17 exposure characterization study participant video recordings collected while practicing
soccer or football on synthetic turf fields in late 2017 (Freeman et al., 2001; Ferguson et al., 2006;
Kwong et al, 2016). In addition, an adapted videography method was developed to quantify the intensity
and duration of the activity levels (resting, low activity, or high activity) of the 17 study participants on
these same videos.
3.5.1 Online Video Assessment (Phase 1)
This videography (Phase 1) work using online sources was classified as non-human subjects research as
defined in the Federal Policy for Protection of Human Research Subjects (the Common Rule) [HHS 45
CFR § 46, Subpart A and EPA 45 CFR § 26, Subpart A], The research also falls under the fair use of
copyrighted materials, as stated in section 107 of the U.S. Copyright Act [Copyright Act of 1976 §
101, 17 U.S.C. § 107 (2012)]. All research activities were conducted in a secure room at the EPA
campus in Research Triangle Park, NC.
3.5.1.1 Videos of Selected Athletes from the Internet
Accessing the video-sharing website in the fall of 2016, YouTube (www.voutube.com). three EPA
technicians randomly found videos of children and adults playing soccer, field hockey, and football on
natural or synthetic turf fields (indoor/outdoor).To be used in the assessment, videos were required to be
of high enough quality and resolution to allow a researcher to be able to clearly observe the hand-to-
mouth, object-to-mouth, hand-to-turf, and body-to-turf events of selected athletes for a minimum of 15
minutes for soccer/field hockey or 10 minutes for football. Due to the nature of each type of sport,
athletes spent varying amounts of time on the turf fields. For example, football teams tended to have
more players; therefore, individual players typically had less time of play. These 10-minute and 15-
minute time periods were chosen based on the total amount of time that individual athletes were
observed playing these three different sports on the videos. Videos were downloaded as MP4 files via a
laptop computer onto an encrypted, 256 MB SanDisk Ultra® thumb drive (Western Digital
Technologies, Inc., Milpitas, CA, USA). A total of 34 videos (soccer = 12, field hockey = 12, and
football =10) were collected. As these were team sports, up to three different athletes were chosen for
assessment per video. Table 3-3 presents the number of children and adults selected by sport from the 34
videos. A technician took a screen shot of each of the 60 selected athletes on video and recorded specific
personal characteristics (i.e., child or adult, sex, type/color of clothing, jersey number, and field position
[e.g., quarterback, goalie]).
Table 3-3. Number of Subjects Selected for Assessment by Sport from Publicly-available Videos3
Sport
Children
Adults
Total
Soccer
10
10
20
Field Hockey
10
10
20
Football
10
10
20
Total
30
30
60
a A total of 34 YouTube videos were assessed (12 soccer videos, 12 field hockey videos, and 10 football videos)
3.5.1.2 Training Technicians for Video Translation
After previewing the 34 YouTube videos, the study investigator noticed that athletes playing football
generally had much higher occurring frequencies of the targeted micro-activity events than soccer or
field hockey athletes. Therefore, it was decided that video translation would be conducted by designated
48
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sport (soccer/field hockey or football). The study investigator held two different training sessions
(session A for soccer/field hockey and session B for football) to train the three EPA technicians to
translate the hand-to-mouth, object-to-mouth, hand-to-turf, and body-to-turf contact of athletes playing
soccer, field hockey or football. A fourth technician was trained later to assist in football video
translations.
Training Session A - The study investigator made two training videos that included 15 minutes of play
of two different athletes participating in soccer or field hockey from the actual study videos. The two
training videos were developed at two levels of difficulty (easy and difficult), based on the number of
targeted micro-activity events of the selected athletes observed on video; the easy level had a total of 8
micro-activity events, and the difficult level had a total of 38 micro-activity events. The study
investigator and three technicians previewed each training video as a group to agree on the type and
number of targeted micro-activity events that occurred by each selected athlete. Each training video was
translated twice by each technician. To pass the training videos, individual technicians were required to
have a total percent error rate of less than 5% for the easy level and 10% for the difficult level. After
translating the training videos, the EPA technicians had a total percent error rate of 0% for the easy level
and less than 9% for the difficult level.
Training Session B - The study investigator made one 10-minute training video, from the actual study
videos, of an athlete playing football. This training video had a total of 69 different micro-activity events
occurring over the 10 minutes of play and was deemed "difficult" based on the high number of observed
targeted micro-activity events made by the football player. The study investigator and four technicians
reviewed this training video together several times to agree on the type and number of targeted micro-
activities made by this athlete.
3.5.1.3 Translation of Targeted Micro-activities of Athletes in Publicly-available Videos
The selected micro-activities of individual athletes were translated from the 34 YouTube videos by
trained EPA technicians. The technicians completed training session A over a two-day period and then
translated the targeted micro-activities of the 20 soccer players and 20 field hockey players in the videos
for 15 minutes per selected player (Table 3-3). Approximately six weeks later, these same technicians
completed training session B over one day and then translated the targeted micro-activities of the 20
selected football players in the videos for 10 minutes per player. Hand-to-mouth events were contacts
made by either an ungloved or gloved hand to the lips or inside the mouth. Object-to-mouth events were
contacts made by an object (i.e., shirt, mouthguard, or water bottle) to the lips or inside the mouth.
Hand-to-turf events were contacts made by either an ungloved or gloved hand to the field. Body-to-turf
events were contacts made by any part of the body (excluding hands and feet) to the field.
The EPA technicians viewed the MP4 files of the study videos using Windows Media Player (Version
12.0, Microsoft® Corporation, Redmond, WA, USA) on a 28-inch computer monitor (ViewSonic®
Corporation, Walnut, CA, USA). The procedures used to translate the targeted micro-activities of the
athletes were specific to the designated sport (soccer/field hockey videos or football videos).
Soccer and Field Hockey Videos - An EPA technician previewed each selected soccer or field hockey
player on video for a total of 15 minutes. During the second viewing of the video, the technician
manually tallied the athlete's observed frequency of hand-to-mouth, object-to-mouth, hand-to-turf, and
body-to-turf contacts on a paper template (Figure 3-13). The athlete's use of specific sporting items,
such as mouthguards and gloves, was also recorded on this paper template. In addition, the technician
re-wound sections of the video, as needed, to more accurately quantify the athlete's micro-activity
contacts. In cases where an athlete was observed having less than 9 total micro-activity events over the
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15 minutes, the video was translated again by the same technician.
Hand-to-mouth
Object-to-mouth
Hand-to-turf
Body-to-turf
Figure 3-13. Paper template for tallying the selected micro-activity events of an athlete.
Football Videos - A group of three or four EPA technicians concurrently viewed each selected football
player on video for a total of 10 minutes. One of the technicians manually tallied, on notebook paper,
each hand-to-mouth, object-to-mouth, hand-to-turf, and body-to-turf contact by the athlete. Sections of
each video were re-wound, as needed, to more accurately quantify the athlete's micro-activity events.
All technicians had to agree that a targeted micro-activity event occurred by the athlete before the event
was recorded. Then, a second technician transcribed the athlete's individual micro-activity events from
the notebook paper to a paper template (Figure 3-13). The athlete's use of specific sporting items, such
as mouthguards and gloves, was also recorded on this paper template.
3.5.1.4 Quality Control Measures
In addition to training the technicians responsible for translating the videos, several additional quality
control measures were taken during video translation.
Soccer and Field Hockey Videos - In cases where a selected soccer or field hockey athlete was observed
having less than 9 total micro-activity events over the 15-minute translation period, the video was
translated again by the same technician. This is because the potential error rate for a technician is much
higher when an athlete has a lower number of micro-activity events compared to a higher number of
events. For example, if a technician records 2 out of 3 actual micro-activity events, the error rate would
be 33%, but if a technician only records 10 out of 11 micro-activity events, the error rate would be 9%.
Football Videos - To ensure high quality data was obtained from the football videos, the micro-activities
of each selected football player were concurrently translated by a minimum of three EPA technicians.
This was done because of the significantly higher frequency of targeted micro-activity events in football.
3.5.1.5 Statistical Analysis
For individual videos that were translated twice (i.e., videos with < 9 micro-activity events by an
athlete), the data were averaged by each type of micro-activity event per person. The frequency of
micro-activity contacts by category (events/hour) were normalized to one hour for each athlete. This
approach assumed that the targeted micro-activity rates of an athlete occurred for the entire one-hour
period. Descriptive statistics (e.g., arithmetic mean and standard deviation, percentiles [25th, 50th, 75th,
and 95th], and range) were presented as frequency of hand-to-mouth, object-to-mouth, hand-to-turf, and
body-to-turf events/hour for children and adult athletes by sport. Welch's /-tests and one-way ANOVAs
were used to analyze differences between frequencies of micro-activity events by field type, gender, age,
equipment and sport type. All statistical analyses were performed using RStudio (RStudio, Inc., Boston,
MA, USA) with R (Version 3.1.2, R Core Team 2014).
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3.5.2 Exposure Pilot Study Participant Video Assessment (Phase 2)
EPA contractor technicians videotaped a select number of exposure study participants, for up to two
hours each, while practicing soccer or football on synthetic turf fields at facilities in the fall of 2017. A
total of 17 athletes (14 children and 3 adults) were videotaped during the study.
3.5.2.1 Videography of Study Participants
An HXR-NX100 Full HD NXCAM camcorder (Sony Corporation, Minato, Tokyo, Japan) attached to a
Manfrotto™ XPRO monopod (Lino Manfrotto + Co. Spa, Cassola, Italy) was used to record a selected
participant athlete's activities while playing on the synthetic turf field simultaneously on two different
Sony 32GB High Speed UHS-I SDHC U3 Memory Cards (Sony Corporation, Minato, Tokyo, Japan).
Only one participant athlete was videotaped by the technician at a time. To be used in assessment,
videos were required to be of high quality and resolution to allow a researcher to be able to clearly
observe the hand-to-mouth, object-to-mouth, hand-to-turf, and body-to-turf contacts, as well as the
intensity and duration of activity levels (i.e., resting, low activity, and high activity), of the athletes
playing on the synthetic turf fields for a minimum of 30 minutes. Table 3-4 presents the number of
children and adult study participants recorded by sport. Ancillary information about each athlete (i.e.,
sex, child or adult, sport, and type of field [indoor or outdoor]) was also recorded.
Table 3-4. Number of Exposure Study Participant Athletes Videotaped by Sport
Sport
Children
Adults
Total
Soccer
9
3
12
Football
5
0
5
Total
14
3
17
3.5.2.2 Training Technicians for Video Translation
In October 2017, the EPA study investigator held two different training sessions (session A for micro-
activity events and session B for activity level intensity and duration) to train two EPA contractor
technicians to quantitatively translate the frequencies of the targeted micro-activity events and the
intensity and duration (in seconds) of the selected activity levels of individual athletes on video.
Training Session A - The study investigator used a study video of a child football player to train to the
two technicians to accurately translate the athlete's micro-activity contacts on a paper template (Figure
3-13). This 1-hour video was chosen based on the total number of micro-activity events (> 50) for the
athlete observed on video. As a group, the study investigator and the two technicians concurrently
viewed the video to agree on the actual type and number of micro-activity contacts that occurred by this
athlete. Then, the two technicians separately translated this 1-hour video twice. The acceptable intra-
person and inter-person error rate was < 10% and < 15%, respectively. Results for the same technician
translating the video twice yielded a total percent error rate of 0% for technician 1 and 2% for technician
2. The total percent error rate between the two technicians was less than 3%.
Training Session B - The study investigator used a study video of an adult soccer player to train the
same two technicians to accurately translate the intensity and duration of the selected participant's
activity levels. This 1-hour video was chosen based on the intensity and duration of activity levels of the
participant observed on video. The study investigator and the two technicians reviewed the video
together to agree on the actual intensity and duration of the activity levels of the athlete. Then, each
technician translated this 1-hour video twice. The acceptable intra-person and inter-person error rate was
< 5% and < 10%, respectively. Results for the same technician translating the video twice, yielded a
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total percent error rate of <1% for technician 1 and 1% for technician 2. The total percent error rate
between the two technicians for this video was less than 2%.
3.5.2.3 Translation of Targeted Micro-activities of Study Participant Athletes
Fourteen of the study participants had their activities recorded for at least 1 hour on video, while
practicing soccer or football on the synthetic turf fields. The remaining three participants (child soccer
players) were videotaped practicing on the synthetic turf fields for less than 1 hour (i.e., 37-48 minutes).
The selected micro-activities of individual athletes were translated from the videos by trained EPA
contractor technicians. The technicians completed training session A over one day and then translated
the targeted micro-activity events of the 17 participants on video for up to one continuous hour.
Approximately two weeks later, the same two technicians completed training session B over one day
and then translated the intensity and duration of the targeted activity levels of the 17 participants on
video for up to one continuous hour.
3.5.2.4 Quantification of the Frequency of Micro-activity Events for Study Participants
In October 2017, a trained EPA contractor technician translated the targeted micro-activity events of the
individual study participants on video for one continuous hour, except for the three child soccer players
who practiced less than one hour. For these three children, the technician translated the total time they
were recorded on video (i.e., 37, 45, and 48 minutes). Each video was viewed on the SD card using
Windows Media Player (Version 12.0, Microsoft® Corporation, Redmond, WA, USA) on a 27-inch
VX2757-MHD computer monitor (ViewSonic® Corporation, Walnut, CA, USA). The technician first
previewed the athlete for the entire length of the video. During the second viewing of the video, the
technician manually tallied the participant's observed frequencies of hand-to-mouth, object-to-mouth,
hand-to-turf, and body-to-turf contact on a paper template (Figure 3-13). Sections of the video were re-
wound, as necessary, to more accurately quantify the athlete's micro-activity events. The athlete's use of
specific sporting items, such as mouthguards and gloves, was also recorded on this paper template.
3.5.2.5 Quantification of the Intensity and Duration of Activity Levels of Study Participants
The CDC (1999) method was modified to classify the selected intensity levels (resting, low activity, or
high activity) of the 17 study participant athletes observed on the videos. For this study, resting was
when a person was observed standing, sitting, or kneeling. Low activity was when a person was
observed walking, stretching, or when stationary (e.g., catching, throwing, or kicking a ball). High
activity was when a person was observed jogging, running, tackling, or had a similar level of intensity
(e.g., jumping jacks, pushups, and grapevines).
From late October to early December 2017, a trained EPA contractor technician translated the intensity
and duration of the selected activity levels of individual study participants on video for one continuous
hour, except for the three child soccer players, which were translated for the total time they were
recorded (i.e., 37, 45, and 48 minutes). Each video was viewed on the SD card using Windows Media
Player (Version 12.0, Microsoft® Corporation, Redmond, WA, USA) on a 27-inch VX2757-MHD
computer monitor (ViewSonic®, Corporation, Walnut, CA, USA). The technician first previewed the
participant for the entire length of the video. During the second viewing of the video, the technician
manually tallied the intensity and duration (in seconds) of the athlete's observed activity levels on a
paper template (Figure 3-14). The technician re-wound sections of the video, as needed.
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Resting
Low Activity
High Activity
Figure 3-14. Paper template for tallying the intensity and duration
of selected activity levels of an athlete.
3.5.2.6 Quality Control Measures
In addition to training the technicians responsible for translating the videos, several additional quality
control measures were taken during video translation.
To maintain high intra- and inter-person accuracy of coding the targeted micro-activity events on the
videos over time, the two trained technicians translated two additional participants' videos — after
completing 50% and 95% of the total videos (n = 17). A 1-hour video of a youth football player was
translated at 50% completion and a 37-minute video of a child soccer player was translated at 95%
completion; both videos had greater than 40 observed micro-activity events. The translation conducted
at 50% completion, yielded a total percent error rate of 7% for technician 1 and 9% for technician 2;
however, the total percent error rate between the two technicians was slightly above the maximum
allowable error rate (i.e., 15%). Therefore, each technician translated this video a third time, and the
total percent error decreased to less than 10% between these two technicians. The translation conducted
at 95% completion, yielded a total percent error rate of 0% for technician 1 and 4% for technician 2. The
total percent error rate between the two technicians was also less than 5% for this video.
To maintain high intra- and inter-person accuracy of coding the intensity and duration of activity levels
for athletes on the videos, the two technicians translated two additional participants' videos — after
completing 50% and 95% of the total videos (n = 17). These videos (1 hour each) consisted of two
different child soccer players. The translation conducted at 50% completion, yielded a total percent error
rate of < 2% for each technician translating the same video twice; the total percent error rate between the
two technicians was less than 7%. The translation conducted at 95% completion, yielded a total percent
error rate of 2% for technician 1 and 1% for technician 2 after translating the same video twice; the total
percent error rate between the two technicians was less than 5%.
3.5.2.7 Statistical Analysis
For the three child athletes (videotaped < 1 hour), their frequency of micro-activity contacts by category
(events/hour) and the intensity and duration of activity levels (seconds/hour) were normalized to 1 hour.
This approach assumed that the selected activity contacts/durations levels of an athlete occurred for an
entire 1-hour period. Descriptive statistics (e.g., arithmetic mean and standard deviation, percentiles
[25th, 50th, 75th, and 95th], and range) were presented as frequency of hand-to-mouth, object-to-mouth,
hand-to-turf, and body-to-turf contacts (events/hour) for the children and adult athletes by sport.
Descriptive statistics were also provided as duration of resting, low activity, or high activity levels
(seconds/hour) for the children and adult athletes by sport. Welch's /-tests and one-way ANOVAs were
used to analyze differences between the frequencies of micro-activity events and duration of activity
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levels by field type, gender, age group, equipment, and sport type. All statistical analyses were
performed using RStudio (RStudio, Inc., Boston, MA, USA) with R (Version 3.1.2, R Core Team 2014).
3.6 Data Processing and Analysis
3.6.1 Data Processing
Chemical analysis data and field sampling data sets produced by the researchers were subjected to a
secondary review by an independent expert. Following secondary review, the field sampling, VOC,
SVOC, metals, and air particulate data sets were submitted to the project's data manager. The data
manager uploaded data sets using SAS/STAT® 13.1 (SAS Institute Inc., Cary, NC, USA) and
performed a series of organizational, review, cleaning, and output steps. Following initial intake and
organization, the data manager provided data reports to the analyst and project manager to review for
potential data issues or labeling problems and to determine whether any additional cleaning or
organization was required. Following resolution, final draft data files were created for further data
processing operations. The analysts and data manager then consulted with the project manager to
interpret the quality control results (shown in Appendix B), make decisions on required adjustments, if
any, and calculation requirements to bring measurement data into the correct final result.
Field blank corrections were performed for all exposure pilot study measurement data. The amount of
chemical measured on a field blank deployed to a specific field was subtracted from the measurement
results for all samples of that type collected from that specific field. Two field blanks were deployed for
most media at the first field, the field blank results were averaged prior to subtraction from the sample
results. The chemical recoveries in the spiked field controls were examined, but no recovery corrections
were performed to any exposure pilot measurement data. In some cases, decisions were made not to
report results for specific chemicals due to poor recoveries from spiked field control samples.
3.6.2 Data Analysis
Air sampling field data were combined with chemical and particulate analysis data to calculate sample
volumes and concentrations of each analyte in air. Field wipe and drag sled data were combined with
field sampling data to allow calculation of surface loadings based on amount of chemical measured per
square centimeter of the field surface. Dust concentrations were calculated by dividing the amount of
chemical measured by the amount of dust that was digested or extracted. Dermal wipe measurement data
were combined with field sample collection data to first organize the results by age and sport, and then
to calculate the amount of chemical measured per square centimeter of skin that was wiped. For hand
wipe samples, the entire hand was wiped, so the surface area used was based on the age-specific value
for hand surface area from the EPA Exposure Factors Handbook (U.S. EPA, 201 lb).
Field metadata were processed separately by transferring information from field data collection forms to
spreadsheet tables, where they were organized among and within groups and categories.
Chemical concentration measurement values and their mean or median statistics and ranges were
presented in tables generated using SAS/STAT® 13.1 (SAS Institute Inc., Cary, NC, USA) with data
reported at two significant figures. Due to small sample sizes, no within- or between-group statistical
analyses were performed for exposure pilot study personal and field sample measurement results.
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4.0 Exposure Characterization Results
The exposure characterization study was a pilot-scale effort aimed at collecting information and data to
characterize how users of synthetic turf fields with tire crumb rubber infill might be exposed to the
chemical constituents present in tire crumb rubber. We enrolled youth and adults taking part in athletic
activities on synthetic turf fields in several locations to participate in questionnaire, exposure
measurement and videographic study elements. In addition, we used publicly available video to further
assess exposure-related activities for people engaged in athletic activities at sports fields. The exposure
characterization activity and measurement results are reported in this section, and the results of further
exposure modeling for a subset of chemicals of interest - lead (Pb), methyl isobutyl ketone (MIBK),
benzothiazole, pyrene, benzo(a)pyrene and zinc - are reported in section 5.
4.1 Exposure Pilot Study Recruitment
Due to scheduling and availability issues, the number of fields and participants available for recruitment
during the field study implementation window was reduced. The target sample size of six fields and 60
participants was not reached during the study period. Overall, the research team recruited 32 participants
at three field locations in the study. Final participant numbers for the different study components are
presented in Table 4-1.
Table 4-1. Exposure Pilot Study Participant Recruitment and Participation Types
Study Participant Activity Types
Outdoor
Field 1
Outdoor
Field 2
Indoor
Field
Total
Exposure characterization study - total
15
15
2
32
Exposure characterization - questionnaire only
4
3
0
7
Exposure measurement - personal air
monitoring and dermal wipe sampling
11
12
2
25
Exposure measurement - blood biomonitoring
10
3
0
13
Exposure measurement - urine biomonitoring
10
4
0
14
Videography
8
8
1
17
4.2 Exposure Pilot Study Field User Questionnaires
4.2.1 Demographics
A total of 32 questionnaires were administered in the field for participants ranging in age from 7 to 51.
For variables with large enough sample sizes, we categorized participants into three age groups for
comparison. The youngest age group (i.e., children between 7 and 10 years of age) and the oldest age
group (i.e., adults 18 years and older), each comprised 22% of the recruited questionnaire participants
(Table 4-2). The largest age group (i.e., 56% of questionnaire participants) included participants that
ranged in age from 11 to 17 years of age. Slightly more than half of the participants were male (i.e.,
53%; Table 4-2). The questionnaire results presented in Tables 4-3 through 4-15 reflect the answers of
all 32 participants; results are presented by age group in the text, where possible.
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Table 4-2. Age and Gender of Questionnaire Participants
Study Participant
Number of (%)
Questionnaire
Participants
Age 7 to 10
Number of (%)
Questionnaire
Participants
Age 11 to 17
Number of (%)
Questionnaire
Participants
Age 18 and older
Number of (%)
Female
Questionnaire
Participants
Number of (%)
Male
Questionnaire
Participants
Questionnaire participant
7 (22%)
18 (56%)
7 (22%)
15 (47%)
17 (53%)
4.2.2 Field Contact Frequency and Duration Questions
Most questionnaire participants reported playing at the facility between 3 and 4 years (31%), followed
by 1 to 2 years (28%; Table 4-3). More than half (57%) of children younger than 11 years of age were
more likely to report using the facility for 1 to 2 years, while 50% of participants ages 11 to 17 reported
using the facility for 3 to 4 years. Approximately 43% of adult questionnaire participants reported using
the facility for less than a year.
For all age groups combined, summer and fall had the highest reported frequency of use (i.e., two or
more days per week; Table 4-4). Younger children tended to minimally use the field year-round,
typically 1 day or less per week. Children ages 11 to 17 years had more diverse uses throughout the
season, with the highest seasonal use reported in the summer (i.e., 4 to 5 days per week) and less
frequent use in the winter (i.e., 0 to 1 day per week). Adults also reported less turf field use in the spring
and winter and higher use in summer and fall (i.e., 4 to 5 days per week).
Table 4-3. How Long Questionnaire Participants Have Been Coming to
the Facility for All Combined Age Groups
Years Coming to Facility
Number of (%) Questionnaire Participants
< 1
6 (19%)
1-2
9 (28%)
3-1
10(31%)
5+
7 (22%)
Table 4-4. Number of Days per Week Questionnaire Participants Typically Spent on the
Synthetic Turf Fields at this Facility, by Season
Days per Week
Number of (%)
Questionnaire
Participants -
Spring
Number of (%)
Questionnaire
Participants -
Summer
Number of (%)
Questionnaire
Participants -
Fall
Number of (%)
Questionnaire
Participants -
Winter
0-1
18 (56%)
11 (34%)
7 (22%)
24 (75%)
2+
14 (44%)
21 (66%)
25 (78%)
8 (25%)
For all questionnaire participants, a majority spent an hour and a half or less per day on synthetic turf
fields in the spring, summer, and winter, though 44% of participants in the summer spent two or more
hours (Table 4-5). Most participants (59%) reported using synthetic turf fields for two or more hours per
day in the fall. Participants under 18 did not report more than 2 hours per day year-round, while some
adults reported three or more hours on synthetic turf fields per day. The majority of all participants
(56%) reported the longest period of time spent on synthetic turf fields in a single day was between 0 to
2 hours (Table 4-6). Adult participants commonly reported a maximum time of 3 to 5 hours per day
(71%), while 0 to 2 hours per day was commonly reported for age groups 7 to 10 years of age (86%) and
11 to 17 years of age (67%).
57
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Table 4-5. Number of Hours per Day Questionnaire Participants Typically Spent on the
Synthetic Turf Fields at this Facility, by Season
Hours per Day3
Number of (%)
Questionnaire
Participants in
Spring
Number of (%)
Questionnaire
Participants in
Summer
Number of (%)
Questionnaire
Participants in
Fall
Number of (%)
Questionnaire
Participants in
Winter
0-1.5
27 (84%)
18 (56%)
13 (41%)
27 (84%)
2+
5 (16%)
14 (44%)
19 (59%)
5 (16%)
a Data is presented in these categories due to the distribution of the data and small cell sizes
Table 4-6. Longest Period of Time Questionnaire Participants
Spent on Synthetic Turf Fields in a Single Day
Hours per Day
Number of (%) Questionnaire Participants
0-2
18 (56%)
3+
14 (44%)
Table 4-7 shows how often all questionnaire participants played on synthetic turf fields, grass fields, or
playgrounds with rubber or synthetic turf in the past year and the past five years. A majority of
participants have played on synthetic turf fields at least once a week in the past year (63%) and past five
years (56%). Additionally, a majority have played on grass fields at least once a week in either the past
year (59%) or past five years (56%). Though not shown due to small cell sizes, playing on playgrounds
with rubber or turf in the past year or five years was less common. Few participants reported playing on
these playgrounds 1 to 3 times a month in the past year (25%) and in the past 5 years (28%).
Concerning age groups, children less than 11 years generally reported playing at least once a week on
synthetic turf fields in the past year or 5 years (57%). Additionally, these participants more often
reported playing on natural grass fields at least once a week in the past year (86%) or 5 years (100%),
frequently reported as 2 to 3 times a week. For the second age group (11 to less than 18 years), a
majority reported playing on synthetic turf fields at least once a week in the past year (56%) as well as
past 5 years (50%). However, this age group less frequently reported playing on grass fields once a week
in the past year or 5 years (44%). Adults commonly reported playing on synthetic turf fields at least
once a week in the past year (86%) and past 5 years (71%), most commonly 2 to 3 times a week (57%)
in the past year and 4 or more times a week (57%) in past 5 years. Adults also reported using natural
grass fields in the past year (57%) and past 5 years (43%).
Table 4-7. How Often Questionnaire Participants Played on Synthetic Turf Fields and Grass Fields in the
Past Year and Past Five Years
Field Use
Number of (%) Questionnaire
Participants Who Used Field
1 to 3 Times per Month
Number of (%) Questionnaire
Participants Who Used Field
At Least Once a Week
Any synthetic turf field in past year
11 (34%)
20 (63%)
Any synthetic turf field in past 5 years
11 (34%)
18 (56%)
Any natural grass in past year
7 (22%)
19 (59%)
Any natural grass in past 5 years
9 (28%)
18 (56%)
58
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4.2.3 Contact Types and Scenarios per Field Use
For all questionnaire participants, diving, falling, sitting, and drinking on synthetic turf fields was more
commonly reported in summer than spring; eating on turf fields was not commonly reported for any
season (Table 4-8). Over 50% of children ages 7 to less than 11 reported falling and/or sitting on
synthetic turf often/sometimes in the spring, summer, and fall. All age groups reported drinking on the
field often/sometimes for all seasons except winter, mostly due to the lack of activities during
wintertime. Participants 11 years and older most commonly reported diving onto turf often/sometimes in
the summer and fall.
Table 4-8. Types and Frequency of Questionnaire Participant Contact with Synthetic Turf Fields in Spring and
Summer a
Contact Type/
Scenario
Spring Contact
Frequency- Number
of (%) Questionnaire
Participants Who
Made Contact
Rarely/Never or
No Response
Spring Contact
Frequency- Number
of (%) Questionnaire
Participants Who
Made Contact
Often/Sometimes
Summer Contact
Frequency - Number
of (%) Questionnaire
Participants Who
Made Contact
Rarely/Never or
No Response
Summer Contact
Frequency - Number
of (%) Questionnaire
Participants Who
Made Contact
Often/Sometimes
Dive
21 (66%)
11 (34%)
13 (41%)
19 (59%)
Fall
17 (53%)
15 (47%)
9 (28%)
23 (72%)
Sit
17 (53%)
15 (47%)
12 (38%)
20 (63%)
Eat
27 (84%)
5 (16%)
25 (78%)
7 (22%)
Drink
16 (50%)
16 (50%)
9 (28%)
23 (72%)
a Possible questionnaire responses included Often (>50% of the time). Sometimes (<50% of the time), and Rarely/Never. Due
to small cell sizes. Often and Sometimes responses are reported together.
4.2.4 Activity Intensity
For all questionnaire participants, 28% reported high/moderate activity less than 25% of the time when
using synthetic turf fields (Table 4-9). Additionally, more participants (38%) reported high/moderate
activity between 25% and less than half of the time, while 20% of participants reported higher intensity
between 50% and less than 75% and only 14% reported 75% or greater. A large majority of participants
(81%) categorized low activity or resting for less than 25% of time when using synthetic turf fields
while 19% of participants categorized this as between 25% and less than 50% of the time. There were
not any visible patterns of differences between age groups and activity intensity. Resting and low
activity was commonly reported as 0 to less than 25% of time for all age groups. All age groups most
frequently categorized high activity as between 50 to less than 90% of time when using synthetic turf
fields and moderate activity between 10 to less than 50%.
Table 4-9. Intensity of Activity Engaged in by Questionnaire Participants When Using Synthetic Turf Fields
Percentage of
Time (%)
Number of (%) Questionnaire Participants
Engaged in High/Moderate Activity
Number of (%) Questionnaire Participants
Engaged in Low Activity/Resting
0 - <25
18 (28%)
52 (81%)
25 - <50
24 (38%)
12 (19%)
50 - <75
13 (20%)
0
75+
9 (14%)
0
59
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4.2.5 Dermal and Non-dietary Ingestion Exposure
Commonly reported activities occurring on synthetic turf fields every time or often included drinking
(81%), hands touching the turf (78%), and body parts (other than hands) touching the turf (75%; Table
4-10). Activities like chewing gum, eating, and using hand wipes did not have large enough cell sizes to
present (i.e., they were not commonly reported). Getting cuts or abrasions from contact with the turf and
touching one's mouth while on the field were also not commonly reported to occur every time/often
(19% and 28%, respectively). Adults were more likely to report playing in the rain often (71%), and
children ages 7 to less than 11 were more likely to report sitting with bare skin on the field every time
(57%) (data not shown).
Shorts and short sleeve shirts were most commonly worn in the spring, summer, and fall for all
questionnaire participants (Table 4-11). Gloves were not commonly worn, but had the highest frequency
of use in the fall (41%). Pads were most commonly worn in summer (53%) and fall (75%). Long sleeve
shirts and long pants did not have large enough cell sizes to be presented, but were most commonly
reported as worn in fall and winter. Little variation was present among age groups.
Table 4-10. Frequency of Different Activities Performed by Questionnaire Participants on
Synthetic Turf Fields
Activity
Number of (%)
Questionnaire
Participants Engaged in
Activity Every
Time/Often
Number of (%) Questionnaire
Participants Engaged in
Activity Sometimes/Never
Drink
26 (81%)
6 (19%)
Play in rain
14 (44%)
18 (56%)
Hand touches turf
25 (78%)
7 (22%)
Body part (other than hand) touches
turf
24 (75%)
8 (25%)
Sit with bare skin
16 (50%)
16 (50%)
Play with turf material/ rubber
granules
6 (19%)
26 (81%)
Touch mouth with hands or fingers
9 (28%)
23 (72%)
Put non-food objects in mouth
18 (56%)
14 (44%)
Cuts/abrasions from contact with turf
6 (19%)
26 (81%)
Table 4-11. Clothing Worn by Questionnaire Participants, by Season
Clothing
Number of (%)
Questionnaire
Participants Who
Wore Clothing in
Spring
Number of (%)
Questionnaire
Participants Who
Wore Clothing in
Summer
Number of (%)
Questionnaire
Participants Who
Wore Clothing in
Fall
Number of (%)
Questionnaire
Participants Who
Wore Clothing in
Winter
Shorts
16 (50%)
26 (81%)
30 (94%)
6 (19%)
Short Sleeve Shirts
16 (50%)
26 (81%)
30 (94%)
7 (22%)
Gloves
6 (19%)
10(31%)
13 (41%)
9 (28%)
Socks
17 (53%)
26 (81%)
32 (100%)
12 (38%)
Helmet
0
6 (19%)
8 (25%)
0
Pads
12 (38%)
17 (53%)
24 (75%)
8 (25%)
60
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4.2.6 Tire Crumb, Dirt and Debris in Other Areas
For all participants, a majority noticed tire crumb rubber, dirt or debris every time or often on their body
(66%), in their car (75%), or at home (59%) after using a synthetic turf facility (Table 4-12). Adults
frequently reported finding tire crumb rubber, dirt or debris on their body often (57% often), as did
youth age 11 to less than 18 years (44% every time; 28% often); however, this was not common for the
youngest participants (29% every time; 14% often; data not shown).
Table 4-12. Frequency of Questionnaire Participants Noticing Tire Crumb Rubber, Dirt or Debris
After Using Facility
Location Tire Crumb, Dirt
and Debris Found
Number of (%) Questionnaire
Participants Who Noticed Every
Time/Often
Number of (%) Questionnaire
Participants Who Noticed
Sometimes or Rarely/Never
Body
21 (66%)
11 (34%)
Car
24 (75%)
8 (25%)
Home
19 (59%)
13 (41%)
Laundry room/mudroom
15 (47%)
17 (53%)
Living room
13 (41%)
19 (59%)
Bedroom
12 (38%)
20 (63%)
Bathroom
12 (38%)
20 (63%)
4.2.7 Hygiene Practices Post-Field Use
Concerning post-field hygiene, 47% of participants reported showering or changing clothes immediately
after facility use, while 53% reported sometimes or rarely/never showering immediately after field use
(Table 4-13). Approximately half of participants (53%) reported removing shoes or equipment every
time or often before entering their homes. A majority of participants age 7 to less than 11 years (71%)
reported rarely or never showering or changing clothes immediately after using the synthetic turf
facility. In contrast, 57% of adult participants reported showering or changing clothes immediately after
facility use every time. Younger children also infrequently reported removing shoes or equipment before
entering a home, while adults and older children (11 to less than 18 years of age) more frequently
reported (every time or often) performing these tasks.
