EPA/600/R-16/364 | December 2016 | www.epa.gov
United States
Environmental Protection
Agency
Federal Research Action Plan on
Recycled Tire Crumb Used on Playing
Fields and Playgrounds
STATUS REPORT
National Exposure Research Laboratory
Office of Research and Development
Atsdr
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Prepared By:
U.S. Environmental Protection Agency (EPA)1
Centers for Disease Control and Prevention / Agency for Toxic Substances and Disease
Registry (CDC/ATSDR)2
U.S. Consumer Product Safety Commission (CPSC)/ Directorate for Health Sciences3
Disclaimer:
This document has been reviewed by the U.S. Environmental Protection Agency, the
Agency for Toxic Substances and Disease Registry, and the Consumer Product Safety
Commission and approved for release.
Any mention of trade names, products, or services does not imply an endorsement by the
US Government.
1 US EPA Contact: Monica Linnenbrink - tirecrumbs@epa. gov
2 CDC/ATSDR Contact: 1-800-CDC-INFO (1-800-232-4636) or visit CDC-INFO website at
https://wwwn.cdc.gov/dcs/CoiitactIJs/Fomi. Reference Tire Crumb Research Status Report or visit the ATSDR webpage titled:
Federal Research Action Plan on Recycled Tire Crumb Used on Playing Fields and Playgrounds at
https://www.atsdr.cdc.gov/frap/index.html.
3 CPSC Contact: Eric Elooker - EH.ook.er@cpsc.gov
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Table of Contents
I. EXECUTIVE SUMMARY 1
II. INTRODUCTION 6
III. STAKEHOLDER OUTREACH 7
IV. STATUS OF ACTIVITIES 8
A. Industry Overview 8
B. Literature Review/Gaps Analysis Overview 15
C. Data Collection for Synthetic Turf Fields/Summary of Activity to Date 19
D. Recycled Tire Materials in Playground Surfaces 25
V. NEXT STEPS AND TIMELINE 28
VI. REFERENCES 29
APPENDICES 34
Appendix A - Stakeholder Outreach 35
Appendix B - State-of-the-Science Literature Review/Gaps Analysis 39
Appendix C- Data Collection for Synthetic Turf Fields/Summary of Activity to Date 133
Appendix D - Playground Surfaces with Recycled Tire Materials 149
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I. Executive Summary
Over the past several years, parents, athletes, schools, and communities have raised concerns
about the safety of recycled tire crumb rubber used as infill for playing fields and playgrounds in
the United States. The public has expressed concerns that the use of these fields could potentially
be related to certain health effects. Studies to date have not shown an elevated health risk from
playing on fields with tire crumb rubber, but these studies have limitations and do not
comprehensively evaluate the concerns about health risks from exposure to tire crumb rubber.
Synthetic turf field systems were initially introduced in the 1960s. Currently, there are between
12,000 and 13,000 synthetic turf recreational fields in the United States, with 1,200 - 1,500 new
installations each year (STC et al., 2016). Synthetic turf fields are installed at municipal and
county parks; schools, colleges and universities; professional team stadiums and practice fields;
and military installations. Potentially millions of people are estimated to use these fields,
including professional and college athletes, youth athletes in school or other athletic
organizations, coaches, team and facility staff, referees, fans, bystanders and local communities.
On February 12, 2016, the Centers for Disease Control and Prevention/Agency for Toxic
Substances and Disease Registry (CDC/ATSDR) and the U.S. Environmental Protection Agency
(EPA)4, in collaboration with the Consumer Product Safety Commission (CPSC)5, released a
Federal Research Action Plan on Recycled Tire Crumb Used on Playing Fields and Playgrounds
(FRAP)6. The purpose of the FRAP is to study key questions concerning the potential for human
exposure resulting from the use of tire crumb rubber in playing fields and playgrounds. This kind
of information is important for any follow up evaluation of risk that might be performed.
The FRAP includes outreach to key stakeholders to obtain information to fill important data
gaps, research to characterize constituents of tire crumb made from recycled tire rubber, studies
to identify ways in which people may be exposed to tire crumb rubber based on their activities
on the fields, and an analysis of existing scientific literature on the topic.
Prior to initiating the study, federal researchers developed a research protocol, Collections
Related to Synthetic Turf Fields with Crumb Rubber Infill1, which describes the study's
objectives, research design, methods, data analysis techniques, and quality assurance/quality
control measures in place to ensure the integrity of the following components of the research:
• literature review and data gaps analysis;
• tire crumb rubber characterization research;
• human exposure characterization research.
4 The specific roles of EPA and CDC/ATSDR are provided in the FRAP
5 This report includes contributions written by the CPSC staff and has not been reviewed and/or approved by, and may not
necessarily reflect the views of, the Commission.
6 The FRAP is available through the Tire Crumb website: www.epa.gov/tirecrumb
7 The research protocol is available through the Tire Crumb website: www.epa.gov/tirecrumb
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The study protocol was reviewed by independent external peer reviewers, CDC's Institutional
Review Board (IRB) and EPA's Human Subjects Research Review Official. The data collection
components of the study went through the Office of Management and Budget's (OMB)
Information Collection Request (ICR) review process. The OMB ICR process included a public
comment period8. On August 5, 2016, EPA, CDC/ATSDR and CPSC received final approval
from OMB to begin the research.
This status report provides a summary of the agencies' activities to-date, including:
• stakeholder outreach;
• tire and tire crumb rubber manufacturing process;
• final peer-reviewed Literature Review/Gaps Analysis;
• Tire Crumb Rubber Characterization and Exposure Characterization research;
• use of recycled rubber tires on playgrounds;
• next steps and a timeline.
Since research is currently ongoing, the status report does not include any preliminary findings
of the research. The results of the research on synthetic turf fields will be available later in 2017.
The purpose of the FRAP is to study key
questions concerning the potential for human
exposure resulting from the use of tire crumb
rubber in playing fields and playgrounds.
Summary of Stakeholder Outreach
EPA, CDC/ATSDR, and CPSC teams have engaged in a number of outreach activities, listed
below, to inform the public, research organizations, industry, government organizations and non-
profit organizations about the FRAP and to gather and share information that may be used to
inform the research. Section III and Appendix A provide additional information on stakeholder
outreach covering the following areas:
• Solicited public comment on components of the study, including collection of tire crumb
rubber samples and information from field users;
• Regularly updated the Tire Crumb Study website (www.epa.gov/tirecrumb). with links to
the FRAP and the research protocol, Tire Crumb Questions and Answers, government
websites that provide recommendations for recreation on fields with tire crumb, and other
information;
• Hosted a public webinar to provide an overview of the FRAP;
• Distributed study updates to an e-mail list of about 800 stakeholders.
8 Public and peer review comments and the agencies' responses are available on the OMB's website -
http://www.reginfo.gov/public/do/PRAViewDocument7ref nbr=201607-0923-001.
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The agencies also reached out to other federal, state, and international government organizations
involved in planning or conducting tire crumb research. These included California's Office of
Environmental Health Hazard Assessment, Washington State Department of Health, the National
Toxicology Program at the National Institute of Environmental Health Sciences, the European
Chemicals Agency, and the Netherlands National Institute for Public Health and the
Environment.
Industry Overview
Agency researchers gathered information from industry, non-governmental organizations, and
others to inform the design and implementation of the research on synthetic turf fields containing
rubber infill. This included collecting information on how tires and tire crumb rubber are
manufactured, and on how synthetic turf fields are constructed, installed, and maintained.
From February to September 2016, the study team held meetings with five industry trade
associations, three synthetic turf field companies, two synthetic turf field maintenance
professionals, one academic institution, and five non-profit organizations. EPA, CDC/ATSDR,
and CPSC scientists toured a total of five tire recycling facilities in the south, west, and northeast
regions of the United States, where they observed different types of tire crumb rubber processing
technologies. The facilities ranged in size from small to large operations with varying degrees of
mechanized technologies to process the tires. The tire crumb rubber infilling process was
observed on two field installations in the Washington, D.C. metropolitan area. Through these
tours, the team gathered information on a number of topics, including:
• The state of tire manufacturing and scrap-tire collection and recycling;
• The nature and varieties of processes and machinery used in the processing of scrap tires
into tire crumb rubber;
• Tire-manufacturing standards;
• Tire recycling process standards and tire crumb rubber product standards;
• Tire crumb rubber infill product types;
• Storage, packaging and transportation of tire crumb rubber to fields;
• The number and distribution of synthetic turf fields;
• Synthetic turf field construction, installation and maintenance practices.
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Peer-Reviewed Literature Review/Gaps Analysis
The research team conducted a Literature Review/Gaps
Analysis (LRGA, included in this status report) that provides
a current summary of the available literature and captures the
data gaps as characterized in those publications. The overall
goals of the LRGA were to inform the interagency research
study and to identify potential areas for future research. The
LRGA does not include critical reviews of the strengths and
weaknesses of each study, but does provide the authors' conclusions regarding their research,
where applicable. The LRGA also does not make any conclusions or recommendations regarding
the safety of recycled tire crumb rubber used in synthetic turf fields and playgrounds.
The LRGA identified 88 references from data sources, including PubMed, Medline (OVID),
Embase (OVID), Scopus, Primo (Stephen B. Thacker CDC Library), ProQuest Environmental
Science Collection, Web of Science, ScienceDirect, and Google Scholar. Each reference
reviewed was categorized according to 20 general information categories (e.g., study topic,
geographic location, sample type, conditions, and populations studied) and more than 100
subcategories (e.g., for study topic: site characterization, production process, leaching, off-
gassing, microbial analysis, and human risk). The research in the FRAP addresses many of the
gaps identified in the LRGA, particularly with respect to tire crumb rubber characterization and
exposure characterization. A summary of the results of the data gaps component of the LRGA is
provided Section IV B. The final peer-reviewed document is included in Appendix B.
Data Collection for Tire Crumb Rubber Characterization
EPA and CDC/ATSDR are conducting a characterization of the components of tire crumb
rubber, which is critical to understanding the potential for exposure. As part of the tire crumb
rubber characterization study, researchers collected tire crumb rubber samples from nine tire
recycling plants and 40 synthetic turf fields (both indoor and outdoor) from the four U.S. census
regions. Laboratory analyses are in progress, including measurements of the amounts of volatile
organic chemicals (VOCs) and semi-volatile organic chemicals (SVOCs) emitted from the tire
crumb rubber under different temperature conditions. Bioaccessibility measurements for metals
and SVOCs are being conducted to better
understand how much of the chemicals present in
tire crumb rubber can be absorbed in the body. In
addition to quantitative target chemical analyses,
samples will be assessed to determine whether
there may be VOCs and SVOCs in tire crumb
rubber that have not been previously reported. In
addition to the potential for chemical exposures
at synthetic turf fields, concerns have been raised
about the potential for exposure to microbial
pathogens. The microbial populations associated
with the tire crumb rubber infill collected from
synthetic turf fields are also being characterized.
The overall goals of the
LRGA were to inform the
interagency research study
and to identify potential
areas for future research.
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Data Collection for Exposure Characterization
Characterizing exposure of individuals to constituents in tire crumb rubber is another important
consideration for understanding potential health risk. The exposure characterization study is a
pilot-scale effort to: (a) collect information on human activity parameters (such as frequency and
duration of field use and contact rates with field materials for different activities) that affect
potential exposures of synthetic turf field users to tire crumb rubber; and (b) conduct a human
exposure measurement study to develop and assess methods for measuring exposures and to
generate data for improved exposure characterization. The field recruitment process has begun;
however, field collection has not yet started because fields with active sports seasons are not
currently available. The agencies are continuing their efforts to identify fields that meet the study
criteria.
Recycled Tire Materials Used in Playgrounds
CPSC's role in the FRAP is to assess the potential risks to consumers associated with the use of
recycled tire crumb rubber in playground surfaces. CPSC staff identified five general types of
playground surfaces that are made with recycled tire materials: (1) loose-fill rubber, (2) rubber
tiles, (3) poured-in-place rubber, (4) bonded rubber, and (5) synthetic turf. Limited information
is available about the chemical safety of recycled tire materials in playground surfaces. CPSC is
using a combination of field observations, focus groups, and a national survey of parents and
child care providers to collect information on children's behaviors on playgrounds and to
identify exposure factors. Specific risk assessment strategies will be determined based on review
of the new data, including the tire crumb rubber characterization and bioavailability studies
currently being performed by EPA and CDC/ATSDR, and likely will focus on the substances of
highest concern.
Next Steps and Timeline
Analysis of the tire crumb samples collected from fields and recycling facilities, and the
exposure characterization component of the study, will continue in 2017. Parts of the exposure
study may be conducted during the hotter months of 2017. The results of the research on
synthetic turf fields are anticipated to be available in 2017. The CPSC playground study also will
continue in 2017.
The agencies will continue to share information with other government agencies that have
ongoing or planned tire crumb rubber. As it is available, updated information will be posted to
EPA's tire crumb rubber website (www.epa.gov/tirecrumb) and stakeholder groups will be
notified of these updates.
The status report does not include any preliminary findings of the research.
The results of the synthetic turf fields research will be available later in 2017.
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II. Introduction
Concerns have been raised by the public about the safety of recycled tire crumb rubber used in
playing fields and playgrounds. Studies to date have not shown an elevated health risk from
playing on fields with tire crumb rubber, but these studies have limitations and do not
comprehensively evaluate the concerns about health risks from exposure to tire crumb rubber.
On February 12, 2016, 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 effort called the Federal Research Action Plan on Recycled Tire Crumb Used on
Playing Fields and Playgrounds (FRAP). The purpose of the FRAP is to study key questions
concerning the potential for human exposure resulting from the use of tire crumb rubber in
playing fields and playgrounds.
To support the goals of the FRAP, federal researchers developed the research protocol titled
Collections Related to Synthetic Turf Fields with Crumb Rubber Infill. The research protocol
describes the following components of the research study:
• Literature Review/Gaps Analysis;
• tire crumb rubber characterization research;
• human exposure characterization research.
The review of the literature and data gaps analysis involved an examination of information
available for tire crumb rubber used for synthetic turf infill, in addition to playgrounds. The tire
crumb rubber characterization research focused on samples collected from tire crumb rubber
manufacturing facilities and indoor and outdoor synthetic turf fields across the country. Exposure
characterization research outlined in the protocol focuses on synthetic turf fields. The CPSC
team is developing research plans for playgrounds.
This status report provides a summary of activities to date, including: (1) stakeholder outreach,
(2) the tire crumb rubber manufacturing industry, (3) the final peer-reviewed Literature
Review/Gaps Analysis (LRGA), (4) progress on the research activities, and (5) next steps and a
timeline for completion of the final report. The research updates included in this document are:
• characterization of the chemicals and materials found in tire crumb rubber,
• characterization of the exposure scenarios for athletes and others using turf fields
containing tire crumb rubber,
• a study to better understand how children use playgrounds containing tire crumb rubber.
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III. Stakeholder Outreach
Completed Activities
EPA, CDC/ATSDR, and CPSC engaged in a number of outreach activities to support the FRAP.
These activities focused on three areas:
1. Informing the public about the FRAP and encouraging them to provide feedback
through a public comment process. This was accomplished by sharing information
through EPA's public website and e-mail updates, public webinars, and providing
opportunities for public comment.
2. Sharing information with other government organizations that are planning or
conducting research on this topic. EPA, CDC/ATSDR, and CPSC engaged U.S. and
international organizations through regular conference calls, webinars, and other
mechanisms for sharing expertise and information.
3. Contacting organizations to obtain information to inform the FRAP. A brief summary
of these efforts is described below. Discussions were held with government
organizations, industry, and other groups to better understand how tires and tire
crumb rubber are manufactured, and how synthetic turf fields are constructed,
installed, and maintained; as well as to obtain other studies or information that could
be used for the study.
Future Activities
EPA, CDC/ATSDR, and CPSC will continue the outreach activities described above. As the
exposure characterization portion of the research is implemented, additional outreach will be
undertaken to gather information from field users. The CPSC team will be engaging parents and
child caregivers in focus groups to gather information about how children use playgrounds.
See Appendix A for more detailed descriptions of the outreach activities to support the FRAP.
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IV. Status of Activities
A. Industry Overview
The agencies used outreach efforts and publicly
available information to gain a better
understanding of the synthetic turf industry, tire
manufacturing process, processes for creating
tire crumb rubber, and procedures for synthetic
turf field installation and maintenance. This
section provides information related to these
topics.
Waste Tire Generation and Recovery
Estimates
A large volume of used automobile and truck
tires enters the waste stream in the United States
each year. An estimated 4.77 million tons of
waste tires were generated in 2013, and 40.5 percent, or 1.93 million tons, were recovered
through recycling and production of retreaded tires (U.S. EPA, 2015). Much of the waste tire
material is used in fuel markets, including cement kilns, utility boilers, industrial boilers, pulp
and paper mills, and dedicated scrap tire-to-energy facilities (RMA, 2016a). In 2013,
approximately 172,000 tons of scrap tires were converted to tire shreds for use in road and
landfill construction, septic tank leach fields, and other construction applications (RMA, 2016a).
Approximately 975,000 tons of scrap tires (i.e., approximately 59.5 million tires) were used in
the ground rubber applications market, which includes the manufacture of new rubber products,
rubber-modified asphalt, and playground and sports surfacing (RMA, 2014 and 2016a). The
Rubber Manufacturers Associati on (RMA) estimated that in 2013, 33 percent of these scrap tires
were used in molded/extruded products, 31 percent in playground mulch, 17 percent in sports
surfaces, 7 percent in asphalt, 6 percent in automotive products, and 6 percent were exported
(RMA, 2014). Recycled rubber from tires is used in several types of recreational venues,
including use as infill material in synthetic turf fields, on playgrounds either as loose rubber
mulch or rubber mats, for running surfaces, and in equestrian arenas. Recycled tire material may
also be used in other applications, such as tire-derived rubber flooring materials (CalRecycle,
2010).
Synthetic Turf Fields
Synthetic turf field systems initially were introduced in the 1960s. Currently, there are between
12,000 and 13,000 synthetic turf sports fields in the United States, with approximately 1,200 to
1,500 new installations each year (See Figure 1) (STC et al., 2016a). Synthetic turf fields are
installed at municipal and county parks; schools and colleges; professional team stadiums and
practice fields; and military installations. Users include professional and college athletes, youth
athletes in school and/or other athletic organizations, adult and youth recreational users, coaches,
Figure 1: A synthetic turf field under construction (USEPA,
2016a)
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team and facility staff, referees, and fans and bystanders of all ages. No data were identified to
estimate the number of individuals using synthetic turf fields in the United States; however,
given the large number of installed fields it can be reasonably anticipated that the number of
users nationwide is in the millions.
Tire Manufacturing Process
The five main components of tires are tread,
sidewalk steel belts, body plies, and bead
(ChemRisk, 2008). Tires are manufactured with
range of materials, including natural and
synthetic rubber and elastomers; reinforcement
filler material; curatives including vulcanizing
agents, activators, accelerators, antioxidants,
antiozonants, inhibitors, and retarders; extender
oils and softeners; phenolic resins and
plasticizers; metal wire; polyester or nylon
fabrics; and bonding agents (Dick and Rader,
2014; Cheng et ah, 2014; ChemRisk, 2008;
NUTS A, 2006). In tire manufacturing, the
natural and synthetic ingredients are mixed together under heat and high pressure and rolled into
rubber sheets. These rubber sheets either can be calendared with textile sheets or extruded
together and forced through a die. A tire is built by applying layers of rubber, rubber-encased
materials, steel belts, and tread rubber. The built tire then is cured at a temperature between 150°
and 180°C (300° and 360°F) (Chemrisk, 2008). This tire-curing process is referred to as
vulcanization, and it involves the formation of crosslinks between polymer chains in rubber.
Figure 2 displays a cross-section of a tire.
Chemicals of Interest or Concern in Tires
Many of the concerns that have been raised by the public are about the potential exposure to
chemicals in tire crumb rubber infill used in synthetic turf fields. Chemicals of interest or
concern used in tire manufacturing range from polyaromatic hydrocarbons (PAHs) in carbon
black to zinc oxide (ZnO), which is used as a vulcanizing agent and could contain trace amounts
of lead and cadmium oxides. Chemicals in many other classes could be used in tire
manufacturing, including sulphenamides, guanidines, thiazoles, thiuams, dithiocarbamates,
sulfur donors, phenolics, phenylenediamines, and others (ChemRisk, 2008). There is limited
information to assess whether some of these chemicals might carry impurities or byproducts.
During vulcanization, the rubber is heated with vulcanizing agents under pressure, which causes
profound chemical changes at the molecular level, altering the initial composition of the tire and
giving it its elasticity (Coran, 1994).
There is uncertainty about whether rubber material in vulcanized tires might undergo chemical
transformation over time. The rubber could serve as a sorbent for chemicals in the air and in dust
that falls onto the field. One laboratory reported irreversible adsorption of volatile organic
i a
Body Ply
Bead Filer ^
Abrasion Gum &rtp
Nyton Cap Ply
#2 Steel Sen
#1 Steel8**t
gjr Sflouttor
iraort
Figure 2: Cross Section of a Tire (NHTSA, 2016)
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compounds (VOCs) and semivolatile organic compound (SVOC) analytes spiked onto tire crumb
rubber (NYDEC, 2009).
Tire Manufacturing Standards
The National Highway Traffic Safety Administration conducts research and mandates certain
requirements for passenger-car tires to ensure crash avoidance and fuel efficiency (NHTSA,
n.d.). The reason NHTSA was established was to implement the provisions of the Congressional
Safety Act of 1966. For example, 49 CFR 571.109 (Standard Number 109: New Pneumatic and
Certain Specialty Tires) requires testing of tires for physical properties and provides standards
for tire labeling and serial numbers. Industry associations, such as the Tire and Rim Association,
also establish engineering standards for tires, rims, and allied parts (NHTSA, 2006).
Tires introduced on the European tire market are also subject to the European Union's
Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) regulation that
restricts the use of high-aromatic oils in tires produced after January 2010 (Eur-Lex-
32005L0069-EN, n.d.). Tires or parts of tires must not contain more than 1 mg/kg of
benzo[a]pyrene, or more than 10 mg/kg of the sum of benzo[a]pyrene, benzo[e]pyrene,
benzo[a]anthracene, chrysene, benzo[A]fluoranthene, benzo[/]fluoranthene, benzo[£]fluoranthene
and dibenzo\a,h\anthracene (Eur-Lex-32005L0069-EN, n.d.).
Tire Crumb Rubber Manufacturing Process
In the United States, tires typically are collected at tire dealerships and automobile service
stations and shipped to tire recyclers. Tires of different types (e.g., passenger cars, trucks) and
from different manufacturers are mixed together at tire collection stations and tire recycling
plants. According to the Synthetic Turf Council (STC)9, there are nine tire crumb rubber
producers in the United States produce approximately 95 percent of the recycled rubber used as
infill in synthetic turf field applications (STC et al., 2016a).
Tire Types
The STC's guidelines state that tire crumb rubber is derived from scrap car and truck tires that
are ground up and recycled (STC, 2011) to a certain size for use in synthetic turf fields. The
exact proportion of each tire type in the infill product is unclear and appears to vary depending
on the tire crumb rubber producer.
The use of off-the-road (OTR) tires to produce tire crumb rubber infill may be more limited. An
article in the newsletter published by the Institute of Scrap Recycling Industries, Inc. (ISRI)
discusses the many challenges and considerations associated with the sourcing, transportation,
and processing of OTR tires, including the needs for downsizing larger tires before feeding them
into primary shredders and for removing bead bundles to reduce the wear on the shredders
9 The Synthetic Turf Council is a non-profit trade association whose objective is to encourage, promote, and
facilitate better understanding among all parties involved in the manufacture, selection, delivery, and use of today's
synthetic turf systems (STC, n.d.-c).
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(Mota, 2013). The logistics, cost, and additional processing required to use OTR tires limits their
use as feedstock for producing tire crumb rubber infill (Sikora, 2016).
Ambient and Cryogenic Processes
Two tire recycling processes, (1) ambient and (2) cryogenic, are used to create tire crumb rubber
in the 10- to 20-mesh (0.84- to 2.0-mm) size, which is generally the size used in synthetic turf
infill. ASTM International a not-for-profit organization that develops and publishes international
voluntary consensus standards10 for materials, products, systems and services (ASTM, n.d.),
developed Method ASTM D564411, which can be used to determine the average particle size
distribution of recycled vulcanizate particulate (ASTM, 2013a). The number of tire recycling
facilities using the ambient process is greater than the number of facilities using the cryogenic
process (STC et al., 2016a).
The ambient process uses granulation or cracker mills to produce tire crumb rubber at room
temperature (Scrap Tire News, 2016). Cracker mills use revolving rollers with serrations in them
to size-reduce the tires. Once the granules are produced, they are fed through screens and sorted
to the appropriate size (Scrap Tire News, 2016). The cryogenic process uses liquid nitrogen to
freeze partially shredded tires, which then are fed into a hammer mill to create tire crumb rubber.
Fabric (i.e., polyester, nylon, or other fibers) and steel belt components of the scrap tire are
separated in both processes (Scrap Tire News, 2016). Fabric is removed from the rubber using
air classifiers or vacuums, while the steel is removed using magnetic separators. Gravity
separators also can be used to remove contaminant particles, such as rocks, and can aid in the
sorting process. Likewise, water can be used for pre-washing to remove gravel and dirt and
cooling during the ambient process; otherwise no chemicals are added to the original rubber
composition during either process. Following processing, tire crumb rubber typically is placed
into one-ton sacks and distributed to fields for spreading.
10 The ASTM standards can be incorporated into contracts; used in laboratories and offices; referenced in codes,
regulations, and laws; or referred to for guidance. Although ASTM standards are voluntary, in cases in which an
ASTM standard is referenced in a law, regulation, or code, compliance with the ASTM standard could be required
(ASTM, n.d.).
11 All ASTM standards can be found at https://www.astm.org/.
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Synthetic Turf Fields
Synthetic turf fields are installed for
various activities played at both the
recreational and professional level,
including football, soccer, and lacrosse.
There are approximately eight major
synthetic field installers in the United
States with the largest four being national
in scope, installing coast to coast
(Sprinturf, 2016). An estimated 95 percent
of the existing fields in North America use
recycled rubber infill exclusively or in a
mixture with sand or alternative infills; the
remaining five percent contain only
alternative infills (STC et al., 2016a). STC
also reports that the use of exclusively
alternative infills in new installations
increased in 2016 (STC et al, 2016b).
Outdoor synthetic turf fields are more
common than indoor fields (FieldTurf,
2016a), with some sources indicating that indoor fields constitute approximately five to 15
percent of the market (Sprinturf, 2016). The differences in the construction between outdoor and
indoor fields are the use of a more durable fiber in indoor fields (Sprinturf, 2016) and the use of
adhesives to glue down the fiber carpet to the floor of indoor facilities (FieldTurf, 2016b)
Figure 3: A cross-section of the layers of a typical synthetic turf field
(STC n.d.-bj
Current generation synthetic turf fields
are typically constructed with a bottom
gravel/stone base layer to allow for
drainage (STC, 2011). On top of the
drainage layer lies the turf component,
which is composed of multi-layered
polypropylene and urethane backing
material with polyethylene fiber blades.
Sometimes a pad can be used for
additional cushioning on a field (STC,
2011). Figure 3 displays a cross-section of
a typical turf field and Figure 4 shows
materials for a synthetic turf field before
installation..
Figure 4: Sand and packaged crumb rubber awaiting field
installation (USEPA, 2016b)
The colored lines, hash marks, numbers, and logos on a field are created either as part of the turf
during the manufacturing process, or at the job site by cutting the original backing material from
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the field and gluing or sewing the colored pieces onto the backing material (STC, n.d.-c). Lines
also can be temporarily painted on the field.
Fields can be infilled with material in a
few different ways. Sand is often used as a
lower layer infill material to act as a
ballast for the turf component. On top of
this lower layer either will be tire crumb
rubber or a sand/tire crumb rubber mix,
topped by additional tire crumb rubber.
Other fields can use an infill exclusively
comprised of tire crumb rubber. On a
small number of fields, tire crumb rubber
could be coated with paint, typically
green, either for aesthetic purposes or heat
control (FieldTurf, n.d.-d; Sprinturf, n.d.).
To a much lesser extent, natural materials
(e.g., ground coconut husk), ethylene propylene diene monomer (EPDM), or thermoplastic
elastomers (TPE) granules are used as the complete infill. These materials also can be used as the
uppermost layer of infill (STC et al., 2016a). Infill material typically is spread using small utility
vehicles that make multiple passes across entire fields, laying the material down in thin layers
that are placed one on top of the other until the appropriate height is reached (Figure 5).
Additional machinery can be used to drag or brush the blades upright to allow the material to fall
between the blades (STC, 2011).
Synthetic Turf Field Standards
The Standard Test Methods for Comprehensive Characterization of Synthetic Turf Playing
Surfaces and Materials (ASTM, 2009) can be used to identify the physical properties and
compare the performance of synthetic turf systems and components of the system. The standard
presents a list of test methods that can be used to test components of the field, including turf
blades, carpet backing material, shock absorbing pads, and infill material.
The Standard Specification for Extr actable Hazardous Metals in Synthetic Turf Infill Materials
(ASTM, 2016a) specifies a test method to determine the amount of hazardous metals that have
the potential to be extracted from synthetic turf infill materials, if ingested. The standard adopts
both the specified test method and the limits on the extractable amounts of heavy metals from the
Consumer Safety Specification for Toy Safety (ASTM 2016 b). It also applies to any infill
material used in synthetic turf, irrespective of whether it is synthetic or natural. On November
30, 2016, recycled rubber and synthetic turf industry groups announced that leading members of
the Recycled Rubber Council, Safe Fields Alliance, and STC are voluntarily moving to ensure all
synthetic turf infill products created and used by their organizations will comply with ASTM
F3188-16 (BusinessWire, 2016).
Figure 5: Tire crumb rubber is placed on afield in layers during
installation (USEPA, 2016c)
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Synthetic Turf Field Maintenance
As is the case with natural fields, synthetic turf fields, too need to be maintained through a set of
routine maintenance practices (STC, 2015). Routine synthetic turf field maintenance is
conducted to maintain a safe playing surface, improve its appearance, and extend the life of the
field (STC, 2015). Recommended maintenance practices include brushing the field for infill
redistribution, raking to rejuvenate the fibers and to relevel the top portion of the infill, and
sweeping for debris removal (STC et al., 2016a; FieldTurf, n.d.-b). It is recommended that some
of these practices be performed more frequently than others, depending on the frequency with
which the field is used and specific guidelines for the sport played on the field. There are also
guidelines that recommend using surfactants, such as liquid laundry fabric softener or static
conditioner, to help reduce static electricity that builds up during maintenance (STC, 2015;
FieldTurf, n.d.-b). Water also is used to reduce the static electricity in synthetic turf fields (Daily,
2016).
It is important to maintain an appropriate amount of infill in the field for proper cushioning and
firmness. Tire crumb rubber can be lost for a number of reasons, such as migration in the shoes
and clothing of athletes, in weather events such as rain or snow, and through routine maintenance
practices (Pennsylvania State University Center for Sports Surface Research, 2016). Because of
tire crumb rubber migration, new infill material sometimes is added to existing fields to refresh
or replace the tire crumb rubber that is lost over time. Infill material also can be added to modify
the sponginess of a field, which, as in the case of the National Football League (NFL), is
required to maintain a certain field firmness level (NFL, 2014). Certain high-use locations on a
field might require replacement material more often than others (STC, 2015). Prior to every
game, the NFL field testing program requires surface hardness to be measured in multiple field
locations using the Clegg Impact Tester device (NFL, 2014) which can determine the surface
hardness of a field by measuring how quickly a weight stops upon impact to that field (NFL,
2014). Through the use of the Clegg Impact Tester, a Gmax12 score can be determined,
quantifying field firmness. Outside the NFL testing program, the Standard Specification for
Impact Attenuation of Turf Playing Systems as Measured in the Field (ASTM F1936) also can be
used to determine the field surface firmness (Sports Turf Managers Association, n.d.). This
standard establishes its own test method (ASTM F355) to determine surface firmness, suggests
test point locations and specifies an upper limit of surface hardness when using another testing
device (ASTM, 2015).
Maintenance practices can vary based on the budget for field maintenance and employee
knowledge of these practices (Pennsylvania State University Center for Sports Surface Research,
2016). Synthetic turf fields typically last about eight years before replacement, but can last
longer, depending on the frequency of their use and level of maintenance (STC, 2016).
12 Surface hardness is measured in Gmax, which is the ratio of maximum negative acceleration on impact in units of
gravities to the acceleration due to gravity (McNitt & Petrunak, 2013). The higher the Gmax value, the harder the
surface. A Gmax value should be related to the device that is measuring hardness. For instance, a 100 Gmax with the
Clegg Impact Tester is not the same as a 100 Gmax with the F355 device (NFL, 2014).
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B. Literature Review/Gaps Analysis Overview
To comprehensively understand the current state-of-the science and data gaps associated with the
toxicity of and human exposure to constituents in tire crumb rubber, CDC/ATSDR, EPA and
CPSC undertook a collaborative effort to review the scientific literature and analyze data gaps
(See Appendix B). The first objective of the Literature Review/Gaps Analysis (LRGA)
collaboration was to identify the existing body of literature related specifically to human
exposure to tire crumb rubber through the use of synthetic turf athletic fields and playgrounds.
The second objective was to characterize and summarize the relevant data from the scientific
literature. The final objective was to review the summary information and identify data gaps to
build on the current understanding of the state-of-the-science and inform the development of
specific research efforts that would be most impactful in the near-term.
Federal researchers examined a wide variety of information sources to build a list of relevant
citations. The literature search included the following databases: PubMed Medline (OVID);
Embase (OVID); Scopus; Primo (Stephen B. Thacker CDC Library); ProQuest Environmental
Science Collection; Web of Science; ScienceDirect and Google Scholar. The LRGA focused on
scientific publications that addressed tire crumb rubber use, physical characteristics and chemical
composition, potential pathways of exposures, bioavailability, and component toxicity and risk
assessment. It included studies that examined occupational exposures at tire recycling plants,
human exposures related to field and playground installations, and subsequent exposures
involved with use of synthetic turf and playground facilities. It did not include studies on
automotive tire manufacturing processes and related exposures and risks. In determining whether
or not to include a publication found in the course of the literature search, a set of relevance
criteria was developed. A Quality Assurance Project Plan was also developed to guide data
collection, organization and analysis. A number of other steps were taken to ensure quality in
data entry and analysis.
The LRGA identified 88 relevant references. Each reference that was reviewed was categorized
according to 20 general information categories (e.g., study topic, geographic location, sample
type, conditions, populations studied) and more than 100 sub-categories (e.g., for the study topic
sub-categories included: site characterization, production process, leaching, off-gassing,
microbial analysis, and human risk). As part of the effort, greater than 350 discrete chemical
compounds also were identified in the literature collected for this effort and a list of potential
chemical constituents was compiled to inform further research efforts.
The studies that were identified covered a wide range of topics and locations, but some topic
areas received greater coverage than others. For example, information on chemical leaching and
offgassing and volatilizing from tire crumb rubber was found in 36 and 25 studies, respectively,
but less information was available on microbiological, bioavailability, and biomonitoring aspects
of tire crumb rubber exposures (i.e., seven, five, and three studies, respectively). No
epidemiological studies were identified in the literature search. Data gaps could be more
pronounced for locations such as playgrounds and indoor fields, and for studies that examine
15
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environmental background levels of tire crumb rubber constituents. Studies on occupational
exposures from turf and playground installations were also limited. Metal constituents of tire
crumb rubber, such as lead and zinc, have been frequently identified in the literature as a
constituents of concern, but research on exposures to these metals by field and playground users
is limited. While a number of volatile and semivolatile organic chemicals (especially polycyclic
aromatic hydrocarbons) have been measured in some studies, research on other organic chemical
constituents identified by the LRGA is more limited.
Other important data gaps include the lack of more in-depth characterizing of dermal and
ingestion exposure pathways, identifying constituents and scenarios resulting in the highest
exposures, developing and applying biomonitoring for constituents of concern, and assessing the
feasibility and approaches for epidemiological investigations. Several important data gaps for
assessing exposures and risks of tire crumb rubber at synthetic fields and playgrounds are
summarized in Table 1.
The LRGA does not include critical reviews of the strengths and weaknesses of each study but
does provide the author's conclusions regarding their research, where applicable. The LRGA
does not make any conclusions or recommendations regarding the safety of the use of recycled
tire crumb rubber in synthetic turf fields and playgrounds. The review provides information
useful for guiding and designing future research efforts needed to further address questions
regarding exposures and risks for tire crumb rubber used in synthetic turf fields and playgrounds.
See Appendix B for the full State-of-the-Science LRGA.
16
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Table 1. Data Gaps for Research on Tire Crumb Rubber in Synthetic Fields and Playgrounds
Research Area
Data Gaps
Tire Crumb Rubber Characterization
Chemical
Characterization
• Studies thai have measured metal. volatile organic chemicals (VOCs). and semi-volatile
organic chemicals (SVOCs) (e.g., polycyclic aromatic hydrocarbons [PAHs] and
benzothiazole) were usually based on small numbers of tire crumb rubber samples. The
wide range of organic chemicals potentially used in tire manufacture, or their degradates,
have not been analyzed systematically across a large range of tire crumb rubber samples
from synthetic fields and playgrounds in the United States.
• Limited information is available on chemical constituents in molded rubber products
made with tire crumb rubber used in some playground settings.
Emissions
Assessments
• Few laboratory-based studies have investigated VOC and SVOC emissions from
synthetic fields and playgrounds under different temperature conditions. Measurements
using dynamic emission chamber measurements have been reported, but the number and
types of measured chemical emissions have been limited.