Table 4-13. Frequency of Hygiene Practices by Questionnaire Partici
)ants, Post-field Use
Hygiene Practice
Number of (%) Questionnaire
Participants Engaged in Practice
Every time/Often
Number of (%) Questionnaire
Participants Engaged in Practice
Sometimes or Rarely/Never
Shower/change clothes immediately
15 (47%)
17 (53%)
Shoes/equipment wiped or removed
before entering home
17 (53%)
15 (47%)
4.2.8 General Hygiene Practices
Most participants (69%) reported washing their hands in general four or more times a day (Table 4-14),
with little variation between age groups. Half of all participants reported bathing or showering between
6 and 10 times a week (Table 4-15; most commonly 7 times per week), but frequency varied with age.
Younger children most commonly reported showering between 5 and 7 times per week, while answers
61
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were more variable for teen participants, ranging from 5 times to more than 10 times a week. The
majority of adults reported showering 10 or more times per week.
Table 4-14. How Many Times per Day Questionnaire Participants Generally Wash T
leir Hands
Number of Times Hands Washed per Day
Number of (%) Questionnaire Participants
1-3
10(31%)
4+
22 (69%)
Table 4-15. How Often Questionnaire Participants Generally Shower or Bathe per Week
Number of Times Bathe/Shower per Week*
Number of (%) Questionnaire Participants
0-5
9 (28%)
6-10
16 (50%)
11+
7 (22%)
*Data is presented in these categories due to the distribution of the data and small cell sizes
4.3 Video Activity Assessments for Field Users
4.3.1 Publicly-Available Video Assessment (Phase 1)
Publicly-available videos of adult and youth engaged in soccer, football, and field hockey were used to
assess specific exposure-related activity frequencies. These included hand-to-turf, body-to-turf, hand-to-
mouth, and object-to-mouth activities. These activities are likely to be important components of skin
(dermal) and ingestion exposures for youth and adults playing sports on synthetic turf fields. (Most of
the videos viewed in Phase 1 included actual game play; activities may be different for sports practice
sessions).
4.3.1.1 General Descriptive Statistics of Athletes and Fields Observed in Publicly-Available
Videos
Table 4-16 presents the general characteristics of the 60 athletes (20 per sport - soccer, football, and
field hockey) and the fields that they were observed playing on in the 34 publicly-available YouTube
videos. Fifty percent of the athletes were adults and 50% were children; of those, 63% were males (n =
38) and 37% were females (n = 22). Gloves were worn by 37% of the players, although a portion of
those athletes wore only one glove. Mouthguards were worn by the majority of the players (53%), but
were not commonly observed being worn by soccer players. Of the players wearing mouthguards, only
6% were soccer players. The 60 athletes were observed in the videos playing on both outdoor fields
(n = 41, 68%) and indoor fields (n = 19, 32%); the majority of the videos (n = 28; 82%) were for athletes
playing on fields with synthetic turf.
Table 4-16. General Characteristics of the Athletes and Fields They
(Phase 1)
Characteristic
Number of (%) Athletes
Child Athlete
30 (50%)
Adult Athlete
30 (50%)
Male Athlete1
38 (63%)
Female Athlete
22 (37%)
Mouthguard Worn - Yes
32 (53%)
Mouthguard Worn - No
28 (47%)
62
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Table 4-16. Continued
Characteristic
Number of (%) Athletes
Glove(s) Worn - Yes
22 (37%)b
Glove(s) Worn - No
38 (63%)
Indoor Field
19 (32%)
Outdoor Field
41 (68%)
a Males were the only sex observed playing football on the selected videos.
b 18% of the athletes (n = 4) wore only one glove.
4.3.1.2 Descriptive Statistics of Micro-activity Events Observed in Publicly-available Videos
Descriptive statistics for the frequencies of hand-to-mouth, object-to-mouth, hand-to-turf, and body-to-
turf events per hour for the children and adults observed playing soccer, field hockey, and football in the
publicly-available videos are provided in Figure 4-1 and in Appendix G. The box-and-whisker plots in
Figure 4-1 present the frequencies of the selected micro-activity contacts (events/hour) by age group
(child or adult) and sport type.
Children - For all sports combined, the total mean frequencies of children's hand-to-mouth, object-to-
mouth, hand-to-turf, and body-to-turf events per hour on the publicly-available videos were 29 ± 47, 7.0
± 11, 33 ± 48 and 21 ± 28 events/hr, respectively. These micro-activity events were consistently higher
for children playing football compared to children playing soccer or field hockey. The mean hand-to-
mouth events per hour were about four times higher for football players (58 ± 75 events/hr) compared to
soccer players (14 ± 9.9 events/hr) and field hockey players (15 ± 13 events/hr; Figure 4-1 and
Appendix G). The mean object-to-mouth events per hour were much greater for football players (17 ±
13 events/hr) than for field hockey players (3.6 ±5.1 events/hr) and soccer players (0.0 ± 0.0 events/hr),
respectively. The mean hand-to-turf events per hour were also much greater when playing football (83 ±
51 events/hr) compared to soccer (12 ± 26 events/hr) and field hockey (5.8 ± 7.5 events/hr). And the
mean body-to-turf events were between 8 and 18 times higher for football (52 ± 25 events/hr) players
than for both soccer (6.4 ± 12 events/hr) and field hockey (2.8 ± 5.0 events/hr) players, respectively.
Adults - For all sports combined, the total mean frequencies of adults' hand-to-mouth, object-to-mouth,
hand-to-turf, and body-to-turf events observed on the publicly-available videos were 30 ± 65, 10 ± 22,
42 ± 99 and 21 ± 37 events/hr, respectively (Figure 4-1 and Appendix G). Like with the children, these
select micro-activity events were consistently higher for adults playing football compared to adults
playing soccer or field hockey. The mean hand-to-mouth events per hour were roughly 7 to 18 times
higher for football players (74 ± 99 events/hr) compared to field hockey players (11 ± 14 events/hr) and
soccer players (4.2 ± 6.5 events/hr). The mean object-to-mouth events per hour were about 5 times
greater for football players (25 ± 33 events/hr) than for soccer players (4.0 ±1.3 events/hr) or field
hockey players (5.2 ±9.1 events/hr). For hand-to-turf events per hour, the mean was much greater when
playing football (110 ±150 events/hr) compared to playing soccer (14 ±17 events/hr) or field hockey
(2.4 ± 6.3 events/hr), respectively. Mean body-to-turf events per hour were as much as 49 times higher
for football players (49 ± 54 events/hr) compared to soccer players (11 ± 11 events/hr) and field hockey
players (1.2 ± 3.8 events/hr).
63
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300
3
O
|
tfi
8 200
£
1
O
E
°100
0-
a
Subject
R Adult
Mi Child
Field Hockey Football Soccer
Type of Sport
Subject
——I Adult
¦ Child
Field Hockey Football Soccer
Type of Sport
200
o 400
¦C
o 200
"O
eT
Subject
F—I Adult
¦ Child
3 150
o
.c
® 100
,
03
*
Subject
E3 Adult
¦ Child
Field Hockey Football Soccer
Type of Sport
Field Hockey Football Soccer
Type of Sport
Figure 4-1. Box-and-whisker plots of athlete micro-activity events per hour observed on
publicly-available video (Phase 1), by age group and sport.
Turf Type - Welch's t-tests were performed to determine if there were differences in the number of
athlete (children and adults combined) individual micro-activity (hand-to-mouth, object-to-mouth, hand-
to-turf, and body-to-turf) events or total micro-activity events occurring per hour when playing on
natural fields. The results showed that there were no significant differences in the mean number of
individual micro-activity events per hour or total micro-activity events per hour observed in publicly-
available videos for athletes by turf type (data not shown).
Age Group - Welch's t-tests were nan to determine if there were differences in individual micro-activity
(hand-to-mouth, object-to-mouth, hand-to-turf, body-to-turf) events or total micro-activity events
occurring per hour between child and adult athletes while playing on turf fields (natural and synthetic).
The results showed that there were not any significant differences in the mean number of individual
micro-activity events per hour or total micro-activity events per hour of athletes by age group in the
publicly-available videos (data not shown).
Type of Sport - In Table 4-17, a one-way ANOVA was performed to determine if there were differences
in the number of individual micro-activity events or total micro-activity events per hour of all athletes
(children and adults) observed in the publicly-available video, by type of sport (field hockey, football, or
soccer). The results showed that there were significant differences in the number of individual and total
micro-activity events per hour of these athletes by sport type. The total mean micro-activity events per
hour were significantly higher (p<0.001) for football players (230 ± 61 events/hr) compared to field
hockey players (23 ± 18 events/hr) or soccer players (31 ± 7.0 events/hr; Table 4-17 and Figure 4-2). In
64
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addition, football players had significantly (p < 0.001) higher hand-to-mouth, object-to-mouth, hand-to-
turf, and body-turf events than either field hockey players or soccer players. Field hockey and soccer
players, however, did not significantly differ from each other by each type of micro-activitv (Table 4-
17).
Table 4-17. One-way ANOVA Results for Select Micro-activity Events Performed per Hour by Athletes
(Children and Adults) Observed on Publicly-available Video (Phase 1), by Sport3
Micro-activity
Field Hockey -
Events per Hour
(mean ± standard
deviation)
Football -
Events per Hour
(mean ± standard
deviation)
Soccer -
Events per Hour
(mean ± standard
deviation)3
F-statistic
/>-valueb
Hand-to-mouth
13 ± 13
66 ±86
9.2 ±9.6
F(2,57) = 7.93
p < 0.001
Object-to-mouth
4.4 ±7.2
21 ±25
0.20 ±0.89
F(2,51) = 11.32
p < 0.001
Hand-to-turf
4.1 ±6.9
96 ± 110
13 ± 1.3
F( 2,57)= 11.70
p < 0.001
Body-to-turf
2.0 ±4.4
51 ±41
8.8 ±11
F(2,57) = 23.25
p < 0.001
Total events
23 ± 18
230 ±61
31 ±7.0
F(2,57) = 31.11
p < 0.001
a Number of athletes in each sport (n=20)
h p = significance level
Field Hockey
Football
Type of Sport
Soccer
o
5
o
o
a
-C
o
Field Hockey
Football
Type of Sport
Soccer
Field Hockey
Football
Type of Sport
Soccer
Field Hockey
Football
Type of Sport
Soccer
Figure 4-2. Micro-activity events per hour for all athletes (children and adults) observed on
publicly-available video (Phase 1), by sport.
65
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Type of Sport by Age Group: Adults - Five one-way bet ween-subject ANOVAs were run to determine if
type of sport played (field hockey, football, or soccer) influenced the number of micro-activity events
per hour of adult athletes observed on publicly-available video (Table 4-18 and Figure 4-3). The results
showed that there was a significant difference in the total mean number of micro-activity events per hour
of adults by sport type [F(2,27) = 12.34, p < 0.001], The total mean number of micro-activity events per
hour for football players (260 ± 6.8 events/hr) were significantly higher than the total mean number of
micro-activity events per hour for field hockey players (20 ± 21 events/hr) or soccer players (30 ± 9.7
events/hr).
Table 4-18. ANOVA Results for Select Micro-activity Events per Hour for Adults Observed on Publicly-
available Video (Phase 1), by Type of Sport3
Micro-activity
Field Hockey -
Events per Hour
(mean ± standard
deviation)
Football -
Events per Hour
(mean ± standard
deviation)
Soccer -
Events per Hour
(mean ± standard
deviation)\
F-statistic
/>-value b
Hand-to-mouth
11 ± 14
74 ±99
4.2 ±6.6
F(227) = 4.49
p = 0.021
Object-to-mouth
5.2 ±9.1
25 ±33
0.40 ± 1.2
F(221) = 4.53
p = 0.020
Hand-to-turf
2.4 ±6.3
110 ±54
14 ±7.0
F(221) = 4.26
p = 0.024
Body-to-turf
1.2 ±3.8
49 ±53
11 ±0.80
F(221) = 6.41
p = 0.005
Total events
20 ±21
260 ± 6.8
30 ±9.7
F(221) = 12.34
p < 0.001
a Number of athletes in each sport (n=10)
h p = significance level
Table 4-18 shows that ANOVAs run by type of micro-activity indicated that differences by sport were
significant for mean hand-to-mouth [F(2,27) = 4.49, p = 0.021]; object-to-mouth [F(2,27) = 4.53, p =
0.020]; hand-to-turf [F(2,27) = 4.26, p = 0.024] and body-to-turf [F(2,27) = 6.41, p = 0.005] events per
hour. Post-hoc analysis revealed that the number of mean hand-to-mouth events per hour were
significantly different between soccer players and football players (p = 0.029), but were not significantly
different between field hockey and football players or field hockey and soccer players. For mean object-
to-mouth events per hour, Tukey post-hoc analysis revealed a similar pattern of significant differences
occurring between soccer and football players (p = 0.022) and no significant differences between field
hockey and football players or field hockey and soccer players. Post-hoc analysis of hand-to-turf events
showed that the mean number of hand-to-turf events per hour were significantly different for field
hockey and football players (p = 0.033); however, hand-to-turf events per hour by soccer players were
not significantly different from those of football players or field hockey players. In addition, mean body-
to-turf events per hour were found to be significantly different between football and soccer players (p <
0.001) and football and field hockey players (p < 0.001), but not between soccer and field hockey
players.
66
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Field Hockey
Football
Type of Sport
Soccer
Field Hockey
Football
Type of Sport
Soccer
Field Hockey
Football
Type of Sport
Soccer
s
o
CO
Field Hockey
Football
Type of Sport
Soccer
Figure 4-3. Micro-activity events per hour for adults observed on publicly-available video
(Phase 1), by sport.
Type of Sport by Age Group: Children - Five one-way between-subject ANOYAs were ran to determine
if type of sport played (field hockey, football, or soccer) influenced the mean number of micro-activity
events per hour of child athletes observed on publicly-available video (Table 4-19 and Figure 4-4). The
results showed that there was a significant difference (p < 0.001) in the total mean number of micro-
activity events per hour of children by type of sport. These results showed that football players had a
significantly higher total mean number of micro-activity events per hour (210 ± 100 events/hr) than field
hockey players (27 ± 13 events/hr) or soccer players (6.4 ± 12 events/hr).
Table 4-19. ANOVA Results for Select Micro-activity Events per Hour for Children Observed on Publicly-
available Video (Phase 1), by Sport3
Micro-activity
Field Hockey -
Events per
Hour (mean ±
standard
deviation)
Football -
Events per
Hour (mean
± standard
deviation)
Soccer -
Events per
Hour (mean ±
standard
deviation)
F-statistic
/j-value b
Hand-to-mouth
15 ± 13
58 ± 75
14 ±9.9
F(2,27) = 3.16
p = 0.058
Object-to-mouth
3.6 ±5.2
1.7'± 14
0.0 ±0.0
F(2,27) = 11.82
p < 0.001
Hand-to-turf
46 ± 7.5
83 ±51
13 ±21
l-\2.27) = 16.77
p < 0.001
Body-to-turf
2.8 ± 5.0
52 ±25
12 ± 26
F(2,27) = 29.61
p < 0.001
Total events
27 ± 13
210±100
6.4 ± 12
F(2,27) = 25.77
p < 0.001
a Number of athletes in each sport =10
11 p = significance level
67
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Field Hockey
Football
Type of Sport
Soccer
Field Hockey
Football
Type of Sport
Soccer
t-
6
Field Hockey
Football
Type of Sport
Soccer
Field Hockey
Football
Type of Sport
Soccer
Figure 4-4. Micro-activity events per hour for children observed on publicly-available
video (Phase 1), by sport.
Table 4-19 also shows that there were not any significant differences in the children's mean hand-to-
mouth events per hour [F(2,27) = 3.16, p = 0.058] among the three different types of sports. However,
there were significant differences in the mean number of micro-activity events per hour for object-to-
mouth events [F(2,27) = 11.82, p < 0.001]; hand-to-turf events [F(2,27) = 16.77, p < 0.001]; and body-
to-turf events [F(2,27) = 29.61, p < 0.001] for child athletes among the three different sports (Table 4-19
and Figure 4-4). Tukey post-hoc analysis showed that each micro-activity specific ANOVA analyzing
differences in mean hand-to-mouth, object-to-mouth, hand-to-turf, or body-to-turf contact between
sports, indicated that football players had a significantly greater number of micro-activity events per
hour for each category than both field hockey and soccer players. However, the number of micro-
activity events per hour in each category did not significantly differ between soccer players and field
hockey players.
Glove Use - Welch's t-tests were performed to determine if wearing at least one glove had a substantial
impact on hand-to-mouth or hand-to-turf events per hour for adults and children combined. Athletes
wearing gloves (n = 22, 10 ± 17 events/hr) had significantly fewer hand-to-mouth events per hour than
those not wearing gloves [n = 38, 40 ± 67 events/hr); t(44.40) = 2.60, p = 0.012; Figure 4-5], However,
there was no significant difference in the mean number of hand-to-turf events per hour between athletes
wearing gloves (n = 22, 59 ± 120 events/hr) and athletes not wearing gloves [n = 38, 25 ± 34 hr; t(23.04)
= 1.33, p = 0.195], For football players, player position (i.e., center or quarterback) appeared to have a
large influence on the observed hand-to-turf events per hour (data not shown).
68
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300
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O
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100-
Gloves
No
Yes
No Yes
Wearing Gloves
5400
o
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E
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X
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I No
Yes
No Yes
Wearing Gloves
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•? 100
TJ
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S5
Yes
§400
i
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Field
Figure 4-
available
Hockey Football
Type of Sport
Soccer
Field Hockey
T?
Football
Type of Sport
Soccer
5. Hand-to-mouth and hand-to-turf events per hour for athletes observed on publicly-
video (Phase 1), by glove use and by glove use and sport.
Mouthguard Use - For children and adults combined, Welch's t-test results showed a significantly
higher mean number of hand-to-mouth events per hour for players wearing mouthguards (n = 32, 50 ±
71 events/hr) compared to players not wearing mouthguards [n = 28, 5.6 ± 7.7 events/hr; t(31.85) = 3.54,
p = 0.001; Figure 4-6], Welch's t-test results also showed a significantly greater mean number of object-
to-mouth events per hour for athletes wearing mouthguards (16 ± 21 events/hr) compared to athletes not
wearing mouthguards [0.14, ± 0.76 events/hr; t(31.09) = 4.27, p < 0.001],
69
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300
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o
j=
£
3
5
1100
o-
300
3
O
£
§200
o
JZ
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No
1 Yes
No Yes
Wearing Mouthguard
No
Yes
Field Hockey Football
Type of Sport
Soccer
i
o
£
«
8
, 75
Mouthguard o
£
3
O
o
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8 25-
1
o
Mouthguard a
i75
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t
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9
5"
O
Mouthguard
No
F^l Yes
No Yes
Wearing Mouthguard
Mouthguard
| No
^ Yes
Field Hockey Football
Type of Sport
Soccer
Figure 4-6. Hand-to-mouth and object-to-mouth events per hour of athletes observed on publicly-
available video (Phase 1), by mouthguard use and by mouthguard use and sport.
4.3.2 Exposure Pilot Study Participant Video Assessment (Phase 2)
4.3.2.1 General Descriptive Statistics of Athletes Videoed in the Exposure Pilot Study
Table 4-20 presents the general characteristics of the seventeen exposure pilot study participants who
consented to being videographed playing soccer (n = 12) and football (n = 5) on synthetic turf fields.
Results showed that 18% (n = 3) of the athletes were adults over the age of 18 (all of which played
soccer), and 82% (n = 14) were children ages 7 to 14 (nine of which played soccer and five of which
pl ayed football). Of these athletes, 53% (n = 9) were males, and 47% (n = 8) were females. Gloves were
worn (on both hands) by 24% (n = 4) of the athletes, and mouthguards were also worn by 23% of
athletes (all football players). Sixteen of the seventeen recaiited athletes played on outdoor fields (94%);
only one athlete was able to be recruited and videoed on an indoor field. (It should be noted that these
observations were made during sports practice activities; different levels of activity may be associated
with games).
70
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Table 4-20. General Characteristics of the Athletes Observed
Playing Soccer and Football in Exposure Pilot Study Videos (Phase 2)a
Characteristics
Number of (%) Athletes
Child Athlete
14 (82%)
Adult Athlete
3 (18%)
Male Athlete'1
9 (53%)
Female Athlete
8 (47%)
Mouthguard Worn - Yes
4 (23%)
Mouthguard Worn - No
13 (77%)
Gloves Worn - Yes
4 (23%)
Gloves Worn - No
13 (77%)
a Only males were videographed playing football on synthetic turf fields
4.3.2.2 Descriptive Statistics of Micro-Activity Events by Athletes Videoed in the Exposure
Pilot Study
Descriptive statistics for the frequencies of the select micro-activity events per hour for the children and
adults videographed playing soccer or football in the Phase 2 video assessment are provided in Figure 4-
7 and in Appendix G. The box-and-whisker plots in Figure 4-7 present the frequencies of hand-to-
mouth, object-to-mouth, hand-to-turf, and body-to-turf contacts (events per hour) by age group (child or
adult) and sport type (soccer or football).
Children (ages 7 to 14) - For both sports combined, the total mean frequencies of the children's hand-to-
mouth, object-to-mouth, hand-to-turf, and body-to-turf events per hour were 16± 12, 10 ± 13, 18 ± 23,
and 4.7 ± 4.9, respectively. Results showed that football players had about 6 times higher mean object-
to-mouth events per hour (22 ±17 events/hr) than soccer players (3.8 ± 3.6 events/hr; Figure 4-7 and
Appendix G). Mean body-to-turf events per hour were about two times higher for football players (6.8 ±
2.6 events/hr) than for soccer players (3.6 ± 5.7 events/hr).
71
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PoQttXH
Sport
$occtf
Spoil
Figure 4-7. Box-and-whisker plots of the micro-activity events per hour by athletes in Exposure Pilot
Study videos (Phase 2), by age group and sport type.
Adults (over 18 years of age) - For all adults (3 soccer players only), the total mean hand-to-mouth,
object-to-mouth, hand-to-turf, and body-to-turf events per hour were 7.3 ± 4.0, 10 ± 13, 26 ± 28, and 2.0
± 3.5, respectively. Results showed that the hand-to-turf contact of adult soccer players (26 ± 28
events/hr) were about 3 times higher compared to hand-to-mouth and object-to-mouth contact and 13
times higher than body-to-turf contacts (Figure 4-7 and Appendix G). However, these results are based
on a small number of participants.
Inferential Results for Athlete Micro-Activity Events - Due to the small sample size of participants (n =
17), Welch's t-tests were used to determine if there were significant differences in the mean number of
micro-activity events between all athletes (children and adults) playing soccer (n = 12) and all athletes
(children only) playing football (n = 5). Results showed that there were no significant differences in the
mean number of individual micro-activity events (hand-to-mouth, object-to-mouth, hand-to-turf, or
body-to turf contacts) per hour by sport (Table 4-21). Flowever, the reader is cautioned that these results
may be due to the small sample size. There were also no significant differences in the mean number of
micro-activity events per hour by category for child soccer players (n = 9) compared to child football
players (n = 5; data not shown).
72
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Table 4-21. Welch's t-test Results for Micro-activity Events Per Hour by Athletes in Exposure Pilot Study
Videos (Phase 2), by Sport3
Micro-activity
Soccer Players -
Events per Hour
(mean ± standard
deviation)
Football Players -
Events per Hour
(mean ± standard
deviation)
^-statistic
/>-valucb
Hand-to-mouth
16 ± 13
10 ±5.2
f(15.0) = 1.40
p = 0.181
Object-to-mouth
5.4 ±7.0
22 ± 17
t( 4.59) = 2.09
p = 0.096
Hand-to-turf
19 ±27
21 ± 10
f(15.0) = .268
p = 0.793
Body-to-turf
3.2 ±5.1
6.8 ±2.6
f(14.0) = 1.93
p = 0.075
Total events
43 ±40
59 ± 12
t(UA) = 1.28
p = 0.220
a Number of athletes. Soccer (n = 12) and Football (n = 5)
h p = significance level
Welch's t-tests were also performed to determine if there were significant differences in the mean
number of hand-to-mouth or hand-to-turf events per hour for players wearing gloves (n = 4, all children)
compared to players not wearing gloves (n = 13). Results showed that there were no significant
differences in the number of hand-to-mouth or hand-to-turf events per hour between athletes wearing
gloves and athletes not wearing gloves (Table 4-22); however, the reader is cautioned that these results
may be due to the small sample size of participants.
Table 4-22. Welch's t-test Results for Hand-to-mouth and Hand-to-turf Events per Hour by Athletes
in Exposure Pilot Study Videos (Phase 2), by Glove Use3
Micro-activity
Athletes Wearing Gloves -
Events per Hour (mean ±
standard deviation)
Athletes Not Wearing Gloves -
Events per Hour (mean ±
standard deviation)
^-statistic
/>-valucb
Hand-to-mouth
11 ±7.1
15 ± 12
t( 9.0) = .953
p = 0.366
Hand-to-turf
22 ± 16
18 ±25
f(8.1) = .386
p = 0.709
a Number of athletes wearing gloves (n = 4), not wearing gloves (n = 13)
h p = significance level
In addition, Welch's t-tests were run to determine if there were significant differences in the mean
number of hand-to-mouth or object-to-mouth events per hour for players wearing mouthguards (n = 4,
all child football players) compared to players not wearing mouthguards (n = 13). Results showed that
there were no significant differences for hand-to-mouth events per hour between athletes wearing
mouthguards and athletes not wearing mouthguards (Table 4-23). However, for object-to-mouth events
per hour, there were marginally significant differences (p = 0.057) between players wearing
mouthguards compared to players not wearing mouthguards.
73
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Table 4-23. Welch's t-test Results for Hand-to-mouth and Object-to-mouth Events per Hour by
Athletes in Exposure Pilot Study Videos (
'hase 2), by Mouthguard Usage
a Micro-activity
Athletes Wearing
Mouthguard -
Events per Hour (mean
± standard deviation)
Athletes Not Wearing
Mouthguard -
Events per Hour (mean
± standard deviation)
^-statistic
/>-valucb
Hand-to-mouth
11 ±5.8
15 ± 12
t( 11.5)= 1.10
p = 0.293
Object-to-mouth
27 ± 15
5.1 ± 6.7
f(3.4) = 2.83
p = 0.057
a Number of athletes wearing mouthguard (n = 4), not wearing mouthguard (n = 13)
h p = significance level
4.3.2.3 Descriptive Statistics of Activity Intensity and Duration by Athletes Videoed in the
Exposure Pilot Study
Descriptive statistics for the number of seconds per hour the videographed football and soccer players
spent in the three different activity levels (resting, low activity, or high activity) while playing on
synthetic turf fields are presented in Appendix G for children and adults. These activity levels were
defined for the video reviewers in section 3.5.2.5 and summarized as follows. Resting included rest and
break periods or periods of extended coaching discussion. Low activity levels included stationary
activities or conducting drills over intervals with instruction or waiting turns in between. High activity
levels included constant or near constant running or, for football, continual 'plays'.
Activity Levels: Children (ages 7 - 14) - The results showed that both child soccer players and football
players spent the least amount of time (seconds per hour) engaged in high-level activity while playing on
the synthetic turf fields (710 ± 410 sec/hr and 500 ± 120 sec/hr, respectively; Appendix G). Child
football players spent the greatest amount of time resting (1800 ±370 sec/hr), followed by low-level
activity (1300 ± 320 sec/hr). In contrast, child soccer players spent the most amount of time engaged in
low-level activity (1900 ± 600 sec/hr) followed by resting (1000 ±610 sec/hr; Appendix G). (It should
be noted that these observations were made during sports practice activities; different levels of activity
may be associated with games).
Activity Levels: Adults (over 18 years of age) - For the three adult soccer players, they spent the greatest
amount of time engaged in low-level activity (1400 ± 37 sec/hr) followed by resting (1200 ± 320 sec/hr),
while practicing on the synthetic turf field (Appendix G). (It should be noted that these observations
were made during sports practice activities; different levels of activity may be associated with games).
Inferential Results for Athlete Activity Levels - Due to the small sample size and the consistent
dispersion pattern, adults and children were combined (n = 17), and an ANOVA was run to determine if
there were significant differences in the amount of time (in seconds) that the athletes spent engaged in
the three different activity levels while playing soccer and football on the synthetic turf fields. The
results showed that there was a significant difference in the amount of time spent (seconds/hour) among
the three activity levels for the athletes playing both sports combined (F(2,47) = 14.03, p < 0.001; Figure
4-8). Tukey post-hoc analysis indicated that these athletes spent significantly less time in high-level
activity (700 ± 370 sec/hr) compared to resting (1300 ± 590 sec/hr) and low-level activity (1600 ± 530
sec/hr; data not shown). However, there was no significant difference in the amount of time athletes
spent resting and at low activity levels (Figure 4-8).
Using Welch's t-tests, the results showed, however, that there was a significant difference [t(l 1.3) =
3.04, p = 0.011] in the amount of time spent resting between soccer players (1100 ± 550 sec/hr) and
74
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football players (1800 ± 370 sec/hr). There were also significant differences [t( 14.3) = 2.25, p = 0.040]
in the amount of time engaged at the high activity level between soccer players (790 ± 400 sec/hr) and
football players (500 ± 120 sec/hr; Table 4-24 and Figure 4-9). It is important to note that all of the
participants were videoed while engaged in sports practice sessions. Activity levels and their durations
may be different for game situations. These results are also based primarily on youth sports, with only a
small number of adults.
Amount of each activity level per/hour; reported in seconds
0-
High Low Rest
Activity level/intensity
Figure 4-8. Box-and-whisker plots of the mean amount of time all
athletes spent (seconds/hour) at the three different activity levels in
Exposure Pilot Study videos (Phase 2).
Table 4-24. Welch's t-test Results for the Mean Amount of Time Athletes in Exposure Pilot Study Videos (Phase
2) Spent (Seconds/hour) in the Three Different Activity Levels, by Sport3
Activity Level
Soccer Players -
Seconds per Hour
Spent at Activity Level
(mean ± standard
deviation)
Football Players -
Seconds per Hour
Spent at Activity Level
(mean ± standard
deviation)
^-statistic
/j-valuc b
Resting
1100 ± 550
1800 ±370
/(11.3) = 3.04
p = 0.011
Low activity
1700 ± 560
1300 ±320
/(13.0) = 1.86
p = 0.086
High activity
790 ± 400
500 ±120
/(14.3) = 2.25
p = 0.040
a Number of athletes. Soccer (n = 12), Football (n = 5)
b p = significance level
75
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60.0%
50.0%
40.0%
30.0%
20.0%
10.0%
0.0%
Proportion of Different Activity Levels
During One Hour by Sport
Resting*
Low
High*
• Football
~ Soccer
Figure 4-9. The proportion of time athletes in Exposure Pilot Study videos (Phase 2) spent
participating at the three different activity levels in one hour, by sport, ("significant
difference between sports, p<0.05)
Welch's t-tests were also performed to determine if there were differences in the three different activity
levels by gender (8 females and 9 males). The results showed that there were not any significant
differences in the amount of time for any activity level (resting, low activity, or high activity) between
female athletes and male athletes (Table 4-25 and Figure 4-10).
Table 4-25. Welch's t-test Results for the Mean Amount of Time Athletes in Exposure Pilot Study Videos
(Phase 2) Spent (Seconds/hour) at the Three Different Activity Levels, by Gender®
Activity Level
Female Players -
Seconds per Hour Spent
at Activity Level (mean
± standard deviation)
Male Players -
Seconds per Hour Spent
at Activity Level (mean
± standard deviation)
^-statistic
77-value b
Resting
1100 ±620
1400 ± 540
/(14.1) 1.24
p = 0.237
Low Activity
1800 ± 580
1500 ± 470
1(13.6) = 1.17
p = 0.264
High Activity
730 ±430
680 ±320
/(12.9) = .278
p = 0.786
a Number of athletes. Female (n = 8), Male (n = 9)
b p = significance level
Proportion of Different Activity Levels
During One Hour by Gender
100.0%
0.0%
Resting
Low Activity
High Activity
Females
Males
Figure 4-10. The proportion of time athletes in Exposure Pilot Study videos (Phase 2) spent
participating at the three different activity levels, by gender.
76
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4.4 Exposure Measurement Pilot Study Meta-Data Summaries
For the exposure pilot study, meta-data were collected around and during the field and participant
measurements to provide information about conditions and activities that might affect or explain field
and personal exposure measurement results. Meta-data types included weather conditions, field and
surrounding area conditions, sport types, participant activities and clothing, and the overall activity
levels at the study field and surrounding fields.
Table 4-26 provides an overview of the exposure measurement pilot study activities performed across
two or more days at the three fields. At Outdoor Field 1, exposure pilot study participants were recruited
from both soccer and football teams that used the field at different times of day. Air sampling at this
field was performed during a soccer practice with study participants on one day and during a football
practice with study participants on a second day. Air samples were also collected during youth soccer
practice activities at another outdoor field (Outdoor Field 2) and at an indoor field (Indoor Field 1). In
some cases, there was more than one practice group on the study field at a time; in these cases, the team
or group with study participants typically used one half of the study field. Personal sampling, including
personal air sampling and dermal wipe sampling, was performed with 25 of the athletes participating in
the exposure pilot study. Field surface wipe, drag sled, and dust sample collections were performed at
these fields when there were no athletic activities on the field.
Table 4-26. Exposure Pilot Study Field Measurement Overview
Pilot Study
Outdoor
Outdoor
Outdoor
Outdoor
Outdoor
Outdoor
Outdoor
Outdoor
Indoor
Indoor
Activity
Field 1 -
Field 1 -
Field 1 -
Field 2 -
Field 2 -
Field 2 -
Field 2 -
Field 2 -
Field -
Field -
Day 1
Day 2
Day 3
Day 1
Day 2
Day 3
Day 4
Day 5
Day 1
Day 2
Field Air
Yes
Yes
No
Yes
No
No
No
No
No
Yes
Sampling
Field Surface
No
Yes
No
No
Yes
No
No
No
Yes
No
Wipe, Drag
Sled and Dust
Sampling
Participant
Soccer
Football
Football
Soccer
N/A
Soccer
Soccer
Soccer
N/A
Soccer
Sport
Number of
1
2
2
1
0
2
2
2
0
1
Practice
Groups
Personal
3
4
4
1
0
3
4
4
0
2
Sampling
(Number of
Athletes
Sampled)
Emissions of some organic chemicals associated with tire crumb rubber infill are affected by
temperature, with higher emissions at warmer temperatures, so attempts were made to perform field and
personal exposure measurements during warm to hot and dry conditions. Wind speed affects the
concentration of emitted chemicals above fields by affecting the rate at which the air above the field is
replaced by air that has not been impacted by emissions from field materials. The amount of tire crumb
rubber infill and field dust particles that athletes were exposed to could depend, in part, on the amount
and types of activities occurring on the field; higher-level, more intense activities may lead to
suspension of more particulates in the air around athletes.
77
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This exposure pilot study was successful at obtaining measurements under conditions that likely
represent the potential for higher inhalation exposures at each field - on days with warm to hot
temperatures, dry conditions, and on most days, relatively low wind, with high-level activity occurring
on the fields. Table 4-27 provides more detailed weather, field, and activity information for each day on
which participant exposure measurement activities occurred. Air temperature, field surface temperature,
and wind speed and direction were measured at the beginning, middle, and end of the exposure
measurement period at each field and recorded. Maximum air temperatures 1 meter above the fields
ranged from 23 to 35 °C. It was sunny or partly cloudy on each sampling day, and maximum field
surface temperatures ranged from 28 to 42 °C. With exception of the first day, practices were conducted
after school in the late afternoon and early evening, so the temperatures decreased rapidly after
sundown. Wind speeds (1-minute average) ranged from 1.7 to 6.7 km/h for practices at the outdoor
fields, with no wind present at the indoor field. Many athletes, coaches, and bystanders were present on
or at the study fields during most study measurement periods. Most study periods also had moderate to
high numbers of people using an adjacent synthetic turf field and, on some days, adjacent grass fields as
well.
78
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Table 4-27. Field Conditions and Overall Activities During Time Periods When Personal Exposure Measurement Sample Collection Activities
Were Performed at Synthetic Turf Fields
Condition or Activity
Outdoor
Field 1 -
Day 1-
Outdoor
Field 1 -
Day 2
Outdoor
Field 1 -
Day 3
Outdoor
Field 2 -
Day 1
Outdoor
Field 2 -
Day 3
Outdoor
Field 2 -
Day 4
Outdoor
Field 2 -
Day 5
Indoor
Field -
Day 2
Participant Sport on Study Field
Soccer
Football
Football
Soccer
Soccer
Soccer
Soccer
Soccer
Activity on Study Field
Practice
Practice
Practice
Practice
Practice
Practice
Practice
Practice
Field Air Sampling Performed
Yes
Yes
No
Yes
No
No
No
Yes
Average Field Air Temperature
(°C at 1-m height)
32
24
22
30
20
22
25
27
Maximum Field Air Temperature
(°C at 1-m height)
33
29
23
35
25
26
30
28
Minimum Field Air Temperature
(°C at 1-m height)
32
21
21
24
14
15
21
26
Average Field Surface Temperature (°C)
36
25
24
31
20
25
26
28
Maximum Field Surface Temperature (°C)
39
33
28
42
29
34
34
29
Minimum Field Surface Temperature (°C)
32
20
20
23
14
14
20
27
Average 1-minute Average Wind Speed
(km/li at 1-meter height)
5.7
3.1
6.7
1.7
1.9
3.4
3.8
0
Maximum 1-minute Wind Speed
(km/li at 1-meter height)
14.1
6.5
12
1.8
3.7
5.6
3.8
0
Conditions3
D,S
D,S,C
D,P
D,S,C
D,S,C
D,S,C
D,S,P,C
D,S,C
Number of Athletes at Study Synthetic Turf
Field
16-22
18-38
28-36
43-55
13-65
23-36
38-58
9- 11
Number of Coaches and Bystanders at Study
Synthetic Turf Field
3 - 18
9- 13
14-22
5-24
9-19
5-35
20-32
14 - 16
Number of People at Adjacent Synthetic Turf
Field(s)
0-26
0-28
18-32
63-72
7-45
25-30
32-48
0
Number of People at Adjacent Grass Field(s)
0
0-80
30-60
0-18
0-10
0 - 10
0- 14
0
aD = dry field; S = sunny; C = clear after sundown; P = partly cloudy
79
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Athlete exposures to chemicals associated with tire crumb rubber infill at synthetic turf fields may be
influenced by the activity duration, activity types, frequency of contact with field materials, and the
clothing and equipment the athletes wear. Higher activity levels may lead to higher inhalation of
airborne chemicals and particles through increased rates of respiration. Higher activity levels can also
lead to increased sweat production that may lead to increased adherence of field dust to the skin.
Increased contact with field materials may lead to increased skin (dermal) exposures, as could higher
amounts of exposed skin. Likewise, higher hand-to-field, hand-to-mouth, and object-to-mouth
frequencies may lead to higher ingestion exposures.
Information on each of these metrics was collected for each participant during their study measurement
period. With exception of athlete clothing and equipment, this information was collected and recorded at
the start and end of the practice and at intervals of approximately 30 minutes during practice; this
resulted in three to six observations over the duration of their on-field activities. Athlete clothing and
equipment was observed and recorded once for each participant during the practice. Results for these
metrics were summarized across the three sports and age groups and are shown in Tables 4-28 and 4-29.
Because these were practice sessions during summer conditions, all participants wore short-sleeved
shirts and short pants, leaving exposed arm and skin surfaces (Table 4-28). A few soccer players wore
goalie gloves for relatively short periods during practice. Although attempts were made to recruit full-
time soccer goalies, none volunteered to participate in the study; this means that the study did not
include the soccer position likely to experience the greatest field contact frequency. Football players
were required to wear protective pads, helmets, and mouthguards during practice; several football
players also wore gloves. With the use of mouthguards, football players had higher rates of object-to-
mouth events (although these frequencies were only counted in the video data analysis).
Table 4-28. Summaries of Observe(
Participant Clothin
g and Safety Equipment in Exposure Pi
Clothing/Safety Equipment Worn
% Soccer Players
Age 11-21 (n = 11)
% Soccer Players
Age 7 - 10 (n = 6)
% Football Players
Age 13 - 14 (n = 8)
Short-sleeved shirt
100
100
100
Short pants
100
100
100
Socks - high
64
100
0
Socks - medium
36
0
63
Socks - low
0
0
37
Gloves
18
0
50
Helmet
0
0
100
Pads
0
0
100
Mouthguard
0
0
100
Practice durations ranged from approximately one hour for the youngest soccer player group to
approximately 1.5 to 2 hours for other soccer and football groups (data not shown). The total time spent
at/on the field ranged from 1 to 2.5 hours, when the times immediately before and after practices were
included. Information on the type of activities, physical activity levels, and athlete contact with the
surface of the synthetic turf field was collected for each athlete regularly throughout the duration of the
practice (Table 4-29).
80
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Table 4-29. Summaries of Observed Participant Activities in Exposure Pilot Study
Participants
Types of
Participant
Activities3
Number of
Activity
Observations
per Personb
Total
Number of
Activity
Observations
Estimated Activity Levels0
(Average % of Total
Activity Observations
Across Participants)
Contact with Synthetic Turf Field Surface
(Average % of Total Activity Observations
Across Participants)
Estimated Frequency of
Contact with Field Surface
High
Medium
Low
Yes
No
Hand
Arm
Leg
Body
Face/Head
> 1/min
> l/5min
< l/5min
Soccer Players
Age 11-21 (n=ll)
S,W,R,D,M
5-6
51
37
59
4
20
80
5
10
20
6
4
7
10
2
Soccer Players
Age 7 - 10 (n=6)
D,M
3-5
23
35
56
9
7
93
7
0
7
0
0
3
0
3
Football Players
Age 13 - 14 (n=8)
W,R,D,M
5-6
43
15
75
10
59
31
63
21
25
21
3
25
38
0
a S = stretching, on field; W = wannup activities; R = running, not as part of drills or scrimmage; D = practice drills; M = practice scrimmage
b Participant activities observed and recorded at start, end, and approximately every 30 minutes during sampling period; observation periods were approximately 5 minutes
°High activity level included constant movement (running or drills or for football, continual "plays"); medium activity level included intermittent movement (running or drills
over intervals with instruction or waiting in between); low activity level included watching teammates, periods of extended coaching instruction or discussion and rest or break
periods
81
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Participant activities during their sports practices included stretching; warm-up activities; running (not
as part of drills or scrimmages); practice drills including ball-kicking exercises; sport skills drills and
offensive and defensive team drills; and within-team practice scrimmages. Note that in this phase of the
research project, activity levels were categorized as low, medium and high, rather than resting, low and
high, as was done in the video assessments because the at-field observations typically did not include
rest periods and water break times. On average, soccer players had longer durations of high-level
physical activity compared to football players, although football players had higher frequencies of hand
and body contact with the field than the soccer players (Table 4-29).
4.5 Exposure Pilot Study Measurement Results
In the exposure pilot study, several types of samples were collected - field environment samples,
personal samples, and biological samples. Field environment samples included field and off-field
(background) air samples, field surface wipe samples, drag sled samples, and dust samples collected
from each field. Researchers used specified sampling locations (Figure 4-11), although air sampling
locations varied with wind direction. Field air samples were analyzed for total suspended particulates,
metals, VOCs and SVOCs; field surface wipe samples and dust samples were analyzed for metals and
SVOCs, and drag sled samples were analyzed for SVOCs. Personal samples included personal air
samples collected during the activity for VOC analysis and dermal wipe samples collected from the
hand, arm and leg of each participant immediately after the sport practice and analyzed for metals and
SVOCs. Urine and blood samples were collected before and after practices for a subset of participants.
Urine samples were analyzed for select PAH metabolites, and blood samples were analyzed for select
metals. The numbers and types of field environment, personal, biological, and quality control samples
that were collected are shown in Table 4-30, and results of these analyses are presented in the following
report sub-sections.
Air
Sampling
Station
Air
Sampling
Station
Off-Field
Sampling
Station
Wipe, Drag Sled,
and Dust Sampling
Areas
Figure 4-11. Sample collection locations of field air, field wipe, drag sled, and dust samples.
Collection locations for air samplers was dependent on wind direction.
82
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Table 4-30. Types and Numbers of Sam
)les and Quality Control Samples
for the Exp
osure Pilot Study
Sample Type
Analvte"
Number
Samples
Number
Duplicate
Samplesb
Number
Field
Blanksb
Number
Field
Controlsb
Number
Lab
Blanksb
Number
Lab
Controlsb
Field Air
PM
12
4
5
0
5
0
Field Air
Metals
12
4
5
0
5
0
Field Air
VOCs (active)
12
4
5
5
5
5
Field Air
VOCs (passive)
12
4
5
5
5
5
Field Air
SVOCs
12
4
5
5
5
5
Field Surface Wipe
Metals
9
3
4
4
4
4
Field Surface Wipe
SVOCs
9
3
4
4
4
4
Field Drag Sled
SVOCs
9
3
4
4
4
4
Field Dust
Metals
3
0
4
4
4
4
Field Dust
SVOCs
3
0
4
4
4
4
Personal
Air VOCs
24
0
0
0
0
0
Personal
Dermal Metals
75
0
5
5
5
5
Personal
Dermal SVOCs
75
0
5
5
5
5
Biological
Urine Pre-Activity
14
0
0
0
0
0
Biological
Urine Post-Activity
14
0
0
0
0
0
Biological
Blood Pre-Activity
13
0
0
0
0
0
Biological
Blood Post-Activity
11
0
0
0
0
0
Totals
319
29
55
45
55
45
a PM = particulate matter; VOC = volatile organic compound; SVOC = semivolatile organic compound
b Quality control samples
4.5.1 Field Environment Sample Measurements
4.5.1.1 Field Air Samples
Air samples were collected to assess the potential for inhalation exposures for athletes during sports
activities at synthetic turf fields. Field air samples were collected during four sport practices conducted
at three synthetic turf fields. Air temperatures were warm to hot during the air sample collection on all
four field air sample collection days. As noted in section 4.2.4, samples were collected on two different
days at Outdoor Field 1 during soccer and football practices and on one day at Outdoor Field 2 and an
indoor field, both during soccer practices. Field air samples were collected at two locations that were
next to the field, in downwind positions (for the outdoor fields), and at another (off-field) location that
was upwind and further away from the field for samples representative of the background, or ambient,
air that was entering the field area.
At Outdoor Field 1, there were no obvious large pollutant sources in the immediate upwind vicinity of
the fields. On the first day of air sampling (i.e., during the soccer practice), the wind came from a
direction that brought it across both an adjacent synthetic turf field, as well as the field where study
activities were performed. On the second day (i.e., during the football practice), the wind was coming
from a direction that did not come over the adjacent field.
At Outdoor Field 2, there was a six-lane road with very heavy traffic upwind of the facility. The facility
had two synthetic turf fields and participants spent time on both fields during the practice session. On
the air sampling day, the wind brought air across the road, across one synthetic turf field, and then
83
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across the second synthetic turf field. The background samples were collected at a position downwind
from the road and upwind from the synthetic turf fields. One set of field samples was collected
downwind from the first synthetic turf field and upwind from the second synthetic turf field. The second
field sample set was collected on the downwind side of the second field, at a location receiving air that
had come across both synthetic turf fields at the facility.
At the indoor field, the background samples were collected at a position outside of the field facility. This
background position may have been affected by road dust from a nearby gravel driveway. The field
samples were collected inside the facility and immediately next to the field, on opposite sides of the
field. A large gable mounted fan and open doors provided some ventilation in the facility during the
soccer practice session.
Particulate Matter - The Teflo membrane disk filters from the two field air samplers and one upwind
(off-field) background air sampler at each field were analyzed for total suspended particulate (TSP). Air
TSP measurement results are shown in Table 4-31. Typically, the TSP concentrations for samples
collected at the fields were not higher than the concentrations measured in the (off-field) background
samples. The background sample collected outside of the indoor facility was not included in the average,
however, because it was apparently impacted by dust from a nearby gravel drive.
Table 4-31. Exposure Pilot Study Field Air Sampling Total Suspended Particulate (TSP) Measurements a
Field Air Sample
Location
Number
Samples
TSP Median
(jig/m3)
TSP Mean
(Hg/m3)
TSP Std. Dev.
(jig/m3)
TSP Maximum
(jig/m3)
Field - Location 1
4
28
39
30
83
Field - Location 2
4
26
29
16
50
Off-field/Backgroundb
3b
32
30
19
49
a Average results for samples collected at three exposure pilot study synthetic turf fields. At each field, two air samples were
collected at the field and one air sample was collected at an upwind (off-field) location to represent background air. Samples
were collected on two different days at one field, resulting in a total of four sets of air samples.
b The background sample measurement from the indoor field was not included, because it was contaminated by road dust.
Metals - The Teflo membrane disk filters from the two field air samplers and one upwind (off-field)
background air sampler at each field were also analyzed for metals. Air metals measurement results are
shown in Table 4-32. Beryllium and selenium were not measured above the minimum reporting limit in
any sample. Except for arsenic, cadmium, cobalt and rubidium, all metals were measured above the
minimum reporting limits (MRL) in 100% of the samples. For most metals, the median concentrations
in the samples collected at the two field locations were not substantially different than concentrations
measured in the background samples. However, maximum concentrations were substantially higher than
background levels for many metals. Air concentrations of many metal analytes associated with tire
crumb rubber were higher in the indoor field facility compared to the outdoor field and background
levels.
84
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Table 4-32. Exposure Pilot Study Field Air Sampling Metals Measurements3
Metal
> Minimum
Reporting
Limit (%)
Background
Air Sample
Median (ng/m3)
Field Air Sample
Location 1
Median (ng/m3)
Field Air Sample
Location 2
Median (ng/m3)
Field Air Sample
Max (ng/m3)
Arsenic
50
0.44
0.46
0.36
0.76
Cadmium
75
0.054
0.017
0.066
0.25
Chromium
100
3.5
3.8
3.4
6.7
Cobaltb
33
0.69
0.21
0.19
2.5
Lead
100
1.8
2.0
2.2
3.9
Zinc
100
30
100
19
640
Aluminum
100
420
330
180
1000
Antimony
100
0.74
0.61
0.95
7.0
Barium
100
12
13
7.5
62
Copper
100
20
7.0
10
51
Iron
100
750
490
340
870
Magnesium
100
160
110
100
510
Manganese
100
27
13
9.8
27
Molybdenum
100
0.16
0.17
0.17
0.89
Nickel
100
0.58
1.5
1.1
15
Rubidiumb
25
0.57
0.27
0.23
1.8
Strontium
100
3.5
2.7
2.2
6
Tin
100
0.64
0.84
0.97
4.9
Vanadium
100
1.3
0.88
0.70
1.5
a Median and maximum results for samples collected at the three exposure pilot study synthetic turf fields. At each field, two
air samples were collected at the field and one air sample was collected at an upwind (off-field) location to represent
background air. Samples were collected on two different days at one field, resulting in a total of four sets of air samples.
Median results were calculated using all measurements from the outdoor fields and indoor field.
b Although cobalt and rubidium had < 50% of the measured values above the quantifiable limits, all measured values from the
analysis, including those reported by the laboratory that were below the MRLs, were used in the calculation of median
values.
Air concentration results are shown for cobalt, lead, and zinc in Figure 4-12. The background results for
Field 3 are not shown due to likely contamination with road dust. The background zinc concentration at
Field 2 was slightly below zero after field blank subtraction. The figure illustrates the higher levels
measured at the indoor field compared to the outdoor fields for cobalt and zinc. The concentrations of
lead in air at Field 2 may have been impacted by the proximity to heavy traffic that was present upwind
of the field during the sampling period.
85
-------
w
c
3
2.5
2
1.5
1
0.5
Cobalt
I Next to Field Location 1
i Next to Field Location 2
I Background Upwind from Field
0j£>
c
Lead
I Next to Field Location 1
i Next to Field Location 2
i Background Upwind from Field
Field 1 Field 1 Field 2 Field 3
Outdoor Outdoor Outdoor Indoor
Day 1 Day 2
Field 1
Outdoor
Day 1
Field 1
Outdoor
Day 2
Field 2
Outdoor
Field 3
Indoor
Zinc
CuQ
c
700
600
500
400
300
¦ Next to Field Location 1
¦ Next to Field Location 2
¦ Background Upwind from Field
Field 1
Outdoor
Day 1
Field 1
Outdoor
Day 2
Field 2
Outdoor
Field 3
Indoor
Figure 4-12. Concentrations of cobalt, lead, and zinc in air samples collected next to fields and
at upwind background sample collection locations.
SVOCs - The polyurethane foam (PUF) filters from the two field air samplers and one upwind (off-field)
background air sampler at each field were analyzed for SVOCs. Air SVOC measurement results are
shown in Table 4-37. Seventeen (17) of the 35 SVOC analytes reported in Table 4-33 were measured
above the minimum quantifiable limits (MQL) in 100% of the samples. Measurement results below the
MQL were included in calculation of median results. Some negative values are reported as a result of
field blank subtractions. Several analytes are not included in Table 4-33 due to low recoveries in field
control samples, including aniline, naphthalene, n-butylbenzene, 2-bromomethylnaphthalene, and
bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate.
Several PAHs, benzothiazole, 4-tert-octylphenol, and bis(2-ethylhexyl) phthalate had median
concentrations in field samples that were higher than concentrations measured in background samples.
Concentrations of the 5- and 6-ring PAHs that are only present in air as part of air particulates
(benzo[a]pyrene, benzo[ghi]perylene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(e)pyrene,
dibenz[a,h]anthracene, and indeno(l,2,3-cd)pyrene) were very low to not measurable (Table 4-33). For
many SVOCs, maximum concentrations were substantially higher than background levels. Air
86
-------
concentrations of most SVOC analytes were higher in the indoor field facility compared to the outdoor
fields and background levels (data not shown); this was a factor in median field concentrations being
higher than median background concentrations.
Table 4-33. Exposure Pilot Study Field Air Sampling SVOC Measurementsa'b'c
Semivolatile Organic
Compound (SVOC)
> Minimum
Quantifiable
Limit (%)
Background
Air Sample
Median (ng/m3)
Field Air Sample
Location 1
Median (ng/m3)
Field Air Sample
Location 2
Median (ng/m3)
Field Air Sample
Max (ng/m3)
Phenanthrene
100
2.0
4.5
5.7
35
Fluoranthene
100
0.37
0.90
1.3
9.9
Pyrene
17
0.15
0.54
0.89
15
Benzo[a]pyrene
0
0
0
0
0.030
Benzo [ghi]perylene
33
0.013
0
0
0.23
Suml5PAHd
N/Ae
3.2
8.4
10
70
Benzothiazole
100
-3.9
6.5
15
214
Dibutyl phthalate
100
12
7.4
19
102
Bis(2-ethylhexyl) phthalate
100
7.5
15
11
77
4-tert-octylphenol
100
1.7
5.4
11
68
n-Hexadecane
100
-0.13
-14
-5.5
14
1 -Methy lnaphthalene
100
-0.16
-0.0965
-0.11
0.70
2-Methylnaphthalene
100
-0.46
-0.25
-0.34
0.58
Acenaphthylene
58
-0.013
0.19
0.16
0.46
Fluorene
100
0.98
2.1
1.9
4.6
Anthracene
17
0.059
0.053
0.30
4.7
1 -Methy lphenanthrene
92
0.12
0.45
0.57
6.8
2-Methylphenanthrene
25
0.16
0.64
0.74
7.0
3 -Methy lphenanthrene
83
0.21
0.81
0.94
8.9
Benz[a]anthracene
0
0.022
0.013
0.015
0.18
Chrysene
17
0.013
0.034
0.047
0.26
Benzo(b)fluoranthene
0
0
0
0
0.29
Benzo(k)fluoranthene
0
0
0
0
0
Benzo(e)pyrene
0
0.022
0
0.015
0.21
DBA + ICDP
0
0
0
0
0
Coronene
0
0
0
0
0.26
Dibenzothiophene
100
0.26
0.44
0.52
6.1
Dimethyl phthalate
100
0.43
0.40
0.32
1.4
Diethyl phthalate
100
-11
-3.2
3.0
38
Benzyl butyl phthalate
100
6.4
4.8
11
75
Di-n-octyl phthalate
42
0.46
-0.58
-0.41
7.9
2,6-Di-tert-butyl-p-cresol
100
0.93
0.31
-0.003
10
Cyclohexylisothiocyanate
0
0
0
0
0
a Median and maximum results for samples collected at the three exposure pilot study synthetic turf fields. At each field, two
air samples were collected at the field and one air sample was collected at an upwind (off-field) location to represent
background air. Samples were collected on two different days at one field, resulting in a total of four sets of air samples.
Median results were calculated using all measurements from the outdoor fields and indoor field.
b Although several chemicals had < 50% of the measured values above the quantifiable limits, all measured values from the
analysis, including those reported by the laboratory that were below the quantifiable limits, were used in the calculation of
87
-------
median values.
0 Several results are reported as negative values. This is a result of the subtraction of field blank values from the sample
measurement results. Although this does not represent a physical reality, the negative results are retained as part of the
distribution of corrected results.
dSuml5PAH = Sum of 15 of the 16 EPA "priority' PAHs, including Acenaphthylene, Anthracene, Benz [a] anthracene,
Benzo[a]pyrene, Benzo(b)fluoranthene, Benzo|ghi Ipen lenc. Benzo(k)fluoranthene, Chrysene, Dibenz[a,h]anthracene,
Fluoranthene, Fluorene, Indeno(l,2,3-cd)pyrene, Naphthalene, Phenanthrene, Pyrene
e N/A = not applicable
'DBA + ICDP = Sum of Dibenz[a,h|anthracene and Indeno( l,2,3-cd)pyrene
Air concentration results are shown for several SVOCs in Figure 4-13. Values that appear to be missing
are near or slightly below zero after field blank subtraction. The figure illustrates the higher levels
measured at the indoor fields compared to the outdoor fields for these SVOC analytes. Except for
dibutyl phthalate, the concentrations next to the outdoor fields were slightly higher than those measured
at the upwind background location for these analytes. The concentrations of several analytes at Field 2
may have been impacted by the proximity to heavy traffic that was present upwind of the field during
the sampling period.
£_
M
4-tert-Octylphenol
on
c
80
70
60
50
40
30
20
10
I Next to Field Location 1
i Next to Field Location 2
i Background Upwind from Field
¦I
Field 1 Field 1
Outdoor Outdoor
Day 1 Day 2
Field 2
Outdoor
Dibutyl Phthalate
120
100
80
60
40
20
I Next to Field Location 1
i Next to Field Location 2
i Background Upwind from Field
J ¦
ll
Field 1
Field 1
Field 2
Outdoor
Outdoor
Outdoor
Day 1
Day 2
Fieid 3
Indoor
Field 3
Indoor
Oil
C
c
Phenantherie
40
35
30
25
20
15
10
I Next to Field Location 1
i Next to Field Location 2
i Background Upwind from Field
Field 1 Field 1
Outdoor Outdoor
Day 1 Day 2
Ik
Field 2
Outdoor
Pyrene
16
14
12
10
8
6
4
2
0
¦ Next to Field Location 1
¦ Next to Field Location 2
¦ Background Upwind from Field
Field 1 Field 1 Field 2
Outdoor Outdoor Outdoor
Day 1 Day 2
Field 3
Indoor
Field 3
Indoor
Figure 4-13. Concentrations of several SVOCs in air samples collected next to fields and at
88
-------
upwind background sample collection locations.
VOCs - The Carbopack™ X FLM sorbent tube samples from the two field air samplers and one upwind
(off-field) background air sampler at each field were analyzed for VOCs. Air VOC measurement results
are shown in Table 4-34. For seventeen (17) of the 29 SVOC analytes reported in Table 4-34, 100% of
the measurements had results above the method detection limits. Measurement results below the method
limit of detection were included in calculation of median and maximum results. Some negative values
are reported as a result of field blank subtractions. Methyl isobutyl ketone and benzothiazole, found to
be associated with tire crumb rubber in the chamber emission experiments, had median concentrations in
next-to-field samples that were consistently higher than concentrations measured in background
samples. Air concentrations of methyl isobutyl ketone and benzothiazole were higher in the indoor field
facility compared to outdoor field and background levels. Several VOCs, including the BTEX
compounds and styrene, had their highest levels at the outdoor field that was potentially impacted by
traffic pollutants.
Table 4-34. Exposure Pilot Study Field Air Sampling VOC Measurementsa'b
Volatile Organic Compound (VOC)
> Method
Detection
Limit (%)
Background
Air Sample
Median (ng/m3)
Field Air Sample
Location 1
Median (ng/m3)
Field Air Sample
Location 2
Median (ng/m3)
Field Air
Sample Max
(ng/m3)
Methyl isobutyl ketone
83
160
430
820
1900
Benzothiazole
17
41
69
96
1600
1,3 -Butadiene
100
24
28
13
50
Styrene
100
92
92
200
670
Benzene
100
500
400
360
590
Toluene
100
2100
1400
1300
5300
Ethylbenzene
100
200
160
170
740
m/p-Xylene
100
650
500
510
2400
o-Xylene
100
150
140
190
520
SuinBTEX0
N/Ad
3700
2700
2500
9500
trans-2-Butene
100
14
17
9.8
31
cis-2-Butene
100
12
15
10
33
4-Ethyltoluene
75
42
42
40
52
1,3,5-Trimethylbenzene
83
24
22
25
45
1,1 -Dichloroethene
0
0.72
13
6.7
17
1,1 -Dichloroethane
58
9.8
11
20
23
cis-1,2-Dichloroethene
0
0
0
0
0
1,2-Dichloroethane
67
26
55
60
95
1,1,1 -Trichloroethane
50
43
43
42
59
Carbon tetrachloride
100
720
760
730
1200
1,2-Dichloropropane
0
0
0
0
0
Trichloroethylene
0
12
13
12
41
Tetrachloroethylene
100
53
52
64
150
Chlorobenzene
100
20
22
22
37
m-Dichlorobenzene
75
10
23
11
30
p-Dichlorobenzene
100
30
32
31
34
o-Dichlorobenzene
100
1.8
5.0
2.3
23
89
-------
Table 4-34. Continued
Volatile Organic Compound (VOC)
> Method
Detection
Limit (%)
Background
Air Sample
Median (ng/m3)
Field Air Sample
Location 1
Median (ng/m3)
Field Air Sample
Location 2
Median (ng/m3)
Field Air
Sample Max
(ng/m3)
Trichlorofluoromethane (Freon™ 11)
100
1300
1300
1300
1400
Dichlorodifluoromethane (Freon™ 12)
100
330
340
370
520
1,1,2-Trichlorotrifluoroethane (Freon™
113)
100
570
560
540
620
a Median and maximum results for samples collected at the three exposure pilot study synthetic turf fields. At each field, two
air samples were collected at the field and one air sample was collected at an upwind (off-field) location to represent
background air. Samples were collected on two different days at one field, resulting in a total of four sets of air samples.
Median results were calculated using all measurements from the outdoor fields and indoor field.
b Although several chemicals had <50% of the measured values above the quantifiable limits, all measured values from the
analysis, including those reported by the laboratory that were below the quantifiable limits, were used in the calculation of
median values.
c SumBTEX = Sum of benzene, toluene, ethylbenzene, m/p-xylene, and o-xylene
d N/A = not applicable
Air concentration results are shown for methyl isobutyl ketone, benzothiazole, benzene, and styrene in
Figure 4-14. The background value that appears to be missing for methyl isobutyl ketone at Field 1 is
near zero. The figure illustrates the higher levels measured at the indoor fields compared to the outdoor
fields for methyl isobutyl ketone and benzothiazole, two analytes associated with tire crumb rubber.
Levels of these two chemicals were higher at the next to field locations as compared to the background
locations at all fields. Benzene illustrates that for the BTEX chemicals the levels at the indoor and
outdoor fields are not different and appear to be related to the concentrations in ambient air. The
concentrations of several analytes at Field 2 may have been impacted by the proximity to heavy traffic
that was present upwind of the field during the sampling period.
90
-------
Methyl Isobutyl Ketone
¦ Next to Field Location 1
¦ Next to Field Location 2
¦ Background Upwind from Field
. J. Id
Field 1 Field 1 Field 2 Field 3
Outdoor Outdoor Outdoor Indoor
Day 1 Day 2
1800
Benzothiazole
¦ Next to Field Location 1
1600
¦ Next to Field Location 2
1400
¦ Background Upwind from Field
"g 1200
iooo
c
800
1
600
400
200
0
—a ¦¦¦
1
Field 1 Field 1 Field 2
Outdoor Outdoor Outdoor
Field 3
Indoor
Day 1 Day 2
Benzene
1000
800
600
400
200
i Next to Field Location 1
: Next to Field Location 2
Background Upwind from Field
Field 1
Outdoor
Day 1
Field 3
Indoor
Styrene
1800
1600
1400
1200
"&B iooo
c
800
600
400
200
0
¦ Next to Field Location 1
¦ Next to Field Location 2
¦ Background Upwind from Fie
¦
¦
¦
¦
i
i
i
Field 1
Outdoor
Day 1
Field 1
Outdoor
Day 2
Field 2
Outdoor
Field 3
Indoor
Figure 4-14. Concentrations of methyl isobutyl ketone, benzothiazole, benzene, and styrene
in air samples collected next to fields and at upwind background sample collection locations.
4.5.1.2 Field Surface Wipe, Drag Sled arid Dust Samples
Field surface wipe and drag sled samples were collected to measure chemicals that may be transferrable
from synthetic turf field surfaces to athletes' skin during sport activities. Field dust was collected to
provide information about a medium that may be important for inhalation, dermal, and ingestion
exposures. Samples were collected at the three synthetic turf fields when it was safe to do so without
posing an obstruction or safety hazard for any activities occurring on the field. Separate surface wipe,
drag sled, and dust samples were collected at three locations on the field (Figure 4-11). Dust samples
were collected from the three locations at each field and were composited at the field to provide
sufficient mass for metal and SVOC analyses.
Metals in Field Dust Samples - The composited dust samples from each field were analyzed for metals.
Field dust metals measurement results are shown in Table 4-35. It should be noted that because the dust
samples were collected with stainless-steel sieves, contributions of stainless steel metal components to
the measured sample concentrations cannot be ruled out. Selenium was not measured above the
minimum reporting limit in any sample. Except for tin and vanadium, the remaining metals were
measured above their minimum reporting limits in at least two of the three field dust samples. Average
concentrations for zinc and cobalt, two tire material constituents based on previous tire crumb rubber
characterization, were measured at 9400 mg/kg and 45 mg/kg, respectively. Average lead and chromium
concentrations were 38 mg/kg and 13 mg/kg, respectively. Cadmium and arsenic were measured at
average concentrations that were < 0.5 mg/kg. Other metals commonly found in crustal particles (i.e.,
91
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soil and other matter from Earth's crust), including aluminum, iron, and magnesium, were measured at
average levels > 1700 mg/kg.
Table 4-35. Exposure
>ilot Study Field Dust Sampling Metals Measurementsab
Metal
> Minimum
Reporting
Limit (%)
Field Dust
Sample Mean
(mg/kg)
Field Dust Sample
Standard Deviation
(mg/kg)
Field Dust Sample
Maximum
(mg/kg)
Arsenic
67
0.50
0.95
1.1
Cadmium
67
0.044
0.61
0.42
Chromium0
67
13
3.7
15
Cobalt
100
45
2.3
48
Lead
67
38
11
50
Zinc
100
9400
2900
11000
Aluminum
100
4700
400
5100
Antimony
67
1.9
0.58
2.3
Barium
67
93
14
108
Beryllium
67
0.14
0.056
0.20
Copper
100
140
87
210
Iron0
100
7700
3400
12000
Magnesium
100
1700
580
2300
Manganese0
100
170
30
200
Molybdenum0
67
0.99
0.25
1.3
Nickel0
100
8.9
2.9
11
Rubidium
100
10
5.2
13
Strontium
100
26
8.5
33
Tin
33
1.8
1.5
3.5
Vanadium
33
7.4
2.9
11
a Results from samples collected across the three exposure pilot study synthetic turf fields. At each field, dust was collected
from three on-field locations (Figure 4-24, locations SI, S2 and S5) and combined to create a single composite sample for the
field.
b Although two chemicals had <67% of the measured values above the quantifiable limits, all measured values from the
analysis, including those reported by the laboratory that were below the quantifiable limits, were used in the calculation of
mean values.
0 These metals may be components of stainless steel 316; a stainless-steel sieve was used for sample collection.
Metals in Field Surface Wipe Samples - Field surface wipe samples collected using Ghost wipe sample
media pre-wetted with water were analyzed for metals. Metals measurement results from field surface
wipe samples are shown in Table 4-36. Selenium was not measured above the minimum reporting limit
in any sample. The remaining metals were measured at concentrations above the minimum reporting
limit in 100% of the samples. Average surface loading values for zinc and cobalt ranged from 93 to 170
ng/cm2 and from 0.4 to 1.4 ng/cm2, respectively. Ranges of average lead and chromium concentrations
were 0.3 to 3.4 ng/cm2 and 0.25 to 1.1 ng/cm2, respectively. Cadmium and arsenic were measured at
average surface loadings that were < 0.021 ng/cm2. Other metals commonly found in crustal particles,
including aluminum, iron, and magnesium, were found at average surface loading levels that were > 20
ng/cm2.
92
-------
Table 4-36. Exposure Pilot Study Field Surface Wipe Sampling Metals Measurements8
Metal
> Minimum
Reporting
Limit (%)
Field Surface
Wipe Sample
1 neat inn SI
Mean (ng/cm2)
Field Surface
Wipe Sample -
Location S2
Mean (ng/cm2)
Field Surface
Wipe Sample -
Location S5
Mean (ng/cm2)
Field Surface
Wipe Sample
Maximum
(ng/cm2)
Arsenic
100
0.012
0.015
0.021
0.033
Cadmium
100
0.0044
0.0068
0.0070
0.015
Chromium
100
0.25
0.50
1.1
2.6
Cobalt
100
0.64
1.4
0.40
2.2
Lead
100
0.31
1.4
3.4
9.5
Zinc
100
93
130
170
360
Aluminum
100
130
110
120
190
Antimony
100
0.051
0.098
0.19
0.42
Barium
100
1.5
1.3
1.4
1.8
Beryllium
100
0.00051
0.0005
-0.00007
0.0023
Copper
100
0.92
0.78
1.1
2.1
Iron
100
150
130
190
270
Magnesium
100
24
22
25
37
Manganese
100
2.2
1.8
2.0
3.5
Molybdenum
100
0.027
0.029
0.038
0.069
Nickel
100
0.12
0.13
0.17
0.27
Rubidium
100
0.17
0.15
0.15
0.24
Strontium
100
0.40
0.35
0.40
0.63
Tin
100
0.58
0.34
0.072
1.7
Vanadium
100
0.37
0.29
0.26
0.71
a Average results from samples collected across the three exposure pilot study synthetic turf fields. Each set of field
measurements had wipe samples collected at three on-field locations (Figure 4-24, locations SI. S2 and S5).