Microbial
Assessments
• Microbiological assessments for synthetic turf fields and playgrounds have been limited
and have been based on traditional culture methods. The use of molecular methods has
not been applied in studies of tire crumb rubber.
Bioaccessibility
• Several studies have examined potential bioaccessibility of metals and PAHs. However,
studies that systematically measure a wider range of metal and organic chemical
constituents, using multiple simulated biological fluids, and across a large range of tire
crumb rubber samples are lacking.
Variability
• Most studies characterizing tire crumb rubber from synthetic fields and playgrounds in
the United States have been relatively small, and restricted to a few fields or
playgrounds. Measurements for samples collected from a wider range of tire recycling
plants, synthetic fields, and playgrounds across the United States is lacking. Also,
information is limited on the range of chemical, microbiological, and physical
characteristics and factors related to variability in tire crumb rubber and potential
exposures.
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Table 1 (continued). Data Gaps for Research on Tire Crumb Rubber in Synthetic Fields and
Playgrounds
Research Area
Data Gaps
Exposure/Risk Characterization
Exposure Factors
• Exposure and risk assessments have typically relied on generic exposure factors.
Information specific to the frequency and duration of synthetic field and
playground uses, physical activities, contact rates, and hygiene are limited.
• Exposure factor data are not available either across the wide variety of sports and
recreational users of synthetic turf fields and playgrounds with tire crumb rubber,
or for occupational exposures.
Dermal/Ingestion
Exposures
• While multiple studies have attempted to characterize potential inhalation
exposures to tire crumb rubber chemical constituents, more limited infonnation is
available for understanding dermal and ingestion exposures.
Broken Skin/Ocular
Exposures
• Little infonnation is available on the potential for increased exposures via broken
skin (i.e., due to cuts and scrapes) and through ocular fluids.
Particle
Exposures
• There is limited infonnation on exposure to tire crumb particles and their
constituents through inhalation, dennal, and ingestion. Infonnation on the
exposure potential as synthetic fields and playgrounds age and weather, and for
various uses and activities on synthetic fields and playgrounds is limited.
Variability
• Few studies have evaluated the variability of exposures to tire crumb rubber
constituents by activity type, exposure scenario, age, material type and condition,
facility type and condition, and ambient conditions such as temperature and wind
or ventilation. Limited infonnation is available on the variability of exposures and
related factors across a wide range of user groups and scenarios.
• A few studies suggest that inhalation exposures at indoor facilities are higher
compared to those at outdoor facilities, but the available infonnation is limited.
Biomonitoring
• Only a few biomonitoring studies have been perfonned. Only hydroxypyrene has
been measured as a biomarker in athletes and workers.
• Additional tire rubber-specific biomarker measurements have not been reported for
synthetic field and playground users and biomarker analysis methods might be
lacking for some chemicals.
• Large scale biomonitoring studies of populations exposed and not-exposed to
synthetic turf fields and playgrounds with tire crumb rubber have not been
reported.
Cumulative/Aggregate
Assessments
• Exposures to multiple tire crumb constituents are likely to occur via multiple
pathways (e.g., inhalation, ingestion, and dennal contact). However, studies that
evaluated cumulative and aggregate exposure and risks are limited.
Epidemiology Studies
• No epidemiological investigations for synthetic turf field or playground users were
identified in the literature review.
• Survey and biomonitoring tools for accurate assessment of relative exposures for
synthetic field and playground users in an epidemiological study are lacking.
Alternative
Assessments
Alternative
Infills/Materials
• Most research to date has focused on characterizing tire crumb rubber infill.
Similar research on other infill materials, including natural materials, ethylene
propylene diene monomer (EPDM), thennoplastic elastomers (TPE), and recycled
shoe rubber are either lacking or limited.
Natural Grass Fields
• Few studies have been perfonned to assess potential chemical exposures from
natural grass playing fields.
Other Exposure
Sources
• Only a few comparative assessments have been perfonned on relative exposures to
chemicals associated with tire crumb rubber from other sources.
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C. Data Collection for Synthetic Turf Fields/Summary of Activity to Date
This section provides updates on the tire crumb rubber characterization and human exposure
characterization research components of the FRAP.
The tire crumb rubber characterization study is an evaluation of tire crumb rubber samples
collected from tire crumb rubber manufacturing plants and from indoor and outdoor synthetic
turf fields in the four U.S. census regions. The human exposure characterization study is a pilot-
scale exposure study to gather activity data and exposure measurements from people who
regularly perform athletic activities on synthetic turf fields.
Prior to initiating the study, federal researchers developed the research protocol titled Collections
Related to Synthetic Turf Fields with Crumb Rubber Infill. The research protocol describes the
following specific elements of the FRAP:
• literature review and data gaps analysis;
• tire crumb rubber characterization research;
• human exposure characterization research.
The study protocol was reviewed by independent external peer reviewers, CDC's Institutional
Review Board (IRB) and EPA's Human Subjects Research Review Official. The data collection
components of the study went through the Office of Management and Budget (OMB)
Information Collection Request (ICR) review process. The OMB ICR process included a public
comment period13. On August 5, 2016, EPA, CDC/ATSDR and CPSC received final approval to
begin the research.
Field collections started in mid-August. Collection of samples for the tire crumb rubber
characterization component of the study is now complete, and analyses of the samples are in
progress. Recruitment of fields and participants for the exposure characterization work is also
underway.
A summary of these activities is provided in this section with more details provided in Appendix
C.
13 Public and peer review comments and the agencies' responses are available on the OMB's website -
http://www.reginfo.gov/public/do/PRAViewDocuraent7ref nbr=201607-0923-001.
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Tire Crumb Rubber Characterization Study
The tire crumb rubber characterization study involved the collection of crumb rubber material
from tire recycling plants and synthetic turf fields from the four U.S. census regions, with
laboratory analysis for a wide range of metals, VOCs, SVOCs, particle characteristics, and
microbes.
Figure 6 summarizes the sampling and proposed analyses under the research protocol. The
sampling of nine recycling plants and 40 indoor and outdoor synthetic turf fields, as proposed,
has been completed. The numbers and types of samples collected from synthetic turf fields are
shown in Table 2. Samples were collected from three lots or storage containers at the nine
recycling plants, giving a total of 27 samples each for metals analyses, SVOC analyses, and
particle characterization.
Table 2. Samples Collected for Analyses at Synthetic Turf Fields
Region
Individual Location Samp
es Collected Across 40 Fields8
Total
Composite
Samples
Prepared0
For Organic
Chemical
Analysis
For Metals
Analysis
For Particle
Characterization
For
Microbial
Analysis
Northeast
63
63
63
63
18
Midwest
56
56
56
56
16
South
91
91
91
91
26
West
70
70
69b
70
20
Total
280
280
279
280
80
aAt each field, samples were collected from seven individual locations.
bThe cap came off of one sample collection container during transport.
Tor each synthetic turf field, one composite sample was prepared in the laboratory from the seven individual location samples
for organic chemical analyses and one composite sample was prepared for metals analyses.
Laboratory analyses are in progress including analysis of metals and SVOCs in the tire crumb
rubber, particle characterization, dynamic emission chamber measurements for VOCs and
SVOCs under different temperature conditions, and bioaccessibility measurements for metals
and SVOCs. The emissions and bioaccessibility experiments will provide important information
about the types and amounts of chemical constituents in the tire crumb rubber material available
for human exposure through inhalation, dermal, and ingestion pathways.
In addition to quantitative target chemical analyses, suspect screening and non-targeted analysis
methods are being applied for VOCs and SVOCs to determine whether there could be potential
chemicals of interest that have not been identified or reported in previous research. In addition to
the potential for chemical exposures at synthetic turf fields, concerns have been raised about the
potential for exposure to microbial pathogens. The study also involved the collection of tire
crumb rubber infill from synthetic turf fields to assess microbial populations. The status of the
ongoing tire crumb rubber sample analyses is shown in Table 3.
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Table 3. Status of Laboratory Analyses for Tire Crumb Rubber Characterization
Sample Type
Status
Direct Constituent Analysis
Metals constituent ICP/MS analyses
Metals constituent XRF analyses
SVOC constituent LC/MS analyses
SVOC constituent GC/MS analyses
In Progress
In Progress
In Preparation
In Preparation
Dynamic Chamber Emissions Experiments
Chamber experiments for VOCs in TC at 25°C
Chamber experiments for VOCs in TC at 60°C
Chamber experiments for SVOCs in TC at 25°C
Chamber experiments for SVOCs in TC at 60°C
Completed
Completed
Completed
Completed
Emissions Sample Analyses
VOC emissions analyses
Formaldehyde emissions analyses
SVOC emissions LC/MS analyses
SVOC emissions GC/MS analyses
In Progress
In Progress
In Progress
In Progress
Particle Characterization Analysis
Particle size characteristics
In Progress
Scanning electron microscopy
In Preparation
Microbial Sample Analysis
Microbial analyses - targeted
Microbial analyses - non-targeted
In Progress
In Progress
Bioaccessibility Analysis
Metals bioaccessibility analyses
SVOC bioaccessibility analyses
In Preparation
In Preparation
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Tire Crumb Rubber Sample Collection
Tire Crumb Rubber Samples from
20 Outdoor Synthetic Turf Fields
20 Composite Samples
9 Individual Samples
Tire Crumb Rubber Samples from
20 Indoor Synthetic Turf Fields
20 Composite Samples
6 Individual Samples
Tire Crumb Rubber Samples
from 9 Recycling Facilities
27 Individual Samples
Tire Crumb Rubber Direct Chemical Extraction and Analysis and Particle Characterization
Particle Size
Characterization
67 Samples
Metals Constituent Analysis
ICP/MS Targeted
100 Samples
SVOC Constituent Analysis
GC/MS Targeted
102 Samples
SVOC Constituent Analysis
LC/MS Targeted
102 Samples
Scanning Electron
Microscopy
67 Samples
Metals Surface Analysis
XRF Targeted
100 Samples
SVOC Constituent Analysis
GC/MS Suspect Screening
& Non-Targeted
12 Samples
SVOC Constituent Analysis
LC/MS Suspect Screening
& Non-Targeted
12 Samples
Tire Crumb Rubber Dynamic Chamber Emissions Testing and Analysis
Chamber Emissions Testing
for VOCs @ 25 °C
82 Samples
Chamber Emissions Testing
for VOCs @ 60 °C
82 Samples
Chamber Emissions Testing
for SVOCs @ 25 °C
82 Samples
Chamber Emissions Testing
for SVOCs @ 60 °C
82 Samples
VOC Emissions Analysis
GC/MS Targeted
82 Samples
VOC Emissions Analysis
GC/MS Targeted
82 Samples
SVOC Emissions Analysis
GC/MS Targeted
82 Samples
SVOC Emissions Analysis
GC/MS Targeted
82 Samples
VOC Emissions Analysis
GC/MS Suspect Screening &
Non-Targeted
12 Samples
VOC Emissions Analysis
GC/MS Suspect Screening
& Non-Targeted
12 Samples
SVOC Emissions Analysis
GC/MS Suspect Screening
& Non-Targeted
12 Samples
SVOC Emissions Analysis
GC/MS Suspect Screening &
Non-Targeted
12 Samples
SVOC Emissions Analysis
LC/MS Targeted
82 Samples
SVOC Emissions Analysis
LC/MS Targeted
82 Samples
SVOC Emissions Analysis
LC/MS Suspect Screening
& Non-Targeted
12 Samples
SVOC Emissions Analysis
LC/MS Suspect Screening &
Non-Targeted
12 Samples
Tire Crumb Rubber Bioaccessibility Extraction and Analysis
SVOC Bioaccessibilty Analysis
GC/MS fluid 1
£_82 Samples
SVOC Bioaccessibilty Analysis
GC/MS fluid 2
< 82 Samples
SVOC Bioaccessibility Analysis
GC/MS fluid 3
< 82 Samples
Tire Crumb Rubber Microbial Analysis
Microbial Analysis
280 Samples (Fields Only)
Metals Bioaccessibilty Analysis
ICP/MS fluid 1
£_82 Samples
Metals Bioaccessibilty Analysis
ICP/MS fluid 2
< 82 Samples
Metals Bioaccessibilty Analysis
ICP/MS fluid 3
^_82 Samples
Figure 6. Proposed Tire Crumb Rubber Characterization
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Exposure Characterization Study
The exposure characterization study is a pilot-scale effort to: (a) collect information on human
activity parameters for synthetic turf field users that affect potential exposures to tire crumb
rubber constituents; and (b) conduct a human exposure measurement study to further develop
and deploy appropriate sample collection methods to generate data for improved exposure
characterization.
While the field recruitment process has begun, field collection has not yet commenced because
fields with active sports seasons are not currently available. The agencies are continuing their
efforts to identify fields that meet the study criteria. The following discussion and Figure 7
provide a summary of the proposed research. Appendix € provides additional details.
The agencies will survey and observe adults and youth (or the parents of children) who use
synthetic turf fields with tire crumb rubber infill. Information will be collected to provide data
about relevant parameters (such as frequency and duration of field use and contact rates with
field materials for different activities) for characterizing and modeling exposures associated with
the use of synthetic turf fields. For a subset of participants, the agencies will video tape the
participants while they are participating in a physical activity on a synthetic turf field. In
addition, publicly available videography of users engaged in activities on synthetic fields will be
acquired. The videos will be used to provide information to characterize types of contact and
contact rates that are difficult to capture consistently using surveys. A subset of participants
providing survey responses also will be asked to participate in an exposure measurement study.
A set of personal, biological, and field environment samples will be collected around a sport or
training activity performed on a synthetic turf field. Personal and environmental samples will be
analyzed for metal, VOC, and SVOC analytes, and a subset of VOC and SVOC samples will
undergo suspect screening and non-targeted analysis. Biological samples will be held in a
biorepository for future analysis once potential biomarker chemicals of interest are identified
based on the tire crumb rubber and exposure characterization studies.
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Synthetic Field User Activity Information Collection
Extant Publicly Available Video
60 Hours extant video
Multiple adult & child activity categories
Questionnaire Data Collection
Up to 60 adult and child participants
At up to 10 facilities
5 Age/activity groups
Video Activity Data Collection
Up to 24 adult and child participants
At up to 6 facilities
3 Age/activity groups
Synthetic Field User Exposure Measurements
Exposure Data Collection
Up to 45 adult and child participants
At up to 6 facilities
3 Age/activity groups
Personal Samples
Air VOC samples (45)
Dermal metals samples (45)
Dermal SVOC samples (45)
Biological Samples
Urine samples (90)
Blood samples (90)
Facility Samples
Air VOC samples (24)
Air particle/metals samples (18)
Air SVOC samples (18)
Surface wipe metals samples (18)
Surface wipe SVOC samples (18)
Surface drag sled SVOC samples (18)
Dust characterization samples (18)
Dust metals samples (18)
Dust SVOC samples (18)
Figure 7. Summary of Proposed Exposure Characterization
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D. Recycled Tire Materials in Playground Surfaces
Playground Surfaces
The role of CPSC in the FRAP is to identify and assess the risks associated with the use of
recycled tire crumb rubber in playground surfaces. Shock-absorbing playground surfaces are
designed to reduce the severity of injury and risk of death from vertical falls from playground
equipment, compared to harder surfaces. The Public Playground Safety Handbook14 from CPSC
is a guide to promote safety awareness to those who purchase, install, and maintain public
playground equipment used by children ages 6 months through 12 years (CPSC, 2010). This
handbook includes guidelines on playground surfacing including those made with recycled tires.
The staff of CPSC identified five general types of playground surfaces that are made with
recycled tire materials: (1) loose-fill rubber, (2) rubber tiles, (3) poured-in-place rubber, (4)
bonded rubber, and (5) synthetic turf. The Public Playground Safety Handbook provides some
guidance on these surfacing types, and all playground surfacing should comply with the impact
attenuation standards per ASTM F1292-13, Standard Specification for Impact Attenuation of
Surfacing Materials Within the Use Zone of Playground Equipment (CPSC, 2010; ASTM,
2013b). Additional ASTM standards are available for specific surfacing types. See Appendix D
for descriptions and standards applicable to each surface type.
Literature Review
The LRGA (Appendix B) notes that data gaps were more pronounced for recycled tire crumb
rubber on playgrounds and indoor fields than for outdoor synthetic turf fields. The LRGA team
and CPSC staff identified the limited scientific literature that examined the chemical safety of
recycled tires in playground surfacing. Laboratory studies reported no evidence of genetic
toxicity and skin sensitization potential associated with recycled tire playground surfacing
(Birkholz, et al., 2003; OEHHA, 2007). Five reports of laboratory analyses identified extractable
organic compounds and metals from recycled rubber playground surfacing, including PAHs,
phthalates, and benzothiazole (Llompart, et al., 2013; Celeiro, et al., 2014; Highsmith, et al.,
2009). California's Office of Environmental Health Hazard Assessment used exposure models of
hand-to-mouth contact and direct ingestion of pieces of tire rubber and found minimal risk of
cancer and non-cancer health effects to children (OEHHA, 2007).
Six literature reviews and other assessments of the health and ecological risks associated with the
use of recycled tire rubber on playgrounds either support the relative safety of tire crumb rubber
playground surfaces (Simon, 2010; Cardno Chem Risk, 2013; LeDoux, 2007; Anderson et al.,
2006) or expressed concerns about hazards to children's health (Sullivan, 2006; Environmental
and Human Health, Inc., 2007). The authors of these reviews discussed the limitations of the
available data and concluded that additional studies are needed to support the safety of recycled
tire rubber in playground surfacing.
14 Public Playground Safety Handbook is available at: https://www.cpsc.gov/s3fs-public/325.pdf.
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CPSC Activities
To support the understanding of exposure at playgrounds, CPSC is planning a survey of parents
to get first-hand perspectives on potential exposures from playground surface materials. A
survey of parents could provide valuable information on the behavioral factors that will be
specific to scenarios of children interacting with recycled tire materials in playground surface. In
late 2016, CPSC staff initiated preliminary data collection activities that will inform
development of the national survey. These include field observations of children at public
playgrounds and focus groups of people who visit and work at playgrounds.
In the field, CPSC staff observed children playing on playgrounds at public parks in a limited
region of Maryland. After gaining permission from playground owners, CPSC staff observed
children on playgrounds with loose-fill and unitary surfaces. Observation sessions were for 20-
minute periods and occurred during approximately two weeks in October 2016. Observers
recorded the incidences of ten behaviors of children interacting with playground surfacing during
the observation session. Subjects were children who appeared to be six months to five years old.
Observers did not interact with the children, parents, or anyone else at the playgrounds, and no
identifying information about the children was collected. Each of the surface-interaction
behaviors of interest was observed at least once for unitary and for loose-fill surfaces. This
observational activity was very limited in scope and not intended to produce statistically
representative data; however, the behaviors observed will be considered while developing the
national survey.
Staff of CPSC engaged with a contractor with experience in conducting behavioral research for
government agencies to perform focus groups as a method for collecting information to support
development of the national survey of parents. A focus group is a collection of people assembled
for a "carefully planned series of discussions designed to obtain perceptions on a defined area of
interest in a permissive, nonthreatening environment" (Krueger & Casey, 2015). The focus
groups will include three sets of participants: (1) parents of children between 1 and 3 years of
age, (2) childcare providers of children between one and three years of age, and (3) playground
inspectors. Participants will be recruited in the Washington, D.C. metropolitan area. The focus
group moderator will lead an informal, but structured, discussion within each group to address a
list of questions regarding playground visitation habits, children's activities and behaviors
observed on playgrounds, clothing worn by children on playgrounds, snacks and refreshments
consumed at playgrounds, hand-washing habits, and other similar topics. Visual aids will be
provided to clarify understanding of the different types of playground surfaces. Participants will
be compensated financially for their time. No recruitment of survey participants will begin until
approvals are obtained from a human subjects IRB and OMB.
The staff of CPSC will work with the contractor to develop a national survey that will be
distributed to parents and child caregivers in various regions of the United States. The survey
questions will be developed based on information collected in the focus groups, playground field
observations, and other research studies. The contractor will develop and propose sampling and
data collection plan options necessary to obtain a nationally representative sample of households
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with children aged five and under. The timing of performance of the survey will depend on the
preceding steps required before recruitment of participants can begin (i.e., OMB and IRB
approval). Findings of the national survey will be used to inform development of exposure
scenarios and exposure factors that can be used to estimate children's exposure to substances of
concern in playground surfaces made with recycled tires.
Specific risk assessment strategies will be determined based on review of the new data, including
the tire crumb rubber characterization and bioavailability studies currently being performed by
EPA and ATSDR. The CPSC team will use exposure modeling to determine whether any of the
bioavailable substances in recycled tires could pose a health hazard to children using
playgrounds. Oral, dermal, and inhalation routes of exposure will be considered individually and
in combination. The CPSC team might explore collection of samples at playgrounds with
recycled tire surfaces for chemical analysis and bioavailability characterization; however, this
plan comes with practical challenges.
More details on CPSC's review of the use of recycled tire materials in playground surfacing,
literature review, and the ongoing data collection efforts can be found in Appendix P.
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V. Next Steps and Timeline
Analysis of the tire crumb samples collected from fields and recycling facilities, and the
exposure characterization component of the study, will continue in 2017. Parts of the exposure
study may be conducted during the hotter months of 2017. The results of the research on
synthetic turf fields are anticipated to be available in 2017. The CPSC playground study also will
continue in 2017.
The agencies will continue to share information with other government agencies that have
ongoing or planned tire crumb rubber. As it is available, updated information will be posted to
EPA's tire crumb rubber website (www.epa.gov/tirecmmb) and stakeholder groups will be
notified of these updates.
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VI. References
Anderson, ME; Kirkland, KH; Guidotti, TL, Rose, C. (2006). A case study of tire crumb use on
playgrounds: risk analysis and communication when major clinical knowledge gaps exist.
Environ Health Perspect. 114(1): 1-3.
ASTM. (2009). Standard Test Methods for Comprehensive Characterization of Synthetic Turf
Playing Surfaces and Materials, https://compass.astm.org/download/F 1551.39284.pdf. accessed
October 31, 2016.
ASTM. (2013a). Standard Test Methods for Rubber Compounding Materials—Determination of
Particle Size Distribution of Recycled Vulcanizate Particulate Rubber.
https://compass.astm.org/download/D5644.16967.pdf. accessed October 31, 2016.
ASTM International. (2013b). ASTMF1292-13 Standard Specification for Impact Attenuation
of Surfacing Materials Within the Use Zone of Playground Equipment. ASTM International,
West Conshohocken, PA, USA. Available at: https://www.astm.org/Standard 2.htm.
ASTM. (2015). Standard Specification for Impact Attenuation of Turf Playing Systems as
Measured in the Field. https://compass.astm.org/download/F1936.434.pdf accessed November
28, 2016.
ASTM. (2016). Standard Specification for Extractable Hazardous Metals in Synthetic Turf Infill
Materials. https://compass.astm.org/EDIT/html annot.cgi?F3188+16. accessed November 14,
2016.
ASTM. (n.d.). Frequently Asked Questions. https://www.astm.0rg/ABOUT/faqs.html#what.
accessed November 15, 2016.
Birkholz, DA: Belton, KL, Guidotti, TL. (2003). Toxicological evaluation of hazard assessment
of tire crumb for use on public playgrounds. J Air Waste Manag. 53:903-07.
BusinessWire. (2016). Leading Recycled Rubber and Synthetic Turf Industry Group Members
Voluntarily Move to Adopt Key Safety Standard.
http://www.businesswire.eom/news/home/20161130005383/en/Leading-Recvcled-Rubber-
Synthetic-Turf-Industry-Group. accessed November 30, 2016.
California Office of Environmental Health Hazard Assessment (OEHHA). (2007). Evaluation of
health effects of recycled waste wires in playground and track products. Prepared for the
California Integrated Waste Management Board. Available at:
http://www.calrecvcle. ca.gov/publications/Detail. aspx?PublicationID=1206.
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CalRecycle. (2010). Tire-Derived Rubber Flooring Chemical Emissions Study: Laboratory Study
Report. California Department of Resources Recycling and Recovery. Publication #DRRR-2011-
002. http://www.calrecYcle.ca.gov/publications/Documents/Tires%5C )2.pdf
Cardno Chem Risk. (2013). Review of the human health & ecological safety of exposure to
recycled tire rubber found at playgrounds and synthetic turf fields. Prepared for: Rubber
Manufacturers Association, Washington, DC. Available at:
https://rma.org/sites/defaiilt/files/literatiire review 0813 .pdf.
Celeiro, M; Lamas, JP; Garcia-Jares, D; Dagnac, T; Ramos, L; Llompart, M. (2014).
Investigation of PAH and other hazardous contaminant occurrence in recycled tyre rubber
surfaces: case study: restaurant playground in an indoor shopping centre. International Journal
of Environmental Analytical Chemistry. 94(12): 1264-1271.
ChemRisk, Inc; DIK Inc. (2008). State of Knowledge Report for Tire Materials and Tire Wear
Particles.
Cheng, H; Hu, Y; Reinhard, M. (2014). Environmental and Health Impacts of Artificial Turf: A
Review. Environ Sci Technol. 48(4):2114-29.
Coran, A. Y. (1994). Vulcanization. Science and Technology of Rubber. Chapter 7, page 339.
Academic Press, 1994.
CPSC. (2010). Public Playground Safety Handbook. CPSC Publication No. 325. Available at:
https://www.cpsc.gov/s3fs-public/325.pdf.
Daily, Darian. (2016). Information provided as part of an informational call between the U.S.
EPA and Darian Daily. Arlington, VA, April 28, 2016.
Dick, JS; Rader CP. (2014). Raw Materials Supply Chain for Rubber Products; Overview of the
Global Use of Raw Materials, Polymers, Compounding Ingredients, and Chemical Intermediates.
Hanser Publications, Cincinnati, OH.
Environment & Human Health Inc. (EHHI). (2007). Artificial Turf - Exposures to ground-up
rubber tires - athletic fields - playgrounds - gardening mulch. Available at:
http://www.ehhi.org/artificial4urf.
Eur-Lex-32005L0069-EN. (n.d.). Document 32005L0069. http://eur-
lex.euroDa.eu/eli/dir/2005/69/oi. accessed November 8, 2016.
FieldTurf. (2016a). Information provided as part of an informational call between the U.S. EPA
and Darren Gill. Arlington, VA, May 5, 2016.
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FieldTurf. (2016b). Information provided as part of communication between the U.S. EPA and
Darren Gill. Arlington, VA, November 28, 2016.
FieldTurf. (n.d.-a). FieldCare Maintenance Program.
http://www.fieldturf.com/en/service/fieldcare-maintenance-program. accessed on October 31,
2016.
FieldTurf. (n.d.-b). FieldTurf Maintenance Guidelines. Montreal, Quebec, Canada.
http://www.fieldturf.com/sites/fieldturf/assets/FT Maintenance%20Guidelines.pdf. accessed on
October 31, 2016.
Highsmith, R; Thomas, KW; Williams, RW. (2009). A scoping-level field monitoring study of
synthetic turf and playgrounds; EPA/600/R-09/135. National Exposure Research Laboratory,
U.S. Environmental Protection Agency. Available at:
http://cfpub.epa.eov/si/si public recei'i i'H>ort.cfm?dirEntryId . I *1 l ' ^ sim p 1 e S earch=1 & sear c
hA.ll=EPA.%2F600%2FR-09%2F 135.
Krueger RA, Casey MA. (2015). Focus groups. 5th ed. Thousand Oaks, CA: Sage Publications.
LeDoux, T. (2007). Preliminary assessment of the toxicity from exposure to crumb rubber: Its
use in playgrounds and artificial turf playing fields. Division of Science, Research and
Technology. New Jersey Department of Environmental Protection. Available at:
http://www.state.ni.us/dep/dsr/research/whitepaper%20-%20rubber.pdf.
Llompart, M; Sanchez-Pardo, L; Lamas, J; Garcia-Jares, C; Roca, E. (2013). Hazardous organic
chemicals in rubber recycled tire playgrounds and pavers. Chemosphere. 90(2):423-31.
McNitt, A. S., & Petrunak, D. M. (2013). Evaluation of Playing Surface Characteristics of
Various In-Filled Systems, http://plantscience.psu.edu/research/centers/ssrc/research/infill
accessed November 30, 2016.
Mota, D. (2013). Thinking Big. Scrap. Institute of Scrap Recycling Industries, Inc. July/August
2013. http://www.scrap.Org/home/scrap-articles/thinking-big#.WBh9 kOOOig. accessed October
31, 2016.
NFL. (2014). Penn St. program tries to prevent concussions by examining surfaces. February 5,
2014. http://www.nfl.eom/news/storv/0ap2000000323619/printable/penn-st-program-tries-to-
prevent-concussions-bv-examining-surfaces. accessed October 27, 2016.
NHTSA. (n.d.). Tires. http://www.nhtsa.gov/Research/Vehicle-Research-&-Testing-
(VRTQ/Tires. accessed November 1, 2016.
NHTSA. (2006). The Pneumatic Tire. National Highway Traffic Safety Administration, U.S.
Department of Transportation. DOT HS 810 561. http://www.nhtsa.gov/Vehicle+Safetv/Tires
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New York Department of Environmental Conservation (NYDEC). (2009). An assessment of
chemical leaching, releases to air and temperature at crumb-rubber infilled synthetic turf fields.
http://www.dec.nv.eov/docs/materials minerals pdf7cmmbrubfr.pdf.
Pennsylvania State University Center for Sports Surface Research. (2016). Information provided
as part of an informational call between the U.S. EPA and members of the Pennsylvania State
University Center for Sports Surface Research. Arlington, VA, May 20, 2016.
RMA. (2014). 2013 U.S. Scrap Tire Management Summary.
http://www.rma.org/download/scrap-tires/market-reports/US STMarket2013.pdf. accessed April
4, 2016.
RMA. (2016). Scrap tire markets. Rubber Manufacturers Association, http://www.rma.org/scrap-
tire/ scrap-tire-markets/, accessed October 24, 2016.
Scrap Tire News. (2016). Crumb Rubber Overview, http://www.scraptirenews.com/crumb.php.
accessed October 26, 2016.
Sikora, Mary. (2016). Information provided as part of email exchange between the U.S. EPA and
Mary Sikora. Arlington, VA, November 14, 2016.
Sprinturf. (n.d.). Infill Options, http://www.sprinturf.com/sprinturf-infill, accessed November 1,
2016.
Simon, R. (2010). Review of the impacts of crumb rubber in artificial turf applications.
University of California, Berkeley, Laboratory for Manufacturing and Sustainability, prepared
for The Corporation for Manufacturing Excellence (Manex). Available at:
https://escholarship.org/uc/item/9zp430wp.
Sprinturf. (2016). Information provided as part of an informational call between the U.S. EPA
and Rom Reddy and Bruce Cheskin. Washington, D.C., May 2, 2016.
Sprinturf. (n.d.). Infill Options, http ://www. sprinturf. com/sprin turf-infill, accessed November 1,
2016.
STC. (2011). Suggested Guidelines for the Essential Elements of Synthetic Turf Systems.
Atlanta, GA. November 2011 .https://c.vmcdn.com/sites/svntheticturfcouncil.site-
ym.com/resource/resmgr/files/stc guidelines essential ele.pdf. accessed November 1, 2016.
STC. (n.d.-a). Glossary of Terms. http://www.svntheticturfcouncil.org/page/Glossary. accessed
October 31, 2016.
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STC. (n.d.-b). Image provided via email communication between US EPA and the Synthetic
Turf Council. Arlington, VA, November 28, 2016.
STC. (n.d.-c). About STC. http://www.svntheticturfcouncil.org/page/About STC. accessed
November 18,2016.
STC. (2015). Guidelines for Maintenance of Infilled Synthetic Turf Sports Fields. Atlanta, GA.
January 2013.
http://c.vmcdn.com/sites/www.svntheticturfcouncil.org/resource/resmgr/files/stc guidelines for
maintenan.pdf
STC. (2016). Frequently Asked Questions. http://www.svntheticturfcouncil.org/page/FAQs.
accessed October 31, 2016.
STC et al. (2016). Information provided as part of an informational meeting between the U.S.
EPA and representatives of the Synthetic Turf Council, Safe Field Alliance, Recycled Rubber
Council, and the Institute of Recycling Industries. Arlington, VA, March 26, 2016.
STC et al. (2016b). Information provided as part of email exchange with Amy Brackin.
Arlington, VA, November 11, 2016 and November 28, 2016.
Sports Turf Managers Association, (n.d.). Field Hardness Testing.
http://www.stma.org/sites/stma/files/STMA Bulletins/Field Hardness%20FINAL.pdf. accessed
November 28,2016.
Sullivan, JP. (2006). An assessment of environmental toxicity and potential contamination from
artificial turf using shredded or crumb rubber. Ardea Consulting: Woodland, CA. p. 1-43.
Available at:
http://www.ardeaconsiiltine.com/pdf/Assessment Environmen deity Report.pdfhttp://ww
w.ardeaconsulting.com/pdf/Assessment Environmental Toxicity Report.pdf.
U.S. EPA (2015). Advancing Sustainable Materials Management: Facts and Figures 2013.
Assessing Trends in Material Generation, Recycling, and Disposal in the United States. Office of
Resource Conservation and Recovery. EPA530-R-002, June, 2015.
USEPA photo (2016a). Synthetic Turf Field Installation. Fairfax, VA.
USEPA photo (2016b). Tire Crumb Processing Facility. Los Angeles, CA.
USEPA photo (2016c). Synthetic Turf Field Installation. Washington, DC.
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Appendices
Appendix A - Stakeholder Outreach
Appendix B - State-of-Science Literature Review/Gaps Analysis
Appendix € - Data Collection for Synthetic Turf Fields/Summary of Activity to Date
Appendix D - Playground Surfaces with Recycled Tire Materials
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Appendix A - Stakeholder Outreach
The EPA, CDC/ATSDR, and CPSC teams have engaged in a number of outreach activities to
inform interested stakeholders about the Federal Research Action Plan (FRAP) and to gather and
share information that may be used to inform the research. These outreach activities focused on
three areas: 1) informing the public about the FRAP and encouraging them to provide feedback
through a public comment process, 2) sharing information with government organizations that
have planned and/or ongoing research efforts on this topic, and 3) conducting targeted outreach
with organizations to gather additional information to help inform the implementation of the
FRAP. These stakeholder outreach activities are further described below.
Informing the Public
Website
The FRAP was released on February 12, 2016. EPA, ATSDR, and CPSC developed a website
(http://www.epa.gov/tirecmmb) describing the action plan and notified interested groups when
the plan was announced. This website has been updated regularly throughout the research
process in an effort to keep all stakeholders informed on the progress of the study. The website
includes:
• An overview of the research;
• Frequently asked questions with answers;
• A fact sheet about the FRAP;
• Links to other available tire crumb rubber informational materials;
• A link to the Federal Register (FR) Notice, link to public comments and the agencies
responses to public comments, and other information.
Using the website, interested individuals can sign-up to receive study updates via e-mail. To-
date, more than 800 stakeholders have requested to receive updates about the study.
Webinar
The agencies published a FR Notice on February 18, 2016 requesting public comment on the
data collection components of the FRAP (tire crumb rubber sample collection and collections
related to the development of exposure scenarios). The data collection components were required
to go through an Information Collection Request (https://www.epa.gov/icr) review conducted by
Office of Management and Budget (OMB).
To encourage the general public to provide comments on the Federal Register Notice, the
agencies hosted a webinar on April 14, 2016 describing the research study for anyone that was
interested. This webinar was promoted on EPA's tire crumb rubber webpage, through the tire
crumb rubber stakeholder e-mail list, and through EPA social media. The EPA, CDC/ATSDR,
and CSPC research teams were available throughout the webinar to answer questions and
provide extra detail where needed. More than 150 people participated in the webinar. The
webinar was recorded and can be accessed through the FRAP website
(http://www.epa.gov/tirecmmb).
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Public Comment Period
The plans for the agencies to collect information (i.e. tire crumb sample collection and exposure
information collection from field users) that are a part of the FRAP were available for public
comment through a FR Notice. The agencies published the 60-day FR Notice on February 18,
2016 and extended the comment period at the public's request for two additional weeks to May
2, 2016. Once the FR Notice was posted, public comments were solicited by promoting the FR
Notice on EPA's tire crumb rubber webpage, through the tire crumb rubber stakeholder e-mail
list and through EPA social media. Members of the public submitted over 80 comments; these
were addressed. The Notice, public comments, and responses to public comments are publicly
available on QMS's website
(http://www.reginfo.gov/public/do/PRAViewDocument?ref_nbr=201607-0923-001).
Sharing Information with Other Government Agencies
The EPA, CDC/ATSDR, and CSPC teams engaged in outreach activities to share information
with government organizations that have planned or ongoing research efforts. These outreach
activities facilitated the sharing of expertise and information to help inform the implementation
of the FRAP. Specific outreach activities included in-person meetings and conference calls.
Examples of government organizations sharing expertise and information through these outreach
activities are included below.
Regular Conference Calls with States
CDC/ATSDR hosts monthly calls with state public health agencies to discuss the FRAP. These
calls were held to share information and updates on the on-going research and to answer
questions. These calls typically have between 10 andl5 state public agencies participating. EPA
also kept the Association of State and Territorial Solid Waste Management Officials
(ASTSWMO) and interested state solid waste agencies informed through periodic conference
calls and updates at meetings throughout 2016.
Webinar
The EPA team hosted a webinar on April 12, 2016 for state and local government organizations
describing the FRAP and the FR Notice. The EPA, CDC/ATSDR, and CSPC research teams
were available throughout the webinar to answer questions and provide extra detail where
needed. About 100 state and local groups participated in the webinar. The webinar was recorded
and shared with states to distribute to others within their organizations who might be interested
in the topic.