SVOCs in Field Dust Samples - The composited dust samples from each field were analyzed for SVOCs.
Field dust SVOC measurement results are shown in Table 4-37. Of the 35 target SVOC analytes
reported in Table 4-37, 29 were measured above the minimum quantifiable limit in 100% of the
samples. 2-methlnaphthylene was not measured above the method detection limit in any samples.
Aniline, napthalene, n-butylbenzene, cyclohexylisothiocyanate, 2-bromomethylnaphthalene, bis(2-
ethylhexyl) adipate, and bis(2,2,6,6-tetramethyl-4piperidyl) sebacate measurement results were not
reported due to poor performance in one or more quality control sample type.
Average concentrations ranged from 0.006 mg/kg for 1-methlynaphthalene to 24 mg/kg for bis(2-
ethylhexyl) phthalate. The average mean sum of 15 PAHs was 19 mg/kg. Averaged benzothiazole and
2-hydroxybenzothiazole mean concentrations were 4.3 mg/kg and 9.4 mg/kg, respectively.
Table 4-37. Exposure Pilot Study Field Dust Sampling SVOC Measurements3,15
Semivolatile Organic
Compound (SVOC)
> Minimum
Quantifiable
Limit (%)
Field Dust
Sample Mean
(mg/kg)
Field Dust Sample
Standard
Deviation (mg/kg)
Field Dust Sample
Maximum (mg/kg)
Phenanthrene
100
0.85
0.61
1.2
Fluoranthene
100
2.2
1.4
3.5
Pyrene
100
5.5
3.4
8.1
93
-------
Table 4-37. Continued
Semivolatile Organic
Compound (SVOC)
> Minimum
Quantifiable
Limit (%)
Field Dust
Sample Mean
(mg/kg)
Field Dust Sample
Standard
Deviation (mg/kg)
Field Dust Sample
Maximum (mg/kg)
Benzo[a]pyrene
100
0.71
0.36
1.1
Benzo [ghi]perylene
100
3.7
0.97
4.8
Suml5PAHc
N/Ad
19
9.9
29
Benzotliiazole
100
4.3
1.5
5.9
2-Hydroxybenzotliiazole
100
9.4
6.6
14
Dibutyl phthalate
67
0.33
0.46
0.86
Bis(2-ethylhexyl) phthalate
100
24
16
43
4-tert-octylphenol
100
5.2
4.1
8.6
n-Hexadecane
100
0.14
0.22
0.40
1 -Methy lnaphthalene
100
0.0063
0.0025
0.0086
2-Methylnaphthalene
0
0.014
0.0061
0.020
Acenaphthylene
100
0.012
0.0038
0.016
Fluorene
100
0.034
0.024
0.050
Antliracene
100
0.15
0.10
0.25
1 -Methy lphenanthrene
100
0.52
0.39
0.83
2-Methylphenantlirene
100
0.63
0.48
1.0
3 -Methy lphenanthrene
100
0.71
0.55
1.2
Benz[a]anthracene
100
0.38
0.27
0.67
Clirysene
100
3.0
1.9
5.1
Benzo(b)fluoranthene
100
1.4
1.0
2.6
Benzo(k)fluoranthene
100
0.32
0.24
0.60
Benzo(e)pyrene
100
1.5
0.48
2.0
DBA + ICDPe
100
0.65
0.34
1.0
Coronene
100
1.9
0.45
2.4
Dibenzothiophene
100
0.10
0.080
0.17
Dimethyl phthalate
67
0.029
0.046
0.082
Diethyl phthalate
33
0.10
0.13
0.25
Diisobutyl phthalate
100
0.29
0.34
0.66
Benzyl butyl phthalate
100
15
24
43
Di-n-octyl phthalate
67
0.14
0.12
0.23
2,6-Di-tert-butyl-p-cresol
100
0.11
0.063
0.15
a Results from samples collected across the three exposure pilot study synthetic turf fields. At each field, dust was collected
from three on-field locations (Figure 4-11, locations SI, S2 and S5) and combined to create a single composite sample for the
field.
b Although several chemicals had <67% of the measured values above the quantifiable limits, all measured values from the
analysis, including those reported by the laboratory that were below the quantifiable limits, were used in the calculation of
mean values.
0 Suml5PAH = Sum of 15 of the 16 EPA 'priority' PAHs, including Acenaphthylene, Anthracene, Benz[a]anthracene,
Benzo[a]pyrene, Benzo(b)fluoranthene, Benzo[ghi]perylene, Benzo(k)fluoranthene, Chrysene, Dibenz[a,h]anthracene,
Fluoranthene, Fluorene, Indeno(l,2,3-cd)pyrene, Naphthalene, Phenanthrene, Pyrene
d N/A = not applicable
eDBA + ICDP = Sum of Dibenz[a,h]anthracene and Indeno(l,2,3-cd)pyrene
94
-------
SVOCs in Field Surface Wipe Samples - The field surface wipe samples collected using wipe sample
media pre-wetted with isopropanol were analyzed for SVOCs. Field surface wipe SVOC measurement
results are shown in Table 4-38. Of the 31 target SVOC analytes reported in Table 4-38, 17 were
measured above the minimum quantifiable limit in 100% of the samples. Some negative values are
reported as a result of field blank subtractions. Measurement results below the minimum quantifiable
limit were included in calculation of average results. Aniline, n-butylbenzene, diethyl phthalate, n-
hexadecane, 2-bromomethylnaphthalene, 2-hydroxybenzothiazole, diisobutyl phthalate, dibutyl
phthalate, benzyl butyl phthalate, and bis(2,2,6,6-tetramethyl-4piperidyl) sebacate measurement results
were not reported due to poor performance in one or more quality control sample type.
Average surface loading values ranged from 0.12 to 0.20 ng/cm2 for benzothiazole, 0.13 to 0.18 ng/cm2
for bis(2-ethylhexyl) phthalate, 0.08 to 0.12 ng/cm2 for 4-tert-octylphenol, and 0.08 to 0.11 ng/cm2 for
the sum of 15 PAHs. Most other SVOC analytes had average surface loading values that were < 0.03
ng/cm2.
Table 4-38. Exposure Pilot Study Field Surface Wipe Sampling SVOC Measurementsa b
Semivolatile Organic
Compound (SVOC)
> Minimum
Quantifiable
Limit (%)
Surface Wipe
Sample
1 neat inn SI
Mean (ng/cm2)
Surface Wipe
Sample
1 neat inn S2
Mean (ng/cm2)
Surface Wipe
Sample
1 neat inn S5
Mean (ng/cm2)
Surface Wipe
Sample
Maximum
(ng/cm2)
Phenanthrene
89
0.0050
0.0059
0.0037
0.0098
Fluoranthene
100
0.014
0.015
0.011
0.024
Pyrene
100
0.028
0.034
0.023
0.064
Benzo[a]pyrene
78
0.0039
0.0049
0.0029
0.0086
Benzo [ghi]perylene
100
0.019
0.020
0.015
0.033
Suml5PAHc
N/Ad
0.099
0.11
0.078
0.19
Benzothiazole
100
0.16
0.20
0.12
0.26
Bis(2-ethylhexyl) phthalate
100
0.18
0.15
0.13
0.28
4-tert-octylphenol
100
0.12
0.12
0.079
0.30
Naphthalene
0
0.00002
0
0
0.00006
1 -Methy lnaphthalene
100
0.00035
0.00076
0.00058
0.0010
2-Methylnaphthalene
0
0.00059
0.0015
0.0011
0.0017
Acenaphthylene
67
0.00035
0.00031
0.0001
0.00064
Fluorene
89
0.00008
0.00017
0.00003
0.00032
Anthracene
100
0.00057
0.00083
0.0004
0.00155
1 -Methy lphenanthrene
100
0.0032
0.0039
0.0029
0.0077
2-Methylphenanthrene
67
0.0031
0.0039
0.0024
0.0061
3 -Methy lphenanthrene
100
0.0034
0.0043
0.0029
0.0069
Benz[a]anthracene
89
0.0023
0.0034
0.0019
0.0063
Chrysene
100
0.017
0.018
0.013
0.027
Benzo(b)fluoranthene
100
0.0046
0.0054
0.0035
0.0091
Benzo(k)fluoranthene
67
0.0011
0.0012
0.00096
0.0021
Benzo(e)pyrene
100
0.0061
0.0069
0.0049
0.011
DBA + ICDPe
89
0.0026
0.0031
0.0022
0.0057
Coronene
100
0.015
0.016
0.011
0.029
Dibenzothiophene
78
0.00022
0.00039
0.00015
0.00097
Dimethyl phthalate
33
0.00034
0.00016
0.00009
0.00089
95
-------
Table 4-38. Continued
Semivolatile Organic
Compound (SVOC)
> Minimum
Quantifiable
Limit (%)
Surface Wipe
Sample
1 neat inn SI
Mean (ng/cm2)
Surface Wipe
Sample
1 neat inn S2
Mean (ng/cm2)
Surface Wipe
Sample -
Location S5
Mean (ng/cm2)
Surface Wipe
Sample
Maximum
(ng/cm2)
Di-n-octyl phthalate
100
0.0018
0.0028
-0.0017
0.0071
2,6-Di-tert-butyl-p-cresol
100
0.0061
0.010
0.0097
0.023
Cyclohexylisothiocyanate
56
0.035
-0.018
-0.012
0.059
bis(2-Ethylhexyl) adipate
100
0.057
0.031
0.018
0.095
a Average results from samples collected across the three exposure pilot study synthetic turf fields. Each set of field
measurements had wipe samples collected at three on-field locations (Figure 4-11, locations SI, S2 and S5).
b Although several chemicals had <67% of the measured values above the quantifiable limits, all measured values from the
analysis, including those reported by the laboratory that were below the quantifiable limits, were used in the calculation of
mean values.
0 Suml5PAH = Sum of 15 of the 16 EPA 'priority' PAHs, including Acenaphthylene, Anthracene, Benz[a]anthracene,
Benzo[a]pyrene, Benzo(b)fluoranthene, Benzo[ghi]perylene, Benzo(k)fluoranthene, Chrysene, Dibenz[a,h]anthracene,
Fluoranthene, Fluorene, Indeno(l,2,3-cd)pyrene, Naphthalene, Phenanthrene, Pyrene
dN/A = not applicable
eDBA + ICDP = Sum of Dibenz[a,h]anthracene and Indeno(l,2,3-cd)pyrene
SVOCs in Field Drag Sled Samples - The field drag sled samples collected using dry wipe sample media
attached to a weighted drag sled body were analyzed for SVOCs. Field drag sled SVOC measurement
results are shown in Table 4-39. Of the 35 target SVOC analytes reported in Table 4-39, 32 were
measured above the minimum quantifiable limit in 100% of the samples. Aniline, n-butylbenzene,
cyclohexylisothiocyanate, 2-bromomethylnaphthalene, bis(2-ethylhexyl) phthalate, and bis(2,2,6,6-
tetramethyl-4piperidyl) sebacate measurement results were not reported due to poor performance in one
or more quality control sample type.
Average transferrable residue values ranged from 0.011 to 0.019 ng/cm2 for benzothiazole, 0.031 to
0.054 ng/cm2 for 2-hydroxybenzothiazole, 0.010 to 0.015 ng/cm2 for 4-tert-octylphenol, and 0.019 to
0.033 ng/cm2 for the sum of 15 PAHs. Most other SVOC analytes had transferrable residue values that
were < 0.01 ng/cm2.
Table 4-39. Exposure Pilot Study Field Drag Sled Sampling SVOC Measurements8
Semivolatile Organic
Compound (SVOC)
> Minimum
Quantifiable
Limit (%)
Drag Sled
Sample
1 neat inn SI
Mean (ng/cm2)
Drag Sled
Sample -
Location S2
Mean (ng/cm2)
Drag Sled
Sample -
Location S5
Mean (ng/cm2)
Drag Sled
Sample
Maximum
(ng/cm2)
Phenanthrene
100
0.0012
0.0020
0.0016
0.0036
Fluoranthene
100
0.0027
0.0045
0.0035
0.0079
Pyrene
100
0.0053
0.0088
0.0070
0.015
Benzo[a]pyrene
100
0.00095
0.0017
0.0016
0.0038
Benzo [ghi]perylene
100
0.0029
0.0048
0.0037
0.0079
Suml5PAHb
N/A°
0.019
0.033
0.027
0.058
Benzothiazole
100
0.011
0.019
0.016
0.034
2-Hydroxybenzothiazole
100
0.031
0.054
0.049
0.094
Dibutyl phthalate
100
0.00099
0.00005
0.0005
0.0021
4-tert-octylphenol
100
0.010
0.015
0.012
0.026
96
-------
Table 4-39. Continued
Semivolatile Organic
Compound (SVOC)
> Minimum
Quantifiable
Limit (%)
Drag Sled
Sample
1 neat inn SI
Mean (ng/cm2)
Drag Sled
Sample -
Location S2
Mean (ng/cm2)
Drag Sled
Sample -
Location S5
Mean (ng/cm2)
Drag Sled
Sample
Maximum
(ng/cm2)
n-Hexadecane
100
0.00095
0.0012
0.0013
0.0022
Naphthalene
100
0.0001
0.00011
0.00012
0.00028
1 -Methy lnaphthalene
100
0.00006
0.00008
0.00006
0.00017
2-Methylnaphthalene
100
0.00009
0.0001
0.00009
0.00026
Acenaphthylene
89
0.00002
0.00004
0.00003
0.00008
Fluorene
100
0.00006
0.00007
0.00006
0.00011
Anthracene
100
0.00015
0.00025
0.00018
0.00034
1 -Methy lphenanthrene
100
0.00069
0.0011
0.00083
0.0016
2-Methylphenanthrene
100
0.00086
0.0014
0.0012
0.0026
3 -Methy lphenanthrene
100
0.00098
0.0016
0.0013
0.0030
Benz[a]anthracene
100
0.00057
0.0010
0.00078
0.0019
Clirysene
100
0.0032
0.0058
0.0046
0.011
Benzo(b)fluoranthene
100
0.0008
0.0012
0.0010
0.0023
Benzo(k)fluoranthene
89
0.00045
0.0019
0.0018
0.0039
Benzo(e)pyrene
100
0.0024
0.0044
0.0037
0.0085
DBA + ICDPd
100
0.00035
0.0006
0.00045
0.0010
Coronene
100
0.0016
0.0022
0.0015
0.0028
Dibenzothiophene
100
0.00007
0.00012
0.00008
0.00016
Dimethyl phthalate
100
0.00014
0.00006
0.00007
0.00026
Diethyl phthalate
100
0.0019
0.00058
0.00094
0.0042
Diisobutyl phthalate
100
0.0019
0.00077
0.00099
0.0029
Benzyl butyl phthalate
100
0.021
0.010
0.0083
0.042
Di-n-octyl phthalate
100
0.0023
0.0011
0.00091
0.0055
2,6-Di-tert-butyl-p-cresol
100
0.00078
0.0004
0.00059
0.0018
bis(2-Ethylhexyl) adipate
100
0.0041
0.0030
0.0017
0.0058
a Average results from samples collected across the three exposure pilot study synthetic turf fields. Each set of field
measurements had drag sled samples collected at three on-field locations (Figure 4-11, locations SI, S2 and S5).
b Suml5PAH = Sum of 15 of the 16 EPA 'priority' PAHs, including Acenaphthylene, Anthracene, Benz[a]anthracene,
Benzo[a]pyrene, Benzo(b)fluoranthene, Benzo[ghi]perylene, Benzo(k)fluoranthene, Clirysene, Dibenz[a,h]anthracene,
Fluoranthene, Fluorene, Indeno(l,2,3-cd)pyrene, Naphthalene, Phenanthrene, Pyrene
0 N/A = not applicable
dDBA + ICDP = Sum of Dibenz[a,h]anthracene and Indeno(l,2,3-cd)pyrene
4.5.1.3 Comparisons of Tire Crumb Rubber Infill, Field Surface Wipe, Drag Sled, and Dust
Measurement Results
Comparisons of metal and SVOC measurement results from tire crumb rubber infill (sampled as part of
the tire crumb rubber characterization efforts), field dust, field surface wipe, and field drag sled samples
collected at the three exposure pilot study synthetic turf fields were made to assess differences in the
chemicals and chemical patterns among the environmental measurements and the chemicals associated
with the tire crumb rubber.
97
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Metal Measurement Comparisons - Table 4-40 shows the comparisons for average metal measurement
results across the three exposure measurement pilot study fields. Zinc and cobalt, found to be chemical
constituents of tire crumb rubber in the tire crumb characterization, had higher concentrations in the tire
crumb rubber as compared to concentrations measured in dust. Lead, on the other hand, had
concentrations in field dust that were higher than in the tire crumb rubber. Higher levels of lead in dust
and relatively higher levels in surface loadings as compared to zinc and cobalt, suggests another source
of lead, in addition to tire crumb rubber infill. Most other metals also had higher average concentrations
in field dust compared to the tire crumb rubber infill. Again, this suggests another source or sources of
metals in addition to the tire crumb rubber infill. Many of the metals (e.g. aluminum, iron, magnesium)
are found in crustal materials, and may be from components of sand or other materials used in field
construction, blown-in soil from other sources, or track-in by the many field users. Several of the metals
also are used in stainless steel, and the stainless-steel sieve used for dust sample collection can't be ruled
out as a source of iron, chromium, manganese, molybdenum and nickel. Interpretation of differences
between concentrations in tire crumb rubber and surface loadings of metals measured using surface
wipes is more difficult. In general, the ratios of metals in tire crumb rubber infill and surface loadings
measured with surface wipe samples were higher for most metals than those measured for zinc and
cobalt, again perhaps suggesting non-infill sources contributing to overall surface metal levels.
Table 4-40. Comparison of Average Tire Crumb Rubber Infill, Field Dust, and Field
Surface Wipe Metal Measurement Results from the Three Exposure Pilot Study Fields3
Metal
Tire Crumb Rubber
Infill Average (mg/kg)
Field Dust Average
(mg/kg)
Field Surface Wipe
Average (ng/cm2)
Arsenic
0.12
0.5
0.016
Cadmium
0.63
0.044
0.0061
Chromium
1.1
13b
0.62
Cobalt
118
45
0.81
Lead
16
38
1.7
Zinc
13900
9400
130
Aluminum
1200
4700
120
Antimony
0.80
1.9
0.11
Barium
69
93
1.4
Beryllium
0.066
0.14
0.0003
Copper
14
140
0.93
Iron
500
7700b
160
Magnesium
270
1700
24
Manganese
6.3
170b
2
Molybdenum
0.15
0.99b
0.031
Nickel
2.3
8.9b
0.14
Rubidium
1.9
10
0.16
Strontium
4.1
26
0.38
Tin
1.6
1.8
0.33
Vanadium
1.9
7.4
0.31
a Average results from samples collected across the three exposure pilot study synthetic turf fields.
b These metals may be components of stainless steel 316; a stainless-steel sieve was used to collect dust samples.
98
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SVOC'Measurement Comparisons - Comparisons for SVOCs measured in tire crumb rubber infill, field
dust, field surface wipe, and field drag sled samples are shown in Table 4-41 for analytes with
acceptable performance in at least three of the four sample types. Concentrations in tire crumb rubber
infill were higher than those in field dust by a factor of 1.3 to 3-fold for benzothiazole, pyrene, the sum
of 15 PAHs, 4-tert-octylphenol, and bis(2-ethyhexyl) phthalate. Concentrations of several 5- and 6-ring
PAHs in tire crumb rubber infill were generally similar to or slightly higher than those in field dust,
while the opposite was observed for benzo[ghi]perylene and coronene. Field surface loading
measurements from surface wipes were generally 3 to 10 times higher than transferrable residues from
the drag sled measurements.
For most of the measured SVOC analytes, there did not appear to be appreciable contributions to the
dust and surfaces from sources other than the tire crumb rubber, or at least not as great as those
potentially seen for many metal analytes. The PAHs benzo[ghi]perylene and coronene were modestly
higher in field dust than in the tire crumb rubber infill, on average and benzyl butyl phthalate was 21
times higher in dust versus infill, suggesting a possible non-infill source.
Table 4-41. Comparison of Average Tire Crumb Rubber Infill, Field Dust, Field Wipe, and Drag Sled SVOC
Measurement Results from the Three Exposure Pilot Study Fieldsa,b
Semivolatile Organic
Compound (SVOC)
Tire Crumb Infill
Average (mg/kg)
Field Dust Average
(mg/kg)
Field Surface
Wipe Average
(ng/cm2)
Field Drag Sled
Average (ng/cm2)
Phenanthrene
1.6
0.85
0.0049
0.0016
Fluoranthene
4.1
2.2
0.013
0.0036
Pyrene
12
5.5
0.028
0.0070
Benzo[a]pyrene°
0.93
0.71
0.0039
0.0014
Benzo [ghi]perylene°
1.9
3.7
0.018
0.0038
Suml5PAHc
28
19
0.096
0.026
Benzothiazole
5.5
4.3
0.16
0.015
Dibutyl phthalate
1.2
0.33
NR
0.00051
Bis(2-ethylhexyl) phthalate
73
24
0.15
NR
4-tert-octylphenol
15
5.2
0.11
0.012
n-Hexadecane
0.47
0.14
NR
0.0012
1 -Methy lnaphthalene
0.0057
0.0063
0.00056
0.00007
2-Methylnaphthalene
0.011
0.014
0.0011
0.00009
Acenaphthylene
0.022
0.012
0.00025
0.00003
Fluorene
0.062
0.034
0.00009
0.00006
Anthracene
0.24
0.15
0.0006
0.00019
1 -Methy lphenanthrene
1.2
0.52
0.0033
0.00087
2-Methylphenanthrene
1.2
0.63
0.0031
0.0012
3 -Methy lphenanthrene
1.7
0.71
0.0035
0.00129
Benz[a]anthracene
0.76
0.38
0.0025
0.00078
Chrysene
4.1
3.0
0.016
0.0045
Benzo(b)fluoranthene°
1.4
1.4
0.0045
0.001
Benzo(k)fluoranthene°
0.50
0.32
0.0011
0.0014
Benzo(e)pyrene°
2.2
1.5
0.0060
0.0035
DBA + ICDP°'e
0.68
0.65
0.0026
0.00047
Coronene0
0.74
1.9
0.014
0.0018
99
-------
Table 4-41. Continued
Semivolatile Organic
Compound (SVOC)
Tire Crumb Infill
Average (mg/kg)
Field Dust Average
(mg/kg)
Field Surface
Wipe Average
(ng/cm2)
Field Drag Sled
Average (ng/cm2)
Dibenzothiophene
0.21
0.10
0.00025
0.00009
Dimethyl phthalate
0.0031
0.029
0.00020
0.00009
Diethyl phthalate
0.13
0.10
NR
0.0011
Diisobutyl phthalate
0.71
0.29
NR
0.0012
Benzyl butyl phthalate
0.70
15
NR
0.013
Di-n-octyl phthalate
0.51
0.14
0.00097
0.0014
Bis(2-ethylhexyl) adipate
2.4
NR
0.035
0.0029
2,6-Di-tert-butyl-p-cresol
0.097
0.11
0.0086
0.00059
2-Hydroxybenzothiazole
15
9.4
NR
0.045
a Average results from three exposure pilot study fields.
bNR = not reported
0 Group of 5 and 6-ring polycyclic aromatic hydrocarbons (PAHs)
dSuml5PAH = Sum of 15 of the 16 EPA 'priority' PAHs, including Acenaphthylene, Anthracene, Benz[a]anthracene,
Benzo[a]pyrene, Benzo(b)fluoranthene, Benzo[ghi]perylene, Benzo(k)fluoranthene, Chrysene, Dibenz[a,h]antliracene,
Fluoranthene, Fluorene, Indeno(l,2,3-cd)pyrene, Naphthalene, Phenanthrene, Pyrene
eDBA + ICDP = Sum of Dibenz[a,h]anthracene and Indeno(l,2,3-cd)pyrene
Overall, these results provide evidence that chemicals associated with tire crumb rubber are present in
field dust, on field surfaces, and in transferrable residues, where they are available for field user
exposures through inhalation, dermal, and ingestion pathways. For many metals, and possibly some
SVOCs, there is evidence that sources other than the tire crumb rubber are adding to amounts found in
the dust and on surfaces, potentially leading to exposures above those that could be attributed solely to
the tire crumb rubber.
4.5.2 Personal Sample Measurements
4.5.2.1 Personal Air Samples
Personal air sample collection during athlete activities on synthetic fields is of interest for understanding
inhalation exposures closer in proximity to the person than can be accounted for by the field samplers.
There are constraints on personal sampling devices due to available device sizes, the relatively high
sampling rates required, and participant safety requirements for athlete personal air monitoring,
especially when working with child research participants. In this study, a small, high-sampling-rate
passive VOC air sampler was used to attempt personal air sample collection during athlete activities.
The passive VOC air sampler was attached to the upper backs of a pinnie (i.e., practice jersey) worn by
study participants during their usual athletic practice sessions on synthetic turf fields. When collecting
air samples from the football players, one sampler was destroyed and another damaged during drills that
involved ground contact. Otherwise, all personal air samples were successfully collected and did not
appear to interfere with any athlete activities.
To be useful for quantitative measurements of VOCs in air, the effective sampling rates of the target
analytes had to be determined. Effective sampling rates were measured in two ways - in chambers under
controlled conditions of temperature, humidity, ventilation and target analyte concentrations; and in field
tests, where the passive VOC samplers were placed next to the active field air VOC samplers. Test
100
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results showed that the passive VOC sampler did not perform as desired in this exposure measurement
pilot study, with inconsistent effective sampling rates measured for laboratory chamber and field
conditions, and low recoveries of the two highest concentration analytes, benzothiazole and methyl
isobutyl ketone. Therefore, no personal air sample VOC results are reported here.
Additional research would be required to determine if any personal air sampling devices can be
successfully used in research studies with youth participants, with sufficiently large effective sampling
rates, and with no safety or activity limitation constraints. It may be necessary to limit personal air
sampling to adult volunteers willing to wear more bulky samplers with pumps; however, this may limit
the types of activities that can be monitored. It is difficult to envision a pump-based sampler that could
be worn successfully and safely during football activities that involve tackling, or by other sports
players, such as soccer goalkeepers and rugby players.
4.5.2.2 Dermal Wipe Samples
Dermal wipe samples were collected from exposure measurement pilot study participants following their
sport practice activities on synthetic turf fields with tire crumb rubber infill. Wipe samples were
collected by wiping an entire hand, and wiping 112-cm2 areas on the arm and leg that were not covered
by clothing during their practice. Samples were collected from the right hand, arm, and leg for metals
and from the left hand, arm, and leg for SVOCs. For both metals and SVOCs, the same types of wipe
materials used to collect field surface wipes were used for dermal wipe sampling.
Dermal wipe measurement results were compiled as median and maximum values for hand, arm, and leg
wipes for three groups of participants:
• Soccer players, 11 to 21 years old (n = 11),
• Soccer players, 7 to 10 years old (n = 6), and
• Football players, 13 to 14 years old (n = 8)
There are limitations for dermal wipe sampling. First, samples were collected only at the end of practice
because the time burden for collection and availability of athletes with sufficient lead times prior to
practice was limited. This means that a portion of some chemicals collected at the end of the practice
period may have been from exposures that occurred before the athletes practiced on the fields; in this
case, the measured amounts may overestimate the exposures that occurred during the sports practice.
Second, the sampling efficiencies for the numerous target analytes have not been tested for the wipe
methods that were used for this study. Thus, the amount of chemicals collected from the skin may be
underestimates. Finally, dermal sampling can only collect chemicals present at the skin surface at the
time of sampling. This approach cannot account for chemicals that may have already been absorbed into
or through the skin, nor can it provide an accurate measurement of what would be absorbed through skin
following the measurement. For example, chemicals on the skin may be removed after a sports practice
due to dislodgement, hand washing and/or showering. Despite these limitations, the dermal wipe
sampling provided valuable information about the potential for dermal exposures that had previously
been identified as a large data gap in understanding potential tire crumb rubber exposures on athletic
fields.
Metals - Dermal wipe samples were collected using Ghost wipe sample media pre-wetted with water.
Mean dermal wipe metals measurement results are shown in Table 4-42. Selenium was not measured
above the method detection limit in any sample. The remaining metals were measured at concentrations
above the minimum reporting limit in 100% of the samples, with exception of beryllium, which was
101
-------
measured above the minimum reporting limit in 61% or more of the samples. Some negative values are
reported as a result of field blank subtractions. Median dermal loading values for zinc and cobalt, two
tire material constituents, ranged from 4.1 to 54 ng/cm2 and from 0.012 to 0.084 ng/cm2, respectively.
Ranges of median lead and chromium dermal loadings were 0.027 to 0.27 ng/cm2 and 0.027 to 0.31
ng/cm2, respectively. Cadmium and arsenic were measured at median surface loadings that were <0.1
ng/cm2. Other metals commonly found in crustal particles, including aluminum, iron and magnesium,
were found at median levels that ranged from 9.9 - 140 ng/cm2.
There was considerable variability in dermal loading measurements within sport/age groups, with
percent relative standard deviation (%RSD) values often exceeding 100% (data not shown). Due to these
large variabilities and the relatively small sample sizes, statistical comparisons between groups were not
performed. In general, median dermal loadings for hand measurements in soccer players age 7 to 10
were higher than those in the other two groups for most metal analytes. Otherwise, there were no clear
patterns of differences in dermal loading between the sports and/or age groups.
Table 4-42. Exposure Pilot Study Participant Dermal Wipe Measurement Results for Selected Metals
Metal
Participants
%>
Minimum
Reporting
Limit
Hand
Wipe
Median
(ng/cm2)
Hand Wipe
Maximum
(ng/cm)2
Arm
Wipe
Median
(ng/cm2)
Arm Wipe
Maximum
(ng/cm2)
Leg Wipe
Median
(ng/cm2)
Leg Wipe
Maximum
(ng/cm2)
Arsenic
Soccer Players,
Age 11-21
100
0.031
0.055
0.059
0.11
0.072
0.18
Arsenic
Soccer Players,
Age 7 - 10
100
0.020
0.22
0.021
0.041
0.018
0.14
Arsenic
Football Players,
Age 13 - 14
100
0.024
0.059
0.070
0.34
0.073
0.19
Cadmium
Soccer Players,
Age 11-21
100
0.007
0.013
0.005
0.054
0.009
0.046
Cadmium
Soccer Players,
Age 7 - 10
100
0.010
0.016
0.0084
0.012
0.007
0.013
Cadmium
Football Players,
Age 13 - 14
100
0.006
0.042
0.019
0.14
0.014
0.038
Chromium
Soccer Players,
Age 11-21
100
0.098
0.19
0.027
0.37
0.090
1.1
Chromium
Soccer Players,
Age 7 - 10
100
0.31
0.59
0.16
0.34
0.30
0.71
Chromium
Football Players,
Age 13 - 14
100
0.10
0.53
0.23
0.31
0.28
0.69
Cobalt
Soccer Players,
Age 11-21
100
0.020
0.047
0.027
0.13
0.012
0.51
Cobalt
Soccer Players,
Age 7 - 10
100
0.082
0.46
0.063
0.10
0.084
0.45
Cobalt
Football Players,
Age 13 - 14
100
0.033
0.12
0.023
0.080
0.080
0.20
Lead
Soccer Players,
Age 11-21
100
0.056
0.16
0.027
0.28
0.043
1.2
Lead
Soccer Players,
Age 7 - 10
100
0.20
0.41
0.076
0.33
0.18
0.34
Lead
Football Players,
Age 13 - 14
100
0.085
0.38
0.093
0.24
0.27
0.66
102
-------
Table 4-42. Continued
Metal
Participants
%>
Minimum
Reporting
Limit
Hand
Wipe
Median
(ng/cm2)
Hand Wipe
Maximum
(ng/cm)2
Arm
Wipe
Median
(ng/cm2)
Arm Wipe
Maximum
(ng/cm2)
Leg Wipe
Median
(ng/cm2)
Leg Wipe
Maximum
(ng/cm2)
Zinc
Soccer Players,
Age 11-21
100
18
65
15
170
38
230
Zinc
Soccer Players,
Age 7 - 10
100
41
140
17
120
13
170
Zinc
Football Players,
Age 13 - 14
100
4.1
28
40
98
54
86
Aluminum
Soccer Players,
Age 11-21
100
30
65
41
160
25
430
Aluminum
Soccer Players,
Age 7 - 10
100
100
330
65
210
97
270
Aluminum
Football Players,
Age 13 - 14
100
43
150
33
110
110
320
Antimony
Soccer Players,
Age 11-21
100
0.032
0.061
-0.0048
0.10
0.010
0.22
Antimony
Soccer Players,
Age 7 - 10
100
0.079
0.20
0.04
0.098
0.045
0.33
Antimony
Football Players,
Age 13 - 14
100
0.033
0.14
0.053
0.59
0.064
0.17
Barium
Soccer Players,
Age 11-21
100
0.81
6.0
1.2
2.6
0.45
4.2
Barium
Soccer Players,
Age 7 - 10
100
1.8
5.3
1.1
2.7
1.3
4.8
Barium
Football Players,
Age 13 - 14
100
1.1
2.7
0.83
4.2
1.8
4.2
Beryllium
Soccer Players,
Age 11-21
91
0.001
0.004
0.0045
0.011
0.006
0.010
Beryllium
Soccer Players,
Age 7 - 10
61
-0.001
0.004
-0.0026
0
-0.003
0.003
Beryllium
Football Players,
Age 13 - 14
100
-0.001
0.003
-0.0035
0
-0.002
0.004
Copper
Soccer Players,
Age 11-21
100
0.99
1.9
0.89
4.4
1.1
5.9
Copper
Soccer Players,
Age 7 - 10
100
1.5
2.3
1.2
3.9
1.8
3.1
Copper
Football Players,
Age 13 - 14
100
0.72
1.9
1.1
2.5
1.2
5.2
Iron
Soccer Players,
Age 11-21
100
29
66
29
150
21
640
Iron
Soccer Players,
Age 7 - 10
100
110
220
50
170
93
170
Iron
Football Players,
Age 13 - 14
100
37
180
36
97
140
320
103
-------
Table 4-42. Continued
Metal
Participants
%>
Minimum
Reporting
Limit
Hand
Wipe
Median
(ng/cm2)
Hand Wipe
Maximum
(ng/cm)2
Arm
Wipe
Median
(ng/cm2)
Arm Wipe
Maximum
(ng/cm2)
Leg Wipe
Median
(ng/cm2)
Leg Wipe
Maximum
(ng/cm2)
Magnesium
Soccer Players,
Age 11-21
100
15
25
12
56
20
110
Magnesium
Soccer Players,
Age 7 - 10
100
42
76
26
87
49
73
Magnesium
Football Players,
Age 13 - 14
100
9.9
38
11
32
33
70
Manganese
Soccer Players,
Age 11-21
100
0.54
1.5
0.83
2.1
0.49
6.0
Manganese
Soccer Players,
Age 7 - 10
100
1.9
4.2
0.95
3.6
1.7
3.2
Manganese
Football Players,
Age 13 - 14
100
1.4
6.2
1.3
3.6
3.8
10
Molybdenum
Soccer Players,
Age 11-21
100
0.010
0.052
-0.0064
0.043
0.016
0.10
Molybdenum
Soccer Players,
Age 7 - 10
100
0.028
0.11
0.023
0.039
0.022
0.039
Molybdenum
Football Players,
Age 13 - 14
100
0.010
0.067
0.034
0.069
0.054
0.22
Nickel
Soccer Players,
Age 11-21
100
0.14
0.52
0.38
4.6
0.37
1.1
Nickel
Soccer Players,
Age 7 - 10
100
0.63
1.3
0.41
1.0
0.48
1.5
Nickel
Football Players,
Age 13 - 14
100
0.11
0.53
0.29
3.3
0.50
1.8
Rubidium
Soccer Players,
Age 11-21
100
0.90
3.9
1.4
2.1
1.7
4.0
Rubidium
Soccer Players,
Age 7 - 10
100
2.1
2.9
1.5
3.5
2.4
3.0
Rubidium
Football Players,
Age 13 - 14
100
0.37
2.6
0.73
2.2
2.5
5.4
Strontium
Soccer Players,
Age 11-21
100
0.20
0.48
0.11
0.51
0.13
0.86
Strontium
Soccer Players,
Age 7 - 10
100
0.65
1.1
0.33
0.92
0.57
0.91
Strontium
Football Players,
Age 13 - 14
100
0.28
1.1
0.31
1.1
0.86
2.0
Tin
Soccer Players,
Age 11-21
100
0.039
0.20
-0.012
0.02
-0.046
0.18
Tin
Soccer Players,
Age 7 - 10
100
0.23
0.28
0.024
0.16
0.06
0.14
Tin
Football Players,
Age 13 - 14
100
0.093
0.35
0.15
0.47
0.31
0.62
104
-------
Table 4-42. Continued
Metal
Participants
%>
Minimum
Reporting
Limit
Hand
Wipe
Median
(ng/cm2)
Hand Wipe
Maximum
(ng/cm)2
Arm
Wipe
Median
(ng/cm2)
Arm Wipe
Maximum
(ng/cm2)
Leg Wipe
Median
(ng/cm2)
Leg Wipe
Maximum
(ng/cm2)
Vanadium
Soccer Players,
Age 11-21
100
0.050
0.14
0.064
0.22
0.036
0.75
Vanadium
Soccer Players,
Age 7 - 10
100
0.19
0.45
0.11
0.37
0.17
0.36
Vanadium
Football Players,
Age 13 - 14
100
0.097
0.50
0.092
0.27
0.30
0.84
' Soccer players, 11 to 21 years old (n = 11); Soccer players, 7 to 10 years old (n= 6); Football players, 13 to 14 years old (n = 8)
Distributions of hand, arm, and leg dermal wipe measurement results for cobalt, lead, and zinc are
shown in Figure 4-15. The zinc results are impacted by the relatively high background levels measured
in the wipe material, resulting in some background corrected values below zero.
Cobalt
Football 13-14 yrs
Soccer 11-21 yrs
Lead
1.2
0.8
E
O
O)
c
0.4
0.0
Football 13-14 yrs
Soccer 11-21 yrs
T A
* JL
A
iT
Hand Arm Leg Hand Arm Leg Hand Arm Leg
Hand Arm Leg Hand Arm Leg Hand Arm Leg
Zinc
Football 13-14 yrs
Soccer 11-21 yrs
Soccer 7-10 yrs
200-
•
•
cn 100J
E
o
CO
c
0"
it
•
-r ^
T
l
•
— *
IT
•
•
-100
•
Hand Arm Leg Hand Arm Leg Hand Arm Leg
Figure 4-15. Distributions of hand, arm and leg dermal measurement results for cobalt, lead and zinc.
SVOCs - Dermal wipe samples were collected using wipe sample media pre-wetted with isopropanol.
105
-------
Median and maximum dermal wipe SVOC measurement results are shown in Table 4-43. Distributions
of hand, arm and leg dermal wipe measurement results in the three age/sport groups are shown in Figure
4-16 for fluoranthene, the sum of 15 PAHs, benzothiazole and di-n-octyl phthalate. There was a wide
range for the percent of measurements greater than the minimum quantifiable limit across the SVOC
analytes. Several analytes were measured above the minimum quantifiable limit in 100% of the samples,
including benzothiazole, bis(2-ethylhexyl) phthalate, benzyl butyl phthalate, 2,6-di-tert-butyl-p-cresol
and bis(2-ethylhexyl) adipate. Some negative values are reported as a result of field blank subtractions.
Measurement results below the minimum quantifiable limit were included in calculation of results.
Cyclohexylisothiocyanate, dimethyl phthalate, diethyl phthalate, 2-bromomethylnaphthalene, 2-
hydroxybenzothiazole, anthracene, diisobutyl phthalate, dibutyl phthalate, and bis(2,2,6,6-tetramethyl-
4piperidyl) sebacate measurement results were not reported due to poor performance in one or more
quality control sample type.
Median dermal loading values ranged from 0.057 to 0.17 ng/cm2 for benzothiazole, 1.7 to 7.0 ng/cm2 for
bis(2-ethylhexyl) phthalate, 0.0021 to 0.019 ng/cm2 for fluoranthene, and 0.018 to 0.13 ng/cm2 for the
sum of 15 PAHs. Several phthalates and other analytes had median dermal loading values >0.1 ng/cm2
in some participant groups, but the majority of analytes had median dermal loadings of < 0.1 ng/cm2,
with some analytes measuring < 0.01 ng/cm2 (although a majority of measurements in this latter group
were not above the minimum quantifiable limit).
There was considerable variability in SVOC dermal loading measurements within sport/age groups, with
%RSD values often exceeding 100% (data not shown). Due to these large variabilities and the relatively
small sample sizes, statistical comparisons between groups was not performed. For many but not all
SVOC analytes, average dermal loadings for hand, arm and leg measurements from soccer players age 7
to 10 were higher than those in the other two groups. This occurred most often for SVOCs found at
lower concentrations, and the percent of measurements above the minimum quantifiable limit was often
higher for soccer players age 7 to 10 than the other two groups. Observations of potential differences
among groups should be treated with caution due to the small sample sizes, high variability, and small
percentages of measurements above the minimum quantifiable limits for some analytes.
Overall, the dermal measurement results for metals and SVOCs showed that dermal exposures to
chemicals associated with tire crumb rubber are likely occurring for athletes participating in sports
activities. However, there may be contributions from sources other than the tire crumb rubber for many
of the metals and for some SVOCs, especially the phthalate analytes. Since no pre-activity dermal
sampling was performed, it is not possible to attribute all the measured dermal loading to exposures that
occurred at the synthetic turf fields.
Table 4-43. Exposure Pilot Study Dermal Wipe Measurement Results for Select SVOCs a'b'c
Semivolatile Organic
Compound (SVOC)
Participants
%>
Minimum
Quantifiable
Limit
Hand
Wipe
Median
(ng/cm2)
Hand
Wipe
Maximum
(ng/cm2)
Arm
Wipe
Median
(ng/cm2)
Arm
Wipe
Maximum
(ng/cm2)
Leg
Wipe
Median
(ng/cm2)
Leg Wipe
Maximum
(ng/cm2)
Phenanthrene
Soccer Players,
Age 11-21
27
0.0023
0.018
0.0076
0.060
0.0060
0.080
Phenanthrene
Soccer Players,
Age 7 - 10
44
0.014
0.018
0.034
0.12
0.027
0.035
Phenanthrene
Football Players,
Age 13 - 14
21
0.0014
0.0044
0.0046
0.0099
0.0033
0.0039
106
-------
Table 4-43. Continued
Semivolatile
Organic Compound
(SVOC)
Participants
%>
Minimum
Quantifiable
Limit
Hand
Wipe
Median
(ng/cm2)
Hand
Wipe
Maximum
(ng/cm2)
Arm
Wipe
Median
(ng/cm2)
Arm
Wipe
Maximum
(ng/cm2)
Leg
Wipe
Median
(ng/cm2)
Leg Wipe
Maximum
(ng/cm2)
Fluoranthene
Soccer Players,
Age 11-21
94
0.0036
0.011
0.0069
0.044
0.0092
0.094
Fluoranthene
Soccer Players,
Age 7 - 10
100
0.019
0.023
0.018
0.34
0.017
0.055
Fluoranthene
Football Players,
Age 13 - 14
92
0.0024
0.0096
0.0024
0.035
0.0021
0.011
Pyrene
Soccer Players,
Age 11-21
21
0.0035
0.0061
0.0033
0.029
0.0021
0.10
Pyrene
Soccer Players,
Age 7 - 10
50
0.0096
0.040
0.014
0.11
0.0081
0.11
Pyrene
Football Players,
Age 13 - 14
17
0.0037
0.012
0.0048
0.027
0.0057
0.019
Benzo[a]pyrene
Soccer Players,
Age 11-21
6
0.0013
0.0031
0.003
0.013
0.0006
0.026
Benzo[a]pyrene
Soccer Players,
Age 7 - 10
28
0.0052
0.0066
0.012
0.023
0.0070
0.014
Benzo[a]pyrene
Football Players,
Age 13 - 14
13
0.0005
0.0051
-0.00025
0.036
-0.0008
0.0034
Benzo [glii]perylene
Soccer Players,
Age 11-21
36
0.0033
0.0095
0.0044
0.034
0.0073
0.10
Benzo [ghi]perylene
Soccer Players,
Age 7 - 10
61
0.014
0.033
0.022
0.046
0.018
0.069
Benzo [glii]perylene
Football Players,
Age 13 - 14
46
0.0032
0.015
0.00075
0.038
0.0018
0.019
Suml5PAHd
Soccer Players,
Age 11-21
N/A
0.022
0.051
0.049
0.23
0.056
0.56
Suml5PAH
Soccer Players,
Age 7 - 10
N/A
0.11
0.14
0.13
1.2
0.098
0.34
Suml5PAH
Football Players,
Age 13 - 14
N/A
0.018
0.063
0.020
0.26
0.020
0.14
Benzotliiazole
Soccer Players,
Age 11-21
100
0.057
1.3
0.086
0.99
0.065
1.3
Benzotliiazole
Soccer Players,
Age 7 - 10
100
0.16
0.24
0.17
0.38
0.16
0.47
Benzotliiazole
Football Players,
Age 13 - 14
100
0.088
0.49
0.14
0.26
0.12
0.38
Bis(2-ethylhexyl)
phthalate
Soccer Players,
Age 11-21
100
1.7
3.2
4.0
9.9
3.9
5.5
Bis(2-ethylhexyl)
phthalate
Soccer Players,
Age 7 - 10
100
2.2
2.8
4.4
6.5
4.3
6.4
Bis(2-ethylhexyl)
phthalate
Football Players,
Age 13 - 14
100
2.0
2.3
6.2
16
7.0
11
107
-------
Table 4-43. Continued
Semivolatile
Organic Compound
(SVOC)
Participants
%>
Minimum
Quantifiable
Limit
Hand
Wipe
Median
(ng/cm2)
Hand
Wipe
Maximum
(ng/cm2)
Arm
Wipe
Median
(ng/cm2)
Arm
Wipe
Maximum
(ng/cm2)
Leg
Wipe
Median
(ng/cm2)
Leg Wipe
Maximum
(ng/cm2)
Aniline
Soccer Players,
Age 11-21
45
0.018
0.26
0
0.70
0
0.81
Aniline
Soccer Players,
Age 7 - 10
61
0.047
0.13
0.036
0.13
0.082
0.31
Aniline
Football Players,
Age 13 - 14
46
0.017
0.12
0
0.15
0.069
0.21
4-tert-octylphenol
Soccer Players,
Age 11-21
100
0.10
1.4
0.10
1.2
0.13
1.6
4-tert-octylphenol
Soccer Players,
Age 7 - 10
100
-0.061
0.48
-0.16
-0.13
-0.11
0.62
4-tert-octylphenol
Football Players,
Age 13 - 14
92
0.096
0.46
0.17
0.39
0.21
0.60
n-Hexadecane
Soccer Players,
Age 11-21
100
0.11
0.44
0.38
1.4
0.69
2.2
n-Hexadecane
Soccer Players,
Age 7 - 10
100
-0.0061
0.48
0.21
2.9
0.13
0.53
n-Hexadecane
Football Players,
Age 13 - 14
92
NR
NR
NR
NR
NR
NR
Naphthalene
Soccer Players,
Age 11-21
24
0.0019
0.0033
0.0066
0.0091
0.0068
0.012
Naphthalene
Soccer Players,
Age 7 - 10
17
0.0029
0.0038
0.0048
0.0072
0.0046
0.0069
Naphthalene
Football Players,
Age 13 - 14
17
-0.0001
0.0015
-0.0006
0.0029
-0.0012
0.002
2-Methylnaphthalene
Soccer Players,
Age 11-21
12
0.0025
0.0099
0.0018
0.033
0.0008
0.042
2-Methylnaphthalene
Soccer Players,
Age 7 - 10
6
0.0092
0.015
0.022
0.029
0.021
0.031
2-Methylnaphthalene
Football Players,
Age 13 - 14
21
0.0022
0.0061
0.0028
0.014
0.0021
0.0095
Fluorene
Soccer Players,
Age 11-21
12
0.0002
0.0003
0.0003
0.0027
0.0004
0.0021
Fluorene
Soccer Players,
Age 7 - 10
17
-0.0002
0.0002
-0.0004
0.0004
-0.0005
0.0003
Fluorene
Football Players,
Age 13 - 14
21
0.0002
0.0008
-0.0004
0.0038
-0.0004
0.0001
1 -Methy lphenanthrene
Soccer Players,
Age 11-21
88
0.0007
0.0048
0.0010
0.011
0.0003
0.015
1 -Methy lphenanthrene
Soccer Players,
Age 7 - 10
44
0.0007
0.0087
0.0016
0.0060
0.0028
0.013
1 -Methy lphenanthrene
Football Players,
Age 13 - 14
100
0.0021
0.0043
0.0032
0.014
0.0030
0.0058
108
-------
Table 4-43. Continued
Semivolatile
Organic Compound
(SVOC)
Participants
%>
Minimum
Quantifiable
Limit
Hand
Wipe
Median
(ng/cm2)
Hand
Wipe
Maximum
(ng/cm2)
Arm
Wipe
Median
(ng/cm2)
Arm
Wipe
Maximum
(ng/cm2)
Leg
Wipe
Median
(ng/cm2)
Leg Wipe
Maximum
(ng/cm2)
Benz(a)anthracene
Soccer Players,
Age 11-21
0
0.0009
0.0021
0.0010
0.0087
0.0016
0.014
Benz(a)anthracene
Soccer Players,
Age 7 - 10
28
0.0036
0.0038
0.0071
0.046
0.0058
0.011
Benz(a)anthracene
Football Players,
Age 13 - 14
13
-0.0001
0.0020
-0.0007
0.020
-0.0008
0.14
Chrysene
Soccer Players,
Age 11-21
48
0.0031
0.0070
0.0056
0.019
0.0028
0.066
Clirysene
Soccer Players,
Age 7 - 10
89
0.014
0.017
0.013
0.11
0.013
0.049
Clirysene
Football Players,
Age 13 - 14
42
0.0029
0.010
0.0013
0.031
0.0031
0.013
B enzo (b )fluoranthene
Soccer Players,
Age 11-21
12
0.0009
0.0041
0
0.015
0.0015
0.037
B enzo (b )fluoranthene
Soccer Players,
Age 7 - 10
61
0.010
0.018
0.015
0.29
0.013
0.023
B enzo (b )fluoranthene
Football Players,
Age 13 - 14
4
0
0.0024
0
0.030
0
0
B enzo (k)fluoranthene
Soccer Players,
Age 11-21
15
0.0001
0.0013
0.0017
0.0077
0.0008
0.012
B enzo (k)fluoranthene
Soccer Players,
Age 7 - 10
67
0.0026
0.0059
0.0077
0.085
0.0041
0.0092
B enzo (k)fluoranthene
Football Players,
Age 13 - 14
8
0.0006
0.0017
0.0018
0.017
0.0013
0.0044
Benzo(e)pyrene
Soccer Players,
Age 11-21
6
0.0001
0.0016
0
0.0063
0
0.027
Benzo(e)pyrene
Soccer Players,
Age 7 - 10
39
0.0046
0.010
0.0069
0.048
0.0028
0.022
Benzo(e)pyrene
Football Players,
Age 13 - 14
17
0.0001
0.0046
-0.0012
0.022
-0.0012
0.0027
Coronene
Soccer Players,
Age 11-21
18
0
0.010
0
0.071
0
0.24
Coronene
Soccer Players,
Age 7 - 10
44
0.015
0.024
0.013
0.037
0.0092
0.038
Coronene
Football Players,
Age 13 - 14
8
0
0.0039
0
0.0096
0
0
Dibenzothiophene
Soccer Players,
Age 11-21
39
-0.0001
0.0010
-0.0004
0.0052
-0.0004
0.0043
Dibenzotliiophene
Soccer Players,
Age 7 - 10
67
-0.0005
0.0031
-0.0009
0.0032
0
0.0031
Dibenzotliiophene
Football Players,
Age 13 - 14
25
0.0002
0.0018
-0.0002
0.0049
-0.0015
0.0004
109
-------
Table 4-43. Continued
Semivolatile
Organic Compound
(SVOC)
Participants
%>
Minimum
Quantifiable
Limit
Hand
Wipe
Median
(ng/cm2)
Hand
Wipe
Maximum
(ng/cm2)
Arm
Wipe
Median
(ng/cm2)
Arm
Wipe
Maximum
(ng/cm2)
Leg
Wipe
Median
(ng/cm2)
Leg Wipe
Maximum
(ng/cm2)
n-Butylbenzene
Soccer Players,
Age 11-21
70
-0.0042
0.11
0.013
0.23
-0.025
0.046
n-Butylbenzene
Soccer Players,
Age 7 - 10
61
0.017
0.033
0.0066
0.14
-0.047
0.063
n-Butylbenzene
Football Players,
Age 13 - 14
75
-0.0008
0.023
-0.0081
0.068
-0.025
0.082
Benzyl butyl phthalate
Soccer Players,
Age 11-21
100
0.21
3.8
0.78
12
0.75
16
Benzyl butyl phthalate
Soccer Players,
Age 7 - 10
100
1.1
2.9
0.79
1.7
1.1
3.9
Benzyl butyl phthalate
Football Players,
Age 13 - 14
100
NR
NR
NR
NR
NR
NR
Di-n-octyl phthalate
Soccer Players,
Age 11-21
94
0.054
0.86
0.15
4.0
0.18
2.3
Di-n-octyl phthalate
Soccer Players,
Age 7 - 10
89
0.10
0.37
0.088
0.59
0.22
0.84
Di-n-octyl phthalate
Football Players,
Age 13 - 14
100
0.058
0.13
0.23
0.65
0.13
0.44
2,6-Di-tert-butyl-p-
cresol
Soccer Players,
Age 11-21
100
0.024
0.14
0.074
0.59
0.13
0.39
2,6-Di-tert-butyl-p-
cresol
Soccer Players,
Age 7 - 10
100
0.033
0.083
0.079
0.30
0.020
0.06
2,6-Di-tert-butyl-p-
cresol
Football Players,
Age 13 - 14
100
0.035
0.068
0.092
0.21
0.15
0.19
bis(2-Ethylhexyl)
adipate
Soccer Players,
Age 11-21
100
0.59
3.5
0.73
8.9
0.76
19
bis(2-Ethylhexyl)
adipate
Soccer Players,
Age 7 - 10
100
0.94
5.3
2.2
19
1.9
3.5
bis(2-Ethylhexyl)
adipate
Football Players,
Age 13 - 14
100
0.68
1.9
3.0
15
1.8
3.4
a Soccer players, 11 to 21 years old (n = 11); Soccer players, 7 to 10 years old (n = 6); Football players, 13 to 14 years old (n = 8)
b Although several chemicals had <50% of the measured values above the quantifiable limits, all measured values from the
analysis, including those reported by the laboratory that were below the quantifiable limits, were used in the calculation of
median values; chemicals that did not have at least 20% of measurements above the method quantifiable limit in one of the
three sport/age groups were not included
0 N/R = not reported
dSuml5PAH = Sum of 15 of the 16 EPA 'priority' PAHs, including Acenaphthylene, Anthracene, Benz[a]anthracene,
Benzo[a]pyrene, Benzo(b)fluoranthene, Benzo[ghi]perylene, Benzo(k)fluoranthene, Chrysene, Dibenz[a,h]anthracene,
Fluoranthene, Fluorene, Indeno(l,2,3-cd)pyrene, Naphthalene, Phenanthrene, Pyrene
110
-------
Fluoranthene
Sum15PAH
0.3
« 0.2
o
o>
c
0.1
0.0
Footeal 13-14 yre Soccer 11-21 yrs Soccer 7-10 yts
Hand Arm leg Hand Ann Leg Hand Arm Leg
1.2
0.8
E
o
o>
c
0.4
0.0
Footbal 13-14 yrs
Soccef 11-21 yrs
4= ^
Soccer 7-10 yrs
£
Hand Arm Leg Hand Arm Leg Hand Arm Leg
Benzothiazole
1.0
,0
o>
c 0.5
0.0
Footbai 13-14 yrs Soccer 11-21 yre Soccer 7-10 yrs
Hand Arm Leg Hand Arm Leg Hand Arm Leg
Di-n-octyl phthalate
o 2
cn
c
Football 13-14 yrs
Soccer 11-21 yrs
,4^
Soccer 7-10 >fB
F»q 1
Hand Arm Leg Hand Arm Leg Hand Arm Leg
Figure 4-16. Distributions of dermal measurement results for fluoranthene, the sum
of 15 PAHs, benzothiazole, and di-n-octyl phthalate.
4.5.3 Pilot-Scale Biological Sample Measurements
4.5.3.1 Urine and Blood Samples
Urine and blood samples were collected from select pilot study participants before and after practicing
on synthetic turf fields with tire crumb rubber infill. Participants were provided with a sealed sterile
urine collection cup to collect the urine samples on-site in facility restrooms. For blood and serum
samples, blood draws were administered on-site at a designated area by a certified phlebotomist.
Biological samples were collected from participants at two outdoor fields on multiple days prior to and
after football and soccer practices. Results are provided in this section for urine and blood measurements
performed for pilot study participants. Results for the supplemental biomonitoring study are presented in
Appendix A.
As previously reported, a total of 13 participants gave blood specimens and 14 participants provided
urine specimens. Participants included soccer players 11 to 21 years of age (n = 7) and football players
13 to 14 years of age (n = 7). For two of the participants, the phlebotomist was unable to obtain blood
samples following their practice activities; this may have been due to dehydration after rigorous on-field
ill
-------
activity. For the urine collection, participants were directed to not touch the inside of the urine specimen
container so as to not contaminate the sample. However, we cannot confirm that all participants
followed the specified procedures.
A variety of measures were used to assess normality of the distribution of biological sample
measurement results, including the Shapiro-Wilk test, as well as skewness and kurtosis values. As the
data were not normally distributed, a Wilcoxon Signed-Rank Test was performed to determine any pre-
activity and post-activity differences for all participants combined and then separately by sport. The
Wilcoxon Signed-Rank Test is a non-parametric statistical hypothesis test that can be used to compare
repeated measurements. Additionally, t-tests were performed and the corresponding p-values included
for comparison. Skewness and kurtosis are measures of a shape of the distribution of measurements.
Urinary PAHs - Exposure pilot study pre- and post-activity measurements for several PAH urinary
biomarkers are shown in Tables 4-44 and 4-45. Individual differences in pre- and post-activity urinary
PAH concentrations are illustrated in Figures 4-17 through 4-2. All measurements were creatinine-
adjusted to account for urinary dilution; measurements were also adjusted for specific-gravity Table 4-
46).
Table 4-44. Exposure Pilot Study Pre- and Post-Activity Creatinine-Adjusted Urinary PAH Measurementsa'b
PAH
Pre-
Activity
Mean
Pre-
Activity
Standard
Deviation
Pre-
Activity
Geo
Mean
Pre-
Activity
95% CI
Post-
Activity
Mean
Post-
Activity
Standard
Deviation
Post-
Activity
Geo
Mean
Post-
Activity
95% CI
1 -Hydroxynaphthalene (ng/g)
1.32
1.51
0.90
0.58-1.39
1.40
1.78
0.90
0.57-1.41
2-Hydroxynaphthalene (ng/g)
7.85
4.49
6.53
4.63-9.19
10.31
5.81
8.74
6.37-12.00
1-Hydroxyphenanthrene (ng/g)
102
89.9
80.9
57.9-113
114
111
91.1
66.9 - 124
2 & 3-Hydroxyphenanthrene
(ng/g)
145
171
111
81 - 152
155
216
110
78.7-154
2-Hydroxyfluorene (ng/g)
188
128
162
125-211
193
150
164
125-214
3-Hydroxyfluorene (ng/g)
69
65.4
56.3
42.3 -74.9
73.0
87.5
54.2
38.5 -76.4
1-Hydroxypyrene (ng/g)
104
85.1
84.6
62.1-115
90.2
73.7
73.8
54.1 - 101
a PAH = Poly cyclic aromatic hydrocarbon; Geo = Geometric; CI = Confidence interval
b Number of samples = 14
112
-------
Table 4-45. Exposure Pilot Stud]
^ Pre- ant
Post-Activity Creatinine-Adjustet
Urinary PAH Measurements,
)y Sport1'b
PAH
Sport
Pre-
Activity
Mean
Pre-
Activity
Standard
Deviation
Pre-
Activity Geo
Mean
Pre-
Activity 95%
CI
Post-
Activi
ty
Mean
Post-
Activity
Standard
Deviation
Post-
Activity
Geo Mean
Post-
Activity 95%
CI
1-Hydroxynaphthalene (ng/g)
Soccer
1.66
2.06
0.943
0.428-2.08
1.79
2.42
0.974
0.439-2.16
1-Hydroxynaphthalene (ng/g)
Football
0.987
0.645
0.850
0.571-1.26
1.01
0.816
0.829
0.532- 1.29
2-Hydroxynaphthalene (ng/g)
Soccer
8.26
4.42
6.91
4.20-11.4
10.4
6.41
8.73
5.46-13.9
2-Hydroxynaphthalene (ng/g)
Football
7.45
4.86
6.17
3.84-9.91
10.2
5.65
8.76
5.68-13.5
1-Hydroxyphenantlirene (ng/g)
Soccer
128
121
97.4
58.1 - 164
142
156
101
57.3-177
1-Hydroxyphenantlirene (ng/g)
Football
75.1
35.3
67.1
46.1 -97.8
86.2
26.9
82.5
65.5-104
2- & 3-Hydroxyphenanthrene
(ng/g)
Soccer
188
241
123
67.1 -225
207
307
121
62.3 -233
2- & 3-Hydroxyphenanthrene
(ng/g)
Football
102
22.3
100
85.0-118
102
17.2
101
88.8-115
2-Hydroxyfluorene (ng/g)
Soccer
220
173
179
114-282
225
206
177
110-285
2-Hydroxyfluorene (ng/g)
Football
156
58.3
147
114-190
160
61.5
151
118-194
3-Hydroxyfluorene (ng/g)
Soccer
85.3
91.0
63.8
38.7-105
95.3
123
61.9
33.4-115
3-Hydroxyfluorene (ng/g)
Football
52.6
18.9
49.7
38.4-64.3
50.7
19.6
47.4
35.8-62.8
1-Hydroxypyrene (ng/g)
Soccer
115
111
87.6
53.0-145
109
101
82.5
48.5 - 140
1-Hydroxypyrene (ng/g)
Football
92.9
55.1
81.7
56.6-118
71.3
28.7
66.0
48.4-89.9
PAH = Poly cyclic aromatic hydrocarbon; Geo = Geometric; CI = Confidence interval
Number of soccer player samples = 7; Number of football player samples = 7
-------
Table 4-46. Exposure Pilot Study Pre- and Post-Activity Specific-Gravity-Adjusted Urinary PAH Measurements, by Sport "'h
PAH
Sport
Pre-
Activity
Mean
Pre-
Activity
Standard
Deviation
Pre-Activity
Geo Mean
Pre-Activity
95% CI
Post-
Activity
Mean
Post-Activity
Standard
Deviation
Post-
Activity
Geo Mean
Post-
Activity
95% CI
1-Hydroxynaphthalene (ng/g)
Soccer
2.40
3.43
1.41
0.712-2.80
4.34
6.52
2.51
1.29-4.89
1-Hydroxynaphthalene (ng/g)
Football
1.27
0.861
1.08
0.718-1.63
2.00
1.60
1.61
1.01-2.58
2-Hydroxynaphthalene (ng/g)
Soccer
11.2
4.70
10.3
7.60-14.1
26.6
18.4
22.5
14.8-34.0
2-Hydroxynaphthalene (ng/g)
Football
9.71
6.87
7.84
4.79-12.8
19.7
10.7
17.1
11.2-26.0
1-Hydroxyphenantlirene (ng/g)
Soccer
196
204
146
86.8-245
365
420
259
150 - 446
1-Hydroxyphenantlirene (ng/g)
Football
102
63.0
85.4
54.3 - 134
177
76.5
161
114-227
2- & 3-Hydroxyphenanthrene
(ng/g)
Soccer
295
408
184
98.5 -343
549
828
310
155-619
2- & 3-Hydroxyphenantlirene
(ng/g)
Football
136
51.7
127
97.2 - 167
208
71.5
197
151-256
2-Hydroxyfluorene (ng/g)
Soccer
356
315
268
156-460
629
608
455
258 - 805
2-Hydroxyfluorene (ng/g)
Football
205
89.1
187
133 -262
318
133
295
220 - 396
3-Hydroxyfluorene (ng/g)
Soccer
136
157
95.4
55.0-166
261
338
159
81.4-312
3-Hydroxyfluorene (ng/g)
Football
67.4
26.4
63.2
48.2-82.7
98.7
38.1
92.5
70.6-121
1-Hydroxypyrene (ng/g)
Soccer
175
189
131
79.9-215
271
265
212
134- 335
1-Hydroxypyrene (ng/g)
Football
119
72.2
104
70.5 - 153
144
61.9
129
86.8-191
PAH = Poly cyclic aromatic hydrocarbon; Geo = Geometric; CI = Confidence interval
Number of soccer player samples = 7; Number of football player samples = 7
-------
Post-Pre Test (Difference) Plots bylD
Analyte=1-NAP
-
n
REC
= Increase
GREEN = Decrease
1 2 3 4 5 6 7 8 9 10 13 14 15 16
Participant ID
Figure 4-17. Exposure pilot study pre- and post-activity differences in creatinine
adjusted 1-hydroxynaphthalene measurements (iig/g). by participant.
Post-Pre Test (Difference) Plots by ID
Analyte=1-PHE
100
>
O
>
TO
C
<
"to
o
Q.
~o
"to
o
0-
50 -
RED = Increase
GREEN = Decrease
6 7 8 9
Participant ID
10
13
14
15
16
Figure 4-18. Exposure pilot study pre- and post-activity differences in creatinine
adjusted 1-hydroxyphenanthrene measurements (ng/g), by participant.
-------
Post-Pre Test (Difference) Plots bylD
Analyte=1-PYR
ns
>
ns
c
<
13
ai
¦o
c
ns
13
o
a.
50
-50
^ -100
RED = Increase
GREEN = Decrease
6 7 8 9
Participant ID
10
13
14
15
16
Figure 4-19. Exposure pilot study pre- and post-activity differences in creatinine-
adjusted 1-hydroxypyrene measurements (ng/g), by participant.
Post-Pre Test (Difference) Plots by ID
Analyte=2-3PHE
200
(0
>
0)
>
(0
c
<
0)
Q_
¦O
c
(0
w
o
Q_
c
0)
0)
100-
5 "10°
RED = Increase
GREEN = Decrease
6 7 8 9
Participant ID
10
13
14
15
16
Figure 4-20. Exposure pilot study pre- and post-activity differences in creatinine-
adjusted 2- & 3-hydroxyphenanthrene measurements (ng/g), by participant.
116
-------
Q)
Q_
"O
c
(0
w
o
Q_
c
Q)
Q)
100
w
Q)
3
(0
>
50 -
(0
c
<
-50 -
-100
-150-
Post-Pre Test (Difference) Plots by ID
Analyte=2-FLU
RED = Increase
GREEN = Decrease
1 2 3 4 5 6 7 8 9 10 13 14 15 16
Participant ID
Figure 4-21. Exposure pilot study pre- and post-activity differences in creatinine-adjusted
2-hydroxyfluorene measurements (ng/g), by participant.
ns
>
<
ts
ts
o
Q.
c
ai
15
10
Z 0
-5
Post-Pre Test (Difference) Plots bylD
Analyte=2-NAP
RED = Increase
GREEN = Decrease
I II 1
nn
6 7 8 9
Participant ID
10
13
14
15
16
Figure 4-22. Exposure pilot study pre- and post-activity differences in creatinine-adjusted
2-hydroxynaphthalene measurements (jig/g), by participant.
117
-------
ns
>
ns
c
<
13
ai
¦o
c
ns
13
o
a.
Post-Pre Test (Difference) Plots bylD
Analyte=3-FLU
75
50
25
RED = Increase
I
-25
GREEN = Decrease
6 7 8 9
Participant ID
10
13
14
15
16
Figure 4-23. Exposure pilot study pre- and post-activity differences in creatinine-adjusted
3-hydroxyfluorene measurements (ng/g), by participant.
The urinary PAH data were not normally distributed as shown in the Shapiro-Wilk test /^-values and
skewness and kurtosis values in Tables 4-47 and 4-48. For all participants, 2-hydroxynaphthalene had
the highest pre-activity mean concentration [geometric mean = 6.53 |ig/g; 95% confidence interval (CI):
4.63 - 9.19 |ig/g], as well as post-activity mean concentration (geometric mean = 8.74 |ig/g; 95% CI:
6.37 - 12.00 |ig/g). There was a significant difference in mean concentrations when comparing pre- and
post-activity levels for 2-hydroxynaphthalene (/;-value = 0.041; Table 4-47). This difference was
increased when comparing pre- and post-activity concentrations from football players only (/;-value =
0.016; Table 4-48). Although there is weak evidence for a difference in pre- and post-activity for 2-
hydroxynaphthalene (/;-value = 0.041), a Bayes Factor was calculated and confirmed no indication for a
real effect. However, there is weak evidence for a difference in pre- and post-activity concentrations of
2-hydroxynaphthalene in football players (/;-value = 0.016; Table 4-48). All seven football players had
increases in 2-hydroxynaphthalene post-activity. While the calculated Bayes Factor indicates weak
evidence, this may largely be a result of the small sample size. In general, the small sample size for these
statistical analyses is a significant limitation, as statistical power was near or below 20% for most of the
statistical tests performed on the data. Note that naphthalene had low values in the field measurement
data sets, including tire crumb rubber infill, field air, field dust, field wipe, and drag sled averages, and
naphthalene was 4 to over 100 times lower than phenanthrene in these media. Only 17% of the dermal
wipe naphthalene measurements were above the quantifiable limit for the football players (Table 4-43).