Government Agencies Sharing Expertise and Information
Other government agencies that are sharing information and have ongoing or planned tire crumb
rubber research include California's Office of Environmental Health Hazard Assessment, the
U.S. National Toxicology Program (NTP), headquartered at the National Institute of
Environmental Health Sciences, the European Chemicals Agency, and the Netherlands National
Institute for Public health and the Environment. The EPA, CDC/ATSDR, and CPSC teams have
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been meeting regularly with these organizations through conference calls and in-person
meetings.
• California. As mentioned above, the state of California's Office of Environmental Health
Hazard Assessment has an in-depth tire crumb rubber study underway. This study
includes a series of scientific studies to determine if chemicals in tire crumb rubber and
synthetic turf field materials can potentially be released under various environmental
conditions and what, if any, exposures or health risks these potential releases may pose to
players who frequently play on artificial fields constructed with tire crumb rubber. The
evaluation includes expert solicitation and stakeholder participation to help guide the
design. EPA, CDC/ATSDR and CPSC have shared information about methodology being
used for the studies. The research plan includes animal toxicity studies, which are being
conducted by NTP/NIEHS.
• International Agencies. Once the FRAP was announced, the European Chemicals
Agency (ECHA) contacted EPA expressing their interest. ECHA is an agency of the
European Union that implements chemical legislation for the protection of human health
and the environment. This interest has resulted in regular calls with ECHA and an in-
person meeting. During these meetings, information related to research efforts are shared.
In addition, the Netherlands and France are also interested in studying tire crumb rubber
exposure and characterization and communications with these organizations are on-
going.
Conducting Targeted Outreach to Gather Additional Information
The purpose of conducting targeted outreach was to request informational resources from
industry and non-profit organization/interest groups to inform the implementation of the FRAP.
The EPA team held discussions with stakeholder groups, toured recycling facilities and observed
field installations. Specifically, EPA, CDC/ATSDR, and CPSC requested information and
existing studies about how tires and tire crumb rubber are manufactured; how synthetic turf
fields are constructed, installed, and maintained; and other studies or information that could be
used for the study
The objective was to enhance the agencies' understanding of how tires and tire crumb rubber are
manufactured; and how synthetic turf fields are constructed, installed, and maintained, in order to
identify potential variabilities in the tire crumb rubber product that is produced and installed in
synthetic turf fields across the country.
Approach
The Paperwork Reduction Act (PRA) limited the number of entities that could be engaged by
EPA to fewer than nine within a stakeholder group. In meetings that involved several different
stakeholders, EPA was not seeking group consensus, input, or advice. Between February and
September of 2016, EPA met or held conference calls with: five industry trade associations, three
synthetic turf field companies, two synthetic turf field maintenance professionals, one academic
institution, and five non-profit organizations. The EPA team also toured a total of five tire
recycling facilities located in the south, west, and northeast regions of the United States., where
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both the ambient and cryogenic tire processing technologies were observed. The facilities ranged
in size from small to large operations with varying degrees of mechanized technologies to
process the tires. EPA observed the tire crumb rubber infilling process on two field installations
in the Washington, D.C. metropolitan area. Study team members from CDC and CPSC also
participated in several of the recycling facility and field installation observations. Collectively,
presentations and information exchanges spanned a number of topics, including:
• The state of tire manufacturing and scrap-tire collection and recycling;
• The nature and varieties of processes and machinery used in the processing of scrap tires
into tire crumb rubber;
• Tire-manufacturing standards;
• Tire recycling processing standards and/or tire crumb rubber product standards;
• Tire crumb rubber infill product types; storage, packaging, and transportation of tire
crumb rubber to fields;
• The number and distribution of synthetic turf fields;
• Synthetic turf field construction, installation, and maintenance practices.
Participants often recommended resources the study team could consult for more information.
Use of Information Obtained
As previously stated, the purpose of the outreach effort was to help inform the study design and
implementation of the FRAP. The information was also used to develop a preliminary summary
of the tire and tire crumb rubber manufacturing process, as well as the process by which
synthetic turf fields are constructed, installed and maintained. Over the next several months, EPA
will continue to review, analyze, and supplement the information included in this status report
and will provide an updated summary in the study's final report.
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Appendix B - State-of-the-Science Literature Review/Gaps Analysis
Tire Crumb Research Study
State-of-the-Science Literature Review/Gaps Analysis
White Paper Summary of Results
December, 2016
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Prepared By
U.S. Environmental Protection Agency / Office of Research and Development
Centers for Disease Control and Prevention / Agency for Toxic Substances and Disease
Registry
U.S. Consumer Product Safety Commission / Directorate for Health Sciences
Disclaimer
This document has been reviewed by the U.S. Environmental Protection Agency, Office of
Research and Development, the Agency for Toxic Substances and Disease Registry, and the
Consumer Product Safety Commission and approved for release. In accordance with
guidance in the US EPA's Peer Review Handbook, the document was sent out for an
independent, external peer review to three subject matter experts with expertise in analytical
chemistry, human exposure assessment, and human exposure modeling. The document was
revised based on reviewer recommendations.
Any mention of trade names, products, or services does not imply an endorsement by the
US Government.
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I. Executive Summary
Concerns have been raised by the public about the safety of recycled tire crumb rubber used in
synthetic turf fields and playgrounds in the United States. Recycled tire materials used for
synthetic turf infill and playground surface applications may lead to human exposures to
chemical constituents in tire material. Human exposures to tire crumb rubber vary with time and
activity associated with use of synthetic fields and playgrounds. Limited studies have not shown
an elevated health risk from playing on fields with tire crumb, but the existing studies have not
comprehensively evaluated the concerns about health risks from exposure to tire crumb rubber
and important data gaps exist (U.S. EPA, 2016).
Because of the need for additional information, the U.S. Environmental Protection Agency
(EPA), the Centers for Disease Control and Prevention/Agency for Toxic Substances and
Disease Registry (ATSDR), and the U.S. Consumer Product Safety Commission (CPSC)
launched a multi-agency action plan to study key environmental human health questions. The
Federal Research Action Plan on Recycled Tire Crumb Used on Playing Fields and Playgrounds
(referred to hereafter as the Federal Research Action Plan) includes numerous activities,
including research studies (U.S. EPA, 2016). The Federal Research Action Plan includes
numerous activities related to the design and implementation of a tire crumb research study. An
important component of the Action Plan is to identify key knowledge gaps to inform the conduct
of other elements of the Federal Research Action Plan.
To comprehensively understand the current state-of-the science and data gaps associated with the
toxicity of and human exposure to constituents in tire crumb rubber, CDC/ATSDR, EPA and
CPSC undertook a collaborative effort to review the scientific literature and analyze data gaps
(See Appendix BY The first objective of the Literature Review/Gaps Analysis (LRGA)
collaboration was to identify the existing body of literature related specifically to human
exposure to tire crumb rubber through the use of synthetic turf athletic fields and playgrounds.
The second objective was to characterize and summarize the relevant data from the scientific
literature. The final objective was to review the summary information and identify data gaps to
build on the current understanding of the state-of-the-science and inform the development of
specific research efforts that would be most impactful in the near-term.
Federal researchers examined a wide variety of information sources to build a list of relevant
citations. The LRGA focused on scientific publications that addressed tire crumb rubber use,
physical characteristics and chemical composition, potential pathways of exposures,
bioavailability, and component toxicity and risk assessment. It included studies that examined
occupational exposures at tire recycling plants, human exposures related to field and playground
installations, and subsequent exposures involved with use of synthetic turf and playground
facilities. It did not include studies on automotive tire manufacturing processes and related
exposures and risks. In determining whether or not to include a publication found in the course
of the literature search, a set of relevance criteria was developed. A Quality Assurance Project
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Plan was also developed to guide data collection, organization and analysis. A number of other
steps were taken to ensure quality in data entry and analysis.
The LRGA identified 88 relevant references. Each reference that was reviewed was categorized
according to 20 general information categories (e.g., study topic, geographic location, sample
type, conditions, populations studied) and more than 100 sub-categories (e.g., study topic sub-
categories: site characterization, production process, leaching, off-gassing, microbial analysis,
and human risk). As part of the effort, greater than 350 discrete chemical compounds also were
identified in the literature collected for this effort and a list of potential chemical constituents
was compiled to inform further research efforts.
The studies that were identified covered a wide range of topics and locations, but some topic
areas received greater coverage than others. For example, information on chemical leaching and
offgassing and volatilizing from tire crumb rubber was found in 36 and 25 studies, respectively,
but less information was available on microbiological, bioavailability, and biomonitoring aspects
of tire crumb rubber exposures (i.e., seven, five, and three studies, respectively). No
epidemiological studies were identified in the literature search. Data gaps could be more
pronounced for locations such as playgrounds and indoor fields, and for studies that examine
environmental background levels of tire crumb rubber constituents. Studies on occupational
exposures from turf and playground installations were also limited. Metal constituents of tire
crumb rubber, such as lead and zinc, have been frequently identified in the literature as a
constituents of concern, but research on exposures to these metals by field and playground users
is limited. While a number of volatile and semivolatile organic chemicals (especially polycyclic
aromatic hydrocarbons) have been measured in some studies, research on other organic chemical
constituents identified by the LRGA is more limited.
Other important data gaps include the lack of more in-depth characterizing of dermal and
ingestion exposure pathways, identifying constituents and scenarios resulting in the highest
exposures, developing and applying biomonitoring for constituents of concern, and assessing the
feasibility and approaches for epidemiological investigations. Several important data gaps for
assessing exposures and risks of tire crumb rubber at synthetic fields and playgrounds are
summarized in Table B-l.
The LRGA does not include critical reviews of the strengths and weaknesses of each study but
does provide the author's conclusions regarding their research, where applicable. The LRGA
does not make any conclusions or recommendations regarding the safety of the use of recycled
tire crumb rubber in synthetic turf fields and playgrounds. The review provides information
useful for guiding and designing future research efforts needed to further address questions
regarding exposures and risks for tire crumb rubber used in synthetic turf fields and playgrounds.
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Table B-l. Data Gaps for Research on Tire Crumb Rubber in Synthetic Fields and Playgrounds
Research Area
Data Gaps
Tire Crumb Rubber Characterization
Chemical
Characterization
• Studies that have measured metal, volatile organic chemicals (VOCs), and semi-volatile
organic chemicals (SVOCs) (e.g., polycyclic aromatic hydrocarbons [PAHs] and
benzothiazole) were usually based on small numbers of tire crumb rubber samples. The
wide range of organic chemicals potentially used in tire manufacture, or their degradates,
have not been analyzed systematically across a large range of tire crumb rubber samples
from synthetic fields and playgrounds in the United States.
• Limited information is available on chemical constituents in molded rubber products
made with tire crumb rubber used in some playground settings.
Emissions
Assessments
• Few laboratory-based studies have investigated VOC and SVOC emissions from
synthetic fields and playgrounds under different temperature conditions. Measurements
using dynamic emission chamber measurements have been reported, but the number and
types of measured chemical emissions have been limited.
Microbial
Assessments
• Microbiological assessments for synthetic turf fields and playgrounds have been limited
and have been based on traditional culture methods. The use of molecular methods has
not been applied in studies of tire crumb rubber.
Bioaccessibility
• Several studies have examined potential bioaccessibility of metals and PAHs. However,
studies that systematically measure a wider range of metal and organic chemical
constituents, using multiple simulated biological fluids, and across a large range of tire
crumb rubber samples are lacking.
Variability
• Most studies characterizing tire crumb rubber from synthetic fields and playgrounds in
the United States have been relatively small, and restricted to a few fields or
playgrounds. Measurements for samples collected from a wider range of tire recycling
plants, synthetic fields, and playgrounds across the United States is lacking. Also,
infonnation is limited on the range of chemical, microbiological, and physical
characteristics and factors related to variability in tire crumb rubber and potential
exposures.
43
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Table B-l (continued). Data Gaps for Research on Tire Crumb Rubber in Synthetic Fields and
Playgrounds
Research Area
Data Gaps
Exposure/Risk Characterization
Exposure Factors
• Exposure and risk assessments have typically relied on generic exposure factors.
Information specific to the frequency and duration of synthetic field and
playground uses, physical activities, contact rates, and hygiene are limited.
• Exposure factor data are not available either across the wide variety of sports and
recreational users of synthetic turf fields and playgrounds with tire crumb rubber,
or for occupational exposures.
Dermal/Ingestion
Exposures
• While multiple studies have attempted to characterize potential inhalation
exposures to tire crumb rubber chemical constituents, more limited infonnation is
available for understanding dermal and ingestion exposures.
Broken Skin/Ocular
Exposures
• Little infonnation is available on the potential for increased exposures via broken
skin (i.e., due to cuts and scrapes) and through ocular fluids.
Particle
Exposures
• There is limited infonnation on exposure to tire crumb particles and their
constituents through inhalation, dennal, and ingestion. Infonnation on the
exposure potential as synthetic fields and playgrounds age and weather, and for
various uses and activities on synthetic fields and playgrounds is limited.
Variability
• Few studies have evaluated the variability of exposures to tire crumb rubber
constituents by activity type, exposure scenario, age, material type and condition,
facility type and condition, and ambient conditions such as temperature and wind
or ventilation. Limited infonnation is available on the variability of exposures and
related factors across a wide range of user groups and scenarios.
• A few studies suggest that inhalation exposures at indoor facilities are higher
compared to those at outdoor facilities, but the available infonnation is limited.
Biomonitoring
• Only a few biomonitoring studies have been perfonned. Only hydroxypyrene has
been measured as a biomarker in athletes and workers.
• Additional tire rubber-specific biomarker measurements have not been reported for
synthetic field and playground users and biomarker analysis methods might be
lacking for some chemicals.
• Large scale biomonitoring studies of populations exposed and not-exposed to
synthetic turf fields and playgrounds with tire crumb rubber have not been
reported.
Cumulative/Aggregate
Assessments
• Exposures to multiple tire crumb constituents are likely to occur via multiple
pathways (e.g., inhalation, ingestion, and dennal contact). However, studies that
evaluated cumulative and aggregate exposure and risks are limited.
Epidemiology Studies
• No epidemiological investigations for synthetic turf field or playground users were
identified in the literature review.
• Survey and biomonitoring tools for accurate assessment of relative exposures for
synthetic field and playground users in an epidemiological study are lacking.
Alternative
Assessments
Alternative
Infills/Materials
• Most research to date has focused on characterizing tire crumb rubber infill.
Similar research on other infill materials, including natural materials, ethylene
propylene diene monomer (EPDM), thennoplastic elastomers (TPE), and recycled
shoe rubber are either lacking or limited.
Natural Grass Fields
• Few studies have been perfonned to assess potential chemical exposures from
natural grass playing fields.
Other Exposure
Sources
• Only a few comparative assessments have been perfonned on relative exposures to
chemicals associated with tire crumb rubber from other sources.
44
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II. Table of Contents
I. Executive Summary
II. Table of Contents
III. Background
a. Problem Statement
b. Goals of Literature Review & Gap Analysis
c. Scope of Effort
IV. Methodology
a. Data Sources and how they were identified
b. Factors & criteria for literature source inclusion
c. Quality Assurance & Assumptions
V. Results
a. Summary Statistics
b. Reference Types
c. Study Topics
d. Geographic Locations
e. Study/Sample Locations
f. Sample Types
g. Conditions Studied
h. Populations Studied
i. Constituents Evaluated
j. Human Exposure Routes
k. Exposure Factors
I. Risk Assessment
VI. Discussion of general conclusions as stated in literature
VII. Gaps Analysis Discussion
VIII. References
IX. Appendices
Appendix A - CDC Review of Published Literature and Select Federal Studies on
Crumb Rubber and Synthetic Turf
Appendix B - Literature Review of Microbial Work Done on Tire Crumb Rubber
Artificial Fields
Appendix C - EPA-NCEA Summary of Available Exposure and Health Risk Assessment
Studies on Artificial Turf, Playgrounds and Tire Crumbs
Appendix D - EPA Library Literature Search Results
Appendix E - List of Literature Reviewed
Appendix F - Constituents List
45
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III. Background
a. Problem Statement
Synthetic turf installations for athletic fields and other applications in the United States began to
rise in popularity in the mid twentieth century. Modern synthetic turf products are typically
composed of three layers - fiber material used to simulate grass blades, infill material for
cushioning and stability, and backing material (Cheng et al., 2014). A common material used for
infill is granulated crumb rubber from recycled tires.
One method of producing crumb rubber involves grinding used tires, removing steel and fiber
tire components and sorting the rubber pellets by size. Pellet sizes can range from about one-
sixteenth to one-quarter inch in diameter and are typically applied at a rate of two to three
pounds per square foot of field surface (NYDOH, 2008). The Rubber Manufacturer's
Association (2014) estimates that 24.4 percent of used scrap tires in the U.S. were recycled into
crumb rubber. A major focus of the LRGA effort was to provide additional information on
potential exposures at synthetic turf fields and playgrounds. Of the total tires recycled into crumb
rubber in 2013, 31 percent was used in playground mulch and 17 percent was used in sports
surfacing.
Given the widespread use of recycled tire rubber in synthetic turf and playground mulch
applications, concerns about the toxicity of the recycled materials have arisen. Human exposures
to the tire crumb rubber vary with time and activity associated with use of synthetic fields and
playgrounds. Limited studies have not shown an elevated health risk from playing on fields with
tire crumb rubber, but the existing studies do not comprehensively evaluate the concerns about
health risks from exposure to tire crumb rubber (U.S. EPA, 2016).
Because of the need for additional information, the U.S. Environmental Protection Agency
(EPA), the Centers for Disease Control and Prevention/Agency for Toxic Substances and
Disease Registry (ATSDR), and the U.S. Consumer Product Safety Commission (CPSC)
launched a multi-agency action plan to study key environmental human health questions. The
Federal Research Action Plan includes numerous activities, including a literature search and data
gap analysis (LRGA) as well as various other research efforts (U.S. EPA, 2016). A key objective
of the Action Plan is to identify key knowledge gaps.
b. Objectives of Literature Review/Gaps Analysis
In order to more fully understand data gaps associated with human exposure to tire crumb rubber
and their toxicity, ATSDR, CPSC and EPA undertook a collaborative effort in the form of a
scientific literature review and subsequent gaps analysis. The first objective of the collaboration
was to identify the existing body of literature related specifically to human exposure to tire
crumb rubber through the use of synthetic turf athletic fields and playgrounds. The second
46
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objective was to characterize and summarize the relevant data from the scientific literature. The
final objective was to review the summary information and identify data gaps to help inform the
development of specific research efforts.
c. Scope of Effort
The ultimate objective of the Literature Review and Gap Analysis (LRGA) effort was to inform
the design of a Tire Crumb Research Study (TCRS) (EPA, 2016). Therefore, the scope of the
LRGA was focused on the needs of the scientists designing the TCRS. The LRGA focused on
identification of scientific publications that studied tire crumb rubber use, physical characteristics
and chemical composition, potential pathways of exposures, bioavailability, and component
toxicity. The LRGA did not include studies related to human or ecological exposures in
automotive tire manufacturing processes. The LRGA focused only on the life cycle of tires that
reach the facilities where they are converted to crumb rubber. Studies that examine occupational
exposures at "tire to crumb rubber" generation facilities, human exposures related to field /
playground installations, and subsequent exposures involved with use of synthetic turf /
playground facilities were considered as part of the scope for this effort. Where literature existed
in these areas of study, it was included in the LRGA analysis.
IV. Methodology
a. Data Sources
Research and commentary on tire crumb rubber is represented in a diverse set of publications.
The LRGA effort explored a wide variety of information sources to build a list of relevant
citations for this effort. Initial searches for relevant material began with the preliminary list of
reports and bibliographic lists below. Additional literature relevant to this effort was identified
by reviewing the references listed in the preliminary lists. Material collection for this document
was completed in late May 2016, with sources ranging in release dates from 1991 to 2015.
Literature sources released after May 2016 have not been included in the LRGA.
Preliminary Lists used to Identify Relevant Literature
• A Scoping-Level Field Monitoring Study of Synthetic Turf Fields and Playgrounds (U.S.
EPA, 2009)
• Tire Crumb and Synthetic Turf Field Literature and Report List as of Nov. 2015 (U.S.
EPA, 2015)
• CDC Review of Published Literature and Select Federal Studies on Crumb Rubber and
Synthetic Turf (see Appendix A)
• Literature review of microbial work done on tire crumb rubber artificial fields (See
Appendix B)
• EPA-NCEA Summary of Available Exposure and Health Risk Assessment Studies on
Artificial Turf, Playgrounds and Tire Crumbs (See Appendix C)
47
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The sources listed in Appendices A, B and C provided an initial starting point for identifying
relevant publications for the LRGA. The scientists working on the LRGA conducted a literature
search using the following databases: PubMed, Medline (OVID), Embase (OVID), Scopus,
Primo (Stephen B. Thacker CDC Library), ProQuest Environmental Science Collection, Web of
Science, ScienceDirect, and Google Scholar. The Key Terms used in these searches included the
following terms: Artificial Turf, Synthetic Turf, Crumb Rubber, Tire Crumb Rubber, Sports
Field, Turf, Exposure, Analytes, Chemicals, Elements, Human Health Effects, Adverse Health
Effects, Environmental Exposure, Health Risk, Health Impact, Toxicity, Toxic, Carcinogen,
Emission, Off-gas, Routes of Exposure, Infill, Risk.
A separate, independent literature search was performed by the EPA library in Durham, NC. The
goal of this search was to identify any relevant tire crumb rubber exposure publications and
sources that were not identified in the initial search conducted by the LRGA scientists. The
following terms were used for both searches:
• Tire Crumb
• Artificial Turf
• Synthetic Turf
• Toxicity
• Health Risks
• Eco Risks
• Leaching
• Human Exposure
• Benzothiazole (BHT)
• Lead
• PAHs
The EPA library literature search can be found in Appendix D.
Based on these information sources, the LRGA team identified relevant literature from the
following areas: (1) Journal publications, (2) Reports, white papers, fact sheets, and similar
publications developed by federal and state agencies (3) Reports on industry-sponsored research,
including white papers, fact sheets, and similar publications and (4) Symposium/conference
proceedings. The list of relevant publications is provided in Appendix E.
The references were stored in an Excel spreadsheet that was also used to synthesize the
information from the studies. A Microsoft SharePoint site was created as a central repository of
all the information relevant to the LRGA, including the literature, spreadsheet, and other
materials.
b. Factors & Criteria for Literature Source Inclusion
Factors outlined by the EPA Science Policy Council in "A Summary of General Assessment
Factors for Evaluating the Quality of Scientific and Technical Information" were considered in
the identification of literature for this project (U.S. EPA, 2003). These are (1) Applicability and
48
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Utility; (2) Evaluation and Review; (3) Soundness; (4) Clarity and Completeness; and (5)
Uncertainty and Variability.
The objective of the LRGA team was to cite literature that conformed to these five factors.
However, several of the studies did not fully conform to some aspect of the outlined criteria. For
instance, there were several white papers and reports in relevant technical areas that were not
independently peer-reviewed or peer review was not documented. Although these and other
references did not fully conform to one or more of the criteria, they were included in the LRGA
because they provided useful information in better understanding risks from tire crumb rubber.
In determining whether or not to include a publication in the LRGA, a set of relevance criteria
were developed. An iterative approach was used to address the relevancy of the publications.
First, the title of the publication was reviewed to see if it included one or more of the criteria
terms below. If it was unclear whether the publication was relevant based upon the title, the
publication abstract was reviewed for relevance. If it was unclear whether the publication was
relevant based upon the abstract, parts or all of the body of the publication was reviewed. If the
information was found to be applicable, the publication was included in the LRGA.
Relevance Criteria
Tire Crumb
Artificial Turf
Synthetic Turf
Tire Crumb Toxicity
Tire Crumb Health Risks
Tire Crumb Ecological Risks
Synthetic Turf Leaching
Human Exposure to Tire Crumb
c. Quality Assurance & Assumptions
A Quality Assurance Project Plan (QAPP) was developed as part of this effort to guide data
collection, organization and analysis. EPA policy (U.S. EPA, 2008) is based on the national
consensus standard ANSI/ASQ E4-2004 Quality Systems for Environmental Data and
Technology Programs: Requirements with Guidance for Use. This standard recommends a
tiered approach that includes the development and use of Quality Management Plans (QMPs).
The organizational units in EPA that generate and/or use environmental data are required to have
Agency-approved QMPs. A programmatic QMP was developed for the overall TCRS. The
TCRS QMP is supported by project-specific QA project plans (QAPPs). A QAPP was prepared
and included the technical details and associated QA/QC procedures for the LRGA components.
Due primarily to time constraints, a number of assumptions were made in the conduct of the
literature review and subsequent analysis of data gaps. For example, while the LRGA team
performed extensive searches to find relevant literature for analysis it is possible that other
sources exist which were inaccessible, unavailable or not found during the literature search.
49
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Because publications were typically "screened" for relevance based upon their title and/or
abstract, but not always the entire publication, it is possible that relevant information may have
been overlooked. Finally, as indicated in Section IV B., it was assumed that most, if not all,
journal articles from the scientific literature had been peer reviewed. However, peer review
status was not always used as a deciding factor whether to include a source in the LRGA (see
Section IV B).
d. Literature Review and Data Extraction
All relevant studies were reviewed and characterized according to the information categories and
sub-categories shown in Table B-2 The information was extracted from the papers and reports
and entered into an Excel spreadsheet that allowed the data to be sorted according to the various
topic areas. The results were filtered according to the various categories and subcategories to
assess the frequency that the various topic categories were represented by the universe of
literature reviewed. A brief description of the results and conclusions from each study was also
provided in the spreadsheet. A screenshot of a portion of the LRGA spreadsheet is provided in
Figure B-l. The entire LRGA spreadsheet can be viewed on the EPA's Federal Research Action
Plan on Recycled Tire Crumb Status Report website.
50
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Table B-2. Information Categories and Subcategories Used
in LRGA Spreadsheet
Categories
Subcategories
1. Reference Type
Journal Article
Report
Report of Peer Review
Abstract
1. Reference Type
2. Study Topic(s)
Literature Review
Data Gaps
Site Characterization
Production Process
Constituent Characterization
Leaching
Stormwater Runoff
Site Monitoring
Headspace/de-gassing-Bulk
Off-gassing/volatilizing
Human Exposure
2. Study Topic(s)
3. Geographic Location
See spreadsheet: Status Report website
4. Study/sample Location
Laboratory
Indoor Field
Outdoor Field
Natural Grass Field
4. Study/sample Location
5. Sample Type
Bulk Crumb Rubber
Bulk Grass Blades or Fibers
Alternative Fill Type
Leachate
Urine
5. Sample Type
6. Conditions Studies
Age or Weathering
Meteorological
Geographical
Indoor vs Outdoor
Synthetic vs Natural
6. Conditions Studies
7. Populations Studied
Children/Teens
Adults
Athletes
7. Populations Studied
8. Constituents Evaluated
VOCs
SVOCs
Inorganics
Lead
8. Constituents Evaluated
9. Specific Constituents Studies
See Appendix F and Status Report website
10. Constituents of Highest Concern
See Status Report website
11. Number of Observations/Samples
See Status Report website
12. Human Exposure Route
Ingestion
Inhalation
Dermal
13. Exposure Factors Used to Assess Exposure
Body Weight
Inhalation Rate
Ingestion Rate
Skin Surface Area
Adherence
Bioavailability Fraction
Absorption Fraction
13. Exposure Factors Used to Assess
Exposure
14. Risk Assessment
Cancer
Non-cancer
Screening
14. Risk Assessment
15. Toxicity or Regulatory Data Used
See Status Report website
16. Risk Characterization
See Status Report website
17. Risk of Highest Concern
See Status Report website
18. Brief Description of Results
See Section VI, and Status Report website
19. Additional Information or Comments
See Status Report website
20. Related References
See Status Report website
51
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Literature Review and Data Gap Analysis Spreadsheet
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Anderson, ME; Kirkland, KH; Guidotti, TL, Rose, C. (2006). A Case Study of Tire
Crumb Use on Playgrounds: Risk Analysis and Communication When Major
Clinical Knowledge Gaps Exist. Environ Health Perspect. 114(1): 1-3.
X
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Anthony, D.H.J, and Latawiec, A. (1993). A preliminary chemical examination
of hydrophobic tire leachate components. National Water Research Institute,
Burlington, Ontario, Canada, Report No. 93-78. Part III. Parts 1 and II not
reviewed: not relevant (see comments).
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Bass, JJ; Hintze, DW. (2013). Determination of Microbial Populations in a
Synthetic Turf System. Skyline-The Big Sky Undergraduate Journal 1(1):1.
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Y
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Beausoleil, M; Price, K; Muller, C. (2009). Chemicals in outdoor artificial turf: a
health risk for users? Public Health Branch, Montreal
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Fi gure B-l. Screenshot of a portion of the LRGA spreadsheet (see full spreadsheet on the Status
Report website).
A list of potential chemical constituents was also developed based on chemicals identified in the
various studies. The list included the name of the chemical, CAS number, synonyms, and
concentrations observed in the various studies. EPA's National Center for Computational
Toxicology assisted by providing CAS numbers and synonyms for constituents for which this
type of information was not provided in the study. The constituents list is provided in Appendix
F. A screenshot of a portion of the chemical constituents' spreadsheet is provided in Figure B-2.
52
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15. CDPH 2010;
Maximum Detected
Analyte
Synonym(s)
CAS#
12. Cheng and
Reinhard 2014;
Potential
Contaminants
that can Leach
4 Outdoor fields
1 Indoor field
from Tires
ug/m3
Monitor type
ug/m3
Monitor typ
Carbon Tetrachloride
56-23-5
Chlorobenzene
108-90-7
Chloroform
Trichloromethane
67-66-3
Chloromethane
Methyl chloride
74-87-3
1.7
Personal
1.57
Personal
Chrysene
218-01-9
X
3.40E-04
Stationary
Coronene
191-07-1
X
o-Cyanobenzoic acid
2-Cyanobenzoic acid
3839-22-3
Cyclohexanamine
Cyclohexylamine
108-91-8
Cyclohexanamine, N-cyclohexyl-
Dicyclohexylamine
101-83-7
Cyclohexanamine, N-cyclohexyl-N-methyl-
N-Cyclohexyl-N-methylcyclohexanamine
7560-83-0
Cyclohexane
110-82-7
17.5
Personal
10.3
Personal
Cyclohexane, isocyanato
Isocyanatocyclohexane
3173-53-3
Cyclohexane, isothiocyanato-
1122-82-3
Cyclohexanone
108-94-1
N-Cyclohexyl-2-benzothiazolesulfenamide (CBS)
N-Cyclohexyl-2-benzothiazolesulfenamide
95-33-0
n-Cyclohexyl-formamide
N-Cyclohexylformamide; Formamide, N-cyclohexyl
766-93-8
Cycloninasiloxane, octadecamethyl-
Octadecamethylcyclononasiloxane
556-71-8
Cyclopenta[cd]pyrene
27208-37-3
x
4H-cyclopenta[def]phenanthren-4-one
4H-Cyclopenta(def)phenanthren-4-one
5737-13-3
X
4H-cvcIoDentafdefl-ohenanthrene
4-H-CvcIoDenta(d.e.flDhenanthrene
203-64-5
X
Figure B-2. Screenshot of a portion of the constituent spreadsheet (see Appendix F for the list of
constituents; the full spreadsheet is available on the Status Report website).
53
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V. Results
a. Summary Statistics
A total of 97 studies were identified by the methods described in Section IV. Seven were
reviewed, but not included in the LRGA analysis because were found to be outside the scope of
the project, and two were found to be duplicates of studies already included in the LRGA (see
the full literature review spreadsheet for additional details on the Status Report website). The
final number of studies evaluated was 88. More than 350 potential chemical constituents were
identified in the resources reviewed for the LRGA (see Appendix F for additional details).
Table B-3. Summary Statistics
References Identified for Consideration in the LRGA
97
References Not Included in LRGA Analysis Due to Irrelevance, etc.
7
Duplicate references
2
TOTAL NUMBER OF REFERENCES INCLUDED IN LRGA
88
Discrete Chemical Compounds Identified in Constituent Analysis
>350
LRGA References Included in Constituents List
38
b. Reference Types
Reference Type refers to the nature of the document reviewed. Journal articles are publications
in the scientific literature that are typically peer reviewed. Reports represent documents prepared
by government, contractor, university, industry or other entities. Reports of peer reviews are
typically summaries of comments by reviewers of reviewed documents. Abstracts include short
descriptions of documents which may precede a more detailed discussion on the relevant topic.
Additional reference types included summaries only, website text, and memos which are self-
explanatory.
The Literature Review/Gaps Analysis (LRGA) team examined all of the above reference types in
the course of the effort. The majority of sources identified were either Journal Articles (43) or
Reports (40). Of the other reference types included in the analysis (i.e., Report of Peer Review,
Abstract, Summary Only, Website, and Memo), only one citation was identified for each
reference type. This demonstrated the extent to which the literature search was oriented toward
Journal Articles and Reports, which typically provided the most relevant, comprehensive
information on tire crumb rubber.
c. Study Topics
The LRGA team identified 20 different Study Topics across the literature reviewed. An "other"
category was also included to capture additional topics not covered by the 20 main categories.
"Study Topic" refers to the focus of the document. In some cases, documents included
information on one topic (e.g., a literature review). In other cases, documents addressed more
than one topic. For example, a document may include both a review of the existing scientific
literature, but also include the results of novel research aimed at addressing specific questions
54
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(e.g., leaching of chemicals from tire crumb rubber, or site monitoring to assess human health
risk from exposure to tire crumb rubber). Table B-4 provides a summary of the number of
studies that addressed each of the various topic areas.
Table B-4. Number of Studies that
Addressed Various Topic Areas
Leaching
36
Human Risk
32
Human Exposure
27
Eco Exposure/Risk
26
Literature Review
24
Toxicity Assessment
19
Constituent Characterization
16
Headspace/de-gassing-Bulk (lab)
13
Off-gassing/volatilizing (field)
12
Site Monitoring
12
Data Gaps
11
Stormwater Runoff
7
Microbial
7
Production Process
6
Bioavailability
5
Modeling
5
Site Characterization
4
Biomonitoring
3
Risk Communication
2
Epidemiologic
0
Other
31
The bulk of the Study Topics identified in the LRGA addressed leaching of tire crumb rubber
constituents, exposures to humans and ecosystems from tire crumb rubber and subsequent risks
from those exposures, and previous literature reviews intended to better understand tire crumb
rubber constituents, exposures or toxicity. Toxicity assessment, characterization of constituents
found in tire crumb rubber and site monitoring, and volatilizing of constituents from crumb
material in either the lab or field were also frequently recorded Study Topics. Studies that were
categorized in the 'Other' topic category included topics such as gastric digestion simulations,
skin abrasion, assessments of study protocols, mutagenicity assessments, etc. A full list of the
"Other" types can be found in the Literature Review Spreadsheet on the Status Report website.
Lack of information in Study Topic areas may be an early indicator of data gaps which may
require more research.
d. Geographic Locations
Information related to geographic location was collected as part of the LRGA effort in order to
provide spatial context for the data. The level of geographic information was typically recorded
at the state or country scale. Geographic location was recorded for more than 50 of the studies
included in the LRGA. Thirteen U.S. states were represented by one or more studies (i.e.,
California, Colorado, Connecticut, Florida, Maine, Nevada, New Jersey, New York, Ohio,
Pennsylvania, Utah, Virginia, and Washington). Other countries identified in the analysis
included nations such as Canada, Denmark, France, Italy, Japan, Korea, Norway, Spain, Sweden,
Taiwan and The Netherlands. There were a total of 30 sources for which no locational
information was provided or was non-applicable.
55
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e. Study/Sample Locations
The Study/Sample Location category differs from the Geographic Location category. It refers to
the type(s) of site(s) where samples were collected or analyzed. For example, a study to identify
the constituents in tire crumb rubber may have been conducted entirely in the laboratory using
manufactured tire crumb rubber. Alternatively, tire crumb rubber samples may have been
collected from an indoor or outdoor field. Samples may also have been collected from both
synthetic turf and natural fields or background locations, or from playgrounds or other locations
where tire crumb rubber may be used.
The subset of Study/Sample Locations included Scientific Laboratories, Indoor Fields, Outdoor
Fields, Natural Grass Fields, Synthetic Grass Fields, Playgrounds and Other types. For the
purpose of the LRGA, "Scientific Laboratories" were defined as indoor facilities with controlled
environments and specific quality assurance procedures. "Indoor Fields" were located inside
enclosed facilities with climate control, and "Outdoor Fields" were in open or partially contained
facilities with some open air access. "Synthetic Grass Fields" included a variety of designs, but
were typically composed of an underlay material, tire crumb rubber infill and synthetic blades.
"Natural Grass Fields" were surfaces with specifically real grass plants with natural soil material.
A variety of "Playgrounds" were included which generally refer to an area with recreational
equipment anchored in the ground with surrounding tire crumb rubber used for cushioning
surface. An eighth type of Study/Sample Location was identified as "Background" which refers
to analyses conducted to determine background levels of tire crumb rubber constituents.
Of the sources included in the LRGA, most (42) involved analysis in a scientific laboratory
(Table B-5). The analysis also showed that 35 literature sources included analysis conducted on
or in the area of a synthetic turf field; 20 of these involved outdoor fields and 8 involved indoor
fields, and others did not specify. There were 8 studies that addressed natural grass fields and 8
that addressed background locations. Nine sources examined playground environments, however
because Kim et al. (2012b) uses the term "playgrounds" to mean facilities traditionally defined
as athletic fields, this number was adjusted to eight sources. The 13 "Other" locations included
roadbeds, parking lots, new/commercial products, test plots, mulch, green roofs, and rubber
running tracks. A full list of the "Other" types can be found in the Literature Review Spreadsheet
on the Status Report website.
The focus of the LRGA was synthetic athletic field and playground environments. Artificial turf
marketed for private residential homes may also provide an additional exposure pathway, and
may contribute to cumulative exposures to a variety of materials found in tire crumb rubber.
However, publications pertaining to residential use were not included in the LRGA.
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Table B-5. Number of Studies in
Each Study/Sample Site Category
Laboratory
42
Synthetic Grass Field
35
Outdoor Field
20
Playground
8
Indoor Field
8
Natural Grass Field
8
Background
8
Other
13
f. Sample Types
The Sample Type category refers to the nature of the sample(s) collected. For example, samples
of bulk tire crumb rubber or artificial grass blades/fibers may have been collected for the purpose
of leaching studies, or air samples may have been collected by stationary area samplers or by
personal breathing zone samplers. Other examples include wipe samples from fields or tire
crumb rubber for assessing dermal exposure, or urine samples from biomonitoring studies.
The term "Alternative Infill Type" was used to designate sources that examined infill materials
other than tire crumb rubber (e.g., sand). Another sample type identified as "Leachate" generally
refers to sources that studied samples of liquid or solid material that had been removed from the
immediate area of the tire crumb rubber via normal maintenance, meteorological or
hydrogeologic processes.
The majority of the literature sources (44) provided information of the analysis of bulk crumb
rubber (Table B-6). Leachate samples were studied in 22 sources, while stationary air samples
were evaluated in another 20 sources. The 20 "Other" sample types included materials such as
elastic compounds, dust, glue, bio-fluid extracts, rubber pavers natural grass and soil from test
plots, and other materials. A full list of the "Other" types can be found in the Literature Review
Spreadsheet on the Status Report website.
Table B-6. Number of Studies
Addressing Sample Type Category
Bulk Crumb Rubber
44
Leachate
22
Stationary Air Samples
20
Bulk Grass Blades or Fibers
13
Personal Exposure (air)
9
Wipe Samples
5
Alternative Fill Type
4
Urine
3
Other
20
g. Conditions Studied
The Conditions Studied category refers to analyses that may have been done to identify
differences in constituent concentrations or exposures based on age or weathering of the artificial
turf, or the effects of meteorological conditions or geography. This study element also refers to
analyses that evaluate for differences between indoor and outdoor environments, synthetic and
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natural turf, site and background conditions, differences based on active or inactive play, or other
activity related conditions.
The LRGA team identified 20 literature sources that examined exposures based upon age or
weathering of the artificial turf, while 10 other sources analyzed the effect of meteorological
conditions on artificial turf and tire crumb rubber (Table B-7). Nine of the literature sources
examined levels of constituents found in tire crumb rubber in relation to background levels of the
same constituents at the study sites. There were 12 "Other" conditions studied types, which
included temperature, coated vs non-coated crumb rubber, tire crumb rubber chip size, and pH. A
full list of the "Other" types can be found in the Literature Review Spreadsheet on the Status
Report website.
Table B-7. Number of Studies by
Conditions Studied
Age or Weathering
20
Meteorological
10
Site vs Background
9
Synthetic vs Natural
6
Indoor vs Outdoor
5
Activity Related
5
Active vs Inactive Play
4
Other Sources
3
Geographical
1
Other
12
h. Populations Studied
Populations Studied are those populations that were considered in an exposure or human health
assessment (e.g., children/teens, adults, workers, athletes). Fourteen literature sources examined
children/teen exposures, while 13 sources studies adults and 10 studied athletes (Table B-8).
Four sources included in the LRGA looked at worker exposures to tire crumb rubber installations
/ maintenance. "Other" types of populations identified in the analysis include athletic coaches,
spectators, gardeners, and microbial populations. A full list of the "Other" types can be found in
the Literature Review Spreadsheet on the Status Report website.
The age groups identified in the various studies differed for non-adult individuals. Thus, for the
purpose of categorizing the studies based on age, children and teens were combined in one
category and adults were categorized separately. Activities based on the ages of the populations
studied may be different due to differing behavior patterns. Likewise, other exposure factors
(e.g., inhalation rates, skin surface area, body weight) may differ based on age, and can affect
exposure levels.
Table B-8. Number of Studies by
Populations Studied
Children/Teens
14
Adults
13
Athletes
10
Workers
4
Other
6
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i. Constituents Evaluated
The Constituents Evaluated results capture the general category of contaminants that were
addressed in the study (e.g., volatile organic compounds (VOCs), semi volatile organic
compounds (SVOCs), inorganics, microbes, particulate matter). Polycyclic aromatic
hydrocarbons (PAHS) are also included as a broad category because they are frequently included
in the literature sources. Likewise, lead and benzothiazole are included because they are
frequently included in the sources. A separate column in the spreadsheet (found on the Status
Report website) is included to capture information on the Specific Constituents Studied. A
separate Constituents Tab in the spreadsheet provides additional information on the constituents
studied (e.g., concentration data) (see Appendix F for a list of constituents with more details
available on the spreadsheet found on the Status Report website).
Forty-nine of the literature sources included in the LRGA evaluated inorganic compounds related
to rubber exposures (Table B-9). The next most prevalent constituents identified in the literature
review were PAHs, identified in 41 sources, followed by VOCs (38 sources), SVOCs (31
sources) and lead (Pb) by 29 sources. Particulate matter, Benzothiazole and Microbes were
constituents studied to a lesser extent. "Other" types of constituents identified included
'extractable substances,' dissolved organic carbon, and 'organics.' A full list of the "Other"
types can be found in the Literature Review Spreadsheet on the Status Report website. Specific
references were made to zinc and a variety of metals, phthalates, benzene, nitrosamines, a variety
of complex organic compounds, and others. Zinc and other metals were identified most often as
the constituents of highest concern in the literature sources.
Table B-9. Number of Studies by
Chemical Constituents Studied
Inorganics
49
PAHs
41
VOCs
38
SVOCs
31
Lead
29
Benzothiazole
20
Particulate Matter
18
Microbes
6
Other
6
j. Number of Samples or Number of Observations
The number of observations or number of samples collected in each of the studies reviewed for
the LRGA varied according to the study purpose and scope. These data were included in the
spreadsheet when they were available in the publication reviewed. For detailed information on
the numbers of observations or number of samples collected, see the LRGA spreadsheet on the
Status Report website.
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k. Human Exposure Routes
Human Exposure Route identifies whether ingestion, inhalation, or dermal exposures were
evaluated in a human exposure/risk assessment. Some studies evaluated more than one route of
exposure. Twenty-two of the LRGA literature sources investigated inhalation exposures. Another
16 sources considered ingestion exposures, while 12 sources reviewed dermal exposure
scenarios. Secondary exposures (e.g., from residual tire crumb rubber contacted through
activities such as washing clothes) is also possible, but were not considered in the literature
reviewed.
I. Exposure Factors
The Exposure Factors category provides specific information on the exposure factors used
studies that estimated human exposure/risk. The U.S. EPA generally defines exposure factors as
factors related to human behavior and characteristics that help determine an individual's exposure
to an agent. The LRGA identified 14 unique exposure factors, as well as an "other" group. The
14 unique factors included: Body Weight, Inhalation Rate, Ingestion Rate, Skin Surface Area,
Surface Area to Body Weight ratio (SA/BW), Adherence, Bioavailability fraction, Absorption
fraction, Hand-to-mouth contacts/hr, Hand-to-surface contacts/hr, Hand-to-mouth transfer
fraction, Exposure Duration, Exposure Frequency, and Exposure Time.
Fourteen literature sources in the LRGA provided information on the use of one or more
exposure factors. The exposure factors that were reportedly used are summarized in Table B-10.
Exposure frequency (d/yr or d/week) (n=13) and exposure time (hr/day) (n=l 1) were the
exposure factors that were most often reported, followed by exposure duration (years) (n=10),
body weight (kg) (n=9), and inhalation rate (m3/hr or rnVday) (n=9). Ingestion rate (g/day) was
reported in 8 studies and skin surface area (cm2) was reported in 6 studies. The other factors were
reported by three or fewer LRGA literature sources (for additional details see the spreadsheet on
the Status Report website).
Table B-10. Exposure Factors Used by LRGA References
Factor
N
Value(s)
Exposure Frequency (d/yr or d/wk)
13
24-365 d/yr; 4-7 d/wka
Exposure Time (hr/day)
11
0.54-103
Exposure Duration (yrs)
10
l-50a'b
Body Weight (kg)
9
15-70b
Inhalation Rate (m3/hr or m3/day))
9
1.9-6 m3/hr; 17.0-22.4 m3/daya'b
Ingestion Rate (g/day)
8
0.02-103
Skin Surface Area (cm2)
6
20-17,084a
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m. Risk Assessment
The Risk Assessment category refers to the type of endpoints evaluated and the type of
assessment conducted. Five endpoints / assessment types were identified. Fifteen quantitative
assessments were identified, in addition to 14 qualitative assessments, and nine screening level
assessments. The LRGA also identified fourteen literature sources with cancer endpoints and 13
sources with non-cancer endpoints. Eight "other" types of assessments were also noted including
ecological risk, aquatic or cell toxicity, worst-case, margin of safety, microbial risks, and growth
inhibition. A full list of the "Other" types can be found in the Literature Review Spreadsheet on
the Status Report website.
Table B-ll. Number of Studies by
Type of Risk Assessment
Quantitative
15
Qualitative
14
Cancer
14
Non-cancer
13
Screening
9
Other
8
n. Toxicity or Regulatory Data Used to Assess Risk
A variety of data sources were used to evaluate risks in the literature sources evaluated in the
LRGA, including reference doses (RfDs) and cancer slope factors (CSFs) from EPA's integrated
Risk Information System (IRIS), Health Effects Assessment Summary Tables (HEAST),
National Ambient Air Quality Standards (NAAQS) and drinking water standards. Other data
sources included the Agency for Toxic Substances and Disease Registry (ATSDR) Minimal Risk
Levels (MRLs), Consumer Product Safety Commission (CPSC) guidance, American Council of
Government Industrial Hygienists (ACGIH) threshold limit values (TLVs), and state and
regional guidance. Some studies used World Health Organization (WHO) drinking water
standards, European acceptable daily intakes (ADIs), or other country-specific national targets,
limits, or regulatory values. In some cases, no observable effects concentrations (NOECs) or no
observable effects limits (NOELs) were used. The Ames test, AhR-based bioassays, and toxicity
characteristic leaching procedures (TCLPs) were used by others (for details see the spreadsheet
on the Status Report website).
VI. General Conclusions as Stated in the Literature
Brief summaries of results, conclusions, and recommendations from the LRGA studies are
provided below. They are provided in chronological order according to eight broad topic areas:
(1) exposure and human health risks to children and athletes, (2) occupational risks, (3)
ecological risks, (4) leaching, (5) air concentrations, volatilization, and particulate matter, (6)
microbial populations, (7) weathering/aging, and (8) data gaps and recommendations for further
study. Although some LRGA studies covered more than one topic area, summaries of their
conclusions are provided primarily under a single topic area. In most cases, the conclusions are
provided exactly as written by the author(s). These summaries are intended to provide the reader
with a general sense of the conclusions of the studies, as provided by the authors. For additional
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details on these studies, see the LRGA spreadsheet on the Status Report website, or refer to the
individual studies which provide the reader with a sense of the distribution of results when
utilizing the LRGA.
Exposure, Toxicity, and Human Health Risk to Children and Athletes from Chemical
Constituents in Tire Crumb Rubber
Several of the LRGA studies provided conclusions with regard to the human health risks
associated with the use of tire crumb rubber in artificial turf fields or other applications. Some of
these conclusions were based on reviews of existing literature. Others were based on data
collection and analysis. Examples of the conclusions are provided below. While many of the
studies indicated that risks to human were minimal, others suggested that potential risks exist and
should be further explored.
Birkholz et al. (2003) "designed a comprehensive hazard assessment to evaluate and
address potential human health and environmental concerns associated with the use of
tire crumb in playgrounds. Human health concerns were addressed using conventional
hazard analyses, mutagenicity assays, and aquatic toxicity tests of extracted tire crumb.
Hazard to children appears to be minimal. Toxicity to all aquatic organisms (bacteria,
invertebrates, fish, and green algae) was observed; however, this activity disappeared
with aging of the tire crumb for three months in place in the playground. We conclude
that the use of tire crumb in playgrounds results in minimal hazard to children and the
receiving environment."
Sullivan (2006) conducted an assessment of environmental toxicity and potential
contamination from artificial turf using shredded or crumb rubber and concluded that
"The impacts on human health of crumb rubber used in artificial turf are not known at
this time. However, there is some evidence that tire rubber can be harmful either from
direct contact or from associated dust. The most common detrimental health effect
resulting from direct exposure to tire rubber is allergic or toxic dermatitis. Inhalation of
components of tire rubber or dust particles from tire rubber can be irritating to the
respiratory system and can exacerbate asthma. It is not clear whether dermal or
inhalation exposure to tire rubber can lead to sufficient absorption of chemicals to cause
mutagenic or carcinogenic effects. The degree of direct contact between the rubber used
in artificial turf is not well enough known at this time to determine whether the level of
the potential for harm to humans playing on artificial turf containing crumb rubber. "
The Norwegian Institute of Public Health and the Radium Hospital (2006) conducted an
assessment of the risks to football players on indoor artificial turf fields, and concluded
that "the use of artificial turf halls does not cause any elevated health risk. This applies to
children, older children, juniors and adults. "
In 2006, KEMI, the Swedish Chemicals Inspectorate, published a status report on
synthetic turf from a chemical perspective. The conclusions were that "Measurement of
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indoor air and exposure calculations have shown that there is probably a small health
risk associated with simply being on or playing on synthetic turf surfaces that use rubber
from recycled tyres. The exposure levels and any allergic reactions, however, have been
poorly studied"(KEMI, 2006).
California's Office of Environmental Health Hazard Assessment evaluated the health
effects of recycled waste tires in playground and track products, and stated "Overall, we
consider it unlikely that a onetime ingestion of tire shreds would produce adverse health
effects." "Only exposure to zinc exceeded its health-based screening value " (OEHHA,
2007).
Hofstra (2007a) stated that "Based on the available literature on exposure to rubber
crumb by swallowing, inhalation and skin contact and our experimental investigations on
skin contact we conclude, that there is not a significant health risk due to the presence of
rubber infill for football players an artificial turfpitch with rubber infill from used car
tyres."
Based on a study involving leaching of lead from turf glades blades, the U.S. Consumer
Product Safety Commission (CPSC, 2008) reported that "The results., for this set of
tested synthetic turffields show no case in which the estimated exposure for children
playing on the field would exceed 15 ug lead/day. "
Johns (2008) conducted an initial evaluation of potential human health risks associated
with playing on synthetic turf fields on Bainbridge Island, Washington using the highest
chemical concentrations obtained from Norwegian Institute of Public Health and Radium
Hospital (2006), Plesser and Lund (2004), and California OHHEA (2007). Health risks
were evaluated for children (8-10 yrs old) and teenagers (11-18 years old) participating in
team sports. Johns (2008) concluded that "Overall, the balance of the studies reviewed
indicate that human health risks from playing on synthetic turffields is minimal, even
though low concentrations of some chemicals have been demonstrated to leach from the
tire crumb, or volatilize as vapor. "
Based on a literature review and the results of the 2007 CalEPA study, Denly et al.
(2008) concluded that "Based on the information reviewed none of the risk assessments
showed concentrations of contaminants that would be at a level of concern, even under
conservative assumptions and thus it does not appear that the ingestion of tire crumb
would pose a significant health risk for children or adults. "
Based on a Danish study conducted by Nilsson et al., (2008), "Four representative
substances were selectedfor the health assessment: benzothiazole, dicyclohexylamine,
cyclohexanamine and dibutylphthalate. These substances are present in high
concentrations in contact water from the leaching tests and are representative of the
harmful substances emittedfrom the products. " Nilsson etal. (2008) reported that "there
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are no health effects associated with exposure to the four substances tested, with the
exception of a potential risk for developing allergy in particularly sensitive individuals
(benzothiazole and the two amines). "
Beausoleil et al. (2009) concluded that "the health risks for players who use artificial turf
are not significant and that it is completely safe to engage in sports activities on this type
of outdoor field" Aased on literature reviews and qualitative reviews of the data.
The New York Department of Environmental Conservation (NYDEC, 2009) conducted a
public health evaluation "on the results from the ambient air sampling and concluded
that the measured levels of chemicals in air at the Thomas Jefferson and John Mullaly
Fields do not raise a concern for non-cancer or cancer health effects for people who use
or visit the fields... the findings do not indicate that these fields are a significant source of
exposure to respirable particulate matter. "
A human health risk assessment of five artificial turf fields in Connecticut indicated that
"cancer risks were only slightly above de minimis levels for all scenarios evaluated
including children playing at the indoor facility, the scenario with the highest exposure "
(CDPH, 2010). The Connecticut Academy of Science and Engineering (CASE) (2010)
Peer Review Committee "concluded based on a review of the state's reports that there is
a limited human health risk, and an environmental risk as shown by the high zinc levels
detected."
Based on a literature review, Van Ulirsch et al. (2010) concluded that "Data collected
from recreational fields and child care centers indicate lead in synthetic turffibers and
dust at concentrations exceeding the Consumer Product Safety Improvement Act of2008
statutory lead limit of300 mg/kg for consumer products intended for use by children, and
the U.S. Environmental Protection Agency's lead-dust hazard standard of 40 ng/ft2 for
floors Synthetic turf can deteriorate to form dust containing lead at levels that may
pose a risk to children. "
Simon (2010) stated that "A review of existing literature points to the relative safety of
crumb rubber fill playground and athletic field surfaces. Generally, these surfaces,
though containing numerous elements potentially toxic to humans, do not provide the
opportunity in ordinary circumstances for exposure at levels that are actually
dangerous."
Van Rooij and Jongeneelen (2010) monitored football players in The Netherlands before
and after playing on artificial turf fields. Only 1 of the 7 participants showed an increase
in post-exposure urine concentration over pre-exposure concentrations. Van Rooij and
Jongeneelen (2010) concluded that there is "evidence that uptake of PAH by football
players active on artificial grounds with rubber crumb infill is minimal. If there is any
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exposure, then the uptake is very limited and within the range of uptake of PAHfrom
environmental sources and/or diet."
Shalat (2011) conducted an evaluation of potential exposures to lead and other metals as
the result of aerosolized particulate matter from artificial turf playing fields in New
Jersey, and concluded that "there is a potential for inhalable lead to be present on turf
fields that have significant amounts of lead present as detectable by surface wipes. It also
would appear likely from this sample that if the lead is present to any appreciable extent
in the wipes it will likely be present in the breathing zone of players who are active on
these fields, and that furthermore, these levels potentially exceed ambient EPA standards.
Given that these are only occasional exposures this tends to reduce the risk of adverse
health effects."
Likewise, Lioy and Weisel (2011) concluded that "Overall the metals, PAHs and semi-
volatile compounds found all classes of materials to be at very low concentrations. Thus,
for the metals and compounds identified there would be de minimus exposures and risk
among anyone using fields with the exception of lead in a single new turf material. It is
therefore prudent to reemphasize the need to avoid lead-based pigments in these
materials as coloring agents. "
Ginsberg et al. (2011) conducted a human health risk assessment of synthetic turf fields
based upon investigation of five fields in Connecticut. The results indicated that "Cancer
and noncancer risk levels were at or below de minimis levels of concern. The scenario
with the highest exposure was children playing on the indoor field. The acute hazard
index (HI) for this scenario approached unity, suggesting a potential concern, although
there was great uncertainty with this estimate. The main contributor was benzothiazole, a
rubber-related semivolatile organic chemical (SVOC) that was 14-fold higher indoors
than outdoors. Based upon these findings, outdoor and indoor synthetic turffields are not
associated with elevated adverse health risks. "
Menichini et al. (2011) concluded that "Compared with the Italian limits for "green
area " soils, high contents of Zn and PAHs were found in the granulates present in
playing fields, whatever the origin of the rubber. Zn and BaP concentrations largely
exceeded such limits by up to two orders of magnitude... PCBs and PCDDs+PCDFs were
found in a recycled tyre granulate, at levels in the order of magnitude of the mentioned
limits."
In a Korean study, Kim et al. (2012a) calculated the risk of ingestion exposure of lead by
particle sizes of crumb rubber in artificial turf filling material with consideration of
bioavailability. The range of bioavailability depended on the particle size and the type of
extraction used. The < 250 um and acid extraction had the highest bioavailability.
"Results of this study confirm that the exposure of lead ingestion and risk level increases
as the particle size of crumb rubber " (Kim et al., 2012a). Average lead exposure ranged
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from 1.7 x 10-5 mg/kg-day to 4.1x 10-4 mg/kg-day with the highest exposure value for
children 7-9 years old with the acid extraction method and the lowest exposure to
children 13-18 years in both the acid and digestion extraction. Mean hazard quotients
were <1.
Kim et al. (2012b) conducted a health risk assessment for artificial turf playgrounds in
school athletic facilities in Korea and concluded that "On the basis of the knowledge that
is currently available concerning health effects and exposure linked to the use of
artificial turfplaygrounds, we did not find a direct health risk for users, except for
children with pica. " The LRGA team noted that this publication uses the term
"playgrounds" to mean facilities traditionally defined as athletic fields in US installations
Cardno Chem Risk (2013) concluded that "adverse health effects are not likely for
children or athletes exposed to recycled tire materials found at playgrounds or athletic
fields...similarly, no adverse ecological or environmental outcomes from field leachate
are likely."
Pavilonis et al. (2014) conducted a study in New Jersey to assess the bioaccessibility and
risk of exposure to metals and SVOCs in artificial turf field fill materials and fibers.
"Artificial biofiuids were hypothesized to yield a more representative estimation of dose
than the levels obtainedfrom total extraction methods. PAHs were routinely below the
limit of detection across all three biofiuids precluding completion of a meaningful risk
assessment. No SVOCs were identified at quantifiable levels in any extracts based on a
match of their mass spectrum to compounds that are regulated in soil. The metals were
measurable but at concentrations for which human health risk was estimated to be low.
The study demonstrated that for the products andfields we tested, exposure to infill and
artificial turf was generally considered de minimus, with the possible exception of lead
for some fields and materials" (Pavilonis et al., 2014).
Ruffino et al. (2013) conducted a risk assessment for synthetic turf fields in Italy,
including the following exposure pathways: "direct dermal contact (DDC)), dermal
contact with the rainwater soaking the infill (rain water contact (RWC)) and inhalation
of dusts and gases from the fields (dust and gas inhalation (DGI)." Based on a variety of
inorganic and organic chemicals, "the cumulative carcinogenic risk proved to be lower
than 10 6 and the cumulative noncarcinogenic risk lower than 1. The outdoor inhalation
of dusts and gases was the main route of exposure for both carcinogenic and non-
carcinogenic substances....the inhalation of atmospheric dusts and gases from vehicular
traffic gave risk values of one order of magnitude higher than those due to playing soccer
on an artificial field" (Ruffino et al., 2013).
Llompart et al. (2013) analyzed rubber recycled tire playgrounds and pavers. "The
analysis confirmed the presence of a large number of hazardous substances including
PAHs, phthalates, antioxidants (e.g. BHT, phenols), benzothiazole and derivatives,
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among other chemicals. The study evidences the high content of toxic chemicals in these
recycled materials. The concentration ofPAHs in the commercial pavers was extremely
high, reaching values up to 1%" (Llompart et al., 2013).
Marsili et al. (2014) conducted a preliminary hazard assessment for athletes based on the
release of polycyclic aromatic hydrocarbons and heavy metals from rubber crumb in
synthetic turf fields in Italy. "The results of the present study demonstrate that PAHs are
continuously releasedfrom rubber crumb through evaporation. Athletes frequenting
grounds with synthetic turf are therefore exposed to chronic toxicity from PAHs. The
main conclusion we can draw from this preliminary study, which will be validated by
further field and laboratory research, is that although synthetic turf offers various
advantages over natural grass, the quantity of toxic substances it releases when heated
does not make it safe for public health" (Marsili et al., 2014).
The health impact assessment of the use of artificial turf in Toronto, Canada concluded
that, "Available evidence indicates that under ordinary circumstances, adverse health
effects among adults and children are unlikely to occur as a result of exposure to
artificial turf infilled with crumb rubber in both outdoor and indoor settings." The
assessment elaborated further by stating, "Based upon a review of the available evidence,
third generation artificial turf is not expected to result in exposure to toxic substances at
levels that pose a significant risk to human health provided it is properly installed and
maintained and users follow good hygienic practices (for example washing hands,
avoiding eating on artificial turf and supervision of young children to ensure they do not
eat the infill material) " (Toronto Public Health, 2015).
Analytical results of lead in crumb rubber from 113 athletic fields In New York City was
provided online by the New York City Department of Parks and Recreation: Synthetic
Turf Lead Results (http://www.dec.nv.gov/docs/materials minerals pdf/crumbrubfr.pdf)
"Aside from Thomas Jefferson Park, the test results for the remaining 112 fields and play
areas were below the acceptable EPA lead level for soil (400 parts per million), the best
standard available, and no potential lead hazards were found. Lead levels for the 112
fields rangedfrom 'not detected' to 240 ppm and 96% of the results were less than 100
ppm. Thomas Jefferson Park was the only field with an elevated lead level above the EPA
standard."
Occupational Exposure and Risk
A limited number of studies evaluated in the LRGA addressed occupational risks. Workers
included coaches and those working in tire crumb rubber production facilities. These studies
provide insight on potential human health risks for potentially exposed populations other than
children and athletes. Examples of conclusions from those studies are provided below.
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Chien et al. (2003) evaluated occupational health hazards in scrap tire shredding facilities
in Taiwan and observed that "Levels of volatile organics were not significant, but a few
mutagens/carcinogens, such as styrene, benzothiazole, phthalate ester and naphthalene
were identified. Total particulate levels rangedfrom 0.43 to 6.54 mg/m3, while respirable
particulates were in the range 0.23-1.25 mg/m3. Ames testing revealed indirect
mutagenicity on strain TA98, indicating possible effects offrame-shift type mutagens.
Chemical analysis of airborne particulates confirmed the presence of amines, aniline,
quinoline, amides and benzothiazole, which are potentially convertible to frame-shift type
mutagenic nitrosoamines. " Chien et al. (2003) concluded that "particulate generated
from scrap-tire shredding may pose a health threat to workers, and should not be
regulated as 'nuisance'. "
Castellano et al. (2008) conducted a study of coaches working in areas where artificial
turf pitches were used in Italy and concluded that "there was no occupational exposure
nor any additional exposure to the substances of interest other than an environmental
exposure in urban areas. "
Savary and Vincent (2011) assessed exposure in four facilities in France where used tires
are turned into rubber granulates. "The results of this study indicate significant exposure
to complex mixtures of rubber dust... exposure levels measured in these four facilities
were between 0.31 and 41.00 mg/m3; the ambient concentrations were between 0.17 and
6.23 mg/m3." "VOC levels > 1 ppm were not detected."
Ecological Toxicity and Risk
While the primary focus of the LRGA was on human health risks, several of the papers reviewed
provided information relevant to ecological risks. Examples of conclusions from these studies is
provided below.
Kallqvist (2005) conducted an environmental risk assessment of artificial turf systems in
Norway and concluded that "The risk assessment shows that the concentration of zinc
poses a significant local risk of environmental effects in surface water which receives
run-off from artificial turf pitches. In addition, it is predicted that concentrations of
alkylphenols and octylphenol in particular exceed the limits for environmental effects in
the scenario which was used (dilution of run-off by a factor of ten in a recipient). The
leaching of chemicals from the materials in the artificial turf system is expected to
decrease only slowly, so that environmental effects could occur over many years. The
total quantities ofpollution components which are leached out into water from a normal
artificial turf pitch are however relatively small, so that only local effects can be
anticipated."
Sullivan (2006) conducted an assessment of environmental toxicity and potential
contamination from artificial turf using shredded or crumb rubber and concluded that
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"The impacts on the environment of using crumb rubber in artificial turf also are not
known at the present time...Zinc is the predominant toxicant to plants... The aquatic
toxicity issue is not very clear cut."
In 2006, KEMI, the Swedish Chemicals Inspectorate, published a status report on
synthetic turf from a chemical perspective. The conclusions were that "Current
knowledge allows the conclusion to be drawn that synthetic turf that contains rubber
from recycled tyres may give rise to local environmental risks. Investigations have shown
that zinc and phenols can leach from the rubber granulate, and these substances can
affect aquatic and sediment dwelling organisms, if they reach neighbouring water
courses" (KEMI, 2006).
Based on an environmental and health evaluation of the use of elastomer granulates used
as filling in artificial turf in France, Moretto (2007) concluded that "From an
ecotoxologicalpoint of view, the nature of the percolates having passed through a 3rd
generation artificial pitch are proven to be without impact on the environment,
irrespective of the type of filling granulates."
California's Office of Environmental Health Hazard Assessment (OEHHA) (2007)
evaluated the effects of recycled waste tires in playground and track products, and stated
"...ecological effects from contaminated soil cannot be ruled out...the selenium level in
the soil was only marginally higher than the PRG and the zinc levels were close to the
normal background levels."
Johns and Goodlin (2008) found that "Toxicity tests on storm water collectedfrom
installedfields, or in laboratory tests using simulated precipitation events, indicate that
water the percolates through turf fields with tire crumb is not toxic in tests that cover a
wide range of aquatic plants and animals, including algae, bacteria, crustaceans, and
fish."
Milone and McBroom (2008) reported that "An analysis of the concentration of metals in
the actual drainage water indicates that metals do not leach in amounts that would be
considered a risk to aquatic life as compared to existing water quality standards. "
The New York Department of Environmental Conservation (NYDEC, 2009) conducted a
risk assessment for aquatic life protection and found that "...crumb rubber may be used as
an infill without significant impact on groundwater quality... Analysis of crumb rubber
samples digested in acid revealed that the lead concentration in the crumb rubber
samples were well below the federal hazard standardfor lead in soil... A risk assessment
for aquatic life protection...found that crumb rubber derived entirely from truck tires may
have an impact on aquatic life due to the release of zinc. "
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Based on an environmental and mutagenicity assessment of artificial turf fields
conducted in Italy, Schiliro et al. (2013) concluded that "On the basis of environmental
monitoring, artificial turffootball fields present no more exposure risks than the rest of
the city."
Leaching
Among the studies reviewed for the LRGA, leaching studies were frequently represented. Some
of these studies addressed laboratory analyses of bulk samples, and other addressed leaching in
the natural environment. Conclusions based on these studies are provided below.
Zelibor (1991) analyzed leachate from tire samples and reported that "The results of the
study indicated that none of the tire and other rubber products tested, cured and uncured,
exceeded proposed TCLP Regulatory Levels or US EPA Drinking Water Standards.
Most compounds detected were found at trace levels (near method detection limits) from
ten to one hundred times less than proposed TCLP regulatory limits. "
Based on a study conducted in Canada, Groenevelt and Grunthal (1998) found "No
elevated levels of VOC's or BNA's were detected in the leachate collected. Slightly
elevated levels of boron, sodium and zinc, leached from acidic sandy loam soil amended
with 30% rubber crumb. Concentrations of these elements from soil mixed with rubber
crumb and lime, however, did not differ from those observedfor control plots...Rubber
also significantly increased the concentration of zinc in turf grass clippings. However,
elevated concentrations were not sufficient to produce zinc toxicity in turfgrass. "
Florida Department of Environmental Protection (FDEP, 1999) evaluated stormwater
runoff from a parking lot surface using ground tire rubber and other water samples and
found that "Except for the iron concentrations detected in groundwater samples collected
from MW-1, MW-3, andMW-4, all remaining soil, groundwater, rainwater, and surface
water runoff concentrations were below State guidance concentrations. "
Plesser and Lund (2004) found that "The leachate from the fibres contained zinc. The
concentration is higher than the Norwegian Pollution Control Authority's limit for zinc in
water with Environmental Quality Class V (very strongly polluted water), but lower than
the permitted zinc concentration in Canadian drinking water... The total concentrations of
zinc and PAH in the recycled rubber granulates exceed the Norwegian Pollution Control
Authority's normative values for most sensitive land use. The concentrations of
dibutylphthalate (DBP) and diisononylphthalate (DINP) exceed the PNEC values for
terrestrial life taken from the EU's programme for risk assessment. The concentration of
isononylphenol is above the limits specifiedfor cultivated land in the Canadian
Environmental Quality Guidelines...The concentration of zinc indicates that the leachate
water is placed in the Norwegian Pollution Control Authority's Environmental Quality
Class V (very strongly polluted water), but is lower than the permissible zinc
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concentration in Canadian drinking water. The concentration of anthracene,
fluoranthene, pyrene and nonylphenols exceed the limits for freshwater specified in the
Canadian Environmental Quality Guidelines. "
A laboratory study conducted in Italy by Gualteri et al. (2005) evaluated the effects of
leachate from tire debris on human lung cells aridX. laevis. Gualteri et al. (2005)
concluded that the "results confirm the significant role of zinc in leached [tire debris]
and the presence of additional organic toxicants. "
Sheehan et al. (2006) conducted a study in Maine and observed "Elevated levels of iron,
manganese, and several other chemicals... in tire shred leachates. However, chronic
toxicity tests with Ceriodaphnia dubia and fathead minnows (Pimephales promelas)
showed no adverse effects caused by leachates collectedfrom tire shreds installed above
the water table. Exposure to leachates collectedfrom tire shreds installed below the
water table resulted in significant reductions to both survival and reproduction in C.
dubia."
Verschoor (2007) observed that zinc from rubber infill in artificial turf in The
Netherlands "leaches to the soil, groundwater and surface water " and "environmental
quality standards for zinc in surface water and groundwater are exceeded. " However,
"The risks of zinc to public health are of no concern: the human toxicity of zinc is low
and WHO drinking water criteria are not exceeded. "
As part of a study conducted in Connecticut, Mattina et al. (2007) examined crumb
rubber produced from recycled tires. According to Mattina et al. (2007), "The laboratory
data... support the conclusion that under relatively mild conditions of temperature and
leaching solvent, components of crumb rubber producedfrom tires (i) volatilize into the
vapor phase and (ii) are leached into water in contact with the crumbs."
Based on a study conducted in Washington, Johns and Goodlin (2008) suggested that
"The available literature demonstrates that some chemicals can leach from tire crumb
when it is exposed to water. While some studies report the presence of organic chemicals
in leachate, the chemicals were detected at such low concentrations that authors
considered them to be of little environmental relevance. The most consistent chemical to
be detected in leachate tests is the metal zinc. "
Based on a study in Japan, Aoki (2008) found that "The concentrations of leaching heavy
metals [from infills on artificial turf] increased with an increase in the acidity of the acid
solutions."
Based on a Danish study, Nilsson et al. (2008) reported that "a number of
environmentally harmful substances were found in the contact water from leaching tests
on infills and artificial turf mats."
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Bocca et al. (2009) conducted a laboratory study in Italy to identify and quantify metal
concentrations in leachate from crumb rubber samples. According to Bocca et al. (2009),
"The total amount and the amount leached during the acidic test variedfrom metal to
metal and from granulate to granulate. The highest median values were found for Zn
(10,229 mg/kg), Al (755 mg/kg), Mg (456 mg/kg), Fe (305 mg/kg), followed by Pb, Ba,
Co, Cu and Sr... The highest leaching was observedfor Zn (2300 ug l) andMg (2500
Lig l), followed by Fe, Sr, Al, Mn and Ba. Little As, Cd, Co, Cr, Cu, Li, Mo, Ni, Pb, Rb, Sb
and V leached, and Be, Hg, Se, Sn, Tl and W were below quantification limits. Data
obtained were compared with the maximum tolerable amounts reported for similar
materials, and only the concentration ofZn (total and leached) exceeded the expected
values."
Based on a study in Portugal, Mota et al. (2009) stated that "PAH leaching is
negligenciable...heavy metals content in the acidic water leachates considerably lower
than the limit values. "
Kanematsu et al. (2009) found that "aqueous extracts of rubber mulches (RM) contain
high concentrations of zinc (Zn) compared with wood mulches (WM), and its
concentration increased at lower pH and higher temperature...Our results suggest that
organic constituents in water extracts of RM which have AhR activity may not be of
significant concern while leaching of Zn from RM appears to be a potentially larger
water quality issue for RM. "
The Connecticut Department of Environmental Protection concluded that "Zinc is the
most prevalent contaminant in the leachate and stormwater studies." "The DEP
concludes that there is a potential risk to surface waters and aquatic organisms
associated with whole effluent and zinc toxicity of stormwater runofffrom artificial turf
fields...This study did not identify any significant risks to groundwater protection criteria
in the stormwater runoff from artificial turf fields" (CDEP, 2010).
Rhodes et al. (2012) found that "zinc leaching from tire crumb rubber increases with
smaller crumb rubber and longer exposure time. "
Cheng et al. (2014) reviewed studies where the toxicity characteristic leaching procedure
(TCLP) was used and indicated that constituent concentrations were well below
maximum contaminant limits (MCLs) or TCLP regulatory limits.
In a case study of PAH and other hazardous contaminant occurrence in recycled tire
rubber surfaces at a restaurant playground in an indoor shopping center, Celeiro et al.
(2014) found that, "fourteen out of the sixteen EPA priority PAHs were identified and
quantified in the investigated recycled tyre rubber playground surfaces. The analytical
measurements also confirmed the presence of other harmful compounds including
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phthalates, adipates, antioxidants and benzothiazole among others, in some cases at high
concentration levels
Crampton et al. (2014) assessed the effects of leachate from crumb rubber and zinc in
green roofs on the survival, growth, and resistance characteristics of Salmonella enterica
subsp. enterica serovar typhimurium. "The median concentration of zinc in the crumb
rubber-amended roof was 0.2 mg/liter ..., while the median concentration of zinc in the
commercial medium was 0.15 mg/liter."