118
-------
Table 4-47. Statistical Analysis of Differences in Exposure Pilot Study Pre- and Post-Activity Creatinine-Adjustet
Urinary
'AH Measurements
PAH
Minimum
Difference"
Maximum
Differencea
Median
Mean
Standard
Deviation
Skewness
Kurtosis
ProbNb
Probtc
Probsrd
1 -Hydroxynaphthalene (ng/g)
-1.25
1.05
0.00
0.08
0.54
-0.43
2.78
0.023
0.596
0.618
2-Hydroxynaphthalene (ng/g)
-5.75
13.9
1.28
2.45
4.32
1.00
3.79
0.048
0.053
0.041
1-Hydroxyphenantlirene (ng/g)
-59.6
95.7
1.78
12.4
43.11
0.94
0.70
0.006
0.301
0.463
2- & 3-Hydroxyphenanthrene (ng/g)
-120
172
0.63
9.12
62.4
0.95
4.42
0.001
0.594
0.820
2-Hydroxyfluorene (ng/g)
-148
105
4.13
4.88
54.7
-1.25
5.44
0.001
0.744
0.153
3-Hydroxyfluorene (ng/g)
-41.1
81.4
-2.75
4.08
28.6
1.51
3.78
0.018
0.603
0.715
1-Hydroxypyrene (ng/g)
-113
75.1
-9.60
-13.6
42.2
-0.28
2.76
0.068
0.249
0.078
a These values represent the difference in the pre- and post-activity polycyclic aromatic hydrocarbon (PAH) concentrations. Number of samples = 14.
b Shapiro-Wilk test for normality /?-valuc
0 T-test /?-\aluc
d Wilcoxon Signed-Rank test /?-value
-------
Table 4-48. Statistical Analysis of Differences in Exposure Pilot Stud;
y Pre- am
PAH
Sport
Minimum
Difference"
Maximum
Difference"
Median
Mean
Standard
Deviation
Skewness
Kurtosis
ProbNb
Probtc
Probsrd
1-Hydroxynaphthalene (ng/g)
Soccer
-1.25
1.05
0.1
0.13
0.77
-0.68
1.08
0.424
0.673
0.688
1-Hydroxynaphthalene (ng/g)
Football
-0.15
0.45
0
0.03
0.2
2.01
4.66
0.023
0.715
0.875
2-Hydroxynaphthalene (ng/g)
Soccer
-5.75
13.85
1.05
2.16
6.13
1.1
2.16
0.38
0.388
0.578
2-Hydroxynaphthalene (ng/g)
Football
0.95
4.7
2.9
2.75
1.64
0.13
-2.14
0.143
0.004
0.016
1-Hydroxyphenantlirene (ng/g)
Soccer
-59.6
95.7
2.35
13.64
51.32
0.48
0.09
0.45
0.508
0.578
1-Hydroxyphenanthrene (ng/g)
Football
-19.4
93.85
1.2
11.16
37.27
2.39
6.13
0.001
0.458
0.688
2- & 3-Hydroxyphenanthrene (ng/g)
Soccer
-120
172.3
-0.7
18.48
90.25
0.38
1.29
0.326
0.608
1
2- & 3-Hydroxyphenantlirene (ng/g)
Football
-14.2
11.75
0.7
-0.24
9.04
-0.4
-0.54
0.636
0.946
0.813
2-Hydroxyfluorene (ng/g)
Soccer
-148
105.1
4.85
5.31
80.1
-1.05
2.31
0.204
0.866
0.578
2-Hydroxyfluorene (ng/g)
Football
-6.05
18.15
3.4
4.45
7.35
0.81
2.21
0.489
0.16
0.109
3-Hydroxyfluorene (ng/g)
Soccer
-41.1
81.35
1.05
9.99
40.32
0.8
0.66
0.83
0.537
0.813
3-Hydroxyfluorene (ng/g)
Football
-8.25
15.7
-3.4
-1.83
8.12
2.14
5.03
0.009
0.573
0.297
1-Hydroxypyrene (ng/g)
Soccer
-53.7
75.05
-7.3
-5.66
40.4
1.36
3.13
0.101
0.724
0.297
1-Hydroxypyrene (ng/g)
Football
-113
38.05
-12.5
-21.5
45.58
-1.38
3.65
0.066
0.258
0.219
Post-Activity Creatine-Adjusted Urinary PAH Measurements, by Sport
a These values represent the difference in the pre- and post-activity polycyclic aromatic hydrocarbon (PAH) concentrations in soccer players (number of samples = 7) and
football players (number of samples = 7).
b Shapiro-Wilk test for normality /?-valuc
0 T-test /?-\aluc
d Wilcoxon Signed-Rank test /?-valuc
120
-------
When compared with PAH analytes reported in the NHANES data (CDC 2013-2014) for ages 11 to 21
(Table 4-49), the synthetic turf field users had similar mean PAH concentrations for the analytes
measured, with exception of 1-hydroxypyrene, 2-hydroxynaphthalene, and 3-hydroxyfluorene (Figure 4-
24). The NHANES geometric mean for 1-hydroxypyrene (156 ng/g) was greater than the exposure pilot
study participants' pre-activity and post-activity geometric means (84.6 ng/g and 73.8 ng/g,
respectively), and the same was true for 3-hydroxyfluorene. The NHANES geometric mean for 3-
hydroxyfluorene (80.7 ng/g) was also greater than the exposure pilot study participants' pre- and post-
activity geometric means (56.3 ng/g and 54.2 ng/g, respectively). However, for 2-hydroxynaphthalene,
the exposure pilot study participants' pre-activity (6.53 ng/g) and post-activity (8.74 ng/g) geometric
means were greater than the NHANES geometric mean (4.89 ng/g), but less than and similar to the
2013-2014 NHANES 75th percentile (8.20 ng/g; 95 % CI: 6.52-9.59 ng/g) for 12 to 19 year olds. Pre-
activity and post-activity geometric means from the exposure pilot study and the NHANES (CDC 2013-
2014) comparison values are presented in Figure 4-24.
Table 4-49. NHANES Weighted and Design-Adjusted Urinary PAH Values (2013-2014) for Ages 11 to 21a,b
PAH
Minimum
Maximum
Median
Mean
95% CI
Geo
Mean
Standard
Error
1 -Hydroxynaphthalene (ng/g Crea)
0.13
48.3
0.88
2.47
1.89-3.05
1.11
0.08
2-Hydroxynaphthalene (ng/g Crea)
0.58
96.7
4.72
6.98
6.11-7.84
4.89
0.25
1-Hydroxyphenanthrene (ng/g Crea)
5.66
830
87.9
112
102-121
90.0
3.49
2 & 3-Hydroxyphenanthrene
(ng/gCrea)
25.3
1386
107
145
127 - 163
118
5.45
2-Hydroxyfluorene (ng/g Crea)
18.4
1937
148
255
215-294
173
9.31
3-Hydroxyfluorene (ng/g Crea)
11.9
1541
68.6
139
109 - 170
80.7
4.72
1-Hydroxypyrene (ng/g Crea)
19.6
2010
147
200
176-225
156
8.15
a Values from 580 National Health and Nutrition Examination Survey (NHANES 2013-2014) participants, age 11 to 21.
b PAH = polycyclic aromatic hydrocarbons; CI = confidence interval; Geo = geometric; Crea = creatine
121
-------
200
180
160
140
120
100
80
60
40
20
1-NAP (|_ig/g) 1-PHE (ng/g) 1-PYR (ng/g) 2 & 3-PHE 2-FLU (ng/g) 2-NAP(pg/g) 3-FLU (ng/g)
(ng/g)
¦ Pre-activity ¦ Post-activity BNHANES
Figure 4-24. Exposure pilot study pre-activity and post-activity creatinine-adjusted urinary PAH
geometric means compared to NHANES (2013-2014) geometric mean values for ages 11 to 21.
[PAH = poly cyclic aromatic hydrocarbon; 1-NAP = 1-Hydroxynaphthlaene; 1-PHE = 1-Hydroxyphenanthrene;
1-PYR = 1-Hydroxypyrene; 2 & 3-PHE = 2- & 3-Hydroxyphenanthrene; 2-FLU = 2-Hydroxyfluorene; 2-NAP =
2-Hydroxynaphthlaene; 3-FLU = 3-Hydroxyfluorene]
Metals in blood serum - Pre-activity and post-activity concentrations of metals in blood and serum
samples taken in the exposure pilot study are shown in Tables 4-50 and 4-51. When comparing pre-
activity measurements to post-activity measurements, there were no significant differences observed in
the mean or geometric mean for any of the whole blood metals. Additionally, there were no significant
differences observed in pre- and post-activity concentrations for the serum metals (Table 4-52). There
were also no significant differences in mean concentrations for pre-activity levels and post-activity
levels in football players or in soccer players (Table 4-53). However, toxicokinetics would suggest that
few differences in blood or serum metal concentrations would be expected over the short timeframe of a
football or soccer practice. Individual differences in pre- and post-activity blood/serum metals
concentrations are illustrated in Figures 4-25 through 4-32.
122
-------
Table 4-50. Exposure Pilot Study Pre- and Post-Activity Blood and Serum Metal Measurements3'b
Medium/Metal
Pre-
Activity
Mean
Pre-
Activity
Standard
Deviation
Pre-
Activity
Geo
Mean
Pre-Activity
95% CI
Post-
Activity
Mean
Post-
Activity
Standard
Deviation
Post-
Activity
Geo
Mean
Post-
Activity
95% CI
Blood cadmium (|ig/L)
0.23
0.06
0.22
0.20-0.24
0.20
0.07
0.21
0.18-0.24
Blood manganese (|ig/L)
9.84
2.69
9.51
8.22-11.0
9.91
3.63
9.40
7.76-11.4
Blood lead (ng/dL)
0.43
0.14
0.41
0.35-0.49
0.44
0.16
0.41
0.33-0.51
Blood mercury, total (|ig/L)
0.78
0.96
0.51
0.32-0.81
0.92
1.13
0.61
0.37-1.01
Blood selenium (|ig/L)
217
15.5
216
208 - 225
222
24.8
221
207 - 235
Serum copper (|ig/dL)
99.2
9.19
98.8
94.0 - 104
98.3
11.4
97.7
91.2-105
Serum selenium (ng/L)
125
9.67
124
120 - 129
127
13.5
127
120-134
Serum zinc (ng/dL)
83.7
10.1
83.1
78.0-88.6
83.4
10.5
82.7
76.2 - 90.0
a Geo = Geometric; CI = Confidence interval; dL = deciliter
b Number of samples = 13 (6 soccer players and 7 football players)
123
-------
Table 4-51. Exposure Pilot Study Pre- and Post-Activity Blood and Serum Metal Measurements, by Sport
Medium/Metal
Sport
Pre-
Activity
Mean
Pre-
Activity
Standard
Deviation
Pre-
Activity
Geo
Mean
Pre-Activity
95% CI
Post-
Activity
Mean
Post-
Activity
Standard
Deviation
Post-
Activity
Geo
Mean
Post-Activity
95% CI
Blood cadmium (|ig/L)
Soccer
0.24
0.08
0.22
0.18-0.27
0.23
0.08
0.22
0.17-0.28
Blood cadmium (|ig/L)
Football
0.21
0.02
0.21
0.2-0.23
0.18
0.04
0.19
0.17-0.21
Blood manganese (|ig/L)
Soccer
8.58
2.23
8.32
6.78-10.2
8.37
2.09
8.12
6.62-9.96
Blood manganese (|ig/L)
Football
10.9
2.73
10.7
9.07-12.51
11.8
4.43
11.2
8.56-14.6
Blood lead (ng/dL)
Soccer
0.42
0.17
0.39
0.29-0.52
0.43
0.18
0.39
0.28-0.54
Blood lead (ng/dL)
Football
0.44
0.11
0.43
0.36-0.52
0.45
0.15
0.44
0.34-0.56
Blood mercury, total (|ig/L)
Soccer
0.59
0.27
0.52
0.35-0.79
0.61
0.29
0.54
0.35-0.83
Blood mercury, total (ng/L)
Football
0.94
1.31
0.5
0.22-1.09
1.3
1.66
0.71
0.27-1.84
Blood selenium (ng/L)
Soccer
215
20.7
214
200-230
220
32.9
218
196-243
Blood selenium (|ig/L)
Football
219
10.7
218
211-226
224
13.4
224
213-235
Serum copper (ng/dL)
Soccer
99.3
10.4
99.0
91.4-107
99.7
12.8
99.0
89.8-109
Serum copper (ng/dL)
Football
99
8.93
99.0
92.7 - 105
96.6
10.8
96.1
87.8-105
Serum selenium (|ig/L)
Soccer
127
13.7
126
117-136
132
16.0
131
120 - 143
Serum selenium (ng/L)
Football
123
4.88
123
120 - 126
122
8.37
122
115-129
Serum zinc (ng/dL)
Soccer
87.7
13.5
86.7
76.8-97.9
82.5
13.5
81.4
70.9-93.5
Serum zinc (ng/dL)
Football
80.3
4.54
80.2
77.1 -83.4
84.4
6.77
84.2
78.9-89.8
a Geo = Geometric; CI = Confidence interval; dL = deciliter
b Number of soccer player samples = 6; Number of football player samples = 7
-------
ns
>
<
13
13
o
Q.
c
ai
0.2
0.1
0.0
Post-Pre Test (Difference) Plots by ID
Analyte=BCD
RED = Increase
GREEN = Decrease
-0.1
1 2 3 4 5 6 7 8 9 10 14 15 16
Participant ID
Figure 4-25. Exposure pilot study pre- and post-activity differences in blood cadmium
measurements (jig/L), by participant.
>
aj
>i
ns
c
<
13
ai
13
o
a.
it
b
Post-Pre Test (Difference) Plots bylD
Analyte=BMN
RED= Increase
GREEN = Decrease
6 7 8
Participant ID
10
14
15
16
Figure 4-26. Exposure pilot study pre- and post-activity differences plots in blood
manganese measurements (jig/L), by participant.
125
-------
Post-Pre Test (Difference) Plots by ID
Analyte=BPB
CO
>
CD
CL
"O
c
(0
w
o
CL
c
Q)
Q)
5
at
n
0.15
0.10
0.05
0.00
-0.05
-0.10
RED = Increase
GREEN = Decrease
6 7 8
Participant ID
10
14
15
16
Figure 4-27. Exposure pilot study pre- and post-activity differences in blood lead
measurements (jig/dL), by participant.
Post-Pre Test (Difference) Plots by ID
Analyte=BSE
w
CD
3
CO
>
0)
>
(0
c
<
CD
CL
"O
c
CO
w
o
CL
c
CD
CD
40
20
-20
RED = Increase
GREEN = Decrease
6 7 8
Participant ID
10
14
15
16
Figure 4-28. Exposure pilot study pre- and post-activity differences in blood selenium
measurements (jig/L), by participant.
126
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Post-Pre Test (Difference) Plots by ID
Analyte=SCU
10
W
Q)
3
(0
>
Q)
>
(0
C
<
to
Q)
Q_
"O
c
(0
to
o
Q_
c
Q)
Q)
RED = Increase
GREEN = Decrease
6 7 8
Participant ID
10
14
15
16
Figure 4-29. Exposure pilot study pre- and post-activity differences in serum copper
measurements (jig/dL), by participant.
Post-Pre Test (Difference) Plots by ID
Analyte=SSE
10-
w
0)
3
(0
>
0)
(0
c
<
to
0)
I—
0)
Q_
¦O
c
(0
to
o
Q_
c
0)
0)
-10
RED = Increase
GREEN = Decrease
6 7 8
Participant ID
10
14
15
16
Figure 4-30. Exposure pilot study pre- and post-activity differences in serum selenium
measurements (jig/L), by participant.
127
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Post-Pre Test (Difference) Plots by ID
Analyte=SZN
ns
>
ns
C
<
Q)
Q_
"O
c
(0
w
o
Q_
c
Q)
Q)
RED = Increase
10
GREEN = Decrease
-10
4 5 6 7 8 9 10 14 15 16
Participant ID
Figure 4-31. Exposure pilot study pre- and post-activity differences in serum zinc
measurements (jig/dL), by participant.
Post-Pre Test (Difference) Plots by ID
Analyte=THG
0.4
(0
>
Z 0.2
w
CD
CD
CL
"O
c
(0
w
o
CL
c
0)
0)
0.0
-0.2
RED = Increase
GREEN = Decrease
1 2 3 4 5 6 7 8 9 10 14 15 16
Participant ID
Figure 4-32. Exposure pilot study pre- and post-activity differences in total blood
mercury measurements (jig/L), by participant.
128
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Overall, the blood metals and serum metals results showed no difference in concentrations before or
after practice on a synthetic turf field with tire crumb rubber infill.
Table 4-52. Statistical Analysis of Differences in Exposure Pilot Study Pre- and Post-Activity Whole Blood
Metals and Serum Metals Measurements
Metal
Minimum
Difference"
Maximum
Difference"
Median
Mean
Standard
Deviation
Skewness
Kurtosis
ProbNb
Probtc
Probsrd
Blood cadmium
(lig/L)
-0.15
0.20
0.00
-0.01
0.08
1.31
4.72
0.004
0.724
0.563
Blood manganese
(lig/L)
-3.70
3.90
-0.20
0.15
2.09
0.13
0.71
0.567
0.822
0.902
Blood lead
(Hg/dL)
-0.10
0.15
0.00
0.01
0.06
0.45
1.82
0.229
0.493
0.656
Blood mercury,
total (|ig/L)
-0.25
0.40
0.00
0.04
0.19
0.94
0.82
0.065
0.537
0.703
Blood selenium
(lig/L)
-20.0
50.00
0.00
5.45
20.7
1.08
0.79
0.200
0.402
0.555
Serum copper
(Hg/dL)
-8.00
10.00
0.00
0.18
4.45
0.38
2.65
0.049
0.895
0.813
Serum selenium
(lig/L)
-10.0
10.00
0.00
1.82
8.74
-0.41
-1.62
0.006
0.506
0.727
Serum zinc
(Hg/dL)
-9.00
13.00
-1.00
-1.45
6.74
0.75
0.72
0.243
0.491
0.492
a These values represent the difference in the pre- and post-activity whole blood and serum metals concentrations. Number of
samples =11.
b Shapiro-Wilk test for normality /?-valuc
0 T-test /?-\aluc
d Wilcoxon Signed-Rank test /?-valuc
129
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Table 4-53. Statistical Analysis of Differences in Exposure Pilot Study Pre- and Post-Activity Whole Blood Metals and Serum Metals Measurements,
Metal
Sport
Minimum
Difference3
Maximum
Difference3
Median
Mean
Standard
Deviation
Skewness
Kurtosis
ProbNb
Probtc
Probsrd
Blood cadmium (|ig/L)
Soccer
-0.15
0.2
0
0
0.11
0.91
2.5
0.266
1
1
Blood cadmium (|ig/L)
Football
-0.05
0
0
-0.02
0.03
-0.61
-3.33
0.006
0.178
0.5
Blood manganese (|ig/L)
Soccer
-3.7
3.9
-0.25
-0.22
2.6
0.4
0.61
0.927
0.846
0.844
Blood manganese (|ig/L)
Football
-0.5
3
0
0.58
1.43
1.73
2.96
0.096
0.415
0.625
Blood lead (n/dL)
Soccer
-0.1
0.15
0
0.02
0.08
0.44
1.67
0.48
0.638
0.75
Blood lead (|i/dL)
Football
-0.05
0.05
0
0.01
0.04
-0.51
-0.61
0.314
0.621
1
Blood mercury, total (ng/L)
Soccer
-0.25
0.35
-0.03
0.02
0.2
0.69
1.53
0.678
0.846
1
Blood mercury, total (ng/L)
Football
-0.1
0.4
0
0.06
0.19
1.94
4.17
0.018
0.529
1
Blood selenium (|ig/L)
Soccer
-20
50
-5
5
25.9
1.25
0.99
0.272
0.656
0.938
Blood selenium (ng/L)
Football
-10
30
0
6
15.2
1.12
1.46
0.492
0.426
0.75
Serum copper (ng/dL)
Soccer
-8
10
0
0.33
5.72
0.52
2.64
0.088
0.892
1
Serum copper (|ig/dL)
Football
-5
2
1
0
2.92
-1.82
3.38
0.05
1
0.875
Serum selenium (ng/L)
Soccer
-10
10
10
5
8.37
-1.54
1.43
0.006
0.203
0.375
Serum selenium (ng/L)
Football
-10
10
0
-2
8.37
0.51
-0.61
0.314
0.621
1
Serum zinc (ng/dL)
Soccer
-9
3
-7.5
-5.17
5.08
1.03
-0.56
0.075
0.055
0.094
Serum zinc (|ig/dL)
Football
-2
13
0
3
6
1.59
2.41
0.14
0.326
0.5
a These values represent the difference in the pre- and post-activity whole blood and serum metals concentrations in soccer players (number of samples = 6) and football
players (number of samples = 5).
b Shapiro-Wilk test for normality /?-valuc
0 T-test /?-\aluc
d Wilcoxon Signed-Rank test /?-valuc
130
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When compared with NHANES (2013-2014) weighted and design-adjusted blood and serum metal
mean concentrations for ages 11 to 21 (Table 4-54), the whole blood or serum metal levels for the
synthetic turf field users were similar, with the exception of blood selenium. The pre-activity (216 |ig/g)
and post-activity (221 |ig/g) geometric means for blood selenium were greater than the NHANES
geometric mean (190 |ig/g). However, selenium was below detection limits in the tire crumb rubber
analyses and field environmental media measurements. Pre-activity, post-activity, and the NHANES
comparison values are illustrated in Figures 4-33 and 4-34.
Table 4-54. NHANES Weighted and Design-Adjusted Blood and Serum Metal Values (2013-2014) for Ages 11
to 21a b
PAH
Minimum
Maximum
Median
Mean
95% CI
Geo
Mean
Standard
Error
Blood cadmium (|ig/L)
0.07
3.54
0.12
0.22
0.18-0.26
0.14
0.01
Blood lead (ng/dL)
0.07
15.6
0.47
0.65
0.56-0.75
0.51
0.03
Blood manganese (|ig/L)
4.33
29.2
9.77
10.6
10.1-11.1
10.1
0.23
Blood mercury, total (|ig/L)
0.20
13.3
0.37
0.63
0.52-0.74
0.42
0.02
Blood selenium (|ig/L)
129
272
191
191
188-195
190
1.72
Serum copper (|ig/dL)
60.9
298
105
111
109-114
108
1.13
Serum selenium (|ig/L)
87.4
183
123
125
123 - 128
124
1.28
Serum zinc (|ig/dL)
44.5
146
83.1
84.33
81.7-87.0
82.9
1.20
a Values from 548 National Health and Nutrition Examination Survey (NHANES 2013-2014) participants, age 11 to 21.
b PAH = polycyclic aromatic hydrocarbons; CI = confidence interval; Geo = geometric
10.5
10
9.5
9
8.5
8
7.5
7
6.5
6
5.5
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
Figure 4-33. Exposure pilot study pre-activity and post-activity blood cadmium, blood
manganese, blood lead and total blood mercury geometric mean levels compared to NHANES
(2013-2014) weighted and design-adjusted values for Ages 11-21.
[NHANES = National Health and Nutrition Examination Survey]
Blood cadmium (|_ig/L) Blood manganese Blood lead (ng/dL) Blood mercury, total
(Hg/L) (|_ig/L)
¦ Pre-activity ¦ Post-activity ¦ NHANES
131
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250
Blood selenium (pg/L) Serum Copper (pg/dL) Serum Selenium (pg/L) Serum Zinc (pg/dL)
¦ Pre-activity ¦ Post-activity ¦ NHANES
Figure 4-34. Exposure pilot study pre-activity and post-activity blood selenium, serum
copper, serum selenium and serum zinc geometric mean levels compared to NHANES (2013-
2014) weighted and design-adjusted values for ages 11-21. [NHANES = National Health and
Nutrition Examination Survey]
4.6 Initial Testing of Silicone Wristbands
Collecting samples to measure personal exposures to chemicals is very challenging for people engaged
in sport activities on synthetic turf fields and for athletic and physical training activities in general.
Personal sampling devices must be relatively small, must not restrict research participant activities, and
must be safe to wear, even during vigorous activities. Due to the relatively short activity periods and
relatively low concentrations of chemicals, personal sampling devices must also overcome the challenge
of collecting sufficient chemical amounts for accurate measurements.
The use of silicone wristbands as a tool for personal and area chemical sample collection is an active
area of exposure assessment research. Silicone wristbands can serve as passive samplers for many types
of organic chemicals and are especially effective for chemicals present in air. With no power
requirements, minimal participant burden and interaction requirements and their ease of use, these
silicone wristbands may be useful for personal sample collection during sport activities. There is interest
in how silicone wristbands might be used in future exposure measurement studies for synthetic field
users, where bulky air sampling equipment can't be worn safely during intense athletic activity.
A critical question regarding their suitability for synthetic turf field personal sampling is whether, and at
what rate, they collect chemicals of interest associated with tire crumb rubber or other field materials.
The Part 1 Report described initial wristband testing in the presence of tire crumb rubber in controlled
dynamic chamber experiments. Another important question is the amount of time needed for wristbands
to be able to collect sufficient amounts of chemicals emitted from tire crumb rubber in synthetic field
environments to enable successful analysis. In order to further assess the potential utility of wristbands
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for synthetic field users, a set of experiments was performed by deploying wristbands as passive
samplers for organic chemicals in the air at an indoor and outdoor synthetic turf field.
4.6.1 Feasibility Assessment of Wristbands at Synthetic Turf Fields
A pilot-scale feasibility assessment was implemented through a contract with Oregon State University
(OSU) to evaluate the performance of silicone wristbands deployed at indoor and outdoor synthetic turf
field facilities with tire crumb rubber infill. The overall goal of the study was to evaluate the
effectiveness of the approach for measuring tire crumb rubber related chemicals in the air at synthetic
turf fields using the wristbands as stationary fixed monitors. Wristbands were deployed for seven days at
multiple locations in or near one indoor and one outdoor synthetic turf field facility with tire crumb
rubber, and in the outdoor ambient air generally upwind and away from fields and other local emission
sources. The wristbands were analyzed quantitatively for select PAHs, select oxygenated-PAHs, and
select VOCs. Another analysis method was applied that provides screening results for approximately
1500 chemicals. The OSU sampling and analysis report is provided in Appendix H.
Three wristband sampling locations were deployed at various locations inside an indoor facility
containing a synthetic turf field with tire crumb rubber. Three wristband sampling locations were
deployed at the perimeter of an outdoor synthetic turf field with tire crumb rubber. A final sampling
location was placed on a lamppost above a natural grass area next to a walkway, approximately 18
meters from the outdoor field to serve as a background air sampler. Samplers were deployed for a seven-
day duration. On six of those seven days the prevailing wind across the outdoor field was in a direction
away from the lamppost-mounted background air sampler. Temperatures during deployment ranged
from 3.1 to 22.7 °C with a mean of 9.7 °C.
A sum measure of 63 PAH analytes was obtained for the silicone wristband samplers following the 7-
day deployment. The £PAH results ranged from 72 to 105 ng/g for three indoor samplers, 29 to 34 ng/g
for three outdoor field samplers, and 32 ng/g for the background sampler. Field blank values for £PAH
were 0 ng/g. The number of individual targeted PAHs with measurable amounts ranged from 13 to 17. A
set of 22 oxidized PAH (OP AH) derivatives were also measured. The amounts of OP AH analytes were
below the detection limit for all samples and blanks, with the exception of
benzo(c)phenanthrene(l,4)quinone (6.7 ng/g) and benzo(cd)pyrenone (0.8 ng/g) measured in one
outdoor field sample.
A sum measure of 29 VOC analytes was also obtained. At two of the indoor locations, measured £VOC
values were 69 and 87 ng/g, while at the third location (a doorway atrium) the measured value was 7.1
ng/g. At the outdoor location, the £VOC values were 2.1, 39, and 90 ng/g. The background air value
was 32 ng/g. Field blank values for £VOC were 0.3 and 15 ng/g. The number of individual targeted
VOCs with measurable amounts ranged from 1 in one of the blanks to 9 in one of the outdoor field
locations. Several of the VOCs measured in field samples were also measured in the background air
sample and three were also measured in at least one of the two field blanks.
Additional wristband analyses included abroad analyte presence/absence screen for 1528 chemicals.
Between two and eight analytes were detected in the field samples. More analytes were detected in
indoor field samples (6 to 8) than outdoor field samples (2 - 4). Benzothiazole, a chemical associated
with tire crumb rubber, was observed in all field samples and was absent in the background air sample.
Three analytes (naphthalene, bis(2-ethylhexyl)phthalate, and 1-methylnapthalene) were measured in the
background air sample, and these analytes also appeared in one or more field sample.
133
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In general, more targeted analytes were detectable and sometimes found at higher concentrations in the
indoor field wristband samples compared to samples collected at the outdoor field and in the background
air sample. Samples collected at the outdoor field had £PAH concentrations similar to the background
air level. £VOC measurements were more variable, with some but not all indoor and outdoor field
samples having higher levels than the background air. Relatively few of the 1528 screening analytes
were detected in any sample.
While this feasibility study provided information on the potential for silicone wristbands to be used as
synthetic turf field facility area monitors, additional research will be needed to further assess the silicone
wristbands for possible use as personal monitors for synthetic turf field users in the future.
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5.0 Assessing Exposure Pathway Modeling
5.1 Exposure Pathway Modeling Methods
5.1.1 Research Design Summary
Accurate estimates of exposures to chemicals from tire crumb rubber on synthetic turf fields are needed
to investigate potential health risks among athletes and bystanders. Athletes may be exposed via the
inhalation, dermal and ingestional routes, while bystanders are likely to encounter only downwind
gasses and experience much lower exposures. Several approaches for calculating such estimates have
been reported (Peterson, Lemay, Shubin, & Prueitt, 2018; RIVM, 2017; Ginsberg, et al., 2011; ECHA,
2017; Kim, et al., 2012). Accurate exposure estimates require sufficient information on chemical
concentrations in all relevant exposure media, an understanding of how people come into contact with
those media under different conditions and scenarios, and knowledge of the extent to which chemicals
are transferred to people and into relevant tissues. Unfortunately, information for many of these
important parameters either remains relatively limited or does not yet exist, particularly for dermal and
ingestion pathways from synthetic turf field sources. In lieu of such information, researchers have made
necessary assumptions for some exposure parameters and have often used what are believed to be
conservative values when data are not available. More data are needed to reduce reliance on these
assumptions and improve modeling of inhalation, dermal and ingestion pathways for human exposure to
tire crumb rubber chemicals at synthetic turf fields.
Exposure pathway modeling for athletes using synthetic turf fields with tire crumb rubber infill was
performed using data available from the literature and supplemented with data collected in this exposure
pilot study. The four primary objectives of this modeling were to:
• Elucidate which exposure pathways are likely to be the biggest contributors to total
exposure for different types of tire crumb rubber constituents;
• Explore whether data produced in the federal study can improve our exposure estimates,
particularly for the dermal and ingestion pathways;
• Assess the availability, robustness and adequacy of tire crumb rubber data, exposure
measurement data and the data needed for exposure model parameters to determine the
accuracy and uncertainties in exposure estimations for athletes using synthetic turf fields;
and
• Prepare modeled estimates of background exposures from residential and dietary sources
for comparison with exposure estimates for synthetic turf field users.
Six chemical substances associated with synthetic turf fields and tire crumb rubber were selected for
exposure pathway modeling - benzo[a]pyrene, pyrene, benzothiazole, methyl isobutyl ketone, lead and
zinc. They were selected based on the availability of previous measurement data and represent a range
of physical and chemical properties (Table 5-1). Pyrene was selected because it is often reported in the
highest concentrations among polycyclic aromatic hydrocarbons (PAHs) in tire crumb rubber, while
benzo[a]pyrene has very low volatility and has been measured in tire crumb rubber in several studies.
Benzothiazole is on the more volatile end of the semivolatile organic compound (SVOC) spectrum and
has been measured in both synthetic turf field air and tire crumb rubber. Methyl isobutyl ketone is a
volatile organic compound (VOC) constituent of tire crumb rubber that has been measured in the air
above synthetic turf fields. Lead and zinc are among the metals most often measured in tire crumb
rubber studies.
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Table 5-1. Select Physico-chemical Properties of Chemicals Used in Exposure Pathway Modeling in this Study (Kim, et al., 2016; U.S. EPA, 2016;
Sander, 2015)a
Chemical
CAS
Numberb
Class
Molecular
Weight (g/mol)
LogKowc
Henry's Law
Constant
Vapor Pressure
(mmHg)
Density
(g/cm3)
Solubility (mg/L (atj, 25 °C,
where applicable)
Benzo[a]pyrene
50-32-8
PAH
SVOC
252.32
6.13
4.57E-07
atm-m3/mol
5.49E-09
25 °C
1.35
1.62E-03 inHiO; soluble in
benzene, toluene, xylene
and ether; slightly soluble in
alcohol
Pyrene
129-00-0
PAH
SVOC
202.26
4.88
1.19E-05 atm-
m3/mol
4.50E-06
25 °C
1.27
0.135 inHiO; soluble in
ethanol, ethyl ether, benzene
and toluene; slightly soluble
in carbon tetrachloride
Benzothiazole
95-16-9
SVOC
135.18
2.0
(experimental)
3.70E-07
atm-m3/mol
0.014
25 °C
1.25
Slightly soluble in H20;
very soluble in ether;
soluble in acetone
Methyl isobutyl
ketone
108-10-1
VOC
100.16
1.31
7.00E-2
mol/m3 Pa
19.9
25 °C
0.80
19,000 in H2O; miscible
with ethanol, ether, acetone,
benzene and most organic
solvents; soluble in
chloroform
Lead (elemental)
7439-92-1
Metal
207.20
No Data
No Data
1.77
1000 °c
11.3
Insoluble in HiO;"1 Soluble
in dilute HNO3
Zinc (elemental)
7440-66-6
Metal
65.38
No Data
No Data
1.10E-08
127 °C
7.1
Insoluble in H20;d Soluble
in acids/alkalines
aPAH = polycyclic aromatic hydrocarbons; SVOC = semivolatile organic compound; VOC = volatile organic compound; lmnHg = millimeters of mercury; H20 =
water; HNO3 = nitric acid
b Unique numerical identifier assigned by the Chemical Abstracts Service (CAS)
0 Kow = octanol/water partition coefficient
d Metal salts are soluble in water
137
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Exposure pathway algorithms published in EPA's Guidelines for Exposure Assessment (U.S. EPA,
1992) were employed in this exposure pathway modeling as standard approaches for exposure
estimation (U.S. EPA, 2013). Model parameter values were taken from EPA's Exposure Factors
Handbook (U.S EPA, 201 lb), where these values were judged to be applicable (e.g., inhalation rates).
Where not applicable, parameter values more appropriate for the athlete exposure scenarios (e.g.,
exposure durations) were obtained from the literature or other EPA documents, as presented in section
5.1.2. Exposure scenarios were developed for youth and adult athletes, informed in part by scenarios
considered by other researchers. Exposure factor and scenario values were compared to those used by
several other research organizations.
Inhalation, dermal and ingestion exposure pathway estimates were calculated for the select tire crumb
rubber constituents using an algorithm-based approach, extant data from previous studies and data from
field measurements in this exposure pilot study. The pathway-specific exposure estimates were
calculated for each of the six chemical substances using the extant data and were compared to identify
the dominant pathway of exposure for each chemical substance (with the exception of methyl isobutyl
ketone, for which only the inhalation pathway was estimated). The pathway-specific estimates were then
re-calculated using tire crumb measurement data and exposure measurement data produced in this
exposure pilot study. These results were compared with the previous pathway-specific estimates
generated using the extant data from other studies to assess whether additional information from the
field surface wipe, dust and dermal measurements (not previously available) might change estimates for
dermal and ingestion pathways. This process is presented in Figure 5-1.