The results of an Ohio study conducted by Dorsey et al. (2015) "suggest that at the
higher temperatures such as those on artificial athletic field surfaces, the crumb rubber
infill on these artificial athletic fields can become the source of a water soluble agent
with mutagenic potential in bacteria."
Selbes et al. (2015) observed "...a constant rate of leaching was observedfor iron and
manganese, which are attributed to the metal wires present inside the tires. Although the
total amounts that leached varied, the observed leaching rates were similar for all tire
chip sizes and leaching solutions. "
Air Concentration, Volatilization/Off-gassing, and Particulate Matter
Several of the studies reviewed collected air samples using stationary, personal breathing zone
monitors, or other methods to assess the potential for volatilization of chemical constituents from
artificial turf or other materials that contain tire crumb rubber. Conclusions from these studies
are provided below.
Dye et al. (2006) conducted a study in Norway to obtain measurements of air quality for
three indoor artificial turf pitches. The measurements were taken in a hall with recently
laid rubber granulate (SBR rubber or Styrene Butadiene Rubber) and a hall with rubber
granulate (SBR rubber) which had been in use for one year and a hall which used
granulate made from thermoplastic elastomer. "In all three halls, the proportion of
organic material is considerable. The airborne dust contains polycyclic aromatic
hydrocarbons (PAH), phthalates, semi-volatile organic compounds, benzothiazoles and
aromatic amines. It also contains organic and inorganic pollutants which are not
specified in this study. Possible problem areas linked to latex exposure via the skin and
air passages should be assessed by specialists."
Van Bruggen (2007) conducted a study in The Netherlands to assess releases of
nitrosamines from crumb rubber by taking measurements at two different levels above
artificial turf surfaces, and found that "None of the measurements showed the presence of
nitrosamines in the atmosphere above the pitch. Supplementary laboratory tests on the
materials showed that nitrosamines can only be releasedfrom rubber crumb to a very
limited extent."
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EHHI (2007) concluded that "It is clear that the recycled rubber crumbs are not inert,
nor is a high-temperature or severe solvent extraction needed to release metals, volatile
organic compounds, or semi-volatile organic compounds. The release of airborne
chemicals and dust is well established by the current information. There are still data
gaps that need to be filled in and additional studies are warranted."
Vetrano and Ritter (2009) stated that "An analysis of the air in the breathing zones of
children above synthetic turf fields [in New York City] did not show appreciable levels
from COPCs contained in the crumb rubber, " but constituent characterization of bulk
samples revealed lead and zinc concentrations that were above soil cleanup objectives for
restricted residential land use.
California OEHHA (2010) collected air samples from 4 artificial fields and 4 natural
fields and found that "PM2.5 and associated elements (including lead and other heavy
metals) were either below the level of detection or at similar concentrations above
artificial turf athletic fields and upwind of the fields" and "The large majority of air
samples collectedfrom above artificial turf had VOC concentrations that were below the
limit of detection."
The University of Connecticut Health Center (UCHC) (2010) found that "Of the 60 VOCs
tested in air, 4 VOCs appear to be associated with turf. Of 22 PAHs, 6 were found in the
air on the turf at 2 fold greater concentrations than in background locations on at least
two fields... benzothiazole and butylated hydroxytoluene were the only chemicals detected
in the personal and area air samples from outdoor turffields ranging from <80-1200
ng/m3 and <80-130 ng/m3, respectively. Nitrosamine air levels were below reporting
levels. PM10 air concentrations were greater in background locations than on the turf at
all fields with the exception of Field B. However, the PM10 air concentration on turf at
Field B, 5.89 ug/m3, was within the range of other PM10 background concentrations. All
of the composite samples of turf fibers and crumb rubber were below the level EPA
considers as presenting a "soil-lead hazard" in play areas (400 ppm)."
Li et al. (2010) found that "Ten volatile compounds were identified in the vapor phase
over all commercial [crumb rubber] samples and two agedfield [crumb rubber] samples
by SPME coupled with GC-MS. Six volatile compounds were quantitated by direct vapor
phase injection. In all 16 virgin commercial [crumb rubber] samples, [benzothiazole]
was the most abundant volatile compound. Zinc was the highest of all extractable metals
in the acidified extraction fluid."
Simcox et al. (2011) conducted a synthetic turf field investigation in Connecticut. The
"Results showed that personal concentrations were higher than stationary concentrations
and were higher on turf than in background samples for certain VOC. In some cases,
personal VOC concentrations from natural grass fields were as high as those on turf.
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Naphthalene, BZT, and butylated hydroxytoluene (BHT) were detected in greater
concentration at the indoor field compared to the outdoor fields. Nitrosamine air levels
were below reporting levels. PM10 air concentrations were not different between on-field
and upwind locations. All bulk lead (Pb) samples were below the public health target of
400 ppm."
Microbial Assessment
Assessments of microbial populations associated with artificial turf were limited compared to
those of other topics areas. Conclusions for some of these studies are summarized below.
McNitt et al. (2006) collected crumb rubber samples from both "high use" areas and "low
used" areas in fields used by elementary to professional athletes in Pennsylvania. " While
microbes exist in the infill media the number was low compared to natural turfgrass field
soils." The range of CFU was 0-80,000 in the infill material compared to 259,500 found
in natural soil.
California OEHHA (2010) found that "Fewer bacteria were detected on artificial turf
compared to natural turf."
Serentis et al. (2011) found that in Pennsylvania, "Indoor fields tended to have lower
overall microbial populations (0-7267CFU/g of infill) than outdoor fields (0-80
OOOCFU/g)... While it is clear that microbes exist on synthetic turf surfaces, the number
was low compared with those on natural turf grass." "S. aureus colonies were not found
to be present on any field; however, S. aureus colonies were found on other tested
surfaces, including blocking pads, used towels, and weight equipment."
Bass and Hintze (2013) compared "the occurrence of microbial populations on two
infilled synthetic turffields (year old turf us. 6 year old turf) in three locations...Much
higher microbial populations were found on the older turffield" compared to the newer
turf. "Counts from the MSA plates revealed a relatively high number of mannitol-
fermenting salt-tolerant bacteria, a possible indication of staphylococci."
W eathering/Aging
Based on a study in Taiwan, Chang et al. (1999) found that "Twoyears after the track
installation, the VOC concentrations measured at 1.5 m above the track, the breathing
height of school children, were not significantly higher than the background levels."
Chang et al. (1999) also noted that the synthetic fields were all installed with adhesive
and backings which might also contribute to VOC offgassing.
Based on a study in The Netherlands, Hofstra (2007b) concluded that "The impact of
weathering of the rubber crumb for the technical lifetime of an artificial turffield
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(approx. 10 to 15 years) does not cause the leaching of zinc from the rubber crumb made
from recycled car tyres to exceed the threshold values for dissolved zinc in surface water
or the derived threshold value from the Decree on Soil Quality for the emission of zinc
into the soil."
Verschoor (2007) observed that "Laboratory experiments and measurements of field
samples of the rubber infill show that the emission of zinc increases over time, due to
chemical and physical changes of the rubber particle. "
Zhang et al. (2008) reported on studies conducted in New York and concluded that
"Rubber granules often, especially when the synthetic turf fields were newer, contained
PAHs at levels above health-based soil standards. PAH levels generally appear to
decline as the field ages. "
A report on a study conducted at the Connecticut Agricultural Experiment Station
(CAES) concluded that "...although there is a decrease in the amounts of all six
compounds which outgas over the ten weeks of this experiment, the decrease is the least
for 4-t-octylphenol. Second, at approximately 20 days of weathering under the conditions
in this experiment, the five compounds appear to reach a consistent level of outgassing"
(CAES, 2010).
Data Gaps/Recommendations for Further Study
Several studies provided information on data gaps and recommendations for further study. These
conclusions ranged from statements about the general need for further investigation to specific
suggestions for further research. Some examples of these recommendations are provided below.
Zelibor (1991) recommended "that a field study be prepared in conjunction with key
states (Ohio, Illinois, Pennsylvania, California, Texas, New York, New Jersey, North and
South Carolina, Florida, Georgia, among others) and coordinated by the Scrap Tire
Management Council. " Its purpose would be to address questions "concerning the effect
ofleachate from scrap tire products in the environment...[specifically], 1) Which
regulatory standards are appropriate to evaluate potential adverse effects on human
health and environment from compounds leachedfrom scrap tire or rubber products?; 2)
Are there any realistic environmental conditions/applications where scrap tires leach
compounds that exceed regulatory standards? 3) Are compounds leachedfrom scrap tire
products in the environment under specific applications? If so, what is the fate of those
compounds in the environment?; [and] 4) Is there an adverse effect on groundwater,
surface water or wetlands from the storage or application of scrap tires? "
Plesser and Lund (2004) found that "recycled rubber granulates give off a significant
number of alkylated benzenes in gaseous form. Trichloromethane (sample 1) and cis-1,2-
dichlorethene (sample 5) were also found. " They also recommended that "measurements
be taken of air quality above pitches to determine whether the air quality is satisfactory."
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Sullivan (2006) concluded that "The actual amount of contamination leaching from
artificial turf used on playgrounds or athletic fields needs further research to determine
the potential harm to human health or the environment." In term of human health,
Sullivan et al. (2006) suggested that "It is not clear whether dermal or inhalation
exposure to tire rubber can lead to sufficient absorption of chemicals to cause mutagenic
or carcinogenic effects. The degree of direct contact between the rubber used in artificial
turf is not well enough known at this time to determine whether the level of the potential
for harm to humans playing on artificial turf containing crumb rubber. " In terms of
aquatic toxicity, Sullivan et al. (2006) stated that "The unknown factor is how much zinc
or organic compounds would be releasedfrom crumb rubber used on or beneath
artificial turf."
In 2006, KEMI, the Swedish Chemicals Inspectorate, published a status report on
synthetic turf from a chemical perspective. Data gaps with regard to health risks from the
use of synthetic turf were summarized as follows: "Certain investigations and
assessments have been carried out in order to illuminate the risks of using synthetic turf
but there remain major gaps in our knowledge. This is particularly true with respect to
the extent to which the hazardous substances are releasedfrom the rubber, and the
subsequent exposure to these substances of people and the environment."
Verschoor (2007) made the following recommendations: "Mechanisms of behaviour and
ageing of (different types of) rubber should be investigated to obtain a better
understanding of the risks of zinc and other components leaching from rubber ...It is
recommended that measurements are first taken in drainage water from existing artificial
turf with rubber infill of differing age and quality. Sampling at several time intervals in
different seasons is preferred...Bioassay is recommended to assess the toxicity of the
drainage water...A mini artificial turf field (lxlxl m) can be built and exposed to outdoor
weather conditions in a lysimeter...more advanced models can be usedfor a refined risk
assessment."
LeDoux (2007) conducted a preliminary assessment of the toxicity from exposure to
crumb rubber based on a literature review and concluded that "Insufficient information
was found to perform a complete formal exposure assessment/risk characterization on
crumb rubber for the stated outdoor use at this time due to existing data gaps in the
available information. After reviewing the information available, with the possible
exception of allergic reactions among individuals sensitized to latex, rubber and related
products, there was no obvious toxicological concern raised that crumb rubber in its
intended outdoor use on playgrounds and playing fields would cause adverse health
effects in the normal population. "
Based on a literature review, ChemRisk (2008) concluded that "The current state of
knowledge indicates that there are data gaps which significantly limit a scientifically
robust analysis of the potential environmental health risks associated with the selected
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tire materials and tire wear particles [TWP]" "It was concluded that the most significant
data gaps are: 1) lack of understanding of the chemical composition of TWP, 2) lack of
understanding of the levels of TWP in the environment (air, soil, and sediments) and their
potential associated health risks; and 3) lack of understanding of the potential for TWP
to leach chemicals into the environment. " "As such is it recommended that the following
research be conducted to allow for environmental health risk assessment of TWP:
chemical composition analysis of TWP generated under representative driving
conditions; acute aquatic toxicity studies of TWP; characterization of TWP leachate
under simulated environmental/biological conditions; development of chemical marker
for TWP in environmental media; and, measurement of TWP in air, soil, water and
sediment to determine representative exposure concentrations. "
In a 2008 editorial, Lioy and Weisel (2008) stated that "At the present time, we believe
that the million dollar expense to produce and install a synthetic field by communities
and athletic facilities demands a much more thorough understanding of the
environmental impacts, human exposure and health risk implications associated with all
synthetic turfproducts available on the market. This calls for a comprehensive evaluation
of artificial turf by exposure scientists, and others in environmental science and
environmental health sciences."
The New York Department of Environmental Conservation (NYDEC, 2008) noted that
"Many governmental bodies including Norway, Sweden and California have recently
reviewed the health issues associated with the use of crumb rubber as infill at
playgrounds and synthetic turffields. Their assessments did not find a public health
threat. However, several recent preliminary studies... indicated the presence of organic
compounds, such as polycyclic aromatic hydrocarbons (PAH) and heavy metals, such as
zinc, and raised concerns that these substances could have potential adverse impacts on
the environment and public health, especially for children playing on these synthetic turf
fields for extended time periods....to address these concerns, the DEC has initiated a
study to assess the potential environmental impacts from the use of crumb rubber as an
infill material in synthetic turffields and to collect data that would be relevant for a
public health and environmental assessment. "
U.S. EPA (2009) conducted a scoping-level field monitoring study of synthetic turf and
playgrounds in the U.S. and concluded that "On average, concentrations of components
monitored in this study were below levels of concern; however, given the very limited
nature of this study (i.e., limited number of components monitored, samples sites, and
samples taken at each site) and the wide diversity of tire crumb material, it is not possible
to reach any more comprehensive conclusions without the consideration of additional
data."
Based on a study conducted by the University of Connecticut Health Center (UCHC,
2010) "airborne concentrations of VOCs, targeted SVOCs (e.g. benzothiazole) and
miscellaneous SVOCs were highest at the indoor field. These data were collectedfrom
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only one indoor facility. Higher concentrations of these chemicals at the indoor field
likely reflects the lack of air movement relative to outdoor fields. " UCHC (2010)
suggested that "more research is needed to better understand chemical exposures in
indoor facilities."
Simcox et al. (2011) concluded that "More research is needed to better understand air
quality at indoor facilities. "
Menichini et al. (2011) suggested that "Further work is needed to assess the actual
scenarios of exposure to PAHs by inhalation and the corresponding risks, and to reach
more comprehensive conclusions."
Kriiger et al. (2012) suggested that "Considering the risk assessment of artificial turf
systems, emphasis should be placed not only on the plastic components but also on
mineral aggregates usedfor basic layers, which might contribute to the release of
contaminants, especially of zinc. For a thorough and realistic risk assessment, column
tests of complete artificial turf systems, simulating the actual installation, may be more
realistic."
Cheng et al. (2014) conducted a literature review of environmental and health impacts of
artificial turf and stated "There remains a significant knowledge gap that must be
urgently addressed with the fast expansion of the artificial turf market. Given the wide
range of designs, ages, and conditions of artificial turffields, it is likely that the
contaminant release and the environmental impacts are variable from site to site. It is
also important to assess more systematically the risk posed by the tire rubber crumb on
the environment and human health ".
The health impact assessment of the use of artificial turf in Toronto, conducted by the
city of Toronto (2015) concluded that there are "still some information gaps: the
allergenic potential of latex in crumb rubber has not been thoroughly investigated;
exposure to lead, other metals, carbon nanotubes, as well as other contaminants have not
been fully evaluated in all types of turf systems
The Virginia Department of Health (VDOH, 2015) suggested that studies "done
exclusively in a controlled laboratory setting may not necessarily represent a "real world
exposure " to chemicals in crumb rubber. However, laboratory analysis provides an
alternative to identifying chemicals (by employing strong extraction techniques and
concentrating chemicals to detectable concentration before analysis) in crumb rubber
that might be present in low concentrations in the environment. "
Dorsey et al. (2015) conducted a study in Ohio and concluded that "Risk assessment
studies are needed to consider the health impact of repeated exposure to crumb rubber at
the conditions relevant to artificial athletic fields."
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VII. Gaps Analysis Based on the Literature Review
Despite the use of tire crumb rubber in synthetic fields over the last several decades, there is not
an extensive body of scientific research on the exposure to and toxicity of tire crumb rubber, and
questions about the effects of this material on human health and the environment remain. The
Literature Review/Gaps Analysis (LRGA) effort considered 97 reference sources for information
related to tire crumb rubber. Eighty-eight of the references were included in the analysis. The
LRGA analysis categorized the studies according to a set of general topic areas, to evaluate the
relative areas of data richness and data gaps. Important data gaps remain in the characterization
of tire crumb rubber material used in synthetic turf fields and playgrounds, assessing exposures
for users of these fields and playgrounds, human and ecological risk assessment, and in health
impact assessments. Selected data gaps described in Table B-12 focused on potential human
exposure and health impact assessments for exposure to tire crumb rubber and its constituents.
Some concerns related to synthetic turf fields and playgrounds were not addressed in this
Literature Review/Gaps Analysis, including heat exposure and injury. Other potential gaps that
might be important, but were not directly addressed in the reviewed literature included
limitations in tools and methodology available for characterizing constituents, exposure, and
health impacts among user populations.
One of the LRGA topic areas was risk assessment characterizing the human and ecological
effects of interaction with tire crumb rubber. While there are many definitions of the term "risk",
the U.S. EPA considers risk to be the chance of harmful effects to human health or to ecological
systems resulting from exposure to an environmental stressor (U.S. EPA, About Risk
Assessment). In general terms, risk depends on the following three factors:
• How much of a stressor (e.g., chemical) is present in an environmental medium (e.g.,
soil, water, air),
• How much contact (exposure) a person or ecological receptor has with the contaminated
environmental medium,
• The inherent toxicity of the stressor.
In the ideal world, risk assessments would be based on a very strong knowledge base (i.e.,
reliable and complete data on the nature and extent of contamination, fate and transport
processes, the magnitude and frequency of human and ecological exposure, and the inherent
toxicity of all of the chemicals). Based on the tire crumb rubber literature reviewed here, data are
not available for all of these factors in all of the studies, and only a limited number of studies
provided quantitative estimates of risk to human or ecological population from tire crumb rubber
constituents.
Only a subset of the 88 available references evaluated risks associated with constituents of tire
crumb rubber. Among the studies that estimated human health risks, both cancer and non-cancer
endpoints were considered, and the available studies each considered one or more routes of
exposure (i.e., inhalation, ingestion, and dermal). A limited number of studies examined the
activity patterns associated with tire crumb rubber exposures or provided population - and
activity-specific exposure factors (e.g., time spent in contact with artificial turf fields) for use in
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risk assessment. There was a balance in the populations studied with respect to adults, children
and athletes. Fewer studies addressed occupational exposures from turf and playground
installations. Given the relative paucity of investigations on worker-associated risks and activity-
related studies, there remains uncertainty in potential risks associated with the use of tire crumb
rubber at synthetic turf fields and playgrounds.
Table B-12. Data Gaps for Research on Tire Crumb Rubber in Synthetic Fields and Playgrounds
Research Area
Data Gaps
Tire Crumb Rubber Characterization
Chemical
Characterization
• Studies that have measured metal, volatile organic chemicals (VOCs), and semi-volatile
organic chemicals (SVOCs) (e.g., polycyclic aromatic hydrocarbons [PAHs] and
benzothiazole) were usually based on small numbers of tire crumb rubber samples. The
wide range of organic chemicals potentially used in tire manufacture, or their degradates,
have not been analyzed systematically across a large range of tire crumb rubber samples
from synthetic fields and playgrounds in the United States.
• Limited information is available on chemical constituents in molded rubber products
made with tire crumb rubber used in some playground settings.
Emissions
Assessments
• Few laboratory-based studies have investigated VOC and SVOC emissions from
synthetic fields and playgrounds under different temperature conditions. Measurements
using dynamic emission chamber measurements have been reported, but the number and
types of measured chemical emissions have been limited.
Microbial
Assessments
• Microbiological assessments for synthetic turf fields and playgrounds have been limited
and have been based on traditional culture methods. The use of molecular methods has
not been applied in studies of tire crumb rubber.
Bioaccessibility
• Several studies have examined potential bioaccessibility of metals and PAHs. However,
studies that systematically measure a wider range of metal and organic chemical
constituents, using multiple simulated biological fluids, and across a large range of tire
crumb rubber samples are lacking.
Variability
• Most studies characterizing tire crumb rubber from synthetic fields and playgrounds in
the United States have been relatively small, and restricted to a few fields or
playgrounds. Measurements for samples collected from a wider range of tire recycling
plants, synthetic fields, and playgrounds across the United States is lacking. Also,
infonnation is limited on the range of chemical, microbiological, and physical
characteristics and factors related to variability in tire crumb rubber and potential
exposures.
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Table B-12 (continued). Data Gaps for Research on Tire Crumb Rubber in Synthetic Fields and
Playgrounds
Research Area
Data Gaps
Exposure/Risk Characterization
Exposure Factors
• Exposure and risk assessments have typically relied on generic exposure factors.
Information specific to the frequency and duration of synthetic field and
playground uses, physical activities, contact rates, and hygiene are limited.
• Exposure factor data are not available either across the wide variety of sports and
recreational users of synthetic turf fields and playgrounds with tire crumb rubber,
or for occupational exposures.
Dermal/Ingestion
Exposures
• While multiple studies have attempted to characterize potential inhalation
exposures to tire crumb rubber chemical constituents, more limited infonnation is
available for understanding dermal and ingestion exposures.
Broken Skin/Ocular
Exposures
• Little infonnation is available on the potential for increased exposures via broken
skin (i.e., due to cuts and scrapes) and through ocular fluids.
Particle
Exposures
• There is limited infonnation on exposure to tire crumb particles and their
constituents through inhalation, dennal, and ingestion. Infonnation on the
exposure potential as synthetic fields and playgrounds age and weather, and for
various uses and activities on synthetic fields and playgrounds is limited.
Variability
• Few studies have evaluated the variability of exposures to tire crumb rubber
constituents by activity type, exposure scenario, age, material type and condition,
facility type and condition, and ambient conditions such as temperature and wind
or ventilation. Limited infonnation is available on the variability of exposures and
related factors across a wide range of user groups and scenarios.
• A few studies suggest that inhalation exposures at indoor facilities are higher
compared to those at outdoor facilities, but the available infonnation is limited.
Biomonitoring
• Only a few biomonitoring studies have been perfonned. Only hydroxypyrene has
been measured as a biomarker in athletes and workers.
• Additional tire rubber-specific biomarker measurements have not been reported for
synthetic field and playground users and biomarker analysis methods might be
lacking for some chemicals.
• Large scale biomonitoring studies of populations exposed and not-exposed to
synthetic turf fields and playgrounds with tire crumb rubber have not been
reported.
Cumulative/Aggregate
Assessments
• Exposures to multiple tire crumb constituents are likely to occur via multiple
pathways (e.g., inhalation, ingestion, and dennal contact). However, studies that
evaluated cumulative and aggregate exposure and risks are limited.
Epidemiology Studies
• No epidemiological investigations for synthetic turf field or playground users were
identified in the literature review.
• Survey and biomonitoring tools for accurate assessment of relative exposures for
synthetic field and playground users in an epidemiological study are lacking.
Alternative
Assessments
Alternative
Infills/Materials
• Most research to date has focused on characterizing tire crumb rubber infill.
Similar research on other infill materials, including natural materials, ethylene
propylene diene monomer (EPDM), thennoplastic elastomers (TPE), and recycled
shoe rubber are either lacking or limited.
Natural Grass Fields
• Few studies have been perfonned to assess potential chemical exposures from
natural grass playing fields.
Other Exposure
Sources
• Only a few comparative assessments have been perfonned on relative exposures to
chemicals associated with tire crumb rubber from other sources.
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Many of the studies that did not characterize risks, examined factors related to potential public or
environmental health impacts (e.g., identifying chemical constituents, or assessing leaching or
off-gassing of chemicals from artificial turf). Among these other topic areas, there was relatively
less information available on microbiological and bioavailability aspects of tire crumb rubber
exposures. The availability of biomonitoring studies was also limited. No studies were identified
that produced or evaluated epidemiological data on potential associations between the incidence
of health effects and exposures related to tire crumb rubber. Related to sampling locations, there
were more studies conducted in laboratories and synthetic fields. Thus data gaps may be more
pronounced for locations such as playgrounds and indoor fields, as well as studies that compare
site-specific concentrations of tire crumb rubber constituents to background levels. Another less-
studied factor relates to potential differences between constituent levels in environmental media
and corresponding exposures based on activity levels (e.g., active versus inactive play) on
artificial turf fields.
A wide range of chemicals were evaluated in the literature reviewed for the LRGA, and a
significant portion of the LRGA involved compiling a list of potential tire crumb rubber
constituents identified in the available literature. The constituents list spreadsheet, which can be
found on the Status Report website, identifies more than 350 distinct chemical compounds. A
list of the chemicals is provided in Appendix F. This spreadsheet is a comprehensive list of
unique chemicals that were identified in the LRGA literature. Some major classes of constituents
identified in the LRGA include inorganics, and VOCs/SVOCs. Frequently studied inorganics
include lead, zinc, cadmium, and chromium. Frequently studied VOCs/SVOCs include
benzothiazole and PAHs. Less frequently studied constituents included microbials, and a variety
of complex organic compounds. In general, the available studies do not establish whether the
observed results are widespread and generalizable. Systematic studies based on larger numbers
of athletic fields and playgrounds designed to include a range of characteristics (rubber material
source, location, age, etc) for the population of such fields and playgrounds across the United
States have not been performed.
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IX. Appendices
Appendix A - CDC Review of Published Literature and Select Federal Studies on
Crumb Rubber and Synthetic Turf
Review of Published Literature and Select Federal Studies on Crumb Rubber and
Synthetic Turf
Product Sampling and Chemical Composition Studies
1. Synthetic Turf Field Investigation in Connecticut
N. Simcox, A. Bracker, G. Ginsberg, B. Toal, B. Golembiewski, T. Kurland, C. Hedman; Journal of Toxicology and Environmental
Health, Part A; 2011.
The purpose of the study is to characterize concentrations of VOCs, SVOCs, rubber-related chemicals, and PM10 in ambient air at
selected fields with crumb rubber infill in Connecticut during summertime conditions and during active field use.
Methods:
• During July 2009, three types of fields were sampled:
o Outdoor field with crumb rubber infill
o Indoor facility with crumb rubber infill
o Outdoor field with grass turf as background location
• Air samples collected at older fields (>3 years) and at new fields (< 2 years).
• Personal air sampling during simulated soccer game:
o VOCs
o SVOCs
o Benzothiazole (BZT)
o 2-mercaptobenzothiazole
o 4-tert-octylphenol
o Butylated hydroxyanisole
o Butylated hydroxytoluene (BHT)
o Nitrosamines
o PM10
Study results and/or conclusions:
• For turf fiber and crumb rubber infill, lead levels were below the EPA "soil-lead hazard" limit and below the 300ppm target set
by Consumer Product Safety Act for products to be used by children.
• Of 60 VOCs, 31 were detected on field.
• Personal air monitoring concentrations were higher on artificial turf than on grass for 21 VOCs.
• Stationary samples on the outdoor fields were similar to background.
• Total VOCs were higher indoors than outdoors, however, only a few VOCs were elevated indoors
compared to background.
• Benzo(a)pyrene was higher at the outdoor field than background (range ND-0.19 versus ND-0.05).
• For the indoor field, 1-methylnapthalene, 2-methylnapthalene, fluorene, napthalene, and pyrene were 10-fold higher than
background.
• There were several other P AHs found only on the indoor turf, acenapthene, acenaphthylene, fluorene, napthalene, and 2,6-
dimethylnapthalene.
• BZT and BHT were higher on the indoor field than outdoor field (BZT range 11,000-14,000 ng/m3 versus <80-1,200 ng/m3;
BHT range 1,240-3900 ng/m3 versus <80-130 ng/m3).
Study limitations:
• Potential selection bias as field location participation was voluntary.
• Sample size was small.
• Summer 2009 temperatures were lower than normal.
• Personal sampling occurred at waist height, not in the breathing zone.
• Some VOCs were found in the personal samples, but not the turf or background indicated non-turf related sources.
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2. Hazardous organic chemicals in rubber recycled tire playgrounds and pavers
M. Llompart, L. Sanchez-Pardo, J. Lamas, C. Garcia-Jares, E. Roca; Chemosphere; 2013.
The purpose of the study was to investigate the presence of hazardous organic chemicals in recycled tire playground surfaces.
Methods:
• 21 samples from 9 urban playgrounds
• 2 types of ground covers - floor tiles compositions and carpet covers
• 7 samples from a local store; 2 puzzle pavers and 5 recycled rubber tire tiles of different colors
• Ultrasound-assisted extraction followed by pressurized solvent extraction
• GC-MS for PAHs, plasticizers and other phthalates (31 compounds total)
• Solid-phase microextraction (SPME) for vapour phase composition profiles
Study results and/or conclusions:
• For playground samples
o Full GC-MS scan identified a large number of VOCs, SVOCs, and POPs.
o All samples contained PAHs with a range of 1.25 jig g-1 to 70.4jag g-1 total PAH amount with one sample having a
concentration of 178ju.g g-1
o Pyrene was the most abundant congener found in all samples.
o Napthalene, phenanthrene, fluoranthene, and chrysene were found in 20 or 21 samples,
o B(a)P was found in 5 samples with values ranging from 0.4jig g-1 to 5.0jag g-1.
o Benzothiazole (BTZ) was found in all playground samples with a mean concentration of lOjag g-1.
o 2-mercaptobenzathiole (MBTZ) was found in playground samples, but there were methodological issues with the
analysis.
o 4-tert-butylphenol (TBP) was present in half the playground samples at low concentrations.
o Butylated hydroxytoluene (BHT) was found in all samples but butylated hydroxyanisole (BHA) was not found in the
samples.
o Phthalates were found in all samples with the most abundant congener being di(2-thylhexyl)phthalate/
concentrations ranging from 4 to 64 |ig g-1.
o Diisononyl phthalate (DINP) was found in 8 of 21 playground samples but was not detected in commercial pavers,
o For the SPME analysis, all PAHs found in the samples were detected excluding the less volatile ones. BZT, DEP, DIBP,
DBP, DEHP, and BHT were found in all cases.
• For commercial pavers:
o Higher PAH concentrations compared to playground samples,
o For 5 of 7 samples, concentrations were extremely high - 2000|ig g-1 to 8000|ig g-1.
o All PAHs were found in all samples with a mean concentration of B(a)P = 500|ig g-1.
o BZT was found in all commercial pavers with concentrations ranging from ~20 to >150 |ig g-1.
o MBTZ was not detected in commercial pavers.
o TBP was present in all pavers with concentrations ranging from 8.6 to 21|ig g-1.
o BHT was found in all pavers with a mean concentration 19|ig g-1.
o Phthalate concentrations were higher in pavers than playground samples. DEHP concentrations ranged from 22 to
1200|ig g-1.
o For the SPME analysis, volatile PAHs and some less volatile PAHs (including B(a)P) were found in some samples.
BZT, DEP, DIBP, DBP, DEHP, and BHT were found in all cases,
o TBP was also found in most samples.
• Research is ongoing as a high number of compounds (excluding the ones in this study) were found in the samples.
Study Limitations:
• The study did not determine bioavailability of the chemicals after ingestion or upon dermal exposure.
• For the SPME analysis, inhalation exposure is indicated as possible by the authors; however, laboratory vapor phase
composition does not mimic field conditions and thus potential exposure conditions.
3. Metals contained and leached from rubber granulates used in synthetic turf areas
B. Bocca, G. Forte, F. Petrucci, S. Costantini, P. Izzo; Science of the Total Environment; 2009.
The purpose of the study was to quantify metals contained in and leached from different types of rubber granulates used in
synthetic turf.
Methods:
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• 32 samples from 32 different playgrounds in Italy were collected with samplings performed at different positions in the
playground to obtain a representative sample for each area with 250g granulate obtained from 12 sectors.
• 50g granulate from each of the 12 samples pooled to obtain 1 sample per playground.
• Each sample was analyzed for metal content.
o Al, As, Ba, Be, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Ni, Pb, Rb, Sb, Se, Sn, Sr, Tl, V, W, Zn
• The levels were compared to the maximum concentrations allowable for soils.
Study results and/or conclusions:
• The rubber granulates contained all the metals included in the analysis, but the concentration range was wide in the different
samples.
• Relatively high levels of Al, Fe, Mg, and Zn were found.
• All samples had metal concentrations significantly lower than the allowable limit, except Co, Sn, and Zn.
• 50% of samples exceeded the Co and Sn limit, while 97% of samples exceeded the limit for Zn with values around lOOx higher
than the standard.
• The highest leaching was observed for Zn (2,300 |ig/L).
• Very low concentrations of As, Cd, CO, Cr, Cu, Li, Mo, Ni, Pb, Rb, Sb, and V were leached and Be, Hg, Se, Sn, Tl, and W were
under the LOQ,
Study Limitations:
• Assessments of risk should be conducted for each individual case at a local level due to differences in local ground conditions,
type of drainage, and the composition of the filler material.
• The results were compared to the allowable limit for metals in soil which may not be an appropriate comparison.
4. Health Risk Assessment for Artificial Turf Playgrounds in School Athletic Facilities: Multi-route Exposure Estimation for Use
Patterns
H. Kim, Y. Lim, S. Kim, I. Yeo, D. Shin, J. Yang; Environmental Health and Toxicology; 2012.
The purpose of the study was to identify major exposure routes and calculate total risk through a health risk assessment for
chemicals released from artificial turf playgrounds and urethane flooring tracks.
Methods:
50 schools with artificial turf and urethane flooring at the playgrounds; 27 elementary schools and 23 middle and high schools
Inhalation of VOCs and formaldehydes due to volatile outdoor air from surfaces of artificial turf and urethane flooring
Dermal uptake from surfaces of artificial turf and urethane flooring
Ingestion exposure to fine particles
Trace metals (Pb, Cr, Ni, Cd, Zn, Hg)
o Dust collected at 5L/min for 8 hours.
o Urethane layer collected from flooring materials in schools,
o Infill chip layer collected from chip flooring material in parks,
o Product surface sampling was conducted using texwipe.
o Hand surface sampling was performed using texwipe after children played on the facility.
VOCs
o Air samples collected at 0.2L/min at 1.5m for 2 hours
o Infill chips (see Metals #2 and #3).
o Air samples collected
o Infill materials (see Metals #2 and #3; surface sampling and hand sampling not performed)
Phthalates
o Infill materials (see Metals #2 and #3)
o Surface sampling (see Metals #4)
o Hand sampling (see Metals #5)
Sampling was conducted at the top of the central playground so as to eliminate other potential emission sources.
Study results and/or conclusions:
• Infill content for heavy metals had highest concentration of Zn > Pb > Cr.
• Pb exceeded standard in infill from 8 of the schools and exceeded the domestic standard (lOmg/kg) in 2 of the schools.
• For the air monitoring, Zn had the highest concentration; Pb was detected but levels were 10% of Korean ambient air
standards.
• Bioavailability values were estimated and for infill chips were shown to be 10-10,000 times lower than the measured content
level; for the urethane flooring, the bioavailability was estimated to be approximately lOx lower than the infill chips.
• The excess cancer risk (ECR) for individual chemicals was estimated to be a level of one person out of one million (1x10-6) or
less.
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• The ECR for carcinogens in children with pica, who represent the most extreme exposure type among the facility users, was
shown to be 1.14x10-7 for benzene and 8.47x10-7 for PAHs.
• The hazard index (HI) of the facility users for each individual chemical according to the mean exposure scenario was shown to
be less than 0.1, which was low, except for children with pica.
• The HI of children with pica for non-carcinogenic materials was shown to be less than O.OOlfor Pb, 0.067 for Cr, Cd and Hg,
0.005 for Zn, 0.001 for VOCs; and 0.273 for phthalates, all of which were low, except for phthalates.
Study Limitations:
• The study did not consider asthma or allergic reactions in the health assessment.
• The authors assumed that all chemicals in the air sampling were from artificial turf or urethane flooring, and that there were
no other air emission sources.
5. Comparison of Batch and Column Test for the Elution of Artificial Turf System Components
O. Kruger, U. Kalbe, W. Berger, K. Nordhaub, G. Christoph, H.P. Walzel; Environmental Science and Technology; 2012
The purpose of the study was to compare the behavior of synthetic sports flooring components at different elution methods.
Methods:
• Artificial turf components from 6 German producers.
• Batch tests were performed with a liquid to solid ratio of 2L/kg.
• Column tests were performed with a liquid to solid ratio of 26.5 L/kg.
• pH, electric conductivity, turbidity of the eluates, and contaminant release were measured.
• Specific emphasis placed on zinc (ICP-OES) and PAHs (15 measured with HPLC).
Study results and/or conclusions:
• Lead and cadmium were under the LOQ while zinc concentrations varied from below LOQ-129 mg/L.
• The PAH concentrations varied from 0.07-3.41 |ig/L.
• The batch testing produced higher concentrations of zinc; however, column testing provides conditions closer to actual field
conditions.
Study Limitations:
• Batch test conditions did not mimic actual field conditions.
6. Release of Polycyclic Aromatic Hydrocarbons and Heavy Metals from Rubber Crumb in Synthetic Turf Fields: Preliminary Hazard
Assessment for Athletes
L. Marsili, D. Coppola, N. Bianchi, S. Maltese, M. Bianchi, M.C. Fossi; Journal of Environmental and Analytical Toxicology; 2014.
The purpose of the study was to quantify the PAHs and heavy metals contained in the crumb rubber (tires produced before 2010), to
determine whether PAHs are released and at what concentrations, and to estimate respiratory uptake by athletes training on these
fields.
Methods:
• Samples were taken from nine different synthetic turfs from football fields in Italy
• 4 samples were new tire crumb rubber that was not yet on a fields.
• 4 samples of tire crumb rubber from fields 1-8 years old, and 1 sample from virgin rubber (i.e. not recycled tires)
• Heavy metals: Pb, Cu, Ni, Zn, Cr, Cd, Fe
o Concentrations determined via spectrophotometer and spectrometer
• PAHs: 14 analytes determine via HPLC
Study results and/or conclusions:
• The majority of samples had concentrations of heavy metals that were below the maximum limits set by the Italian National
Amateur League.
• Cd exceed the limit in 3 samples, 2 new and 1 installed.
• Zn was very high in all samples, exceeding the limit by a minimum factor of 20.
• PAH concentrations varied by sample. For all crumb rubber samples, highest concentrations were benzo(b)fluoranthene or
pyrene.
• The data indicate that PAHs are released continually from the crumb rubber via evaporation and athletes frequenting fields
could be exposed to chronic toxicity from PAHs.
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Study Limitations:
• The preliminary hazard assessment overestimates the PAH contribution.
• Theoretical approach which must be considered as an extreme worst case scenario.
7. A Scoping-Level Field Monitoring Study of Synthetic Turf Fields and Playgrounds
U.S. Environmental Protection Agency; 2009.
The purpose of the study was to generate limited field monitoring data that will be used by EPA to help determine possible next
steps to address concerns regarding the safety of tire crumb infill in recreational fields.
Methods:
• Scoping level study evaluating environmental concentrations of tire crumb constituents in recreational fields.
• Two synthetic turf fields and one playground were chosen as the sampling locations.
• Air sampling was conducted at lm height:
o PM10 analyzed for mass, metals, and particle morphology
o VOCs for 56 analytes (2pm collection time at the fields and at an upwind background location).
• Wipe sampling was conducted at the fields and also with tire crumb infill and turf blade samples
o Pb, Cr, Zn, As, Al, Ba, Cd, Cu, Fe, Mn, Ni (ICP/MS).
• Percent bioaccessible Pb was calculated.
Study results and/or conclusions:
• All VOCs, PM, and metals were similar to all background levels and were below the national ambient air quality standards.
• Methyl isobutyl ketone was detected at one synthetic turf field and was not detected in the background samples.
• The extractable lead concentrations from the infill, turf blades, and tire crumb materials were low and below the EPA standard
for lead in soil.
• Lead concentrations in the wipe samples were low and below the EPA standard for lead in residential floor dust.
Study Limitations:
• Semi volatile organic compounds were not measured in this study.
• Sites where samples were taken could have many variabilities in the materials used and possible environmental differences.
• There were some difficulties obtaining permission to access the playgrounds and synthetic turf fields.
8. CPSC Staff Analysis and Assessment of Synthetic Turf "Grass Blades"
Consumer Product Safety Commission
The purpose of the study was to determine the total lead content and accessibility of the lead.
Methods:
• Samples of synthetic turf at the time of installation and samples from when 1 field was dismantled.
• Lead content of grass blades was determined using ICP.
• Samples with detectable lead were tested for accessibility of lead.
• For in-service fields, X-ray fluorescence was used to detect the presence of lead.
Study results and/or conclusions:
• Synthetic turf lead content ranged from 0.09% to 0.96% and varied between the turfs and also within a field depending on
color.
• The results for this set of tested synthetic turf fields show no case in which the estimated exposure for children playing on the
field would exceed 15 mg lead/day (according to the CPSC's recommendation for chronic lead ingestion not exceeding 15 mg
lead/day, daily).
Study Limitations:
• Accuracy of wipe sampling method for estimating exposure to lead contact residue is unknown.
• Dermal contact to skin with lead residue during a typical play event on a field was assumed.
• Experimental wipe method overestimated transfer to a persons' bare skin by a factor of 5 to 13.
• Bioavailability of lead from synthetic turf may not be the same as it is for the food and drink exposures that were the basis of
the dose-response.
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• Staff did not make adjustments in the assessment to account for differences in lead content as fields can have areas with
different lead content (i.e. painted areas, etc.).
9. Environmental-sanitary risk analysis procedure applied to artificial turf sports fields
B. Ruffino, S. Fiore, M. C. Zanetti; Environmental Science and Pollution Research; 2013.
The purpose of the study was to characterize chemicals in crumb rubber and assess their capacity to release the chemicals on
contact with water. The study also evaluated if the rubber granules may pose a risk to child and adult players via direct contact,
contact with rainwater soaking the field, or inhalation of dusts and gases released.
Methods:
• Four sports turf fields with crumb rubber infill, 1 field with thermoplastic elastomer, and 1 natural turf field.
• Field age varied from 1-3 years old.
• Rubber and soil samples were analyzed for BTX (GC-MS), PAHs (8, GC-MS), and metals (18, ICO-OES).
• In-water extractable compounds (BTX, PAHs, and metals) were analyzed.
• Gases and dusts were collected immediately above the ground, close to the sports fields, and at a point in the center of the
city.
o Samples were analyzed for BTX (gases) and PAHs (dust).
Study results and/or conclusions:
• Concentration of benzene is similar to those in the natural turf field.
• Pyrene concentrations in synthetic turf are approximately 20 mg/kg and B(a)P concentrations were 10 mg/kg.
• Zinc concentrations were substantially higher in synthetic turf compared to the natural turf sample; 115 times higher at the
synthetic turf field with the lowest percentage zinc.
• The leaching tests identified higher BTX and PAHs in leachates from new infill material was higher than the old infill materials.
• For all turf fields examined and for all routes considered, the cumulative CR proved to be lower than 10-6 and the non-
carcinogenic risk (for the sum of COCs) lower than 1, in line with Italian guidelines.
• Additionally, for the inhalation route, the inhalation of dust and gases from activity on artificial turf fields gave risk values less
than those due to inhalation of atmospheric dust and gases from vehicular traffic.
Study Limitations:
• Some of the artificial turf fields were in various stages of age (the samples that were from newer fields had higher chemical and
metals concentrations than older fields).
• Sample comparison was limited to one city's atmospheric dusts and gases and may not be the best representation of typical
vehicular dust and gases being emitted.
10. Human Health Risk Assessment of Synthetic Turf Fields Based Upon Investigation of Five Fields in Connecticut
G. Ginsberg, B. Toal, N. Simcox, A. Bracker, B. Golembiewski, T. Kurland, C. Hedman; Journal of Toxicology and Environmental Health,
Part A; 2011.
The purpose of the study was to develop a screening level risk assessment in which high-end assumptions for exposure were used
for uncertain parameters and surrogate data were employed for chemicals with inadequate toxicity information so that chemicals
did not fall out of the assessment on the basis of missing data.
Methods:
• Personal air samples were taken from volunteers during 2-h sampling event at 5 artificial grass fields (4 outdoor and 1 indoor)
with crumb rubber infill.
• Stationary air samples were also taken near the field.
• Air samples were analyzed for VOCs (60), SVOCs (120, including 22 PAHs), lead, nitrosamines (7), and PM10.
Study results and/or conclusions:
• 10 VOCs were considered chemicals of potential concern (COPC) for the outdoor and fields and 13 VOCs for the indoor fields.
• Personal monitoring results were higher for VOCs than the stationary sampling results.
• The VOCs of potential concern were above background concentrations at only one of the outdoor fields (not the same field in
every case), except for toluene and hexane which were above background at two fields.
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• Personal monitoring samples showed VOCs were 1.5-to-3-fold greater than background at outdoor fields, except methylene
chloride which was 12.8-fold higher.
• Indoor VOCs detections tended to have greater elevations relative to background.
• 2 SVOCs were selected as COPC, benzothiazole (BTZ) and butylated hydroxytoluene (BHT).
• BZT was above background at indoor and outdoor fields; max indoor result was 11.7-fold higher than max outdoor result.
• BHT was detected at all fields and results were higher for stationary monitoring.
• BHT is a COPC for the indoor field.
• A variety of PAHs were detected above background but the concentrations were generally low (well below l|ig/m3).
• Less volatile PAHs were detected in the outdoor field while the more volatile PAHs were found indoors but generally not
outdoors
• Lead results were below the 300ppm target set by the CPSC for lead in products intended for children.
• Based upon the findings, outdoor and indoor synthetic turf fields are not associated with elevated adverse health risks.
Study Limitations:
• Small number of fields in the study.
• Only one indoor field was included in the study.
• Some limitations in weather variables when taking samples at outdoor fields.
• Small number of samples taken per field.
• The study did not attempt to measure latex antigen in the crumb rubber or in the PM10 collected from on field air samples.
• Some VOC detections in the personal monitoring may have originated in the device.
11. Artificial Turf Football Fields: Environmental and Mutagenicity Assessment
T. Schiliro, D. Traversi, R. Degan, C. Pignata, L. Alessandria, D. Scozia, R. Bono, G. Gilli; Archives of Environmental Contamination and
Toxicology; 2013.
The purpose of the study is to develop an environmental analysis drawing a comparison between artificial turf football fields and
urban areas relative to concentrations of particles (PM10 and PM2.5) and PAHs, BTEX, and mutagenicity of organic extracts from
PM10 and PM2.5.
Methods:
• 24 Air samples were taken from 6 football fields (5 were artificial turf) and 2 urban locations in 2 sampling events to study
influence of meteorological and seasonal conditions and the presence of play.
• PM10, PM2.5, BTX (benzene, toluene and Xylene), and PAHs were measured in the air samples.
• The mutagenicity of the organic extracts of the PM and PM2.5 samples were studied using the Ames test.
Study results and/or conclusions:
• Air samples from the artificial turf field had no significant differences from the samples from the urban sites.
• BTX concentrations at the urban site were significantly greater than on the turf fields.
• Seasonal differences were also seen.
• In regards to environmental monitoring, artificial turf fields present no worse exposure risks than those found in the city.
• PAH concentrations, when detected, were low.
• PAH concentrations were greater in the winter than the summer.
• B(a)P was present on the football fields during the winter sampling.
• During the winter season sampling, PAHs, except anthracene, were often present on each football field and at the urban site.
• The mutagenicity showed a seasonal trend and was greater on fields characterized by traffic and/or industrial emissions in the
surrounding area.
Study Limitations:
• Urban locations used to compare field results might not be a good overall representation of urban areas in general.
• Non-turf related environmental variables at both the fields and urban areas could be of influence.
12. Artificial-turf playing fields: Contents of metals, PAHs, PCBs, PCDDs and PCDFs, inhalation exposure to PAHs and related
preliminary risk assessment
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E. Menichini, V. Abate, L. Attias, S. De Luca, A. di Domenico, I. Fochi, G. Forte, N. lacovella, A. L. lamiceli, P. Izzo, F. Merli, B. Bocca;
Science of the Total Environment; 2011
The purpose of this study was to identify some potential chemical risks and to roughly assess the risk associated with inhalation
exposure to PAHs from materials used to make up artificial turf fields.
Methods:
• Rubber granulates were collected from 13 Italian fields. For the 13 fields, samplings were performed at different positions in
the playground to obtain a representative sample for each area (see Bocca et al #4).
• Rubber samples varied and included virgin thermoplastic, coated and uncoated recycled tires, recycled vulcanized rubber, and
recycled ground gaskets.
• Samples were analyzed for 25 metals and 9 PAHs.
• Air samples were collected on filter at two fields, using static and personal samplers, and at background locations outside the
fields.
Study results and/or conclusions:
• High contents of Zn and benzo(a)pyrene were found in the granules present in playing fields (above the Italian standards for
soils).
• Other chemicals such as PAHs, VOCs, PCBs, PCDDs and PCDFs were found in the recycled crumb rubber but were at levels
within the mentioned limits.
• Based on the 0.4 ng/m3 concentration and using a worst-case conservative approach, an excess lifetime cancer risk of lx 10-6
was calculated for an intense 30-year activity (5h/d, 5d/w, all year long).
Study Limitations:
• Only particle phase air samples were taken (TSP or PM10). So the inhalation exposure may be under-estimated for missing
information on contaminants in the gaseous phase.
• Inhalation risk assessment was based on limited data and the risk assessment should be regarded as preliminary.
• Fields may vary in age and type of rubber used which could affect the samples and chemicals found in them. Environmental
factors such as climate and weather could have an effect on study samples at the time of sampling.
13. Characterization of substances released from crumb rubber material used on artificial turf fields
X. Li, W. Berger, C. Musante, M. I. Mattina; Chemosphere; 2010.
The purpose of the study was to assess major volatilized and leached chemicals from crumb rubber material (CRM); assess the
change of alteration of the pattern of volatile compounds with time after installation for both laboratory and field-aged samples
under natural weathering conditions.
Methods:
• Vapor offgas and leachate samples from 15 crumb rubber material (CRM) samples were analyzed.
• The CRM samples were obtained from local schools and commercial suppliers.
• 10 organic chemicals (PAHs and VOCs) were measured in the vapor phase over CRM.
Study results and/or conclusions:
• During the vapor phase, CRM emitted volatile PAHs and other compounds.
• Benzothiazole (BTZ) was the most abundant volatile compound found in all the samples.
• Zinc was found to be the highest of all metals found in the samples' extraction fluid.
• There was a significant reduction in volatile compounds found in samples that were from artificial turf fields that were 2 years
old compared to newer fields.
• It was also determined that there is some variability in the out-gassing profile of CRM from different manufacturers.
Study Limitations:
• This study provides mostly qualitative, not quantitative results, which makes the results difficult to compare to other studies.
14. Toxicological Assessment of Coated Versus Uncoated Rubber Granulates Obtained from Used Tires for Use in Sports Facilities
J. Gomes, H. Mota, J. Bordado, M. Cadete, G. Sarmento, A. Ribeiro, M. Baiao, J. Fernandes, V. Pampulim, M. Custodio, I. Veloso;
Journal of the Air and Waste Management Association; 2012.
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The purpose of the study was to investigate whether coating rubber granulates decreased emissions of leachates and airborne
substances.
Methods:
• Raw rubber granulates were obtained along with two coatings, a polyvinyl chloride and a cross-linked alquidic polymer, both
which contained color additives and a flame-retarding agent.
• The coated rubber granulates were compared with the raw rubber granulates.
• Chemicals analyzed:
o PM2.5 and PM10
o PAHs (16; GC-MS)
o Heavy metals (Cd, Cr, Hg, Pb, Sn, Zn; ICP-OES)
Study results and/or conclusions:
• Rubber granulates obtained cryogenically and semicryogenically have lower inhalable particles than those obtained
mechanically
• For PAHs in raw and coated samples, one type of coating resulted in increased content of some PAHs.
• However, the leaching of PAHs from raw, R1 coated or R2 coated is negligible.
• For heavy metals, the concentrations in the leachate is very small and the coating does appear to prevent leaching of the
metals.
• Both R1 and R2 coatings showed lower ecotoxicity than the non-coated rubber granulates.
Study Limitations:
• There are only two types of coating included in the analysis.
• It is noted that one of the coatings include polyvinyl chloride which has been excluded from certain textile products due to
concerns over potential adverse health effects after human exposure.
15. Evaluating and Regulating Lead in Synthetic Turf
G. Van Ulirsch, K. Gleason, S. Gerstenberger, D. B. Moffett, G. Pulliam, T. Ahmed, and J. Fagliano; Environmental Health Perspectives;
2010
The purpose of the study was to present data showing elevated lead in fibers and turf-derived dust; identify risk assessment
uncertainties; recommend that government agencies determine appropriate methodologies for assessing lead in synthetic turf; and
recommend an interim standardized approach for sampling, interpreting results, and taking health-protective actions.
Methods:
• This is a commentary on lead in synthetic turf, using data collected from recreational fields and child care centers on lead levels
in turf fibers and surface dusts.
Study results and/or conclusions:
• Synthetic turf can deteriorate to form dust containing lead at levels that may pose a risk to children.
• Given elevated lead levels in turf and dust on recreational fields and in child care settings, it is imperative that a consistent,
nationwide approach for sampling, assessment, and action be developed.
Study Limitations:
• N/A. This is a commentary.
• Updated guidelines/standards for lead in synthetic turf blades were released after publication of the article.
Biomonitoring Study
1. Hydroxypyrene in urine of football players after playing on artificial sports field with tire crumb infill
J. G. M. Van Rooij, F. J. Jongeneelen; International Archives of Occupational and Environmental Health; 2010.
The purpose of the study was to assess the exposure of football players to PAHs from sporting on synthetic ground with rubber
crumb infill (by measuring urinary 1-hydroxypyrene).
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Methods:
• All urine samples were collected over 3 days (the days before, of, and after a 2.5-h football match) from 7 football players.
• 1-Hydroxypyrene (PAH biomarker) was measured in urine.
Study results and/or conclusions:
• The football players spent a total of 2.5 hours on the synthetic turf field.
• Three players likely had PAH exposure from pre-sporting activities and were omitted from the analysis.
• Uptake of PAH by football players playing on synthetic turf with rubber crumb infill is minimal.
• If there is any exposure, then the uptake is very limited and within the range of uptake of PAH from environmental sources
and diet.
Study Limitations:
• Only 7 football players were in the study. The sample size is too small to represent the target population.
• Short exposure duration (2.5-h) and PAHs from other sources (such as diet) could have affected the player's results.
• Dietary and lifestyle questionnaires were not administered.
Bioavailability Studies
1. Bio-accessibility and Risk of Exposure to Metals and SVOCs in Artificial Turf Field Fill Materials and Fibers
B. T. Pavilonis, C. P. Weisel, B. Buckley, P. J. Lioy; Risk Analysis; 2014
The purpose of the study was to determine whether the bio-accessible fraction of metals and SVOCs found in artificial turf fields
exceeded non-cancerous risk-based guidance values for children and adult athletes.
Methods:
• New crumb infill (n=9), new turf fiber products (n=8), and field samples (n=7) were collected.
• Using synthetic biofluid solutions, bio-accessibility analyses for metals and SVOCs were performed for the digestive system,
respiratory system, and dermal absorption.
Study results and/or conclusions:
• PAHs were generally below the limit of detection in all three artificial biofluids.
• SVOCs found were not present in toxicological databases evaluated and were in everyday consumer products.
• Trace metals found were at minimal levels.
Study Limitations:
• Possible selection bias and the small number of fields used in this study.
• The simulated digestive fluid may not reflect accurately true digestive capabilities in humans.
• A large amount of variability was found among the field samples used in this study (some samples may have been from older
fields or different versions/types of artificial turf).
2. Health Risk Assessment of Lead Ingestion Exposure by Particle Sizes in Crumb Rubber on Artificial Turf Considering Bioavailability
S. Kim, J. Yang, H. Kim, I. Yeo, D. Shin, Y. Lim; Environmental Health and Toxicology; 2012.
The purpose of the study was to assess the risk of ingestion exposure of lead by particle sizes of crumb rubber in artificial turf filling
material with consideration of bioavailability
Methods:
• Lead was measured using ICP-MS in the extracts of tire crumb particles of various size (larger or smaller than 250 um)
extracted using artificial digestive and acid extraction methods.
• Average lead exposure amounts were calculated for students.
Study results and/or conclusions:
• Lead was found in the digestion extracts of tire crumb material.
• Acid extraction method resulted in lead concentrations 6.5 times higher than content concentration.
• Digestive extraction resulted in lead concentration 10.3 times higher than content concentration.
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• Results of this study confirm that the exposure of lead via ingestion and risk level increases as the particle size of crumb rubber
gets smaller.
Study Limitations:
• It appears that only one type of crumb rubber was investigated.
• There is uncertainty as to whether or not the EDPM rubber powder prototype used in the study is representative of the entire
artificial turf.
3. Hazardous chemicals in synthetic turf materials and their bio-accessibility in digestive fluids
J. Zhang, I. Han, L. Zhang, W. Crain; Journal of Exposure Science and Environmental Epidemiology; 2008.
The purpose of the study was to obtain data that will help assess potential health risks associated with chemical exposure from
artificial turf and to determine the bio-accessibility of PAHs and toxic metals in synthetic human saliva, gastric fluid and intestinal
fluid.
Methods:
• Seven samples of rubber granules and one sample of artificial grass fiber from synthetic turf fields at different ages of the
fields.
• PAHs (15) and metals (Cr, Zn, As, Cd, Pb; ICP-MS) were measured in the granule/grass fiber samples and synthetic digestive
fluids (saliva, gastric fluid, intestinal fluid).
Study results and/or conclusions:
• Total PAHs ranged from 4.4ppm to 38.15ppm.
• PAHs in rubber granules had low bio-accessibility (i.e., hardly dissolved) in synthetic saliva, gastric fluid, and intestinal fluid.
• Rubber granules often contained PAHs at levels above health-based soil standards.
• PAH levels declined as the field ages.
• Decay trend may be complicated by adding new rubber granules to compensate for loss of the material.
• Zinc contents were found to far exceed the soil limit, range 5710-9988.
• Lead content was low in all the samples compared to soil standards.
• Lead in the rubber granules was highly bioaccessible in the synthetic gastric fluid.
Study Limitations:
• The digestive system is difficult to simulate, and the simulated digestive fluid may not accurately reflect true digestive
capability in humans.
Toxicological Studies
1. Toxicological Evaluation for the Hazard Assessment of Tire Crumb for Use in Public Playgrounds
D. A. Birkholz, K. L. Belton, T. L. Guidotti; Journal of the Air and Waste Management Association; 2012.
The purpose of the study was to design a comprehensive hazard assessmentto evaluate and address potential human health and
environmental concerns associated with the use of tire crumb in playgrounds.
Methods:
• 200g tire crumbs were leached in water to produce the test leachate.
• Genotoxicity was assessed using Salmonella typhimurium mutagenicity fluctuation assay, SOS chromotest, and Mutatox.
• Human health concerns were addressed using conventional hazard analyses.
Study results and/or conclusions:
• All samples analyzed did not meet the criteria for genotoxicity and were considered negative.
• Genotoxicity testing of tire crumb samples following solvent extraction concluded that no DNA or chromosome-damaging
chemicals were present.
• This suggests that ingestion of small amounts of tire crumb by small children will not result in an unacceptable hazard/risk for
development of cancer.
• The use of tire crumb in playgrounds results in minimal hazard to children and the receiving environment.
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Study Limitations:
• The authors of this study concentrated only on potential genotoxicity from the exposure to tire crumb material in playgrounds,
other adverse health effects that may be caused by other elements/compounds in the tire crumbs may have been overlooked.
2. Benzothiazole toxicity assessment in support of synthetic turf field human health risk assessment
G. Ginsberg, B. Toal, T. Kurland; Journal of Toxicology and Environmental Health, Part A; 2011.
The purpose of the study was to assess benzothiazole (BZT) toxicity in support of a risk assessment of synthetic turf fields conducted
by the Connecticut Department of Public Health.
Methods:
• The study reviewed the following information on BZT and its surrogate, 2-mercaptobenzothiazole (2MBZT), to derive BZT
toxicity values for cancer and non-cancer effects:
o properties and uses
o BZT exposure
o toxicokinetics of BZT and 2MBZT
o toxicity of BZT and 2MBZT with regard to acute toxicity, mutagenicity, subchronic and chronic toxicity and cancer,
developmental and reproductive effects
Study results and/or conclusions:
• The following BZT toxicity values were derived:
o Acute air target of 110 |ig/m3 based upon a BZT RD50 study in mice relative to results for formaldehyde,
o A chronic, noncancer target of 18 |ig/m3 based upon the no observed adverse effect level (NOAEL) in a subchronic
dietary study in rats, dose route extrapolation, and uncertainty factors that combine to 1000.
o A cancer unit risk of 1.8E-07/|ig-m3 based upon a published oral slope factor for 2-MBZT and dose-route
extrapolation.
Study Limitations:
• There were numerous uncertainties and limited information in the BZT toxicology database.
• BZT was not tested in sub-chronic/ chronic studies, cancer bioassay, or developmental and reproductive studies.
• Some endpoints were studied using 2-MBZT as a surrogate, which makes an imperfect comparison due to differences in
structure and metabolic pathways.
• Only a screening-level assessment for BZT exposure.
• The proposed toxicity values are for BZT in general, not specifically for BZT in synthetic turf.
3. Evaluating the Risk to Aquatic Ecosystems Posed by Leachate from Tire Shred Fill in Roads Using Toxicity Tests, Toxicity
Identification Evaluations, and Groundwater Modeling
P.J. Sheehan, J.M. Warmerdam, S. Ogle, D. Humphrey, S. Patenaude; Environmental Toxicology and Chemistry; 2006.
The purpose of the study was to evaluate the toxicity of leachates from tire shreds used as roadbed fill and to define the
circumstances under which use of the tire shreds as roadbed fill, both above and below the water table, will pose a negligible hazard
to adjacent surface-water ecosystems.
Methods:
• Shred infill obtained from two study sites, one above the water table and one at and below the water table. For this infill, tire
shreds contain a mixture of steel and glass belted scrap tires and substantial amounts of steel belts are exposed at the cut
edges.
• Site #1 constructed in 1993 with 3 sample collection areas with precipitation infiltrating the road embankment and into
collection basins for sampling. There was one "control" basin without a tire shred layer.
• Site #2 was constructed in 1994 and tire shreds come into direct contact with groundwater. Water samples were collected
from 3 wells: 1 upgradient, 1 within the trench with direct contact to tire shreds and 1 downgradient.
• Leachates analyzed for metals, VOCs, and sVOCs.
• Short-term chronic C. dubia test and short-term chronic fathead minnow test used to determine toxicity.
Study results and/or conclusions:
• Site#l:
o No adverse effects on P. promelas survival or growth
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Site #2:
Substantial reduction in C. dubia survival in phase 2 of the reference water likely due to high conductivity of the
leachate sample.
Metals, VOCs and sVOCs were detected in two samples but the concentrations were low and not indicative of
leaching substantial amounts of chemicals.
o Slight reductions in P. promelas survival in both phase 1 and 2 of the reference sample,
o No impairment in survival seen in the two samples (at and down gradient).
o Significant reductions in growth seen for both the reference sample and the other two site samples,
o For C. dubio, > 80% mortality was seen in the leachate samples (phase 1); significant reductions in reproduction also
seen but reductions in reproduction were also seen in the reference samples,
o Elevated levels of some VOCs and metals (especially iron and manganese) indicated chemicals leach from shred fill;
however, the leaching of iron is likely from the steel belts exposed on the cut edge.
Study Limitations:
• The type of infill used in road beds is quite different from the crumb rubber infill used in synthetic turf.
• The modeling estimates used numerous different scenarios to determine amount of filtration needed which is not applicable
to studies investigating human exposure to chemicals synthetic turf.
4. Impact of tire debris on in vitro and in vivo systems
M. Gualteri, M. Andrioletti, P. Mantecca, C. Vismara, M. Camatini; Particle and Fibre Toxicology; 2005.
The purpose of the study was to investigate tire debris effects on the development of X. loevis and on human cell lines.
Methods:
• Tire debris samples were obtained from laboratory processing using tire scrap materials.
• Eluates were obtained after soaking in water (pH 3); organic extracts obtained and used for the cell line test (A549) and the
tests using X. loevis embryos
• Cell viability assay and Comet assay were used to determine toxicity, doses 10, 50, 60, 75 |ig/mL
• in vivo: X. loevis embryos were exposed to 50,80,100, 120 |ig/mL organic extracts
Study results and/or conclusions:
• A time-dependent increase of Zn in the human liver cell line was seen after treatment with 50|ig/ml zinc at 2, 4, and 24 hours.
• An increase in cell death was seen at the higher doses (50, 60, 75 |ig/ml) compared to controls.
• Cell proliferation was decreased in a time and dose-dependent manner.
• DNA damage increased at 50 and 60|ig/mL as shown by the comet assay.
• Cell morphology was impacted after 72 hours treatment. The highest dose showed visible vacuolization in the cytoplasm and
apoptotic nuclear images; present in 50% of cells at 72 hours with 75|ig/ml treatment.
• Zn concentration of 44.73|ig/ml (50 g/l tire debris) resulted in 80% mortality of embryos and a concentration of 35.28|ig/ml
(100 g/L tire debris) resulted in 26.8% mortality. Malformation was similar between the two doses. Dilutions of the organic
extracts showed significant increases at 1% for 44.73 and at 10% for 35.28.
• The eluates had teratogenic effects for both doses.
• For X. loevis development, 80|ig/ml and above resulted in significant mortality with 15.9% mortality at 120|ig/mL.
• Increase in malformed larvae found at 80 and 100|ig/mL; at 120 |ig/mL, 37.8% of larvae were malformed.
• Most frequent malformation was gut roiling.
Study Limitations:
• The type of sample used in the analysis (tire debris) is not the same type of tire material as seen in crumb rubber infill.
• The analysis only looked at zinc and did not include other known contaminants of tire crumb/tire debris.
• No indication if the doses used in the laboratory analysis are similar to doses/exposure levels in the environment.
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Appendix B - Literature review of microbial work done on tire crumb rubber
artificial fields
Overall summary:
Most of the work in tire crumb rubber use in synthetic turf fields has focused on chemicals such as polycyclic aromatic hydrocarbons
(PAH), metals, volatile organic carbons (VOCs), polychlorinated biphenyls (PCBs), or ecotoxicity work using sensitive bioindicators such
as Pseudokirchneriella subcapitata and Daphnia magna. There is a very limited amount of literature on health risks from biological
material (i.e., human pathogens) in tire crumb rubber artificial fields. Of the literature that does exist, most studies have been conducted
by academia, or published in open access journals, or by state government/environmental groups, and thus have not undergone thorough
peer review and therefore may show inherent bias. Regardless, most work has focused on quantifying total bacteria using non-selective
agar, reporting colony forming units per gram (CFU/g) of infill material. Additional work has been done on the ability of opportunistic
human pathogens (methicillin-resistant staphylococcus aureus (MRS A) and Burkholderia cepacia complex) to survive in tire crumb rubber
leachate, including toxicity to these bacteria due to chemicals such as zinc. There has been no work published on enteric pathogens/risks
from artificial turf fields.
1) Keller, Marcus. "The fate of methicillin-resistant staphylococcus aureus in a synthetic field turf system." (2013).
This study looked the survivability of methicillin-resistant staphylococcus aureus (MRS A) on turf infill (rubber, sand, organic, or polymer
materials), and turf fibers (monofilament, slit-film or nylon turf blades), and the toxicity of infill materials to MRS A. MRSA was
measured as the incubation time in which 50% of the inoculated MRSA are still viable (A50). MRSA persisted longer in infill (A50 =
13hr) vs turf fibers (A50 = 4hr, p<0.05). A50 for crumb rubber was 13hr. The role of infill toxicity to the MRSA A50 was assessed using
a dialysis assay, which showed that 94% of MRSA cells remained viable following 6 h of exposure to organic infill, 91% for sands, 79%
for polymer coated materials, 71% for crumb rubber, 68% for TPE rubber, and 17% for EPDM rubber.
Conclusion: MRSA survived less in crumb rubber materials than other fill materials such as sand/organic.
2) Miller, Suzanne CM, John J. LiPuma, and Jennifer L. Parke. "Culture-based and non-growth-dependent detection of the Burkholderia
cepacia complex in soil environments." Applied and environmental microbiology 68.8 (2002): 3750-3758.
This study looked at Burkholderia cepacia complex (Bcc) - an opportunistic human pathogen, in a variety of soils and other surfaces,
including turf athletic fields from 3 US cities (Philadelphia, Cleveland, Portland, OR). Bcc was not isolated from any turf samples (n=6).
Conclusion: using PCR, Bcc appears to be prevalent in soil from urban and suburban sites.
3) A Survey of Microbial Populations in Infilled Synthetic Turf Fields. McNitt, Andrew, and Petrunak, Dianne. A Draft Report by
Faculty of the Center for Turgrass Science at Penn State University. 2006.
Took samples from a couple of fields in PA, both crumb rubber and soil, specifically looking for MRSA and non-selective cultural
bacteria on R2A agar over a 2-week period in 2006. Total number of samples not provided. Sampled areas included a "high use" and "low
use" area of each field taking approx. 2-3mL sample of the crumb rubber, and cut fibers from synthetic fields. No samples were S. aureus
positive via selective media, gram stain or latex agglutination tests. Of the 8 fields that were tested with crumb rubber only, total culturable
bacteria from R2A agar averaged 3.971ogl0 CFU per gram of crumb rubber. Soil (silty loam and sand-based soil) samples (n=2) averaged
5.41ogl0 CFU/g soil. S. aureus was positively identified from other public areas and/or athletic facilities such as blocking pads, weight
equipment, stretching tables, and used towels.
Conclusion: lower counts of microbes were found indoors as opposed to outdoors, and soil fields had over an order of magnitude more
microbes than synthetic crumb-rubber fields.
4) Safety Study of Artificial Turf Containing Crumb Rubber Infill Made From Recycled Tires: Measurements of Chemicals and
Particulates in the Air, Bacteria in the Turf, and Skin Abrasions Caused by Contact with the Surface. Report produced under contract by:
Office of Environmental Health Hazard Assessment. Pesticide and Environmental Toxicology Branch. California Department of
Resources Recycling and Recovery. 2010.
Chapter 3: Sampled 5 artificial turf (soccer) fields with crumb rubber mixed with sand and 2 natural fields in San Francisco, CA in
September or October 2009 (all outdoor). l-2g of material was sampled per event, and each field was sampled 3 times in various areas.
The three most prominent species assay was used to quantify culturable bacteria in samples (agar not provided). Artificial turf (n=30)
ranged from 0-50,000 CFU per gram crumb rubber compared to 637,000-305,000,000 CFU/g natural soil (n=12). 2/12 and 6/12 samples
were positive for Staphylococci in crumb rubber and soil, respectively. No MRSA was detected in crumb rubber or synthetic blades of
grass; one sample (n=12) was positive for MRSA from a blade from natural turf.
Conclusion: Synthetic turfs, including crumb rubber, harbor fewer bacteria than soil, which, according to authors, could be due to lower
moisture content and high temperatures of artificial turf compared to natural turf.
Chapter 4: using a survey of 33 trainers from collegiate athletic programs in CA and NV, it was reported that athletes experienced -2-3
times higher turf burn ratios compared to natural soil, but the severity of turf burns between soil and synthetic turfs remained similar.
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5) Crampton, Mollee, et al. "Effects of leachate from crumb rubber and zinc in green roofs on the survival, growth, and resistance
characteristics of Salmonella enterica subsp. enterica serovar typhimurium." Applied and environmental microbiology 80.9 (2014): 2804-
2810.
This study investigated the impact of rainwater leachate from crumb rubber in green roofs on the growth of Salmonella enterica subsp.
enterica serovar Typhimurium ATCC 14208S. S. Typhimurium was incubated for up to 48hr in crumb rubber leachate from synthetic
rainwater (pH=4.3). When compared to a control of just synthetic rainwater incubation over the same time period, S. Typhimurium
survived less in crumb rubber leachate than the control, leading the authors to suggest that crumb rubber contains compounds that are
inhibitory to bacterial growth. Dilutions of the crumb rubber leachate showed increased survivability of the bacteria, supporting the idea
that crumb rubber contains compounds that are toxic to S. Typhimurium. The same crumb rubber extract was washed 10 separate times
with lOmL of synthetic rainwater. The leachate exhibited the same effects on microbial growth, with the authors concluding that the toxic
effects that crumb rubber are not expected to decrease with time and additional rainfall/washing events.
Conclusion: crumb rubber leachate contains compounds that inhibit microbial growth and survivability.
6) Bass, Jason J., and David W. Hintze. "Determination of Microbial Populations in a Synthetic Turf System." Skyline-The Big Sky
Undergraduate Journal 1.1 (2013): 1. - Open access journal
This study took samples from 2 infilled crumb rubber fields, one 1-year old field and one 6-year old field over a 14-week period in late
fall/early winter in Ogden, Utah. Indoors/outdoors field information was not provided. Tryptic Soy Agar was used to determine total
microbial load, Mannitol Salt Agar for Staphylococcus, and Eosin Methylene Blue Agar to count the number of enteric organisms such as
Escherichia coli. Bacterial counts in the older field were up to 10,000 times higher than the newer field. Bacterial counts were highest on
the sideline of the older field with average of 1.1x108 CFU/g soil infill compared to 2.5x105 CFU/g on the sideline of the newer field. A
higher number of salt-tolerant organisms were able to grow on MSA, indicating possible staphylococci, with an average of 2.77x102
CFUs per gram on the new field and 6.58x103 CFUs per gram on the older field.
Conclusion: bacterial populations are much higher in older fields and newer fields, and the sideline near the 50-yd line contained the
highest bacterial populations. This data suggests that microbial populations can accumulate from year to year in synthetic turf.
Below is less related to micro-related work, but focused on ecotoxicity of turf field leachates
7) Kruger, O., et al. "New approach to the ecotoxicological risk assessment of artificial outdoor sporting grounds." Environmental
Pollution 175 (2013): 69-74.
Kruger et al., 2013 investigated growth inhibition (Pseudokirchneriella subcapitata) and acute toxicity tests (Daphnia magna) with
leachates obtained from batch tests of granular infill material and column tests of complete sporting ground assemblies. Ethylene
propylene diene monomer rubber (EPDM) leachate showed the highest effect on Daphnia magna (EC50 < 0.4% leachate) and the leachate
of scrap tires made of styrene butadiene rubber (SBR) had the highest effect on P. subcapitata (EC10 V* 4.2% leachate; EC50 V* 15.6%
leachate). No correlations between ecotoxicity of leachates and zinc or polycyclic aromatic hydrocarbons (PAH) was found.
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Appendix C - EPA-NCEA Summary of Available Exposure and Health Risk
Assessment Studies on Artificial Turf, Playgrounds and Tire Crumbs
Summary of Available Exposure and Health Risk Assessment Studies on
Artificial Turf, Playgrounds and Tire Crumbs
Bulleted Summary
Artificial turf is made of plastic blades that simulate grass and a layer of "infill" material made of recycled tire crumb or
crumb rubber.