• Measurement data were collected from
previously existing studies
• Measurement data were produced in this
exposure pilot study
• EPA's route-specific exposure algorithms
were chosen
• EPA's exposure algorithms were updated
for compatibility with new measurements
• Parameters were obtained from EPA
guidance documentation
• Parameter values were update based on
new data
•Scenarios were defined to complement
those used in previous studies
•Scenarios were defined to complement
age ranges and other factors from field
study participants
• Model was automated using Excel and
results were compiled
• Model was automated using Excel and
results were compiled
Figure 5-1. Process for generating pathway-specific exposure estimates using both existing data
(on left) and new data from this exposure pilot study (on right).
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Finally, the availability, robustness and adequacy of tire crumb rubber data, exposure measurement data
and the data needed for exposure model parameters were assessed to determine the accuracy and
uncertainty of individual and cumulative chemical exposure estimates.
5.1.2 Synthetic Turf Field User Exposure Estimation Using Existing Measurements
To aid in exposure characterization, extant data from previous studies were used to obtain chemical
concentration information, define parameter values and identify exposure scenarios to be applied for
inhalation, dermal and ingestion exposure pathway estimates (Figure 5-2). Initially, five chemicals of
interest were identified - lead, methyl isobutyl ketone, benzothiazole, pyrene and benzo[a]pyrene. Upon
further discussion, zinc was added to the chemicals of interest due to its presence in tire crumb rubber at
relatively high concentrations.
Figure 5-2. Diagram of exposure pathway modeling, showing possible media for
each route-specific exposure estimate. Red arrows designate media employed for
estimates using data from previous studies.
Measurement values for each chemical of interest were initially identified and extracted from the
Literature Review/Gap Analysis (LRGA) spreadsheet available in Appendix C of the Part 1 Report (U.S.
EPA, CDC/ ATSDR, & CPSC, 2016b). The original study documents referenced in the LRGA
spreadsheet were then reviewed for additional data on the chemicals of interest. Air, dust, tire crumb or
crumb rubber granules, field surface residue and bioaccessibility measurements (i.e., quantity of a
compound released from its matrix) measurements in synthetic fluids were determined to be relevant
measurements of interest for the exposure pathway modeling effort. Leachate studies and their
measurement values (deemed more relevant for ecological studies) were excluded from the data
extraction, as were measurements from turf blades and material classified as anything other than tire
crumb or crumb rubber.
A new Excel spreadsheet was created that included for the chemicals of interest, an entry for each
relevant reference study identified in the LRGA, sortable by chemical name and reference number (as
found in the LRGA spreadsheet). For each entry, data extraction was carried out by performing a
multiple keyword search for each chemical in the reference study (e.g., for lead, both "lead" and "Pb"
were searched). The following study-specific data were extracted for each entry, where available:
reference information; location of the study; chemical name; medium; medium type; additional
information to classify the medium; number of measured values; limit of detection (LOD), if given;
139
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percent of samples greater than the LOD; minimum and maximum measured values; and reported
descriptive statistics, including arithmetic and geometric means and standard deviations, where
available.
Measurement values for each entry were recorded and added to the spreadsheet based on available data.
Data for air concentrations included sample measurements collected at different heights above the field,
although this height distinction was not made when recording the data in the spreadsheet; however, a
distinction was made in the spreadsheet between indoor, outdoor and personal air sample collections. All
excluded measurements were explained in each entry's comments section on the spreadsheet.
Before calculating descriptive statistics, measured values for each medium (air, dust, tire crumb or
crumb rubber, field surface residue and synthetic fluids) were converted to consistent units where
necessary. Air concentrations were converted to ng/m3, dust concentrations to ng/g, crumb rubber
concentrations to ng/g, residue concentrations to ng/m2 and bioaccessibility synthetic fluid
concentrations to ng/g. Where necessary, reported masses were converted to loadings. For example, in
the Consumer Product Safety Commission's (CPSC) 2008 report, field surface wipe data for lead was
originally reported as 98.7 |ig, collected using a 15xl5-cm wipe, rubbed along 50 cm (CPSC, 2008).
The entire area for wipe sampling was found by multiplying 15 cm (wipe height) by 50 cm (surface
length), giving a total wipe sampling surface area of 750 cm2. Dividing the total mass of residue found
on the wipe (98.7 |ig) by the total surface area wiped (750 cm2), a mass per unit area loading of 0.132
|ig/cm2 was obtained; this value was then converted to ng/m2.
Mean, median, geometric mean, and arithmetic standard deviation values were calculated for each
chemical in each medium, using the '=AVERAGE' (arithmetic mean), '=STDEV.P', '=MEDIAN' and
'=GEOMEAN' (geometric mean) functions in Excel. Geometric standard deviation was calculated in a
separate spreadsheet by listing all the measured values, taking the natural logarithm of each of those
numbers, calculating the standard deviation of those natural log values, and then taking the inverse
natural logarithm (exponential function) of that standard deviation value (Figure 5-3). In studies where
the value was reported as less than the LOD, V2 LOD was used in the calculations.
Measured
Values
Natural Log
Values
Standard
Deviation
Inverse
Natural Log
• '=LN'
• '=STDEV'
•'=EXP'
Geometric
Standard
Deviation
Figure 5-3. Process flowchart of the commands used in Excel to calculate the geometric standard
deviation.
Once all measurement values were extracted from the literature and summary statistics were calculated,
specific parameter values were obtained using a weighted average for both the arithmetic and geometric
means for each chemical in each medium (Tables 5-2 and 5-3). Weighted averages were calculated by
multiplying each mean value from the study by the number of sample measurements taken, adding all
those values together and dividing by the total number of sample measurements of all the studies. In
studies that reported only minimum and maximum values, the maximum was used along with mean
values from other studies in calculating weighted averages, but these studies did not provide enough
information to be included in calculations of arithmetic and geometric standard deviations.
140
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Table 5-2. Weighted Arithmetic Means for Chemicals of Interest in Exposure Pathway Modeling3
Chemical
Air-
Outdoor
(ng/m3)
Air-
Indoor
(ng/m3)
Air-
Combined
(ng/m3)b
Air-
Personal
(ng/m3)
Tire
Crumb
(ng/g)
Field Surface
Wipes Without
Contaminated
Blades (ng/m2)0
Benzo[a]pyrene
0.066
0.708d
0.062
N/A
1640
N/A
Pyrene
2.41
5.71
2.95
3.19d
13100s
723
Benzothiazole
235
12300
1040
4050
2700f
N/A
Methyl isobutyl ketone
742
36000«
12000
11600
N/A
N/A
Lead
0.978
N/A
N/A
N/A
41300
6010d
Zinc
18
N/A
N/A
N/A
9580000
273000
a Arithmetic mean for each chemical was calculated from measurement values found in reference studies identified in the
Literature Review/Gaps Analysis; N/A = not available.
b "Combined" air includes both indoor and outdoor air without distinction between the two.
0 Does not include measurements from fields that were likely to have blades with lead-containing pigments.
d Benzo[a]pyrene indoor air concentration, pyrene personal air concentration, and lead field surface wipe concentration each
represent the arithmetic mean from one study.
e Pyrene tire crumb concentration contains a reported maximum value of 28700 ng/g, which skews the weighted average.
fBenzothiazole tire crumb concentration is the reported median from one study.
g Methyl isobutyl ketone indoor air concentration arithmetic mean is based on two data points.
Table 5-3. Weighted Geometric Means for Chemicals of Interest in Exposure Pathway Modeling3
Chemical
Air-
Outdoor
(ng/m3)
Air-
Indoor
(ng/m3)
Air-
Combined
(ng/m3)b
Air-
Personal
(ng/m3)
Tire
Crumb
(ng/g)
Field Surface
Wipes Without
Contaminated
Blades (ng/m2)0
Benzo[a]pyrene
0.073
0.636
0.069
N/A
998
N/A
Pyrene
1.22
5.68
1.77
3.06
12400
679
Benzothiazole
159
12200
575
2440
2700d
N/A
Methyl isobutyl ketone
742
36000e
2280
11900
N/A
N/A
Lead
0.98f
N/A
N/A
N/A
28300
4490
Zinc
15.9
N/A
N/A
N/A
7660000
255000
a Geometric mean for each chemical was calculated from measurement values found in reference studies identified in the
Literature Review/Gaps Analysis; NA = not available.
b "Combined" air includes both indoor and outdoor air without distinction between the two.
0 Does not include measurements from fields likely to have blades with lead-containing pigments.
dBenzothiazole tire crumb concentration is the reported median from one study.
e Methyl isobutyl ketone indoor air concentration geometric mean is based on two data points.
fLead outdoor air concentration calculated using maximum values.
Upper confidence limits (UCLs) of the means were obtained by using ProUCL 5.1 software (U.S. EPA,
Washington, DC; https://www.epa.gov/land-research/proucl-software). In most cases, the ProUCL-
recommended values were used (i.e., the software uses several methods for calculating point estimates
and identifies the recommended one), except where the value exceeded the maximum observation.
UCLs are shown in Table 5-4.
141
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Table 5-4. Upper Confidence Limits (UCLs) for Chemicals of Interest in Exposure Pathway Modeling3
Chemical
Air-
Outdoor
(ng/m3)
Air-
Indoor
(ng/m3)
Air-
Combined
(ng/m3) b
Air-
Personal
(ng/m3)
Tire
Crumb
(ng/g)
Field Surface
Wipes Without
Contaminated
Blades (ng/m2)0
Benzo[a]pyrene
0.145
1.097d
0.615
NC
2758
NC
Pyrene
5.549
10.53
5.873
NC
11877
1288
Benzothiazole
297.7
13731
5148
9422
NC
NC
Methyl isobutyl ketone
586.5
NC
NC
47955
NC
NC
Lead
NC
NC
NC
NC
77584
8583
Zinc
37.58
NC
NC
NC
19960747
318805
aUpper confidence limits were recommended values from the ProUCL 5.1 software (U.S. EPA, Washington, DC), unless
otherwise noted. NC= not calculated due to limited data.
b "Combined" air includes both indoor and outdoor air without distinction between the two.
0 Does not include measurements from fields likely to have blades with lead-containing pigments.
dBenzo[a]pyrene indoor air ProUCL-recommended upper confidence limit exceeded the maximum observation; 95% Central
Limit Theorem UCL was used.
Three age ranges available from EPA's Exposure Factors Handbook (U.S. EPA, 201 lb) were selected
for use in the exposure pathway modeling and are shown in Table 5-5. These three age ranges used for
modeling are based on the availability of exposure factor information for specific age ranges; however,
they differ somewhat from the age ranges used for reporting exposure pilot study participant results in
Section 4. The age ranges reported in Section 4 were based on numbers of participants of different ages
in the two sport types. Inhalation and ingestion rates were obtained from the Handbook (U.S. EPA,
201 lb) and converted to the units needed for each exposure algorithm. Short-term inhalation rates
corresponding to a high intensity activity level were extracted and converted from units of cubic meters
per minute (m3/min) to hourly rates (m3/hr) by multiplying each rate value by 60 minutes per hour (U.S.
EPA, 2011b).
Table 5-5. Age Ranges from the EPA Exposure Factors Handbook (U.S. EPA, 2011b)
Age Group
Age Range
Children
6 to <11 years
Adolescents
11 to <16 years
Young Adults
16 to <21 years
Average daily dose (ADD, expressed as mg/kg-day) over a year from use of fields was calculated using
equations 5-1 through 5-3 and route-specific spreadsheets modified to include route-specific absorption
fractions for the inhalation and ingestion routes. Estimates of daily dose on a day that included synthetic
turf field activity were obtained by multiplying the ADD output by Averaging Time (AT) / Exposure
Frequency (EF).
hR x ET x EF xED x ABS)/(BW x AT) (Equation 5-1)
ngR x EF x ED xABS)/(BW x AT) (Equation 5-2)
\dh x 5i4 x EF x ED x ABS)/(BW x AT) (Equation 5-3)
Inhalation
ADDabs =
(^air ^
Ingestion
ADDabs =
solid
Dermal
ADDabs =
solid
142
-------
Where:
ADDabs = average daily dose absorbed (mg/kg-day)
Cair = concentration of contaminant in air (mg/m3)
InhR = inhalation rate (m3/hour)
ET= exposure time (hours/day)
EF = exposure frequency (days/year)
ED = exposure duration (years)
ABS = fraction absorbed (%/100)
BW= body weight (kg)
AT= averaging time (days)
Csolid = concentration of contaminant in crumb rubber (mg/g)
IngR = ingestion rate (g/day)
Adh = Solids adherence on skin (g/cm2-day)
SA = skin surface area available for contact (cm2)
Exposure scenarios from several other studies that examined exposure to tire crumb rubber constituents
from synthetic turf provided potential parameter input values for the modeling (Table 5-6). Parameter
input values for each exposure route used in this exposure pathway modeling are shown in Table 5-7.
Age-specific adherence factors were calculated by estimating the percentage of a body part exposed
while wearing a typical sports uniform during the summer, multiplying those percentages by the total
surface area per body part found in EPA's Exposure Factors Handbook (U.S. EPA, 201 lb), summing
the products and then dividing by the total exposed body surface area of the body parts to get a weighted
adherence factor (Equation 5-4); this equation can be found in Chapter 7 of the Handbook (U.S. EPA,
201 lb). Body part percentages were assumed to be 100% of the face, 72.5% of the arms, 40% of the
legs (to account for socks and short pants), and 100% of the hands.
AFwtd = (AF1 X 5i4x) + (AF2 X SA2) + ••• (AFt X SAi)/(SA1 + SA2 + •••SAt) (Equation 5-4)
Where:
AFwtd = weighted adherence factor (mg/cm3)
AF = adherence factor (mg/cm3)
SA = skin surface area of body part available for contact (cm3)
Table 5-6. Exposure Scenarios from Several Studies, Including this Exposure Pilot Studyab
Study
Age (years)
Sportb
Player
Activity Level
Location
ECHA
3 to 6
Soccer
Not Specified
Heavy Exercise
Not Specified
ECHA
6 to 11
Soccer
Not Specified
Heavy Exercise
Not Specified
ECHA
6 to 11
Soccer
Goalkeepers
Heavy Exercise
Not Specified
ECHA
11 to 18
Soccer
Active, non-professional
Heavy Exercise
Not Specified
ECHA
18 to 31
Soccer
Professional
Heavy Exercise
Not Specified
ECHA
18 to 31
Soccer
Professional Goalkeepers
Heavy Exercise
Not Specified
RIVM
4 to 11
Soccer
Not Specified
Recreational
Outdoor
RIVM
7+
Soccer
Goalkeepers
High Intensity
Outdoor
RIVM
11 to 18
Soccer
Performance
High Intensity
Outdoor
RIVM
18 to 35
Soccer
Performance
High Intensity
Outdoor
Connecticut
6 to 18
Soccer
Not Specified
Not Specified
Outdoor
Connecticut
30
Soccer
Not Specified
Not Specified
Outdoor
Peterson
6 to 18
Soccer
Not Specified
Not Specified
Outdoor
143
-------
Table 5-6. Continued
Study
Age (years)
Sportb
Player
Activity Level
Location
Peterson
6 to 18
Soccer
Not Specified
Not Specified
Indoor
Peterson
6 to 18
Soccer
Not Specified
Not Specified
Composite
Peterson
Adult
N/A
Not Specified
Not Specified
Spectator
Peterson
Child
N/A
Not Specified
Not Specified
Spectator
Pilot Study
6 to <11
N/A
Not Specified
High Intensity
Composite
Pilot Study
11 to <16
N/A
Not Specified
High Intensity
Composite
Pilot Study
16 to <21
N/A
Not Specified
High Intensity
Composite
"¦Exposure scenarios identified from the following studies: ECHA (2017), RIVM (2017), Connecticut (Ginsberg, et al.,
201 la), Peterson (Peterson, et al., 2018), and this exposure pilot study.
bN/A = not applicable
Table 5-7. Exposure Parameters for Extant Data
Exposure Parameter
Parameter Value
Source
Absorption Fraction - Ingestion (Metals)
30%
Zartarian et al., 2017
Absorption Fraction - Ingestion (All Other
Chemicals)
50%
Morgan et al., 2005
Absorption Fraction - Dermal (Metals)
1%
U.S. EPA, 2004
Absorption Fraction - Dermal (All Other
Chemicals)
10%
U.S. EPA, 2004
Absorption Fraction - Inhalation
70%
Ross, et al., 2001
Ingestion Rates - 6 to <11 years of age
0.06 g/event
U.S. EPA, 2011b, Chapter 5, Table 5-1 Soil + Dust
(converted to g/event, assuming 1 event per day)
Ingestion Rates - 11 to <16 years of age
0.03 g/event
U.S. EPA, 2011b, Chapter 5, Table 5-1 Soil + Dust
(converted to g/event, assuming 1 event per day)
Ingestion Rates - 16 to <21 years of age
0.03 g/event
U.S. EPA, 2011b, Chapter 5, Table 5-1 Soil + Dust
(converted to g/event, assuming 1 event per day)
Dermal Adherence Factor
2.70E-06 g/cnf
U.S. EPA, 201 lba. Chapter 7, Table 7-4
Skin Surface Area - 6 to <11 years of age
3069 cm2
U.S. EPA, 201 lba. Chapter 7, Table 7-2
Skin Surface Area - 11 to <16 years of age
4541 cm2
U.S. EPA, 201 lba. Chapter 7, Table 7-2
Skin Surface Area - 16 to <21 years of age
5202 cm2
U.S. EPA, 201 lba. Chapter 7, Table 7-2
Inhalation Rates - 6 to <11 years of age
2.52 m3/hr
U.S. EPA, 2011b, Chapter 6, Table 6-2 High
Intensity (converted to m3/hr)
Inhalation Rates - 11 to <16 years of age
2.94 m3/hr
U.S. EPA, 2011b, Chapter 6, Table 6-2 High
Intensity (converted to m3/hr)
Inhalation Rates - 16 to <21 years of age
2.94 m3/hr
(U.S. EPA, 201 lb) Chapter 6, Table 6-2 High
Intensity (converted to m3/hr)
Body weight - 6 to <11 years of age
31.8 kg
U.S. EPA, 2011b, Chapter 8, Table 8-3
Body weight - 11 to <16 years of age
56.8 kg
U.S. EPA, 2011b, Chapter 8, Table 8-3
Body weight - 16 to <21 years of age
71.6 kg
U.S. EPA, 2011b, Chapter 8, Table 8-3
Exposure Timeb - 6 to <11 years of age
1 hr/event
Assumed
Exposure Timeb - 11 to <16 years of age
3 hrs/event
Assumed
Exposure Timeb - 16 to <21 years of age
2 hrs/event
Assumed
144
-------
Table 5-7. Continued
Exposure Parameter
Parameter Value
Source
Exposure Frequency - 6 to <11 years of age
78 days/year
Assumed
Exposure Frequency - 11 to <16 years of age
138 days/year
Assumed
Exposure Frequency - 16 to <21 years of age
138 days/year
(Ginsberg, et al., 2011)
Exposure Duration - all ages
1 year
Assumed
Averaging Time - all ages
365 days/year
Assumed
a Calculated using body part percentages and adherence factors per body part.
b Assumes one event per day.
Comparisons of parameter values from other studies and those used in this study are shown in Table 5-8.
Modeling parameter inputs from other studies were chosen using the age groups most analogous with
those used in this exposure pilot study. From the European Chemicals Agency (ECHA 2017) study, the
6- to 11- year old non-goalkeeper; 11- to 18-year old active, non-professional; and adult (18- to 31-year
old) professional non-goalkeeper scenarios were used. The Netherlands National Institute for Public
Health and the Environment (RIVM 2011) scenarios used in modeling were the 4- to 11-year old
recreational players and the 11- to 18-year old and 18- to 35-year old performance oriented players.
Both Connecticut scenarios (Ginsberg, et al. 201 la) were used - 6- to 18-year old players and 30-year
old players. Estimated exposure results were generated for each exposure pathway using the EPA
ExpoBox tools (U.S. EPA, 2013). Exposure estimates using extant data are shown in section 5.2.1. The
following assumptions were made in the calculations using extant data:
• Adherence of tire crumb to skin was approximated by adherence of soil and dust during
similar activities as there is no specific adherence rate available for tire crumb itself.
• Dermal absorption was estimated in the absence of data on the bioaccessibility of
chemicals in tire crumb.
• Despite participants in the Exposure Pilot Study reporting occasional abrasions, which
could lead to an increase in absorption rate, dermal abrasions were not considered in
these modeling exercises due to the complexity of physiological processes involved in
vascular absorption and transport.
• Ingestion rates assume tire crumb is ingested at the same rate as that of dust and soil.
145
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Table 5-8. Parameter Input Value Comparisons Among Select Studies8
Age
(years)
Study
Inhalation
Rate
(m3/hr)
Ingestion
Rate
(g/event)
Dermal
Adherence
(g/cm2)
Inhalation
Absorption
Fraction
(%)
Ingestion
Absorption
Fraction
(*100%)
Dermal
Absorption
Fraction
(*100%.)
Exposure
Time
(hrs/day)
Exposure
Frequency
(days/year)
Weight
(kg)
Skin
Surface
Area
(cm2)
6 to <11
This Study
(extant data)
2.52
0.06
2.70E-06
70
0.3 -0.5b
0.01 -0.1b
1
78
31.8
3069
6 to 11
ECHA (non-
goalkeeper)
1.92
0.05
0.001
NR
0.5
0.2
1.5
NR
24.3
1750
6 to 18
Connecticut
3.36°
N/A
N/A
NR
N/A
N/A
3
138
NR
N/A
4 to 11
RIVM
N/A
0.2
0.001
N/A
0.3
0.2
2
NR
15.7
1260
6 to 18
Peterson et
al.
NR
0.05
0.00004
NR
0.06
0.002/0. ld
3
138
49
4881
11 to <16
This Study
(extant data)
2.94
0.03
2.70E-06
70
0.3 -0.5b
0.01 -0.1b
3
138
56.8
4541
11 to 18
ECHA
2.53
0.01
0.001
NR
0.5
0.2
1.5
NR
44.8
2680
11 to 18
RIVM
N/A
0.05
0.001
N/A
0.3
0.2
1.5
NR
44.8
2680
16 to <21
This Study
(extant data)
2.94
0.03
2.70E-06
70
0.3 -0.5b
0.01 -0.1b
2
138
71.6
5202
18 to 31
ECHA
3.07
0.01
0.001
NR
0.5
0.2
4
NR
68.8
3680
30
Connecticut
3.36°
N/A
N/A
NR
N/A
N/A
3
138
NR
N/A
18 to 35
RIVM
N/A
0.05
0.001
N/A
0.3
0.2
2
NR
68.8
3680
a N/A = Specified pathway not included in study; NR = Parameter value not reported.
bThis study, using existing measurements (extant data) - Ingestion absorption fraction - 30% metals, 50% all other chemical substances (Zartarian et al., 2017; Morgan et
al., 2005); Dermal absorption fraction - 1% metals, 10% all other chemical substances (U.S. EPA, 2004)
0 Connecticut reported using a mixture of moderate to intense activity levels for inhalation rate - 2.34 m3/hr for moderate and 4.38 m3/hr for intense activity; the inhalation
rate of 3.36 m3/hr reported here is the midpoint between the two. They used a ventilation adjustment for adults and children for this reason.
d Peterson et al., 2018 - Dermal absorption fraction - 0.002 for PAHs, 0.1 for SVOCs
146
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5.1.3 Synthetic Turf Field User Exposure Estimation Using Exposure Pilot Study
Measurements
After collection and analysis of the exposure pilot study field measurements, model concentrations and
parameters were updated to reflect measured concentrations from the fields; this included the addition of
dermal wipe concentrations, metals bioaccessibility (biological) measurements, and concentrations for
some chemical substances that were missing from existing data (Table 5-9). All other parameters used in
modeling the exposure pathways using extant data remained the same, apart from the dermal and
ingestion absorption factors for metals and the use of field dust concentration measurements for
chemical substances that previously used tire crumb concentrations. The dermal absorption factor used
for metals was chosen to be 0.1%, because that was the mean percent zinc found to be bioaccessible in
simulated sweat and sebum fluid. Lead bioaccessibility measurements were < 0.1%, so the use of 0.1%
would provide a conservative estimate. Mean gastric fluid lead and zinc bioaccessibility values for field
tire crumb (3.2% for lead and 1.0% for zinc) were used for ingestion (gastrointestinal) absorption.
With the additional dermal wipe sample concentrations, the use of adherence factors was avoided, and
loadings on skin were used in the exposure algorithms. The amount of chemical substance directly in
contact with the skin (i.e., the "loading on skin") was calculated by multiplying the dermal wipe
concentration (Cwipe) by the sum of the exposed surface areas of each body part (Equation 5-5). For each
scenario, exposed skin surface area was estimated using the percentage of the total surface area found in
EPA's Exposure Factors Handbook (U.S. EPA, 201 lb) for each body part exposed in a typical player
uniform (see Table 5-7).
Dermalpiiot ADDabs = (Cwjpe X Si4 X EF X ED XABS^/(BW X AT) (Equation 5-5)
Loading on skin calculated from dermal wipe concentrations provided a potentially more accurate
dermal exposure measurement than using the highly uncertain assumptions concerning amount of tire
crumb adhering to skin and amount of chemicals substance transferring from tire crumb onto the skin
from the exposure modeling with extant data. There are, however, limitations in dermal measurements
as well, including the assumption of 100% wipe efficiency and the possibility that post-activity
measurements may have included exposures to the chemical that occurred prior to the synthetic turf field
activity.
Despite the collection of air samples from both indoor and outdoor playing fields in the exposure pilot
study, the information on the type of sample is not available due to concerns over privacy with the small
number of participants in the study. Instead, the medium for the air samples is identified as "combined."
Additionally, no attempt was made to quantify dietary ingestion as part of the exposure pilot study.
147
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Table 5-9. Mean Concentrations and Estimated Total Dermal Loads of Chemical Substances Measured in the
Exposure Pilot Studya'b'c
Chemical
Average Air
Concentration -
Combined
(ng/m3)
Average Tire
Crumb
Concentration
(ng/g)
Average Dust
Concentration
(ng/g)
Dermal
Loading -
Players Age
6 to <11 (ng)
Dermal
Loading -
Players Age
11 to <16 (ng)
Dermal
Loading -
Players Age
16 to <21 (ng)
Benzo[a]pyrene
7.00E-03
7.80E+02
7.10E+02
2.93E+01
1.85E+01
2.28E+00
Pyrene
3.57E+00
1.20E+04
5.49E+03
7.77E+01
4.79E+01
8.52E+00
Benzothiazole
3.87E+02
1.10E+04
4.30E+03
6.09E+02
1.06E+03
3.65E+02
Methyl isobutyl ketone
7.87E+02
N/A
N/A
N/A
N/A
N/A
Lead
2.17E+00
2.40E+04
3.80E+04
4.92E+02
7.69E+02
1.88E+02
Zinc
1.57E+02
1.50E+07
9.44E+06
1.13E+05
2.15E+05
7.23E+04
a Exposure pilot study measurements used in exposure modeling included both field samples (air, tire crumb, field surface
wipes and dust samples) and personal samples (dermal wipe sample). N/A = not applicable (i.e., no measurements obtained)
b Temperature and wind conditions at the fields during the air and dermal sample collections are reported in Table 4-27.
0 Total dermal load calculated by summing products of measured body part-specific dermal loadings and exposed surface
areas.
5.1.4 Background Exposure Estimation from Residential and Dietary Sources
Estimates of exposures to chemicals from tire crumb rubber on synthetic turf fields among athletes and
bystanders can be put into the context of exposure to these same chemical substances in typical
residential settings, including the contribution from dietary sources. The purpose of this comparative
analysis was to present "background" concentrations encountered in residences, and the resulting daily
intake estimates provide some perspective on the magnitude of the estimated daily dose for synthetic
turf field users. The same algorithms used for exposure estimates to chemicals from tire crumb rubber
on synthetic turf fields were used for this exercise, except that the exposure factor parameters were
altered to represent a 24-hour residential exposure including a dietary component. These changes
included: (1) an assumption that 21 hours/day were spent indoors, (2) use of inhalation rates
corresponding to long-term inhalation as defined by the Exposure Factors Handbook as "repeated
exposure for more than 30 days"(U.S. EPA, 201 lb), and (3) application of residential indoor dermal
adherence factors. These contrast with the assumptions of 1-3 hours spent on synthetic turf, inhalation
rates corresponding to high intensity activity, and dermal adherence factors appropriate to an active
setting. The remaining exposure factor parameters remained the same, namely, route-specific absorption
fractions, dust/soil ingestion rates, and age-group specific body weights. All exposure factor parameters
used to estimate residential and dietary exposures can be found in Table 5-10. Additional literature
review was conducted to obtain background concentrations needed to estimate resulting daily doses. The
concentration values used for each chemical substance and medium can be found in Table 5-11. Table 5-
12 illustrates the types of exposure media that were available for the three modeling exercises.
148
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Table 5-10. Exposure Parameters for Residential and Dietary Estimates
Exposure Parameter
Parameter
Parameter
Parameter
Source
Value-
Value -
Value -
Age 6 to <11
Age 11 to <16
Age 16 to <21
Total Food Intake
1.118 kg/day
1.209 kg/day
1.184 kg/day
U.S. EPA 2011b, Chapter 14,
Table 14-3 (converted to
kg/day)
Absorption Fraction - Ingestion
(Metals)
30%
30%
30%
Morgan et al., 2005
Absorption Fraction - Dermal
1%
1%
1%
U.S. EPA, 2011b
(Metals)
Absorption Fraction -Inhalation
70%
70%
70%
Assumed value
Soil/Dust Ingestion Rates
0.06 g/event
0.03 g/event
0.03 g/event
U.S. EPA, 2011b, Chapter 5,
Table 5-1 Soil + Dust
(converted to g/event,
assuming 1 event per day)
Dermal Adherence Factor
5.00E-06 g/cm2
5.00E-06 g/cm2
5.00E-06 g/cm2
U.S. EPA, 2011b, Chapter 7
Skin Surface Area
3069 cm2
4541 cm2
5202 cm2
U.S. EPA, 2011b, Chapter 7,
Table 7-2
Inhalation Rates
0.50 m3/hr
0.63 m3/hr
0.68 m3/hr
U.S. EPA, 2011b, Chapter 6,
Table 6-2 Sedentary/Passive
activity level (converted to
m3/hr)
Bodyweight
31.8 kg
56.8 kg
71.6 kg
U.S. EPA, 2011b, Chapter 8,
Table 8-3
Exposure Time
21 hrs/day
21 hrs/day
21 hrs/day
Assumed for this comparative
analysis
Exposure Frequency
365 days/year
365 days/year
365 days/year
Assumed for this comparative
analysis
Exposure Duration
1 year
1 year
1 year
Assumed for this comparative
analysis
Averaging Time
365 days/year
365 days/year
365 days/year
Assumed for this comparative
analysis
This analysis of residential and dietary exposure has several limitations, principally due to the
availability of only sparse data, often from studies conducted decades ago. Due to a lack of information
on concentration variability, only point estimates of central tendency were used. Exposure was assumed
to occur indoors for 21 hours, neglecting commuting and other activities that may lead to higher
exposures for some of the candidate chemicals. Additionally, demographic and urban/rural differences
were not considered. These assumptions could lead to underestimation of the total amount of exposure
for some chemicals.
149
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Table 5-11. Residential and Dietary Concentrations Re
ported in the Literature for Chemicals of Interest
Chemicala
Medium
Mean
Source
Benzo[a]pyrene
Indoor Residential Air
0.224 ng/m3
Morgan et al., 2005
Benzo[a]pyrene
Food Intake
20-80 ng/day
Ma & Harrad, 2015
Benzo[a]pyrene
Indoor Residential Dust
793 ng/g
Morgan et al., 2005
Pyrene
Indoor Residential Air
1.9 ng/m3
Clayton et al., 2003
Pyrene
Food Concentration
0.4 ng/kg
Clayton et al., 2003
Pyrene
Indoor Residential Floor Dust
0.43 ng/g
Chuang et al., 1999
Benzothiazole
Indoor Residential Air
41.6 ng/m3
Wanet al., 2016
Methyl isobutyl ketone
Air (Outdoor)
0.078 ng/m3
U.S. EPA 2011a
Methyl isobutyl ketone
Food Intake
2 ng/day
World Health Organization, 2013
Lead
Indoor Residential Air
14.4 ng/m3
Clayton et al., 1999
Lead
Dietary Dose
0.25 ng/kg/day
Thomas et al., 1999
Lead
Indoor Residential dust
463 ng/g
Clayton et al., 1999
Zinc
Dietary Dose
220 ng/kg/day
Thomas et al., 1999
Zinc
Indoor Residential Dust
833 ng/g
Rasmussen et al., 2013
a Unique numerical identifier assigned by the Chemical Abstracts Service (CAS) for each chemical: Benzo[a]pyrene
(50-32-8), Pyrene (129-00-0), Benzothiazole (95-16-9), Methyl isobutyl ketone (108-10-1), Lead (7439-92-10), Zinc
(7440-66-6)'
Table 5-12. Data Availa
jility by Chemical and Medium.