There are benefits to using these materials, but concerns have been raised by the public and others regarding health
issues associated with their use.
EPA formed a workgroup in 2008; performed a scoping study, and published a report in 2009.
There are several studies found in the literature conducted by federal and state governments, academia, and industry.
The studies varied in scope ranging from studies focused on environmental concentrations found in air; concentrations of
the chemicals found in the bulk material; and health risk assessments. Some studies focused the inhalation pathway,
while others considered other pathways including ingestion and dermal exposures. Chemicals studied included VOCs,
sVOCs, PMio, and metals. Other studies examine the potential for environmental impacts, including leaching of metal
into waterways.
Federal and state government studies include:
Norwegian Institute of Public Health (2006) "Artificial turf pitches - an assessment of the health risks for football
players"
OEHHA 2007 "Evaluation of Health Effects of Recycled Waste Tires in Playground and Track Products"
CPSC 2008 "CPSC Staff Analysis and Assessment of Synthetic Turf Grass Blades"
New Jersey Department of Health and Senior Services (April 2008) "New Jersey Investigation of Artificial Turf and
Human Health Concerns; Fact Sheef'
New York Department of Health (2008) "A Review of the Potential Health and Safety Risks From Synthetic Turf Fields
Containing Crumb Rubber Infill"
New York City Department of Health and Mental Hygiene (March 2009) "Air Quality Survey of Synthetic Turf Fields
New York State Department of Environmental Conservation (May 2009) "An Assessment of Chemical Leaching.
Releases to Air, and Temperature at Crumb-Rubber Infilled Synthetic Turf Fields
EPA (2009) "A Scoping-Level Field Monitoring Study of Synthetic Turf Fields and Playgrounds"
Connecticut Department of Health (2010) "Human. Health Risk Assessment of Artificial Turf Fields Based Upon ]
from Five Fields in Connecticut"
New Jersey Department of Environmental Protection (July 2011) "An Evaluation of Potential Exposures to Lead and
Other Metals as the Result of Aerosolized Particulate Matter from Artificial Turf Playing Fields"
These studies concluded that there is no or limited health risk associated with the use of these materials. However, the
studies were limited in scope and not all of them carried out a complete exposure/risk assessment. There are
uncertainties associated with the assumptions used to derive these conclusions.
Some potential future activities can be undertaken including: reviewing additional reports and scientific literature;
examining the available data more closely; reviewing exposure assumptions; determine if an exposure/risk assessment
can be conducted with the available data; studying other factors that may influence exposure; identify key data gaps;
and assess the potential for microbiological exposures.
Background
Artificial turf is made of plastic blades that simulate grass and a layer of "infill" material to keep the blades upright. This
"infill" is made of recycled "tire crumb" or "crumb rubber" material. This artificial or synthetic turf is often used to cover
the surfaces of athletic field. Tire crumbs and crumb rubber are also used as groundcover under playground equipment,
running track material, and as a soil additive on sports and playing fields. Although use of these materials has been
recognized as beneficial (e.g., recyling, reduction of sports injuries), concerns have been raised by the public and others
regarding health issues associated with these materials.
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In 2005, EPA Region 8 Pediatric Environmental Health Specialty Unit (PEHSU) received telephone inquiries from parents
concerned about health risks to children exposed to a recycled tire crumb product used in fields and school playgrounds.
EPA Region 8 requested that the Agency consider this issue and a workgroup was formed and charged to consider the state
of science and make recommendations for future research. A second science workgroup was formed to consider available
methods to study the situation, and they recommended conducting a scoping study to assess approaches and methods, and to
provide limited measurement data for consideration. The workgroup produced a report entitled "Scoping-level Field
Monitoring Study of Synthetic Turf Fields and Playgrounds" published in 2009.
Over the years, there have been several published articles on the health concerns resulting from exposures to the materials
used in artificial turf. In October of 2014, a soccer coach reportedly suggested an association between cancer cases found in
soccer players and exposures to artificial turf. A list of 38 American soccer players (34 of them goalies) had been diagnosed
with cancer (http://www.nbcnews.com/news/investigations/how-safe-artificial-turf'-your-child-plays-n220166). In response
to the news report, a representative from FieldTurf, an artificial field turf company, requested a meeting with EPA to present
their views with regard to the safety of turf fields. A conference call was hosted by Michael Firestone of OCHP. FieldTurf
stated that scientific research from academia, federal and state governments has failed to find any link between synthetic turf
and cancer. More recently, in March 16, 2015, another news article in claimed that the federal government is promoting
artificial turf despite health concerns (http://www.usatoday.com/story/iiews/2015/03/15/ai-tificial-turf-liealth-safety-
studies/247271.1.1/1
Several studies have been conducted on artificial turf and the use of tire crumb materials. Some focused primarily on
obtaining concentration data for various compounds that may off-gas from recycled tire materials, while others attempted to
estimate health risks associated with their use. There are also several studies that focus on characterizing the compounds
contained in bulk samples of artificial turf. Summarized below are the studies conducted by EPA, CPSC, and the states of
New York, Connecticut, and California. Included also is a study conducted in Norway. It is important to note that this list is
not comprehensive and focuses primarily on studies conducted by federal and state governments.
Norwegian Institute of Public Health fNIPHl and the Radium Hospital 2006
NIPH conducted a health risk assessment of football players that played in artificial turf fields. They examined 9 scenarios
including: inhalation, dermal, and ingestion exposures (only for children) for adults, juniors, older children and children.
The assessment included various constituents in the tire crumb: VOCs, PAHs, phthalates, PCBs, PMio, and alkyl phenols.
The study was limited because of the absence of toxicity data. The study concluded that the use of artificial turf does not
cause any elevated health risk. The estimated Margins of Safety (MOS) were no cause for concern.
OEHHA California study 2007
Office of Environmental Health Hazard Assessment (OEHHA) conducted a risk assessment of the recycled waste tires in
playgrounds and track products in 2007. Their study included VOCs, sVOCs and metals. The pathways included in the risk
assessment were the ingestion of the tire crumbs via hand to mouth or surface to mouth and dermal contact. They concluded
that risk levels were below the di minimis level of 1 x 10~6.
The U.S. Consumer Product Safety Commission investigated the potential hazards from lead in some artificial turf sports
fields across the country. The study focused on ingestion of lead from the material that transfers to the mouth from the skin
after contact with the lead containing turf. The study concluded that exposure to children playing on the field would not
exceed 15 jig of lead/day.
http://www.cpsc.gOv//PageFiles/104716/turfassessment.pdf
New Jersey Department of Health and Senior Services 2008
NJDHSS collected samples of artificial turf fibers from 12 fields. Ten fields with polyethylene fibers had very low Pb levels.
Two fields with nylon fibers had 3,400 to 4,100 mg/kg of Pb. In addition, they collected artificial turf samples from
consumer products that are used for residential lawns and play surfaces. Two of the products that were nylon or
nylon/poly ethylene contained Pb at 4,700 and 3,500 mg/Kg. These concentrations higher than the Residential Direct
Contact Soil Cleanup Criteria (which is 400 mg/kg). "There is a need for a comprehensive and coordinated approach to
evaluating the public health risks and benefits of artificial turf fields." http://www.nj.gov/dep/dsr/publications/artificial-turf-
report.pdf
New York Department of Health Study 2008
In 2008, the NY Department of Health conducted a study where they reviewed data from 11 different risk assessments found
in the literature on exposures to artificial turf and concluded that the levels found of the contaminants of concern did not
result in an increased risk for human health effects as a result of ingestion, dermal or inhalation exposure to crumb rubber.
They stated, however, that additional air studies at synthetic turf fields as well as background air measurements would
.ca. gov/publications/Documents/Tires%5C6220601.3 .pdf
CPSC 2008
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provide more representative data for characterizing potential exposures related to synthetic field use in NYC, particularly
among children.
http://www.nvc.gov/html/doh/dowaloads/pdf/eode/turf report 05-08.pdf
New York C'itv Department of Health and Mental Hygiene March 2009
NYCDHMH conducted field sampling for VOCs, SVOCs, metals, particulate matter (PM2.5) in two synthetic fields, one
grass field. They used stationary samplers on field during simulate playing conditions. The sampling was conducted during
the summer under simulated playing conditions. Eight of the 69 VOC were detected, but concentrations were similar
between upwind background and turf fields. None of the SVOCs were detected, including benzothiozole a "chemical
marker" for synthetic rubber. Two of 10 metals were detected, but similar concentrations were found in upwind and grass
field. PM was within background levels upwind and at grass field. The report concluded that air in the breathing zones of
children above synthetic turf fields did not show appreciable levels from contaminants of potential concern contained in the
crumb rubber and that a risk assessment from exposure through the inhalation route was not warranted.
http://www.nYC.Bov/html/doh/dowiiloads/pdf7ecxle/turf aqs report0409.pdf
New York State Department of Environmental Conservation May 2009
In 2008, NYDEC conducted a laboratory evaluation of four types of tire-derived crumb rubber to assess the release of
chemicals using the simulated precipitation leaching procedure. Results indicated that zinc, aniline, phenol, and
benzothiazole can potentially be release to ground water. Zinc, aniline, phenol were all below standards; there are no
standards for benzothiazole. Lead concentration in the crumb rubber was below federal hazard standard for soil. Risk
assessment for aquatic life indicated that zinc may be a problem for aquatic life. Air samples were collected above fields at
two locations. Many of the analytes detected (e.g., benzene, 1,2,4-trimethylbenzene, ethyl benzene, carbon tetrachloride)
are commonly found in an urban environment. A number of analytes found were detected at low concentrations (e.g., 4-
methyl-2-pentanone, benzothiazole, alkane chains. Public health evaluation at the two fields tested concluded measured air
levels do not raise a concern for non-cancer or cancer human health Indicators. PM concentrations were not different from
concentrations upwind from the fields, http://www.dec.nv.gov/docs/materials minerals pdf/crumbrubfr.pdf
EPA 2009
The overall objectives of EPA's study were to evaluate the methodology and protocols for monitoring and analyzing data
needed to characterize the contribution of tire crumb constituents to environmental concentrations and to collect limited
environmental data from playgrounds and synthetic turf fields. EPA analyzed air samples for 56 volatile organic compounds
(VOCs), air particulate matter (PMio) for selected metals and the relative contribution of tire crumb particles to the overall
particle mass, wet surface wipe samples for metals including Pb, Cr, Zn, and others, and turf field tire crumb infill granules,
turf blades, and playground tire crumb materials for metals. The study protocol was implemented at two synthetic turf fields
and one playground. Conclusions: "On average, concentrations of components monitored in the study were below levels of
concern." Concentrations for many of the analytes were close to background levels. Due to the limitations of the study, the
authors concluded that "it is not possible to reach any more comprehensive conclusions without the consideration of
additional data." The study did not evaluate semivolatile organic compounds such as PAHs because of resource limitations.
No exposure or risk assessment was conducted by EPA. Potential exposure pathways include: ingestion of loose tire crumbs
via hand to mouth or surface to mouth; dermal contact; and inhalation exposures of VOCs and PMio.
Connecticut Department of Public Health study 2010
Connecticut Department of Public Health conducted a human health risk assessment of artificial turf in 2010. They collected
data from one indoor and four outdoor artificial turf fields. The study focused on two pathways, inhalation of offgassed and
particle-bound chemicals. The study included 27 chemicals (VOCs, sVOCs, leand and PMio). Using conservative
assumptions, Connecticut Department of Public Health Program found that cancer risks are slightly above de minimis in all
scenarios, and two fold higher at the indoor field compared to outdoors and being higher for children than adults. The non-
cancer risk estimate is below unity for all analytes in all scenarios.
http://www.ct.gov/deep/hb/deep/artificialturf/dph_artificial turf_report.pdf
New Jersey Department of Environmental Protection 2011
In 2009, NJDEP tested 5 artificial turf fields. They tested for PM and metals including Pb using wipe samples as well as
stationary sampling and mobile robot sampling. In addition, a 12 year old boy was recruited to simultaneously collect a
personal breathing zone sample. The age of the fields ranged between 1 and 8 years. The testing was done during the
summer time. No levels exceeded guidance or NAAQS values; robot air Pb value on one field was 71 ng/m3 (approx 50% of
NAAQS), remainder below 10 ng/m3
Potential Future Activities
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• Review additional reports and scientific literature that may provide information on the chemical constituents in artificial
turf, and their bioavailability and toxicity, exposure pathways and factors, and potential human health risks.
• Examine more closely all the available data, especially for indoor fields where inhalation exposures may be higher.
• Determine if sufficient data exist to conduct an exposure/risk assessment with the available data. Given the uncertainties
with some of the exposure factors assumptions (e.g., amount of material ingested, exposure frequency), several "what if'
scenarios can be developed to determine for example the amount of material that would need to be ingested to exceed some
health level. If an assessment cannot be done, identify key data gaps.
• Examine the exposure factor assumptions used by the studies in the literature to evaluate their "reasonableness."
• Study other factors that may influence exposure levels; for example; the age of the fields, uncertainties about the amount of
material that can be inadvertently ingested, potential for dermal exposures, and exposure frequency and duration.
• Examine the literature for microbiological exposures and risks from exposures to the materials in these fields and
playgrounds.
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Other Potentially Useful Sources (not yet reviewed: not based on a comprehensive search)
Reports
CDEP (2010) (Connecticut Department of Environmental Protection). Artificial Turf Study: leachate and stormwater characteristics.
http://www.ct.gov/deep/ljb/deep/artjftcjalturtydep artificial turf report.pdf
EHHI (2007) (Environment and Human Health, Inc.). Artificial Turf: exposures to ground-up rubber tires.
http://www.ehhj .org/reports/turt'/turf report07.pdf
FDEP (1999) (Florida Department of Environmental Protection) Study of the suitability of ground rubber tire as a parking lot surface.
http://www.dep.state.il.us/waste/qujck topics/publications/shw/tires/F€-€-istudy.pdf
NYDEC (2008) (New York Department of Environmental Conservation) A study to assess potential environmental impacts from the use of
crumb runner as infill material in synthetic turf fields. http://vAvw.dec.nv.gov/docs/materials minerals pdf/tirestudy.pdf
News, Websites, and Fact Sheets
CDEP (2010) (Connecticut Department of Environmental Protection). Recent news concerning artificial turf fields.
http://wwwiieldturfxom/sites/fieldturf/assets/Circular%20Ltr%202015-
02%2QConnecticut%2QReaffirms%2QSafety%2Qof%2QArtificial%2QTurf.pdf
CPSC. CPSC Staffl Analysis and Assessment of Synthetic Turf "Grass Blades"
http://www.cpsc.gOv//PageFjles/104716/turtassessment.pdf
CPSC (2008) Press release: CPSC Staff Finds Synthetic Turf Fields OK to Install, OK to Play On.
European Tyre and Rubber Association (2008) Rubber infilled artificial turf environmental and health risk assessment.
http://tools.etrma.org/public/Pdt%20lTQm%20Julv/PR/20080305 ETRMA - Synthesis on synthetic turf studies - final.pdf
PEER.org. (2013) EPA retracts synthetic turf safety assurances, http://www.peer.org/news/news~release/2013/12/23/epa~retracts~synthetie~
turf-safety-assurances
Soccer America (2015) Are tire crumbs on fields a cancer threat? http://www.socceramerica.com/artjcle/62922/are~tjre-cmmbs~on~ftelds~a~
cancer~threat.html
USA Today (2014) Ground up tires give new meaning to synthetic turf. January 9, 2014.
http://www.usatoday.com/stoiy/sports/ntl/2014/0 l/09/ground-up-tires-svnthetic-turt'~mettifestadiuni 4395673/
USA Today (2015) Fed promote artificial turf as safe despite health concerns. March 17, 2015.
http://www.usatodav.com/stoiy/news/2015/03/15/artiftcial-turt-health-satety-studies/24727111/
US Army. Guidance on Lead in Artificial Turf Including Child Care Centers.
http://phc.amedd.armv.mil/PHC%20R.esource%20Library/LeadArtificialTurfw-child%20care%20centers%20Mar%20 10.pdf
US EPA. Health and Environmental Concerns: Common wastes and materials: Playgrounds and synthetic turf fields.
http://www.epa.goy/solidwaste/conserve/materiats/tires/health.htm
Scientific papers
Birkholz, DA; Belton, KL; Guidotti, TL (2003) Toxicological evaluation for the hazard assessment of tire crumb for use in public
playgrounds. J Air & Waste Manage Assoc 53:903-907. http://www.tandtbnline.com/doi/pdf/lQ-l080/10473289-2003-10466221
Bocca, B; Forte, G; Petrucci, F; Costantini, S; Izzo, P (2009) Metals contained and leached from rubber granulates used in
synthetic turf areas. Sci Total Environ 407:2183-2189. http://ac.eis~edn.eom/SQ048969708Q12904/l~s2.Q~SQQ48969708Q12904~
main.pdf? tid=70225ce6-cf0b-lle4-91f5-00000aab0f01&acdnat=1426861056 50bfc390clda7ac3d8644667757ce9d2
Cheng, H; Hu, Y; Reinhard, M (2014) Environmental and health impacts of artificial turf: a review. Environ Sci Technol 48(4): 2114-2129.
http://pubs.acs.org/doj/pdf/10.lQ2 l/es4044193
Claudio, L (2008) Synthetic turf: health debate takes root. Environ Health Persp 116(3): A116-A122.
http://www.ncbi.nlm.nih. gov/pmc/articles/PMC2265Q67/pdf/ehp0116-aQQ 116.pdf
Ginsberg, G; Toal, B; Simcox, N; Bracker, A; Golembiewski, B; Kurland, T; Hedman, C (201 la) Human Health Risk Assessment of
Synthetic Turf Fields Based Upon Investigation of Five
Fields in Connecticut, Journal of Toxicology and Environmental Health, Part A: Current Issues, 74:17, 1150-1174,
DQI:10.1080/15287394.2011.586942; http://dx.doi.org/10.108Q/15287394.2011.586942
Ginsberg, G; Toal, B; Kurland, T (2011b) Benzothiazole Toxicity Assessment in Support of
in
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Synthetic Turf Field Human Health Risk Assessment, Journal of Toxicology and Environmental Health, Part A: Current Issues, 74:17,
1175-1183, DOI: 10.1080/15287394.2011.586943; http://dx.doi.org/10.1080/15287394.2011.586943
Kim, S; Yang, J; Kim, H; Yeo, Y; Shin, D; Lim, Y (2005) Health Risk Assessment of Lead Ingestion Exposure by Particle Sizes in Crumb
Rubber on Artificial Turf Considering Bioavailability. Environmental Health and Toxicology, Volume: 27, Article ID: e2012005: 10 pages
http://dx.doj.org/10.562Q/eht.2012.27.e2012005 elSSN 2233-6567 http://www.ncbj.nlm.nih.gov/pmc/articles/PMC3278598/pdl7eht-27-
e2012005.pdf
Li, X; Berger, W; Musante, C; Incorvia Mattina, MJ (2010) Characterization of substances released from crumb rubber material used on
artificial turf fields. Chemosphere 80: 279-285.
Menichini, E; Abate, V; Attias, L; De Luca, S; di Domenico, A; Fochi, I; Forte, G; Iacovella, N; Iamiceli, L; Izzo, P; Merli, F; Bocca, B
(2011) Artificial-turf playing fields: Contents of metals, PAHs, PCBs, PCDDs and PCDFs, inhalation exposure to PAHs and related
preliminary risk assessment. Sci Total Environ 409(23):4950-4957. httpi//ac.els-cdn.com/S004896971100760 l/l-s2.0-
S0048969711007601-main.pdf? tid=lb9c79f6-cf09-lle4-a4eb-00000aab0f6c&acdnat=1426860055 3acl79a31ccd83f2Q8bl39Qedfd80cl5
Pavilonis, BT; Weisel, CP; Buckley, B; Lioy, PJ (2014) Bio-accessibility and Risk of Exposure to Metals and SVOCs in Artificial Turf
Field Fill Materials and Fibers. Risk Analysis.
http://www.ncbi .nlm.nih.gov/pmc/artjcles/PMC4038666/pdi7njhms565643.pdf
Schiliro, T; Traversi, D; Degan, R; Pignata, C; Alessandria, L; Scozia, D; Bono, R.; Gilli, G(2012) Artificial turf football fields:
environmental and mutagenicity assessment. Arch Environ Contam Toxicol. 64(1): 1-11. doi: 10.1007/s00244-012-9792-l. Epub 2012 Sep
25 http://www.ncbj.nlm.njh.gov/pubmed/23007896
Simcox, NJ; Bracker, A; Ginsberg, G; Toal, B; Golembiewski, B; Kurland, T; Hedman, C (2011) Synthetic Turf Field Investigation in
Connecticut, Journal of Toxicology and Environmental Health, Part A: 74:17, 1133-1149, DOI: 10.1080/15287394.2011.586941;
http://dx.doj.org/10.1080/15287394.2011.586941
Zhang, J; Han, I; Zhang, L; Crain, W (2008) Hazardous chemicals in synthetic turf materials and their bioaccessibility in digestive fluids. J
Exposure Sci Environ Epidemiol 18:600-607. http://www.nature.com/jes/journal/vl8/n6/pdi7jes200855a.pdf
Websites
http://www.nycgovparks.org/news/reports/synthetic-turf-tests
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Appendix D - EPA Library Literature Search Results
EPA-RTP
LIBRARY Literature Search Results
February 2016
Summary
Subject: Health effects associated with exposure to tire crumbs or artificial turf fields
Databases searched: ProQuest Environmental Science Collection, Web of Science,
ScienceDirect, Google Scholar
Number of citations: 55
Search terms:
"crumb rubber" OR "tire crumb"
AND
(field or infill or turf)
AND
(exposure or risk or toxic*)
Anderson, M. E., et al. (2006). "A Case Study of Tire Crumb Use on Playgrounds: Risk Analysis and Communication
When Major Clinical Knowledge Gaps Exist." Environmental Health Perspectives 114(1): 1-3.
Physicians and public health professionals working with the U.S. Environmental Protection Agency's Region 8
Pediatric Environmental Health Specialty Unit (PEHSU) received several telephone calls requesting information
regarding the safety of recycled tire crumb as a playground surface constituent placed below children's play
structures. There were no reported symptoms or adverse health effects in exposed children. The literature
available on the safety and risk of exposure to crumb rubber constituents was limited and revealed no
information quantifying exposures associated with product use. Callers were informed by the PEHSU that no
evidence existed suggesting harm from intended use of the product, but gaps in knowledge about the product
were identified and communicated. Here the case of crumb rubber on playgrounds is used as a model to present
an approach to similar environmental medicine questions. From defining the question, to surveying traditional
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and nontraditional resources for information, synthesis of findings, and risk communication, the case provides a
model to approach similar questions. Already on our list.
Aoki, T. (2011). "Current State and Perspective for Artificial Turf as Sport Environment: Focusing on Third-
generation Artificial Turf as Football Playing Surface." - This paper was added to our list.
Beausoleil, M., et al. (2009). "Chemicals in outdoor artificial turf: a health risk for users." Public Health Branch.
Montreal Health and Social Services AaencvJaccessed 2015 April 221. http://www. ncceh.
ca/sites/default/files/Outdoor Artificial Turf, pdf. Already on our list.
Birkholz, D. A, et al. (2003). "Toxicological evaluation for the hazard assessment of tire crumb for use in public
playgrounds." Journal of the Air & Waste Management Association 53(7): 903-907.
Disposal of used tires has been a major problem in solid waste management. New uses will have to be found to
consume recycled tire products. One such proposed use is as ground cover in playgrounds. However, concern
has been expressed regarding exposure of children to hazardous chemicals and the environmental impact of
such chemicals. We designed a comprehensive hazard assessment to evaluate and address potential human
health and environmental concerns associated with the use of tire crumb in playgrounds. Human health concerns
were addressed using conventional hazard analyses, mutagenicity assays, and aquatic toxicity tests of extracted
tire crumb. Hazard to children appears to be minimal. Toxicity to all aquatic organisms (bacteria, invertebrates,
fish, and green algae) was observed; however, this activity disappeared with aging of the tire crumb for three
months in place in the playground. We conclude that the use of tire crumb in playgrounds results in minimal
hazard to children and the receiving environment. Already on our list.
Bocca, B., et al. (2009). "Metals contained and leached from rubber granulates used in synthetic turf areas."
Science of the Total Environment 407(7): 2183-2190.
The aim of this study was to quantify metals contained in and leached from different types of rubber granulates
used in synthetic turf areas. To investigate the total content of metals, ca 0.5 g of material was added with HN03,
HF and HCI04 and microwave digested with power increasing from 250 W to 600 W. Leachates were prepared by
extraction of about 5.0 g of material at room temperature for 24 h in an acidic environment (pH 5). Leaching with
deionized water was also performed for comparison. Aluminium, As, Ba, Be, Cd, Co, Cr, Cu, Hg, Fe, Li, Mg, Mn,
Mo, Ni, Pb, Rb, Sb, Se, Sn, Sr, Tl, V, W and Zn were quantified by high-resolution inductively coupled plasma mass
spectrometry (HR-ICP-MS) and ICP optical emission spectrometry (ICP-OES). Results indicated that the developed
method was accurate and precise for the multi-element characterization of rubber granulates and leachates. The
total amount and the amount leached during the acidic test varied from metal to metal and from granulate to
granulate. The highest median values were found for Zn (10,229 mg/kg), Al (755 mg/kg), Mg (456 mg/kg), Fe
(305 mg/kg), followed by Pb, Ba, Co, Cu and Sr. The other elements were present at few units of mg/kg. The
highest leaching was observed for Zn (2300 (j.g/1) and Mg (2500 (j.g/1), followed by Fe, Sr, Al, Mn and Ba. Little As,
Cd, Co, Cr, Cu, Li, Mo, Ni, Pb, Rb, Sb and V leached, and Be, Hg, Se, Sn, Tl and W were below quantification limits.
Data obtained were compared with the maximum tolerable amounts reported for similar materials, and only the
concentration of Zn (total and leached) exceeded the expected values. Already on our list.
Brown, D. "Artificial Turf: Exposures to Ground-up Rubber Tires." - This is the same as EHHI2007 which is
already on our list.
Cheng, H., et al. (2014). "Environmental and Health Impacts of Artificial Turf: A Review." Environmental Science &
Technology 48(4): 2114-2129.
With significant water savings and low maintenance requirements, artificial turf is increasingly promoted as a
replacement for natural grass on athletic fields and lawns. However, there remains the question of whether it is
an environmentally friendly alternative to natural grass. The major concerns stem from the infill material that is
typically derived from scrap tires. Tire rubber crumb contains a range of organic contaminants and heavy metals
that can volatilize into the air and/or leach into the percolating rainwater, thereby posing a potential risk to the
environment and human health. A limited number of studies have shown that the concentrations of volatile and
semivolatile organic compounds in the air above artificial turf fields were typically not higher than the local
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background, while the concentrations of heavy metals and organic contaminants in the field drainages were
generally below the respective regulatory limits. Health suggested that users of artificial turf fields, even
professional athletes, were not exposed to elevated risks. Preliminary life cycle assessment suggested that the
environmental impacts of artificial turf fields were lower than equivalent grass fields. Areas that need further
research to better understand and mitigate the potential negative environmental impacts of artificial turf are
identified. Already on our list.
Claudio, L. (2008). "Synthetic Turf Health Debate Takes Root." Environmental Health Perspectives 116(3): A116-
122. Already on our list.
Dorsey, M. J., et al. (2015). "Mutagenic Potential of Artificial Athletic Field Crumb Rubber at Increased
Temperatures." The Ohio Journal of Science 115(2). This paper was added to our list.
Drakos, M. C., et al. (2013). "Synthetic playing surfaces and athlete health." Journal of the American Academy of
Orthopaedic Surgeons 21(5): 293-302. - This paper was added to our list, but it is not suitable. It addresses
injuries to athletes.
Ginsberg, G„ et al. (2011). "BENZOTHIAZOLE TOXICITY ASSESSMENT IN SUPPORT OF SYNTHETIC TURF FIELD
HUMAN HEALTH RISK ASSESSMENT." Journal of Toxicology and Environmental Health-Part a-Current Issues
74(17): 1175-1183.
Synthetic turf fields cushioned with crumb rubber may be a source of chemical exposure to those playing on the
fields. Benzothiazole (BZT) may volatilize from crumb rubber and result in inhalation exposure. Benzothiazole has
been the primary rubber-related chemical found in synthetic turf studies. However, risks associated with BZT have
not been thoroughly assessed, primarily because of gaps in the database. This assessment provides toxicity
information for a human health risk assessment involving BZT detected at five fields in Connecticut. BZT exerts
acute toxicity and is a respiratory irritant and dermal sensitizer. In a genetic toxicity assay BZT was positive in
Salmonella in the presence of metabolic activation. BZT metabolism involves ring-opening and formation of
aromatic hydroxylamines, metabolites with mutagenic and carcinogenic potential. A structural analogue 2-
mercaptobenzothiazole (2-MBZT) was more widely tested and so is used as a surrogate for some endpoints. 2-
MBZT is a rodent carcinogen with rubber industry data supporting an association with human bladder cancer.
The following BZT toxicity values were derived: (1) acute air target of 110 mu g/m(3) based upon a BZT RD(50)
study in mice relative to results for formaldehyde; (2) a chronic noncancer target of 18 mu g/m(3) based upon the
no-observed-adverse-effect level (NOAEL) in a subchronic dietary study in rats, dose route extrapolation, and
uncertainty factors that combine to 1000; (3) a cancer unit risk of 1.8E-07/mu g-m(3) based upon a published oral
slope factor for 2-MBZT and dose-route extrapolation. While there are numerous uncertainties in the BZT
toxicology database, this assessment enables BZT to be quantitatively assessed in risk assessments involving
synthetic turf fields. However, this is only a screening-level assessment, and research that better defines BZT
potency is needed. Already on our list.
Ginsberg, G„ et al. (2011). "HUMAN HEALTH RISK ASSESSMENT OF SYNTHETIC TURF FIELDS BASED UPON
INVESTIGATION OF FIVE FIELDS IN CONNECTICUT." Journal of Toxicology and Environmental Health-Part a-
Current Issues 74(17): 1150-1174.
Questions have been raised regarding possible exposures when playing sports on synthetic turf fields cushioned
with crumb rubber. Rubber is a complex mixture with some components possessing toxic and carcinogenic
properties. Exposure is possible via inhalation, given that chemicals emitted from rubber might end up in the
breathing zone of players and these players have high ventilation rates. Previous studies provide useful data but
are limited with respect to the variety of fields and scenarios evaluated. The State of Connecticut investigated
emissions associated with four outdoor and one indoor synthetic turf field under summer conditions. On-field
and background locations were sampled using a variety of stationary and personal samplers. More than 20
chemicals of potential concern (COPC) were found to be above background and possibly field-related on both
indoor and outdoor fields. These COPC were entered into separate risk assessments (1) for outdoor and indoor
fields and (2) for children and adults. Exposure concentrations were prorated for time spent away from the fields
and inhalation rates were adjusted for play activity and for children's greater ventilation than adults. Cancer and
noncancer risk levels were at or below de minimis levels of concern. The scenario with the highest exposure was
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children playing on the indoor field. The acute hazard index (HI) for this scenario approached unity, suggesting a
potential concern, although there was great uncertainty with this estimate. The main contributor was
benzothiazole, a rubber-related semivolatile organic chemical (SVOC) that was 14-fold higher indoors than
outdoors. Based upon these findings, outdoor and indoor synthetic turf fields are not associated with elevated
adverse health risks. However, it would be prudent for building operators to provide adequate ventilation to
prevent a buildup of rubber-related volatile organic chemicals (VOC) and SVOC at indoor fields. The current
results are generally consistent with the findings from studies conducted by New York City, New York State, the
U. S. Environmental Protection Agency (EPA), and Norway, which tested different kinds of fields and under a
variety of weather conditions. Already on our list.
Gomes, J., et al. (2010). "Toxicological Assessment of Coated versus Uncoated Rubber Granulates Obtained from
Used Tires for Use in Sport Facilities." Journal of the Air & Waste Management Association 60(6): 741-746.
Reuse of tire crumb in sport facilities is currently a very cost-effective waste management measure. Considering
that incorporation of the waste materials in artificial turf would be facilitated if the rubber materials were already
colored green, coatings were specifically developed for this purpose. This paper presents an experimental
toxicological and environmental assessment aimed at comparing the obtained emissions to the environment in
terms of polycyclic aromatic hydrocarbons (PAHs), heavy metals, and ecotoxicity for coated and noncoated
rubber granulates. This study is a comprehensive evaluation of the major potential critical factors related with the
release of all of these classes of pollutants because previous studies were not systematically performed. It was
concluded that between the two types of coatings tested, one is particularly effective in reducing emissions to
the environment, simultaneously meeting the requirements of adherence and color stability. Already on our
list
Groenevelt, P. H. and P. E. Grunthal (1998). "Utilisation of crumb rubber as a soil amendment for sports turf." Soil
and Tillage Research 47(1-2): 169-172.
In Canada, the Province of Ontario generates about ten million waste tires per year. According to 1991
government statistics less than 20% of these tires are recycled, some of which are granulated to produce crumb
rubber. An innovation application for this secondary resource is as an efficient, economical and environmentally
sound soil amendment. A rubber crumb-based soil amendment can enhance the physical properties of soils
susceptible to the negative effects of compaction. Highly compacted sports fields require constant aeration to
maintain a healthy and safe playing surface. Rubber crumb adds resiliency to sports turf. Standard United States
Golf Association tests revealed that admixtures containing 20% or less crumb rubber maintained recommended
total porosity values. Field tests showed that 10-20% crumb rubber significantly reduced surface hardness.
Analysis of metals, VOC's and BNA extractable compounds from admixture leachate revealed no deleterious
effects to the environment due to inclusion of rubber crumb in turfgrass root zones. This paper was added to
our list.
Haering, S. A. (2012). "Alexandria Health Department."
This memorandum provides information regarding the infill material used in synthetic turf fields in the City
of Alexandria - This is a memo; not suitable for this effort.
Johns, D. M. (2008). "Initial evaluation of potential human health risks associated with playing on synthetic turf
fields on Bainbridge Island." Windward Environmental LLC. Already on our list.
Johns, D. M. and T. Goodlin (2008). "Evaluation of Potential Environmental Risks Associated with Installing
Synthetic Turf Fields on Bainbridge Island." Seattle. Washington: Windward Environmental LLC. This paper was
added to our list.
Kim, H.-H., et al. (2012). "Health Risk Assessment for Artificial Turf Playgrounds in School Athletic Facilities: Multi-
route Exposure Estimation for Use Patterns." Asian Journal of Atmospheric Environment 6(3): 206-221. This
paper was added to our list.
Kim, S., et al. (2012). "Health risk assessment of lead ingestion exposure by particle sizes in crumb rubber on
artificial turf considering bioavailability." Environmental health and toxicology 27: e2012005-e2012005.
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OBJECTIVES: The purpose of this study was to assess the risk of ingestion exposure of lead by particle sizes of
crumb rubber in artificial turf filling material with consideration of bioavailability. METHODS: This study estimated
the ingestion exposure by particle sizes (more than 250 um or less than 250 um) focusing on recyclable ethylene
propylene diene monomer crumb rubber being used as artificial turf filling. Analysis on crumb rubber was
conducted using body ingestion exposure estimate method in which total content test method, acid extraction
method and digestion extraction method are reflected. Bioavailability which is a calibrating factor was reflected in
ingestion exposure estimate method and applied in exposure assessment and risk assessment. Two methods
using acid extraction and digestion extraction concentration were compared and evaluated. RESULTS: As a result
of the ingestion exposure of crumb rubber material, the average lead exposure amount to the digestion
extraction result among crumb rubber was calculated to be 1.56*10(-4) mg/kg-day for low grade elementary
school students and 4.87*10(-5) mg/kg-day for middle and high school students in 250 um or less particle size,
and that to the acid extraction result was higher than the digestion extraction result. Results of digestion
extraction and acid extraction showed that the hazard quotient was estimated by about over 2 times more in
particle size of lower than 250 |_im than in higher than 250 |_im. There was a case of an elementary school student
in which the hazard quotient exceeded 0.1. CONCLUSIONS: Results of this study confirm that the exposure of
lead ingestion and risk level increases as the particle size of crumb rubber gets smaller. Already on our list.
Kruger, O., et al. (2013). "New approach to the ecotoxicological risk assessment of artificial outdoor sporting
grounds." Environmental Pollution 175: 69-74.
Artificial surfaces for outdoor sporting grounds may pose environmental and health hazards that are difficult to
assess due to their complex chemical composition. Ecotoxicity tests can indicate general hazardous impacts. We
conducted growth inhibition (Pseudokirchneriella subcapitata) and acute toxicity tests (Daphnia magna) with
leachates obtained from batch tests of granular infill material and column tests of complete sporting ground
assemblies. Ethylene propylene diene monomer rubber (EPDM) leachate showed the highest effect on Daphnia
magna (EC50 & It; 0.4% leachate) and the leachate of scrap tires made of styrene butadiene rubber (SBR) had the
highest effect on P. subcapitata (EC10 = 4.2% leachate; EC50 = 15.6% leachate). We found no correlations
between ecotoxicity potential of leachates and zinc and PAH concentrations. Leachates obtained from column
tests revealed lower ecotoxicological potential. Leachates of column tests of complete assemblies may be used
for a reliable risk assessment of artificial sporting grounds. Already on our list.
Li, X., et al. (2010). "Characterization of substances released from crumb rubber material used on artificial turf
fields." Chemosphere 80(3): 279-285.