Chemical
Medium
Data Available in
Data Available in
Data Available in Residential
Previous Studies
Current Study
Exposure Literature
Benzo[a]pyrene
Outdoor Air
Y
N
N
Benzo[a]pyrene
Indoor Air
Y
N
Y
Benzo[a]pyrene
Combined Air
Y
Y
N
Benzo[a]pyrene
Personal Air
N
N
N
Benzo[a]pyrene
Tire Crumb
Y
Y
N
Benzo[a]pyrene
Dust
N
Y
Y
Benzo[a]pyrene
Field Surface Residue
N
Y
N
Benzo[a]pyrene
Dermal Residue
N
Y
N
Benzo[a]pyrene
Food Conc./Intake
N
N
Y
Benzo[a]pyrene
Bioaccessibility
N
N
N
Pyrene
Outdoor Air
Y
N
N
Pyrene
Indoor Air
Y
N
Y
Pyrene
Combined Air
Y
Y
N
Pyrene
Personal Air
Y
N
N
Pyrene
Tire Crumb
Y
Y
N
Pyrene
Dust
N
Y
Y
Pyrene
Field Surface Residue
Y
Y
N
Pyrene
Dermal Residue
N
Y
N
Pyrene
Food Conc./Intake
N
N
Y
Pyrene
Bioaccessibility
N
N
N
150
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Table 5-12. Continued
Chemical
Medium
Data Available in
Previous Studies
Data Available in
Current Study
Data Available in Residential
Exposure Literature
Benzothiazole
Outdoor Air
Y
N
N
Benzothiazole
Indoor Air
Y
N
Y
Benzothiazole
Combined Air
Y
Y
N
Benzothiazole
Personal Air
Y
N
N
Benzothiazole
Tire Crumb
Y
Y
N
Benzothiazole
Dust
N
Y
N
Benzothiazole
Field Surface Residue
N
Y
N
Benzothiazole
Dermal Residue
N
Y
N
Benzothiazole
Food Conc./Intake
N
N
N
Benzothiazole
Bioaccessibility
N
N
N
Methyl isobutyl ketone
Outdoor Air
Y
N
Y
Methyl isobutyl ketone
Indoor Air
Y
N
N
Methyl isobutyl ketone
Combined Air
Y
Y
N
Methyl isobutyl ketone
Personal Air
Y
N
N
Methyl isobutyl ketone
Tire Crumb
N
N
N
Methyl isobutyl ketone
Dust
N
N
N
Methyl isobutyl ketone
Field Surface Residue
N
N
N
Methyl isobutyl ketone
Dermal Residue
N
N
N
Methyl isobutyl ketone
Food Conc./Intake
N
N
Y
Methyl isobutyl ketone
Bioaccessibility
N
N
N
Lead
Outdoor Air
Y
N
N
Lead
Indoor Air
N
N
Y
Lead
Combined Air
N
Y
N
Lead
Personal Air
N
N
N
Lead
Tire Crumb
Y
Y
N
Lead
Dust
N
Y
Y
Lead
Field Surface Residue
Y
Y
N
Lead
Dermal Residue
N
Y
N
Lead
Food Conc./Intake
N
N
Y
Lead
Bioaccessibility
N
Y
N
Zinc
Outdoor Air
Y
N
N
Zinc
Indoor Air
N
N
N
Zinc
Combined Air
N
Y
N
Zinc
Personal Air
N
N
N
Zinc
Tire Crumb
Y
Y
N
Zinc
Dust
N
Y
Y
Zinc
Field Surface Residue
Y
Y
N
Zinc
Dermal Residue
N
Y
N
Zinc
Food Conc./Intake
N
N
Y
Zinc
Bioaccessibility
N
Y
N
a Y = yes, N = no
151
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5.2 Exposure Pathway Modeling Results
The purpose of this portion of the study was to identify gaps in the data, as well as to compare exposure
estimates from this study against those from previous studies. Despite an extensive literature review,
data could not be found for components of some key pathways, including dermal residue loadings for
dermal exposure and measurements for some of our chemicals of interest in indoor air for inhalation
exposure. No measurements of methyl isobutyl ketone were found in tire crumb rubber, despite the
compound being measured in air above synthetic turf in multiple studies. Due to the scarcity of chemical
measurement data, including limited numbers of studies and typically small numbers of measurements
per study (e.g., only one or two measured values), estimates of upper confidence level (UCL) values
were not judged to be reliable. For this reason, UCL data was reported, but was not used to calculate
estimated exposures. Some key information on exposure factors specific to tire crumb rubber is not
known at this time; therefore, some of the exposure factors that were used for tire crumb rubber that are
applicable to soil and dust (e.g., adherence to skin and absorption fractions applicable to soil and dust)
may not actually be applicable to tire crumb rubber.
5.2.1 Synthetic Turf Field User Exposure Estimation Results Using Extant
Measurements
Results from exposure pathway modeling using weighted arithmetic means of extant measurements are
shown in Table 5-13. "Average Daily Dose" (i.e., dose averaged over a year using assumed frequency of
exposure events) is presented to represent prolonged, repeated exposures, whereas "Daily Dose"
represents the exposure on the day of use.
152
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Table 5-13. Estimated Exposure Results Using Extant Measurements, by Exposure Pathway8
Chemical
Age
(years)
Average
Daily Dose -
Ingestion
(mg/kg-day)
Average
Daily Dose -
Dermal
(mg/kg-day)
Average Daily
Dose - Outdoor
Inhalation
(mg/kg-day)
Average Daily
Dose - Indoor
Inhalation
(mg/kg-day)
Daily Dose -
Ingestion
(mg/kg-day)
Daily Dose -
Dermal
(mg/kg-day)
Daily Dose -
Outdoor
Inhalation
(mg/kg-day)
Daily Dose -
Indoor
Inhalation
(mg/kg-day)
Benzo[a]pyrene
6 to <11
3.31E-07
9.13E-09
7.82E-10
8.40E-09
1.55E-06
4.27E-08
3.66E-09
3.93E-08
Benzo[a]pyrene
11 to <16
1.64E-07
1.34E-08
2.71E-09
2.91E-08
4.33E-07
3.54E-08
7.17E-09
7.70E-08
Benzo[a]pyrene
16 to <21
1.30E-07
1.22E-08
1.46E-09
2.36E-08
3.44E-07
3.22E-08
3.87E-09
6.23E-08
Pyrene
6 to <11
2.64E-06
7.29E-08
2.86E-08
6.77E-08
1.24E-05
3.41E-07
1.34E-07
3.17E-07
Pyrene
11 to <16
1.31E-06
1.07E-07
9.90E-08
2.35E-07
3.46E-06
2.83E-07
2.62E-07
6.21E-07
Pyrene
16 to <21
1.04E-06
9.72E-08
5.34E-08
1.90E-07
2.74E-06
2.57E-07
1.41E-07
5.03E-07
Benzothiazole
6 to <11
5.44E-07
1.50E-08
2.79E-06
1.46E-04
2.55E-06
7.03E-08
1.30E-05
6.82E-04
Benzothiazole
11 to <16
2.70E-07
2.20E-08
9.66E-06
5.05E-04
7.13E-07
5.83E-08
2.55E-05
1.34E-03
Benzothiazole
16 to <21
2.14E-07
2.00E-08
5.21E-06
4.09E-04
5.66E-07
5.30E-08
1.38E-05
1.08E-03
Methyl isobutyl
ketone
6 to <11
NC
NC
8.80E-06
4.27E-04
NC
NC
4.12E-05
2.00E-03
Methyl isobutyl
ketone
11 to <16
NC
NC
3.05E-05
1.48E-03
NC
NC
8.07E-05
3.91E-03
Methyl isobutyl
ketone
16 to <21
NC
NC
1.65E-05
1.20E-03
NC
NC
4.35E-05
3.17E-03
Lead
6 to <11
5.00E-06
2.30E-08
1.16E-08
NC
2.34E-05
1.08E-07
5.43E-08
NC
Lead
11 to <16
2.47E-06
3.37E-08
4.02E-08
NC
6.54E-06
8.91E-08
1.06E-07
NC
Lead
16 to <21
1.96E-06
3.06E-08
2.17E-08
NC
5.19E-06
8.10E-08
5.74E-08
NC
Zinc
6 to <11
1.12E-03
5.14E-06
2.13E-07
NC
5.22E-03
2.40E-05
9.98E-07
NC
Zinc
11 to <16
5.53E-04
7.53E-06
7.40E-07
NC
1.46E-03
1.99E-05
1.96E-06
NC
Zinc
16 to <21
4.39E-04
6.85E-06
3.99E-07
NC
1.16E-03
1.81E-05
1.06E-06
NC
a Daily Dose is calculated by multiplying Average Daily Dose (ADD) by AT/EF [i.e., averaging time (days)/exposure frequency (days)]; NC = not calculated.
153
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5.2.2 Synthetic Turf Field User Exposure Estimation Results Using Exposure Pilot
Study Measurements
Results from exposure pathway modeling using the results of modeling using exposure pilot study
measurements are shown in Table 5-14.
Table 5-14. Estimated Exposure Results Using Exposure Pilot Study Measurements, by Exposure Pathway3
Chemical
Age
(years)
Average
Daily Dose -
Ingestion
(mg/kg-day)
Average
Daily Dose -
Dermal
(mg/kg-day)
Average
Daily Dose -
Combined
Inhalation
(mg/kg-day)
Daily Dose -
Ingestion
(mg/kg-day)
Daily Dose -
Dermal
(mg/kg-day)
Daily Dose -
Combined
Inhalationb
(mg/kg-day)
Benzo[a]pyrene
6 to <11
1.43E-07
1.97E-08
8.30E-11
6.70E-07
9.20E-08
3.88E-10
Benzo[a]pyrene
11 to <16
7.09E-08
1.23E-08
2.88E-10
1.88E-07
3.26E-08
7.61E-10
Benzo[a]pyrene
16 to <21
5.62E-08
1.21E-09
1.52E-10
1.49E-07
3.19E-09
4.02E-10
Pyrene
6 to <11
1.11E-06
5.22E-08
4.23E-08
5.18E-06
2.44E-07
1.98E-07
Pyrene
11 to <16
5.48E-07
3.19E-08
1.47E-07
1.45E-06
8.44E-08
3.88E-07
Pyrene
16 to <21
4.35E-07
4.50E-09
7.76E-08
1.15E-06
1.19E-08
2.05E-07
Benzothiazole
6 to <11
8.67E-07
4.09E-07
4.59E-06
4.06E-06
1.91E-06
2.15E-05
Benzothiazole
11 to <16
4.29E-07
7.06E-07
1.59E-05
1.14E-06
1.87E-06
4.21E-05
Benzothiazole
16 to <21
3.41E-07
1.93E-07
8.41E-06
9.01E-07
5.10E-07
2.23E-05
Methyl isobutyl
ketone
6 to <11
NC
NC
9.33E-06
NC
NC
4.37E-05
Methyl isobutyl
ketone
11 to <16
NC
NC
3.23E-05
NC
NC
8.55E-05
Methyl isobutyl
ketone
16 to <21
NC
NC
1.71E-05
NC
NC
4.52E-05
Lead
6 to <11
4.90E-07
3.31E-09
2.58E-08
2.29E-06
1.55E-08
1.21E-07
Lead
11 to <16
2.43E-07
5.12E-09
8.93E-08
6.42E-07
1.35E-08
2.36E-07
Lead
16 to <21
1.93E-07
9.93E-10
4.72E-08
5.09E-07
2.63E-09
1.25E-07
Zinc
6 to <11
3.81E-05
7.58E-07
1.87E-06
1.78E-04
3.55E-06
8.74E-06
Zinc
11 to <16
1.88E-05
1.43E-06
6.47E-06
4.98E-05
3.79E-06
1.71E-05
Zinc
16 to <21
1.50E-05
3.82E-07
3.42E-06
3.95E-05
1.01E-06
9.05E-06
a Daily Dose is calculated by multiplying Average Daily Dose (ADD) by AT/EF [i.e., averaging time (days)/exposure
frequency (days)]; NC = not calculated.
b Combined inhalation includes both indoor and outdoor air.
5.2.3 Synthetic Turf Field User Estimated Exposures for Chemicals of Interest by
Exposure Route
Route-specific exposures for each chemical of interest are illustrated, using both the extant data and
exposure pilot study data, in Figures 5-4 through 5-13.
154
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5.2.3.1 Benzo[a]pyrene Exposure Estimates
Benzo[a]pyrene - Extant
Daily Dose (mg/kg-day) log scale
1.00E+00
1.00E-01
1.00E-02
1.00E-03
1.00E-04
1.00E-05
1.00E-06 M
ii I I I
6 to <11 11 to <16 16 to <21
Years of Age
¦ Ingestion ¦ Dermal ¦ Outdoor Inhalation ¦ Indoor Inhalation
Figure 5-4. Benzo[a]pyrene daily dose calculated for three age groups, by
route of exposure, using extant data.
Benzo[a]pyrene - Exposure Pilot Study
Daily Dose (mg/kg-day) log scale
1.00E+00
1.00E-01
1.00E-02
1.00E-03
1.00E-04
1.00E-05
1.00E-06
__
1.00E-08
¦ ¦ ¦
1.00E-10
6 to <11 11 to <16 16 to <21
Years of Age
¦ Ingestion ¦Dermal ¦ Inhalation
Figure 5-5. Benzo[a]pyrene daily dose calculated for three age groups, by
route of exposure, using exposure pilot study data.
-------
5.2.3.2 Pyrene Exposure Estimates
Pyrene - Extant
Daily Dose (mg/kg-day) log scale
1.00E+00
1.00E-01
1.00E-02
1.00E-03
1.00E-04
1.00E-05 _
1.00E-06
= llll I I
6 to <11 11 to <16 16 to <21
Years of Age
¦ Ingestion ¦ Dermal ¦ Outdoor Inhalation ¦ Indoor Inhalation
Figure 5-6. Pyrene daily dose calculated for three age groups, by route of
exposure, using extant data.
1.00E-01
1.00E-02
1.00E-03
1.00E-04
1 nnp.nc;
Pyrene - Exposure Pilot Study
Daily Dose (mg/kg-day) log scale
l.UUL UJ
1 hop n£
i.uut-uo
1 nnp_n7
I.UUl-U/
1 nnp or
i.uut-uo
1 nnp no
1.UUL-U3
6 to <11 11 to <16
Years of Age
¦ Ingestion ¦Dermal ¦ Inhalation
16 to <21
Figure 5-7. Pyrene daily dose calculated for three age groups, across by route
of exposure, using exposure pilot study data.
-------
5.2.3.3 Benzothiazole Exposure Estimates
1.00E+00
1.00E-01
1.00E-02
1.00E-03
1.00E-04
1.00E-05
1.00E-06
1.00E-07
1.00E-08
Benzothiazole - Extant
Daily Dose (mg/kg-day) log scale
I
I i.l i.ll
6 to <11 11 to <16 16 to <21
Years of Age
I Ingestion ¦ Dermal ¦ Outdoor Inhalation ¦ Indoor Inhalation
Figure 5-8. Benzothiazole daily dose calculated for three age groups, by route
of exposure, using extant data.
Benzothiazole - Exposure Pilot Study
Daily Dose (mg/kg-day) log scale
1.00E+00
1.00E-01
1.00E-02
1.00E-03
1.00E-04
1.00E-05
1.00E-06
1.00E-07
1.00E-08
III III III
6 to <11 11 to <16 16 to <21
Years of Age
¦ Ingestion ¦Dermal ¦ Inhalation
Figure 5-9. Benzothiazole daily dose calculated for three age groups, by route
of exposure, using exposure pilot study data.
157
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5.2.3.4 Methyl Isobutyl Ketone Exposure Estimates
1.00E+00
1.00E-01
1.00E-02
1.00E-03
1.00E-04
1.00E-05
Methyl Isobutyl Ketone - Extant
Daily Dose (mg/kg-day) log scale
I .1
I
6 to <11
11 to <16
Years of Age
16 to <21
I Outdoor Inhalation
Indoor Inhalation
Figure 5-10. Methyl isobutyl ketone inhalation daily dose calculated for three
age groups, using extant data.
1.00E+00
1.00E-01
1.00E-02
1.00E-03
1.00E-04
1.00E-05
Methyl Isobutyl Ketone - Exposure Pilot Study
Daily Dose (mg/kg-day)
6 to <11
11 to <16
Years of Age
16 to <21
I Inhalation
Figure 5-11. Methyl isobutyl ketone inhalation daily dose calculated for three
age groups, using exposure pilot study data.
158
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5.2.3.5 Lead Exposure Estimates
Lead - Extant
Daily Dose (mg/kg-day) log scale
1.00E+00
1.00E-01
1.00E-02
1.00E-03
1.00E-04
1.00E-05
1.00E-06
IE ||| ||| |||
1.00E-10
6 to <11 11 to <16 16 to <21
Years of Age
¦ Ingestion ¦ Dermal ¦ Outdoor Inhalation
Figure 5-12. Lead daily dose calculated for three age groups, by route of exposure,
using extant data.
Lead - Exposure Pilot Study
Daily Dose (mg/kg-day) log scale
1.00E+00
1.00E-01
1.00E-02
1.00E-03
1.00E-04
1.00E-05
1.00E-06
= III III 1.1
1.00E-10
6 to <11 11 to <16 16 to <21
Years of Age
¦ Ingestion ¦Dermal ¦ Inhalation
Figure 5-13. Lead daily dose calculated for three age groups, by route of exposure,
using exposure pilot study data.
-------
5.2.3.6 Zinc Exposure Estimates
Zinc - Extant
Daily Dose (mg/kg-day) log scale
1.00E+00
1.00E-01
1.00E-02
1.00E-03
1.00E-04
1.00E-05
1.00E-06
1.00E-07
I.
6 to <11 11 to <16 16 to <21
Years of Age
¦ Ingestion ¦ Dermal ¦ Outdoor Inhalation
Figure 5-14. Zinc daily dose calculated for three age groups, by route of exposure,
using extant data.
Zinc - Exposure Pilot Study
Daily Dose (mg/kg-day) log scale
1.00E+00
1.00E-01
1.00E-02
1.00E-03
1.00E-04
1.00E-05
1.00E-06
1.00E-07
III lil
6 to <11 11 to <16 16 to <21
Years of Age
¦ Ingestion ¦Dermal ¦ Inhalation
Figure 5-15. Zinc daily dose calculated for three age groups, by route of exposure,
using exposure pilot study data.
160
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5.2.4 Background Exposure Estimation Results from Residential and Dietary Sources
Daily residential plus dietary dose rate estimates for inhalation, dietary and non-dietary ingestion, and
dermal absorption were calculated for three age groups (Table 5-15). Dietary and non-dietary ingestion
are summed as "Total Ingestion," and inhalation, total ingestion, and dermal absorption are summed as
"Total Estimated Daily Dose." Estimates are missing where no media-specific background data could be
located; for example, no values were found through a literature search for benzothiazole concentrations
in food or dust/soil, so no dietary or non-dietary ingestion or dermal absorption intake rates could be
estimated. "Total Estimated Daily Dose" represents the summation of all available estimates, assuming
zero for any missing route-specific estimates.
In general, route-specific and total estimated doses are highest for the youngest age group and lowest for
adults. Total estimated dose largely reflects ingestion, with dietary ingestion dominating for some
chemicals substances and non-dietary ingestion dominating for others. This result is not surprising since
the highest dust/soil ingestion rates and the highest dietary consumption rates per unit body weight are
for the youngest age group.
Table 5-15. Estimated Residential Plus Dietary Daily Dose for Chemicals of Interest, by Age Group8
Age
(years)
Chemical
Substance
Daily Dose -
Inhalation
(mg/kg-day)
Daily Dose -
Dietary
Ingestion
(mg/kg-day)
Daily Dose -
Non-Dietary
Ingestion
(mg/kg-day)
Daily Dose -
Total
Ingestion
(mg/kg-day)
Daily Dose -
Dermal
(mg/kg-day)
Total
Estimated
Daily Doseb
(mg/kg-day)
6 to <11
Benzo[a]pyrene
5.18E-08
7.86E-07
2.09E-06
2.88E-06
3.83E-08
2.97E-06
6 to <11
Pyrene
4.39E-07
7.03E-06
4.06E-07
7.44E-06
2.07E-08
7.90E-06
6 to <11
Benzothiazole
9.62E-06
NC
NC
NC
NC
9.62E-06
6 to <11
Methyl isobutyl
ketone
1.80E-05
3.14E-05
NC
3.14E-05
NC
4.95E-05
6 to <11
Lead
3.33E-06
7.50E-05
2.62E-04
3.37E-04
2.23E-06
3.43E-04
6 to <11
Zinc
NC
6.60E-02
4.72E-04
6.65E-02
4.02E-06
6.65E-02
11 to <16
Benzo[a]pyrene
3.65E-08
4.40E-07
5.86E-07
1.03E-06
3.17E-08
1.09E-06
11 to <16
Pyrene
3.10E-07
4.26E-06
1.14E-07
4.37E-06
1.72E-08
4.70E-06
11 to <16
Benzothiazole
6.78E-06
NC
NC
NC
NC
6.78E-06
11 to <16
Methyl isobutyl
ketone
1.27E-05
1.76E-05
NC
1.76E-05
NC
3.03E-05
11 to <16
Lead
2.35E-06
7.50E-05
7.34E-05
1.48E-04
1.85E-06
1.53E-04
11 to <16
Zinc
NC
6.60E-02
1.32E-04
6.61E-02
3.33E-06
6.61E-02
16 to <21
Benzo[a]pyrene
3.13E-08
3.49E-07
4.65E-07
8.14E-07
2.88E-08
8.74E-07
16 to <21
Pyrene
2.65E-07
3.31E-06
9.01E-08
3.40E-06
1.56E-08
3.68E-06
16 to <21
Benzothiazole
5.81E-06
NC
NC
NC
NC
5.81E-06
16 to <21
Methyl isobutyl
ketone
1.09E-05
1.40E-05
NC
1.40E-05
NC
2.49E-05
16 to <21
Lead
2.01E-06
7.50E-05
5.82E-05
1.33E-04
1.68E-06
1.37E-04
16 to <21
Zinc
NC
6.60E-02
1.05E-04
6.61E-02
3.03E-06
6.61E-02
a NC = not calculated.
b Total estimated daily dose across all exposure pathways incorporates inhaled, total ingested and dermal estimations.
161
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5.3 Comparison of Synthetic Turf Field User Exposure Estimates Using Extant Data and
Exposure Pilot Study Data
Using existing measurement data for six chemicals and exposure pathway model parameters that
included many values not necessarily developed for these specific chemicals, tire crumb rubber infill
material, or synthetic turf field athlete scenarios, we observed the following:
• In general, chemicals of like or similar classifications (i.e., VOCs) followed similar
patterns of exposure for each age group.
• Ingestion appears to be the most significant route of exposure for the PAH SVOCs
pyrene and benzo[a]pyrene. Estimated exposures were highest for the 6 to <11 age group,
with lower exposures for older age groups, as the amount of tire crumb rubber
constituents ingested is assumed to decrease with age due to the decrease in hand-to-
mouth contact.
• Ingestion is also the dominant route of exposure for the metals lead and zinc and is also
highest in the 6 to <11 age group. A decrease in exposure is observed for the other age
groups due to an assumed decrease in incidental ingestion of tire crumb rubber with age.
• The predominant exposure pathway for the SVOC benzothiazole appears to be inhalation,
with much higher inhalation exposures at indoor fields than outdoor fields (based only on
a very small number of indoor field air measurements).
• Dermal exposures are estimated to be lower than ingestion exposures for the metals and
PAH SVOCs and much lower than the inhalation exposure for benzothiazole. Dermal
exposure was not observed to be the dominant route of exposure for any of the
compounds of interest; however, there are large uncertainties in the model adherence and
dermal absorption parameters.
Using measurements of bioaccessibility of metals in tire crumb rubber and exposure-related
measurement data from this exposure pilot study (including measurements of chemical substances in
field dust and on dermal wipes), the exposure pathway models were re-run. We observed the following
using the data from this study:
• There was no change in the dominant route of exposure for each chemical substance, and
trends were consistent with each age group.
• Estimates for ingested dose using data from the exposure pilot study were lower than
dose estimates using extant measurements, based on lower metal and PAH SVOC levels
in field dust compared to tire crumb rubber and lower exposure pilot study ingestion
absorption for metals based on the bioaccessibility (biological sample) results.
• There are no objective data for assessing incidental ingestion of tire crumb rubber or
synthetic turf field dust for synthetic field turf scenarios, leaving ingestion exposure
estimates still highly uncertain.
• Direct dermal loading measurements in the exposure pilot study provided the ability to
calculate the amount of chemical directly in contact with the exposed skin, avoiding more
uncertain adherence assumptions concerning adherence of crumb to skin. Exposure pilot
study dermal estimates for metals were lower than results obtained using extant
measurement data together with assumed tire crumb rubber dermal adherence values.
• Exposure via the dermal route was relatively low for each chemical substance, especially
for lead and zinc, when this exposure pilot study's bioaccessibility measurements
162
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replaced the more conservative (i.e., higher) dermal absorption estimates for metals using
extant data.
The following observations were made regarding potential improvements in exposure estimates based
on additional data collected in the exposure pilot study:
• Laboratory bioaccessibility measurements for lead and zinc reduced uncertainty from
assumptions concerning the amount of the metal available to be absorbed.
• Dermal wipe measurements reduced uncertainty from assumptions concerning the
amount of chemical substances (excluding methyl isobutyl ketone) transferred from tire
crumb directly onto skin.
• In the absence of dermal wipe measurements, measurements of chemical substances in
crumb rubber field dust (instead of in the larger crumb rubber granules) is likely to
provide better estimates of the amount of chemical substances likely to transfer to skin.
• Measurements from field dust are also likely to provide better estimates of exposure
through ingestion, compared to measurements from the larger granules.
Even with the data from the exposure pilot study, several limitations remain. These include the
following:
• The exposure pilot study field measurements were not able to provide any measurements
of methyl isobutyl ketone in tire crumb rubber granules or dust or on field surfaces.
• No additional pathways could be completed for methyl isobutyl ketone based on new
data collected during the exposure pilot study.
• Both extant data and exposure pilot study field data ignore the contribution of dietary
intake from off-field activities to the total intake for relevant chemical substances.
• Small sample size of the exposure pilot study necessitated the combining of
measurements from indoor and outdoor fields, limiting the scope of the modeling effort.
• A lack of data on bioaccessibility for chemical substances in crumb rubber field dust
serves to increase the uncertainty of the route-specific exposure estimates for all three
routes (see Figure 5-2).
5.4 Comparisons Between Synthetic Turf Field and Background Exposure Estimates
Total daily dose estimates calculated from residential plus dietary concentrations, from extant synthetic
turf field data from the literature, and from the synthetic turf field data collected in this exposure pilot
study are presented in Table 5-16. The table includes daily dose estimates for all three age groups in the
exposure pilot study. Dose estimates for benzothiazole are not shown due to scarcity of data. Daily
residential plus dietary dose estimates for benzo[a]pyrene are similar to estimates using extant synthetic
turf field data and associated model parameters, but higher than estimates for synthetic turf field users
based on data from this exposure pilot study. Daily residential plus dietary dose estimates for pyrene are
slightly lower than estimates using extant synthetic turf field data but higher than estimates for synthetic
turf field users based on data from this study. For lead and zinc, the total estimated daily doses are
substantially higher for residential plus dietary than for synthetic turf fields. The differences among the
three sets of results (residential plus dietary background, extant synthetic turf, and measurements in the
exposure pilot study) are illustrated for benzo[a]pyrene, pyrene, lead, and zinc in Figures 5-16 through
5-19, respectively.
163
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Table 5-16. Total Estimated Daily Dose Across all Pathways by Age Group8
Age
(years)
Chemical Substance
Estimated Total
Daily Dose -
Residential Plus
Dietary Background
(mg/kg-day)
Estimated Total
Daily Dose -
Synthetic Field,
Extant Data
(mg/kg-day)
Estimated Total
Daily Dose -
Synthetic Field,
Exposure Pilot Study
(mg/kg-day)
6 to <11
Benzo[a]pyrene
2.97E-06
1.64E-06
7.62E-07
6 to <11
Pyrene
7.90E-06
1.32E-05
5.62E-06
6 to <11
Methyl isobutyl ketone
4.95E-05
2.04E-03
4.37E-05
6 to <11
Lead
3.43E-04
2.36E-05
2.43E-06
6 to <11
Zinc
6.65E-02
5.24E-03
1.90E-04
11 to <16
Benzo[a]pyrene
1.09E-06
5.53E-07
2.21E-07
11 to <16
Pyrene
4.70E-06
4.63E-06
1.92E-06
11 to <16
Methyl isobutyl ketone
3.03E-05
3.99E-03
8.55E-05
11 to <16
Lead
1.53E-04
6.74E-06
8.92E-07
11 to <16
Zinc
6.61E-02
1.48E-03
7.08E-05
16 to <21
Benzo[a]pyrene
8.74E-07
4.42E-07
1.52E-07
16 to <21
Pyrene
3.68E-06
3.64E-06
1.37E-06
16 to <21
Methyl isobutyl ketone
2.49E-05
3.21E-03
4.52E-05
16 to <21
Lead
1.37E-04
5.33E-06
6.37E-07
16 to <21
Zinc
6.61E-02
1.18E-03
4.96E-05
a Total estimated daily dose across all pathways for each part of the study; benzothiazole comparison not shown due
to scarce data.
Benzo[a]pyrene Total Estimated Dose Comparison
(mg/kg-day)
¦ 6 to <11
¦ 11 to <16
¦ 16 to <21
Figure 5-16. Total estimated benzo[a]pyrene background (residential/dietary) and
synthetic turf field daily dose rate comparison across all pathways, by age group.
1.80E-06
1.60E-06
1.40E-06
1.20E-06
1.00E-06
8.00E-07
6.00E-07
4.00E-07
2.00E-07
0.00E+00
,
-------
Pyrene Total Estimated Dose Comparison
(mg/kg-day)
1.40E-05
1.20E-05
1.00E-05
8.00E-06
6.00E-06
4.00E-06
2.00E-06
0.00E+00
,
-------
Zinc Total Estimated Dose Comparison
(mg/kg-day)
7.00E-02
6.00E-02
5.00E-02
4.00E-02
3.00E-02
2.00E-02
1.00E-02
0.00E+00
&
P
I 6 to <11
111 to <16
116 to <21
Figure 5-19. Total estimated zinc background (residential/dietary) and synthetic
turf field daily dose rate comparison across all pathways, by age group.
Differences between total estimated doses using extant data from synthetic turf fields versus data from
the tire crumb rubber characterization portion of the study (U.S. EPA & CDC/ATSDR (2019) and the
exposure pilot study can be attributed to several factors, including: a) different concentrations measured
in this study, b) the use of dust measurement data in this study instead of tire crumb rubber for ingestion
estimates, c) the use of direct dermal measurements in this study instead of an assumed adherence factor
for tire crumb rubber, and d) the use of laboratory-measured bioaccessibility of zinc and lead instead of
the assumed values used for the extant data.
Measurements of the six compounds of interest in media from environments not known to be impacted
by contamination are relatively sparse. In addition, some of the data that were available for U.S.
populations were collected almost 20 years ago and may not reflect current exposures in the population.
Due to the paucity of background concentration measurements, the total residential plus dietary
background daily dose estimates should be considered highly uncertain. Benzothiazole estimates could
not be calculated, and methyl isobutyl ketone data were missing for key media, especially residential
indoor air and indoor dust measurements. The air concentrations for methyl isobutyl ketone were
measured in outdoor air and are not considered a good surrogate of residential indoor air. Zinc was also
missing indoor air measurements.
The process of modeling using algorithms that rely on exposure factor parameters required some large
assumptions. For example, EPA's Exposure Factors Handbook (U.S. EPA, 201 lb) provides no
applicable indoor dust adherence rates for adults, and the adherence factor recommended for children
had to be used across all age groups.
The six chemical substances evaluated in this comparative analysis are only indicative of a small subset
of the chemicals associated with tire crumb rubber; however, due to the limited or unavailable
environmental concentration, dietary intake, and bioaccessibility and concentration data available for
those chemicals, testing protocols have not been fully developed, and at this time, gathering enough
information to apply to modeling residential and dietary exposures is not feasible.
166
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5.5 Conclusions
Based on these modeling exercises, we report the following observations regarding the accuracy and
uncertainties in exposure estimates for athletes using synthetic turf fields:
• The data are not adequate to support probabilistic exposure modeling approaches. For
many chemicals found to be associated with tire crumb rubber infill on synthetic turf
fields, there is a lack of robust data for many exposure media, including air (particularly
in athlete breathing zones), field surfaces and field dust, and dermal residue loadings.
This lack of robust data likely results in increased uncertainty in exposure estimation.
• Current exposure estimates are somewhat limited by the lack of exposure scenarios that
more fully account for actual activity levels and types and frequencies of contact, and
their differences among sport types (e.g., football vs. soccer) and specific positions (e.g.,
goalkeepers) that likely involve higher rates of contact with turf materials.
• There are limited or no data available for some of the important parameters needed to
estimate exposures for athletes using synthetic turf fields with tire crumb rubber infill.
The lack of parameter data leads to applications of assumed values or values applied from
non-equivalent scenarios, both of which can lead to considerable uncertainties in
exposure estimates. In some cases, conservative values are applied that may lead to
exposure over-estimation but are considered to be protective in assessments for exposed
populations. In other cases, important exposure mechanisms may not be correctly
accounted for, potentially leading to exposure under-estimation. Some of the important
parameters with no or limited data include:
o Concentration of tire crumb rubber particles of various size fractions in the
breathing zones of athletes under different athletic activity conditions
o Ingestion rates for tire crumb rubber particles of various sizes during athletic
activities
o Skin adherence rates of tire crumb rubber particles of various sizes, for both dry
skin and sweaty skin conditions
o Skin adsorption rates for organic chemicals associated with tire crumb rubber
particles of various sizes
o Respiratory absorption rates for inorganic and organic chemicals associated with
tire crumb rubber particles of various sizes
o Ingestion (gastrointestinal) absorption rates for organic chemicals associated with
tire crumb rubber
• There are a large number of chemical substances associated with tire crumb rubber infill
that have not been included in most exposure assessments. Lack of certainty in the
identification of many of these chemicals and lack of quantitative measurements inhibits
a more complete cumulative exposure assessment.
Estimates of "background" exposures to benzo[a]pyrene, pyrene, lead and zinc from residential and
dietary sources were calculated and compared to modeled exposure estimates for synthetic turf field
users to provide perspective on the magnitude of the exposures estimated for athletes. The following
observations were made from that analysis:
167
-------
• Benzo[a]pyrene and pyrene exposures from residential plus dietary sources were
estimated to be 1.5 to 3 times higher than modeled exposure estimates for synthetic turf
field users based on data produced in this exposure pilot study.
• When using previously published literature results for synthetic turf fields and somewhat
different model parameters (e.g., duration of exposure), benzo[a]pyrene exposures from
residential plus dietary sources were similar to those for synthetic turf field users. Pyrene
exposures were <1.5 times higher for synthetic turf field users using extant literature data
compared to residential plus dietary sources.
• Lead and zinc exposures from residential plus dietary sources were estimated to be over
100 times higher than modeled exposure estimates for synthetic turf field users based on
data produced in this exposure pilot study and over 10 times higher for estimates using
extant data from the literature to model exposures for synthetic turf field users.
Previous exposure estimates for athletes have primarily focused on soccer players of various age groups
and playing intensities. More work is needed to examine potential exposures for other sport types and
for certain positions within sports. For example, football athletes, rugby athletes, and soccer goalies are
likely to experience substantially different dermal and ingestion exposures than soccer field players due
to their much more frequent contact with turf materials. They may also experience higher particle
inhalation due to the nature of their play and more frequent proximity to the turf surface. Players using
mouthguards, typically required in football, may also experience higher oral contact rates with residues.
More data are needed on activity types and contact rates, along with improved approaches for measuring
chemicals in the relevant exposure media, dermal wipes, and biological samples to develop or improve
exposure pathway model parameter values for estimating athlete exposures at synthetic turf fields.
Some researchers have developed exposure estimates for non-athletes at synthetic turf fields. More
information regarding time and activities by coaches, referees, maintenance workers, parents and young
siblings could be beneficial to extending and improving exposure estimation for these groups.
Finally, a large number of inorganic and organic chemical substances have been found to be associated
with tire crumb rubber. These chemicals have a large range of chemical and physical properties that
affect how they are released from the tire crumb rubber material and absorbed in the body. It remains a
challenge to accurately estimate inhalation, dermal and ingestion exposures across this large range of
chemicals, and even more of a challenge to estimate potential risks on a cumulative exposure basis.
Studies that investigate biomarker identification of chemical substances found in tire crumb rubber can
contribute to exposure modeling for a more robust exposure profile. Currently, data are likely to be
sparse for estimating background exposures for many of the chemicals associated with tire crumb rubber
for comparison with synthetic turf field user exposure estimates.
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7.0 Appendices
The following Appendices can be found in Volume 2 of this report:
A Supplemental Biomonitoring Study
B Quality Assurance and Quality Control
C Standard Operating Procedures (SOP) for Exposure Characterization Research
D Synthetic Field Facility User Questionnaires
E Exposure Characterization Meta-Data Collection Forms
F Blood Metals and Serum Metals Analysis Protocols
G Video Activity Data
H Feasibility Assessment for Silicone Wristband Passive Samplers at Synthetic Turf Fields
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oEPA
United States
Environmental Protection
Agency
Office of Research and Development (8101R)
Washington, DC 20460
Official Business
Penalty for Private Use
$300
PRESORTED
STANDARD POSTAGE
& FEES PAID EPA
PERMIT NO. G-35
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