Crumb rubber material (CRM) used as infill on artificial turf fields can be the source of a variety of substances
released to the environment and to living organisms in the vicinity of the CRM. To assess potential risks of major
volatilized and leached substances derived from CRM, methods were developed to identify organic compounds
and elements, either in the vapor phase and/or the leachate from CRM. A qualitative method based on solid
phase micro-extraction (SPME) coupled with gas chromatography/mass spectrometry (GC-MS) was developed to
identify the major volatile and semi-volatile organic compounds out-gassing from CRM samples under defined
laboratory conditions. Direct vapor phase injection into the GC-MS was applied for the quantitative analysis. Ten
organic compounds were identified in the vapor phase by the SPME method. Volatile benzothiazole (BT) was
detected at the highest level in all commercial CRM samples, in the range 8.2-69 ng g-1 CRM. Other volatile
PAHs and antioxidants were quantified in the vapor phase as well. A decrease of volatile compounds was noted
in the headspace over CRM samples from 2-years-old fields when compared with the virgin CRM used at
installation. An outdoor experiment under natural weathering conditions showed a significant reduction of out-
gassing organic compounds from the CRM in the first 14 d; thereafter, values remained consistent up to 70 d of
observation. Zinc was the most abundant element in the acidified leachate (220-13 000 |ag g-1), while leachable
BT was detected at relatively low amounts. Already on our list.
Li, X., et al. (2010). "Corrigendum to "Characterization of substances released from crumb rubber material used on
artificial turf fields" [Chemosphere 80 (3) (2010) 279-285]." Chemosphere 80(11): 1406-1407. Already on our
list.
Lioy, P. J., et al. "UMDNJ-EOHSI Crumb Infill and Turf Report-October 31, 2011." Already on our list.
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Lioy, P. J. and C. P. Weisel (2008). "Artificial turf: safe or out on ball fields around the world." Journal of Exposure
Science and Environmental Epidemiology 18(6): 533-534. Already on our list.
Llompart, M., et al. (2013). "Hazardous organic chemicals in rubber recycled tire playgrounds and pavers."
Chemosphere 90(2): 423-431. Already on our list.
Marsili, L., et al. (2015). "Release of Polycyclic Aromatic Hydrocarbons and Heavy Metals from Rubber Crumb in
Synthetic Turf Fields: Preliminary Hazard Assessment for Athletes." Journal of Environmental & Analytical
Toxicology 5(2): 1-8.
Synthetic turf, made with an infill of rubber crumb from used tyres or virgin rubber, is now common in many
sporting facilities. It is known that it contains compounds such as polycyclic aromatic hydrocarbons (PAH) and
heavy metals. The researchers evaluated in nine samples of rubber crumb the total content of some heavy metals
(Zn, Cd, Pb, Cu, Cr, Ni, Fe) normally found in tyres by microwave mineralization and the levels of the 14 US EPA
priority PAHs by Soxhlet extraction and HPLC analysis. The results showed high levels of PAHs and zinc in all
rubber crumb samples compared to rubber granulate limits set by Italian National Amateur League. Finally, the
aim of this study was to estimate the hazard for athletes inhaling PAHs released at the high temperatures this
synthetic turf may reach. Then a sequence of proofs was carried out at 60 degrees Celsius, a temperature that this
rubber crumb can easily reach in sporting installations, to see whether PAH release occurs. Already on our list.
Mattina, M. I., et al. (2007). "Examination of crumb rubber produced from recycled tires." The Connecticut
Agricultural Experiment Station. New Haven. CT. Available online at: http://www. ct.
gov/caes/lib/caes/documents/publications/fact sheets/examinationofcru mbrubberac005. pdf. Accessed on
12(10): 07. Already on our list as Incorvia Mattina.
Menichini, E., et al. (2011). "Artificial-turf playing fields: Contents of metals, PAHs, PCBs, PCDDs and PCDFs,
inhalation exposure to PAHs and related preliminary risk assessment." Science of the Total Environment 409(23):
4950-4957.
The artificial-turf granulates made from recycled rubber waste are of health concern due the possible exposure of
users to dangerous substances present in the rubber, and especially to PAHs. In this work, we determined the
contents of PAHs, metals, non-dioxin-like PCBs (NDL-PCBs), PCDDs and PCDFs in granulates, and PAH
concentrations in air during the use of the field. The purposes were to identify some potential chemical risks and
to roughly assess the risk associated with inhalation exposure to PAHs. Rubber granulates were collected from 13
Italian fields and analysed for 25 metals and nine PAHs. One further granulate was analysed for NDL-PCBs,
PCDDs, PCDFs and 13 PAHs. Air samples were collected on filter at two fields, using respectively a high volume
static sampler close to the athletes and personal samplers worn by the athletes, and at background locations
outside the fields. In the absence of specific quality standards, we evaluated the measured contents with respect
to the Italian standards for soils to be reclaimed as green areas. Zn concentrations (1 to 19 g/kg) and BaP
concentrations (0.02 to 11 mg/kg) in granulates largely exceeded the pertinent standards, up to two orders of
magnitude. No association between the origin of the recycled rubber and the contents of PAHs and metals was
observed. The sums of NDL-PCBs and WHO-TE PCDDs + PCDFs were, respectively, 0.18 and 0.67 x 10- 5 mg/kg.
The increased BaP concentrations in air, due to the use of the field, varied approximately from < 0.01 to 0.4
ng/m3, the latter referring to worst-case conditions as to the release of particle-bound PAHs. Based on the 0.4
ng/m3 concentration, an excess lifetime cancer risk of 1 x 10- 6 was calculated for an intense 30-year activity.
Already on our list.
Moretto, R. (2007). "Environmental and health assessment of the use of elastomer granulates (virgin and from
used tyres) as filling in third-generation artificial turf." EEDEMS fAdeme. Aliapur. Fieldturf Tarkett. Already on our
list.
Mota, H., et al. (2009). "Coated rubber granulates obtained from used tyres for use in sport facilities: A
toxicological assessment." Ciencia & Tecnologia dos Materials 21(3-4): 26-30. This paper was added to our list.
Pavilonis, B. T., et al. (2014). "Bioaccessibility and Risk of Exposure to Metals and SVOCs in Artificial Turf Field Fill
Materials and Fibers." Risk Analysis 34(1): 44-55.
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To reduce maintenance costs, municipalities and schools are starting to replace natural grass fields with a new
generation synthetic turf. Unlike Astro-Turf, which was first introduced in the 1960s, synthetic field turf provides
more cushioning to athletes. Part of this cushioning comes from materials like crumb rubber infill, which is
manufactured from recycled tires and may contain a variety of chemicals. The goal of this study was to evaluate
potential exposures from playing on artificial turf fields and associated risks to trace metals, semi-volatile organic
compounds (SVOCs), and polycyclic aromatic hydrocarbons (PAHs) by examining typical artificial turf fibers (n =
8), different types of infill (n = 8), and samples from actual fields (n = 7). Three artificial biofluids were prepared,
which included: lung, sweat, and digestive fluids. Artificial biofluids were hypothesized to yield a more
representative estimation of dose than the levels obtained from total extraction methods. PAHs were routinely
below the limit of detection across all three biofluids, precluding completion of a meaningful risk assessment. No
SVOCs were identified at quantifiable levels in any extracts based on a match of their mass spectrum to
compounds that are regulated in soil. The metals were measurable but at concentrations for which human health
risk was estimated to be low. The study demonstrated that for the products and fields we tested, exposure to
infill and artificial turf was generally considered de minimus, with the possible exception of lead for some fields
and materials. Already on our list.
Rhodes, E. P., et al. (2012). "Zinc leaching from tire crumb rubber." Environmental Science & Technology 46(23):
12856-12863. Already on our list.
Ruffino, B., et al. (2013). "Environmental-sanitary risk analysis procedure applied to artificial turf sports fields."
Environmental Science and Pollution Research International 20(7): 4980-4992.
Owing to the extensive use of artificial turfs worldwide, over the past 10 years there has been much discussion
about the possible health and environmental problems originating from styrene-butadiene recycled rubber. In
this paper, the authors performed a Tier 2 environmental-sanitary risk analysis on five artificial turf sports fields
located in the city of Turin (Italy) with the aid of RISC4 software. Two receptors (adult player and child player) and
three routes of exposure (direct contact with crumb rubber, contact with rainwater soaking the rubber mat,
inhalation of dusts and gases from the artificial turf fields) were considered in the conceptual model. For all the
fields and for all the routes, the cumulative carcinogenic risk proved to be lower than 10Asup -6A and the
cumulative non-carcinogenic risk lower than 1. The outdoor inhalation of dusts and gases was the main route of
exposure for both carcinogenic and non-carcinogenic substances. The results given by the inhalation pathway
were compared with those of a risk assessment carried out on citizens breathing gases and dusts from traffic
emissions every day in Turin. For both classes of substances and for both receptors, the inhalation of atmospheric
dusts and gases from vehicular traffic gave risk values of one order of magnitude higher than those due to
playing soccer on an artificial field. [PUBLICATION ABSTRACT] Already on our list.
Schiliro, T., et al. (2013). "Artificial Turf Football Fields: Environmental and Mutagenicity Assessment." Archives of
Environmental Contamination and Toxicology 64(1): 1-11.
The public has recently raised concerns regarding potential human health and environmental risks associated
with tire crumb constituents in the artificial turf of football fields. The aim of the present study was to develop an
environmental analysis drawing a comparison between artificial turf football fields and urban areas relative to
concentrations of particles (PM10 and PM2.5) and related polycyclic aromatic hydrocarbons (PAHs), aromatic
hydrocarbons (BTXs), and mutagenicity of organic extracts from PM10 and PM2.5. No significant differences were
found between PM10 concentrations at an urban site and on a turf football field, both during warm and in cold
seasons, either with or without on-field activity. PM2.5 concentrations were significantly greater at the urban site
in the cold season as was the ratio of PM2.5 to PM10. BTXs were significantly greater at urban sites than on turf
football fields on both on warm and cold days. The ratio of toluene to benzene (T/B ratio) was always comparable
with that of normal urban conditions. The concentration of PAHs on the monitored football fields was
comparable with urban levels during the two different sampling periods, and the contribution of PAHs released
from the granular material was negligible. PM10 organic extract mutagenicity for artificial turf football fields was
greater, whereas PM2.5 organic extract mutagenicity was lower, compared with the urban site studied. However,
both organic extract mutagenicity values were comparable with the organic extract mutagenicity reported in the
literature for urban sites. On the basis of environmental monitoring, artificial turf football fields present no more
exposure risks than the rest of the city. Already on our list.
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Simcox, N. J., et al. (2011). "SYNTHETIC TURF FIELD INVESTIGATION IN CONNECTICUT." Journal of Toxicology and
Environmental Health-Part a-Current Issues 74(17): 1133-1149.
The primary purpose of this study was to characterize the concentrations of volatile organic compounds (VOC),
semivolatile organic compounds (SVOC), rubber-related chemicals such as benzothiazole (BZT) and nitrosamine,
and particulate matter (PM(10)) in air at synthetic turf crumb rubber fields. Both new and older fields were
evaluated under conditions of active use. Three types of fields were targeted: four outdoor crumb rubber fields,
one indoor facility with crumb rubber turf, and an outdoor natural grass field. Background samples were
collected at each field on grass. Personal air sampling was conducted for VOC, BZT, nitrosamines, and other
chemicals. Stationary air samples were collected at different heights to assess the vertical profile of release. Air
monitoring for PM(10) was conducted at one height. Bulk samples of turf grass and crumb rubber were analyzed,
and meteorological data were recorded. Results showed that personal concentrations were higher than stationary
concentrations and were higher on turf than in background samples for certain VOC. In some cases, personal
VOC concentrations from natural grass fields were as high as those on turf. Naphthalene, BZT, and butylated
hydroxytoluene (BHT) were detected in greater concentration at the indoor field compared to the outdoor fields.
Nitrosamine air levels were below reporting levels. PM(10) air concentrations were not different between on-field
and upwind locations. All bulk lead (Pb) samples were below the public health target of 400 ppm. More research
is needed to better understand air quality at indoor facilities. These field investigation data were incorporated
into a separate human health risk assessment. Already on our list.
Simon, R. (2010). "Review of the impacts of crumb rubber in artificial turf applications." University of California.
Berkeley. Laboratory for Manufacturing and Sustainabilitv. prepared for The Corporation for Manufacturing
Excellence fManexl. - This paper was added to our list.
Sullivan, J. P. (2006). "An assessment of environmental toxicity and potential contamination from artificial turf
using shredded or crumb rubber." Ardea Consulting 43. Already on our list.
van Rooij, J. G. and F. J. Jongeneelen (2010). "Hydroxypyrene in urine of football players after playing on artificial
sports field with tire crumb infill." International Archives of Occupational and Environmental Health 83(1): 105-
110.
Artificial sports fields are increasingly being used for sports. Recycled rubber from automotive and truck scrap
rubber tires are used as an infill material for football grounds. There are concerns that football players may be at
risk due to exposure from released compounds from rubber infill. Compounds from crumb infill may be inhaled
and dermal exposure may occur. A study was performed to assess the exposure of football players to polycyclic
aromatic hydrocarbons due to sporting on synthetic ground with rubber crumb infill. In this study, football
players were trained and had a match on the artificial turf pitch during 2.5 h. They had an intensive skin contact
with rubber infill. All urine of seven nonsmoking football players was collected over a 3-day period, the day
before sporting, the day of sporting and the day after sporting. Urine samples were analyzed for 1-
hydroxypyrene. Confounding exposure from environmental sources and diet was controlled for. The individual
increase of the amount of excretion over time was used as a measure to assess the uptake of PAH. It appeared
that the baseline of excreted 1-hydroxypyrene in 4 of 7 volunteers was sufficient stable and that 1 volunteer out
of 4 showed after the 2.5-h period of training and match on the playground an increase in hydroxypyrene in
urine. However, concomitant dietary uptake of PAH by this volunteer was observed. This study provides evidence
that uptake of PAH by football players active on artificial grounds with rubber crumb infill is minimal. If there is
any exposure, than the uptake is very limited and within the range of uptake of PAH from environmental sources
and/or diet. [PUBLICATION ABSTRACT] Already on our list.
Zhang, J., et al. (2008). "Hazardous chemicals in synthetic turf materials and their bioaccessibility in digestive
fluids." Journal of Exposure Science and Environmental Epidemiology 18(6): 600-607.
Many synthetic turf fields consist of not only artificial grass but also rubber granules that are used as infill. The
public concerns about toxic chemicals possibly contained in either artificial (polyethylene) grass fibers or rubber
granules have been escalating but are based on very limited information available to date. The aim of this
research was to obtain data that will help assess potential health risks associated with chemical exposure. In this
small-scale study, we collected seven samples of rubber granules and one sample of artificial grass fiber from
synthetic turf fields at different ages of the fields. We analyzed these samples to determine the contents
120
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(maximum concentrations) of polycyclic aromatic hydrocarbons (PAHs) and several metals (Zn, Cr, As, Cd, and
Pb). We also analyzed these samples to determine their bioaccessible fractions of PAHs and metals in synthetic
digestive fluids including saliva, gastric fluid, and intestinal fluid through a laboratory simulation technique. Our
findings include: (1) rubber granules often, especially when the synthetic turf fields were newer, contained PAHs
at levels above health-based soil standards. The levels of PAHs generally appear to decline as the field ages.
However, the decay trend may be complicated by adding new rubber granules to compensate for the loss of the
material. (2) PAHs contained in rubber granules had zero or near-zero bioaccessibility in the synthetic digestive
fluids. (3) The zinc contents were found to far exceed the soil limit. (4) Except one sample with a moderate lead
content of 53 p.p.m., the other samples had relatively low concentrations of lead (3.12-5.76 p.p.m.), according to
soil standards. However, 24.7-44.2% of the lead in the rubber granules was bioaccessible in the synthetic gastric
fluid. (5) The artificial grass fiber sample showed a chromium content of 3.93 p.p.m., and 34.6% and 54.0%
bioaccessibility of lead in the synthetic gastric and intestinal fluids, respectively. Already on our list.
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gsh
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05
06
07
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11
12
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15
16
17
18
19
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21
22
23
24
25
26
27
28
Appendix E - List of Literature Reviewed
A Case Study of Tire Crumb Use on Playgrounds: Risk Analysis and
Communication When Major Clinical Knowledge Gaps Exist
Anderson et al.
A preliminary chemical examination of hydrophobic tire leachate components
Note: This reference is part III of III. Parts I and II were not relevant and
therefore, not reviewed
Anthony, D.H.J, and Latawiec
Determination of Microbial Populations in a Synthetic Turf System
Bass JJ, Hintze DW
Chemicals in outdoor artificial turf: a health risk for users?
Beausoleil M, Price K, Muller C
Toxicological Evaluation of Hazard Assessment of Tire Crumb for Use on Public
Playgrounds
Birkholz et al.
Metals contained and leached from rubber granulates used in synthetic turf
areas
Bocca B, Forte G., Petrucci F., Costantini S., Izzo
P.
Evaluation of Health Effects of Recycled Waste Tires in Playground and Track
Products
California Office of Environmental Health Hazard
Assessment
Safety Study of Artificial Turf Containing Crumb Rubber Infill Made from
Recycled Tires: Measurements of Chemicals and Particulates in the Air,
Bacteria in the Turf, and Skin Abrasions Caused by Contact with the Surface
California Office of Environmental Health Hazard
Assessment
Review of the Human Health & Ecological Safety of Exposure to Recycled Tire
Rubber found at Playgrounds and Synthetic Turf Fields
Cardno Chem Risk
Assessment of exposure to chemical agents in infill material for artificial turf
soccer pitches: development and implementation of a survey protocol
Castellano P, Proietto AR, Gordiani A, Ferrante R,
Tranfo G, Paci E,
Emission characteristics of VOCs from athletic tracks
Chang, F; Lin, T.; Huang, C.; Chao, H.; Chang, T.;
Lu, C.
Environmental and Health Impacts of Artificial Turf: A Review
Cheng H., HuY., Reinhard M.
Assessment of occupational health hazards in scrap-tire shredding facilities
Chien YC, Ton S, Lee MH et al.
Synthetic Turf: Health Debate Takes Root
Claudio L.
Human Health Risk Assessment of Artificial Turf Fields Based Upon Results
from Five Fields in Connecticut
Connecticut Department of Public Health.
(CDPH)
Artificial Turf Field Investigation in Connecticut Final Report
Connecticut: University of Connecticut Health
Center (UCHC)
2009 Study of Crumb Rubber Derived from Recycled Tires, final report
Connecticut Agricultural Experiment Station
(CAES)
Artificial Turf Study: leachate and stormwater characteristics
Connecticut Department of Environmental
Protection (CDEP)
Peer Review of an Evaluation of the Health and Environmental Impacts
Associated with Synthetic Turf Playing Fields
Connecticut Academy of Science and
Engineering. (CASE)
CPSC Staff Analysis and Assessment of Synthetic Turf Grass Blades
CPSC
Effects of leachate from crumb rubber and zinc in green roofs on the survival,
growth, and resistance characteristics of Salmonella enterica subsp. enterica
serovar typhimurium
Crampton M, et al.
A Review of the Potential Health and Safety Risks from Synthetic Turf Fields
Containing Crumb Rubber Infill
Note: See reference #59
Denly E., Rutkowski K., Vetrano K.M.
Measurement of Air Pollution in Indoor Artificial Turf Halls
Dye C., Bjerke A, Schmidbauer N., Mano S.
Artificial Turf- Exposures to Ground-Up Rubber Tires - Athletic Fields -
Playgrounds - Gardening Mulch
Environment & Human Health Inc. (EHHI)
Study of the suitability of ground rubber tire as a parking lot surface
Florida Department of Environmental Protection
(FDEP)
Human Health Risk Assessment of Synthetic Turf Fields Based Upon
Investigation of Five Fields in Connecticut
Ginsberg et al.
Benzothiazole Toxicity Assessment in Support of Synthetic Turf Field Human
Health Risk Assessment
Ginsberg, G; Toal, B; Kurland, T.
Toxicological Assessment of Coated Versus Uncoated Rubber Granulates
Obtained from Used Tires for Use in Sports Facilities
Gomes et al.
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Gomes JF, Mota HI, BordadoJC, Baiao M,
29
Design of a New Test Chamber for Evaluation of the Toxicity of Rubber Infill
Sarmento GM, Fernandes J, Pampulim VM,
Custodio ML, Veloso 1.
30
Impact of tire debris on in vitro and in vivo systems
Gualteri, M.; Andrioletti, M.; Mantecca, P.;
Vismara, C.; Camatini; M.
31
Identification of Benzothiazole Derivatives and Polycyclic Aromatic
He, G., Zhao, B., Denison, M.S.
Hydrocarbons as Aryl Hydrocarbon Receptor Agonists Present in Tire Extracts
32
A Scoping-Level Field Monitoring Study of Synthetic Turf and Playgrounds
U.S. Environmental Protection Agency (U.S. EPA)
33
Environmental and Health Risks of Rubber Infill: Rubber crumb from car tyres
as infill on artificial turf
Hofstra, U
34
Examination of Crumb Rubber Produced from Recycled Tires. Department of
Incorvia Mattina, MJ; Isleyen, M; Berger, W;
Analytical Chemistry
Ozdemir, S.
35
Initial evaluation of potential human health risks associated with playing on
synthetic turf fields on Bainbridge Island
Johns, DM
36
Characterization and potential environmental risks of leachate from shredded
Kanematsu, M; Hayashi, A; Denison, MS; Young,
rubber mulches
TM.
37
The fate of methicillin-resistant staphylococcus aureus in a synthetic field turf
system
Keller, M.
38
Synthetic turf from a chemical perspective—a status report
Keml (Swedish Chemicals Inspectorate)
39
Health Risk Assessment of Lead Ingestion Exposure by Particle Sizes in Crumb
Kim, S; Yan, JY; Kim, HH; Yeo, IY; Shin, DC; Lim,
Rubber on Artificial Turf Considering Bioavailability
YW.
40
New approach to the ecotoxicological risk assessment of artificial outdoor
Kruger, 0; Kalbe, U; Richter, E; Egeler, P;
sporting grounds
Rombke, J; Berger, W.
41
Comparison of Batch and Column Tests for the Elution of Artificial Turf System
Kruger, 0; Kalbe, U; Berger, W; Nordhau(3, K;
Components
Christoph, G; Walzel, HP.
42
Preliminary Assessment of the Toxicity from Exposure to Crumb Rubber: Its
LeDoux, T.
Use in Playgrounds and Artificial Turf Playing Fields
43
Characterization of Substances Released from Crumb Rubber Material Used on
Li, X; Berger, W; Musante, C; Incorvia Mattina,
Artificial Turf Fields
MJ.
44
Artificial Turf: Safe or Out on Ball Fields Around the World
Lioy, P; Weisel, C.
45
Crumb Infill and Turf Characterization for Trace Elements and Organic
Materials
Lioy, P; Weisel, C.
46
Hazardous organic chemicals in rubber recycled tire playgrounds and pavers
Llompart, M; Sanchez-Pardo, L; Lamas, J; Garcia-
Jares, C; Roca, E.
47
Release of Polycyclic Aromatic Hydrocarbons and Heavy Metals from Rubber
Marsili, L; Coppola, D; Bianchi, N; Maltese, S;
Crumb in Synthetic Turf Fields: Preliminary Hazard Assessment for Athletes
Bianchi, M; Fossi, MC.
48
A Survey of Microbial Populations in Infilled Synthetic Turf Fields
McNitt, AS; Petrunak, D; Serensits, T.
49
Artificial-turf Playing Fields: Contents of Metals, PAHs, PCBs, PCDDs and PCDFs,
Menichini, E; Abate, V; Attias, L; DeLuca, S;
DiDomenico, A; Fochi, 1; Forte, G; lacovella, N;
lamiceli, AL, Izzo, P; Merli, F; Bocca, B.
Inhalation Exposure to PAHsand Related Preliminary Risk Assessment
Culture based and non growth dopondont dotoction of the Burkholdoria
50
cepacia complex in soil environments
Note: This reference is not relevant, therefore not reviewed.
Miller ot al
51
Evaluation of the Environmental Effects of Synthetic Turf Athletic
Milone and MacBroom, Inc.
52
Environmental and Health Evaluation of the Use of Elastomer Granulates
Moretto, R.
(Virgin and From Used Tyres) as Filling in Third-generation Artificial Turf
Emission and evaluation of health effects of PAHs and aromatic aminos from
53
Note: This study does not meet our search criteria (focuses on problematic
substances in whole tires).
Nilsson, NH; Foilborg, A; Pommor, K. (2005).
54
Mapping Emissions and Environmental and Health Assessment of Chemical
Substances in Artificial Turf
Nilsson, NH; Malmgren-Hansen, B; Thomsen, US.
55
Artificial Turf Pitches: An Assessment of the Health Risks for Football Players
Norwegian Institute of Public Health and the
Radium Hospital
56
A study to assess potential environmental impacts from the use of crumb
New York Department of Environmental
runner as infill material in synthetic turf fields
Conservation (NYDEC)
57
An assessment of chemical leaching, releases to air and temperature at
New York Department of Environmental
crumb-rubber infilled synthetic turf fields
Conservation (NYDEC)
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58
New York City Department of Parks and Recreation: Synthetic Turf Lead Results
New York City Department of Parks and
(online)
Recreation
59
A Review of the Potential Health and Safety Risks From Synthetic Turf Fields
Containing Crumb Rubber Infill
Now York City Department of Health and Mental
Hygiene (DOHMH)
Note: Same as Denly et al. 2008. See reference # 22.
60
Bioaccessibility and Risk of Exposure to Metals and SVOCs in Artificial Turf Field
Fill Materials and Fibers
Pavilonis, BT; Weisel, CP; Buckley, B; Lioy, PJ.
61
Potential health and environmental effects linked to artificial turf systems-final
report
Plesser, T; Lund, O.
62
Zinc Leaching From Tire Crumb Rubber
Rhodes, EP; Ren, Z; Mays, DC.
63
Environmental Sanitary Risk Analysis Procedure Applied to Artificial Turf Sports
Fields
Ruffino, B; Fiore, S; Zanetti, MC.
Used Tire Recycling to Produce Granulates: Evaluation of Occupational
64
Exposure to Chemical Agents
Savary, B; Vinvent, R.
Schilird, T; Traversi, D; Degan, R; Pignata, C;
65
Artificial Turf Football Fields: Environmental and Mutagenicity Assessment
Alessandria, L; Scozia, D; Bono R; Gilli, G.
66
Leaching of DOC, DN and inorganic Constituents from Scrap Tires
Selbes, M; Yilmaz, O;, Khan, AA; Karanfil, T.
67
Human health issues on synthetic turf in the USA
Serentis,T J; McNitt, AS; Petrunak, DM.
An Evaluation of Potential Exposures to Lead and Other Metals as the Result
68
of Aerosolized Particulate Matter from Artificial Turf Playing Fields
Shalat, SL.
Evaluating the Risk to Aquatic Ecosystems Posed by Leachatefrom Tire Shred
Fill in Roads Using Toxicity Tests, Toxicity Identification Evaluations, and
Sheehan, PJ; Warmerdam, JM; Ogle, S;
69
Groundwater Modeling
Humphrey, D; Patenaude, S.
Simcox, NJ; Bracker, A; Ginsberg, G; Toal, B;
70
Synthetic Turf Field Investigation in Connecticut
Golembiewski, B; Kurland, T; Hedman, C
An Assessment of Environmental Toxicity and Potential Contamination from
71
Artificial Turf using Shredded or Crumb Rubber
Sullivan, JP.
72
Environmental risk assessment of artificial turf systems
Torsten Kallqvist
Hydroxypyrene in Urine of Football Players After Playing on Artificial Sports
73
Fields with Tire Crumb Infill
Van Rooij, JGM; Jongeneelen, FJ.
Van Ulirsch, G; Gleason, K; Gerstenberger, S;
74
Evaluating and Regulating Lead in Synthetic Turf
Moffett, DB; Pulliam, G; Ahmed, T; Fagliano, J.
75
Leaching of Zinc from rubber infill in artificial turf (football pitches)
Verschoor, AJ.
76
Air Quality Survey of Synthetic Turf Fields Containing Crumb Rubber Infill
Vetrano, KM; Ritter, G.
Memo to Gloria Addo-Ayensu, Fairfax County Health Dept., from Dwight
77
Flammia, Virginia Department of Health
Virginia Department of Health (VDH)
78
The RMA TCLP assessment project: Leachate from tire samples
Zelibor, J L.
Hazardous Chemicals in Synthetic Turf Materials and Their Bioaccessibility in
79
Digestive Fluids
Zhang, J; Han, IK; Zhang, L; Crain, W.
Technical and environmental properties of tyro shreds focusing on ground
80
engineering applications
Note: Not reviewed-not applicable.
Edoskar, T.
Export Witness: Evaluation of health risks caused by skin contact with rubber
81
granulates used in synthetic turf pitches
Note: Not a scientific study, expert opinion only; Not reviewed.
Hamotnor, C.
Investigation of PAH and other hazardous contaminant occurrence in recycled
tyre rubber surfaces: case study: restaurant playground in an indoor shopping
82
centre
Celeiro, M. et al.
Current State and Perspective for Artificial Turf as Sport Environment: Focusing
on Third generation Artificial Turf as Football Playing Surface
83
Note: This document reviews many of the documents already on this list that
have been reviewed. Also includes information from Aoki 2008, see reference
91.
Aoki, T.
Mutagenic Potential of Artificial Athletic Field Crumb Rubber at Increased
84
Temperatures
Dorsey et al.
85
Synthetic playing surfaces and athlete health
Note: Not suitable; it addresses injuries to athletes.
Drakos, M. C., et al.
124
-------
86
Utilisation of crumb rubber as a soil amendment for sports turf
Groenevelt, P. H. and P. E. Grunthal
87
Evaluation of Potential Environmental Risks Associated with Installing Synthetic
Turf Fields on Bainbridge Island.
Johns, DM; Goodlin, T.
88
Health Risk Assessment for Artificial Turf Playgrounds in School Athletic
Facilities: Multi-route Exposure Estimation for Use Patterns
Kim, HH et al.
89
Coated rubber granulates obtained from used tyres for use in sport facilities: A
toxicological assessment
Mota, H., et al.
90
Review of the impacts of crumb rubber in artificial turf applications
Simon, R.
91
Leaching of heavy metals from infills on artificial turf by using acid solutions
Aoki, T.
92
Environmental and Health Evaluation of the use of Elastomer Granulates
(Virgin and From Used Tyres) as Filling in Third Generation Artificial Turf
Note: Same as Moretto et al 2007. See Study 52.
French National Institute for Industrial
Environment and Risks
93
ACT Global Crumb Rubber Safety Study
Note: Summary only; no information on the types and source of materials
studied
Tilford, RW
94
State of Knowledge Report for Tire Materials and Tire Wear Particles
ChemRisk, Inc.
95
Health Impact Assessment of the Use of Artificial Turf in Toronto
Toronto Public Health
96
Nitrosamines released from rubber crumb
van Bruggen et al.
97
FOLLOW-UP STUDY OF THE ENVIRONMENTAL ASPECTS OF RUBBER INFILL A lab
study (performing weathering tests) and a field study rubber crumb from car
tyres as infill on artificial turf
Hofstra et al.
125
-------
Appendix F - Constituents List
Analyte
Synonym(s)
CAS#
Aluminum
7429-90-5
Antimony
7440-36-0
Arsenic
7440-38-2
Barium
7440-39-3
Beryllium
7440-41-7
Cadmium
7440-43-9
Calcium
7440-70-2
Chloride
16887-00-6
Chromium
7440-47-3;
16065-83-1 (Crlll);
18540-29-9 (CrVI)
Cobalt
7440-48-4
Copper
7440-50-8
Iron
7439-89-6
Lead
7439-92-1
Lithium
7439-93-2
Magnesium
7439-95-4
Manganese
7439-96-5
Mercury
7439-97-6
Molybdenum
7439-98-7
Nickel
7440-02-0
Phosphorous
7723-14-0
Potassium
7440-09-7
Rubidium
7440-17-7
Selenium
7782-49-2
Silver
7440-22-4
Sodium
7440-23-5
Strontium
7440-24-6
Sulfur
7704-34-9
Thallium
7440-28-0
Tin
7440-31-5
Titanium
7440-32-6
Tungsten
7440-33-7
Vanadium
7440-62-2
Zinc
7440-66-6
Cadmium and Zinc Soaps
Acenaphthene
83-32-9
Acenaphthylene
208-96-8
Acetaldehyde
Ethanone
75-07-0
Acetamide, N-cyclohexyl-
1124-53-4
Acetone
67-64-1
Acetone-diphenylamine condensation product (ADPA)
Acetonitrile
75-05-8
Acetophenone
98-86-2
6-Acetoxy-2,2-dimethyl-m-dioxane
Dimethoxane
828-00-2
Acrolein
107-02-8
Alcohols
Ethanol
64-17-5
Aldehydes
Alkyl benzenes
Alkyl dithiols
Alkyl naphthalenes
Alkyl phenols
Alpha pinene
alpha-Pinene
80-56-8
126
-------
Amine (N-dialkyl analine derivative)
Amines
Anathrene
Aniline
Benzeneamine; aminobenzene
62-53-3
Anthanthrene
191-26-4
Anthracene
120-12-7
Aromatic oil
9,10-Anthracenedione, 2-ethyl
2-Ethylanthracene-9,10-dione
84-51-5
Azobenzene
103-33-3
Benz(e)acenaphthylene
Acephenanthrylene
201-06-9
Benzaldehyde, 3-hydroxyl-4-methoxy
3-Hydroxy-4-methoxy-benzaldehyde
621-59-0
Benz(a)anthracene
56-55-3
Benzene
71-43-2
Benzene, l,3-bis(l-methylethenyl)-
l,3-bis(l-methylethenyl)benzene; 1,3-
Diisopropenylbenzene
3748-13-8
Benzene, l,4-bis(l-methylethenyl)-
l,4-Bis(l-methylethenyl)benzene
1605-18-1
1,4-Benzenediamine, N,N'-diphenyl-
N,N'-Diphenyl-p-phenylenediamine
74-31-7
1,4-Benzendiamin, N-(l-methylethyl)-N'-phenyl-, (IPPD)
N-lsopropyl-N'-phenyl-p-phenylenediamine,
Isopropylaminodephenylamine (IPPD)
101-72-4
Benzene, isocyanato-
Phenyl isocyanate
103-71-9
Benzenemethanol
Benzyl alcohol
100-51-6
Benzo(def)dibenzothiophene
Phenanthro[4,5-bcd]thiophene
30796-92-0
Benzo(g)dibenzothiophene
Benzo(b)fluoranthene
205-99-2
Benzo(bjk)fluoranthene
2,ll-(Metheno)benzo[a]fluorene
Benzo(ghi)fluoranthene
Benzo[ghi]fluoranthene,
203-12-3
Benzo(i)fluoranthene
Benzo(j)fluoranthene
205-82-3
Benzo(k)fluoranthene
207-08-9
Benzo(mno)fluoranthene
Benzo(a)fluorene
llH-Benzo[a]fluorene
238-84-6
Benzo(b)fluorene
2,3-Benzofluorene
243-17-4
Benzo(def)naphthobenzothiophene
6H-Benzo[cd]pyren-6-one
6H-Benzo(cd)pyren-6-one
3074-00-8
Benzo(a)pyrene
50-32-8
Benzo(e)pyrene
192-97-2
Benzo(ghi)perylene
Benzo(g,h,i)perylene
191-24-2
Benzoic acid
65-85-0
Benzothiazole
95-16-9
Benzothiazole, 2-(methylthio)
2-(Methylthio)benzothiazole
615-22-5
Benzothiazole, 2-phenyl
2-Phenylbenzothiazole
883-93-2
Benzothiazolone
2-Hydroxybenzothiazole, 2(3H)-Benzothiazolone,
2(3H) benzothiazolone
934-34-9
Benzoyl and other peroxides
Benzylbutyl phthalate
Butyl benzyl phthalate
85-68-7
Biphenyl
l,r-Biphenyl
92-52-4
l,r-Biphenyl, 4, 4', 5', 6'-tetramethoxy-
(N,l\T-Bis(l,4-dimethylpentyl)pphenylendiamine) (7PPD)
N/N'-Bis(l/4-dimethylpentyl)-4-phenylenediamine
3081-14-9
Bis(2-ethylhexyl) phthalate
Di(2-ethylhexyl) phthalate
117-81-7
Bis-(2,2,6,6-tetramethyl-4-piperidinyl)sebacate
Bis(2/2/6/6-tetramethyl-4-piperidyl) sebacate
52829-07-9
Bisthiol acids
Black rubber
Bromodichloromethane
75-27-4
Bromoform
75-25-2
Butadiene oligomers
Butoxyethoxyethanol
2-(2-Butoxyethoxy)ethanol; diethylene glycol
monobutyl ether
112-34-5
Butylated hydroxyanisole
25013-16-5
Butylated hydroxytoluene
2,6-Di-tert-butyl-4-methylphenol (BHT)
128-37-0
Butylbenzene
104-51-8
Caprolactam disulfide (CLD)
l/l'-Disulfanediyldiazepan-2-one
23847-08-7
127
-------
Carbazole
86-74-8
Carbon Black
Furnace Black
1333-86-4
Carbon Disulfide
75-15-0
Carbon Tetrachloride
56-23-5
Chlorobenzene
108-90-7
Chloroform
Trichloromethane
67-66-3
Chloromethane
Methyl chloride
74-87-3
Chrysene
218-01-9
Coronene
191-07-1
o-Cyanobenzoic acid
2-Cyanobenzoic acid
3839-22-3
Cyclohexanamine
Cyclohexylamine
108-91-8
Cyclohexanamine, N-cyclohexyl-
Dicyclohexylamine
101-83-7
Cyclohexanamine, N-cyclohexyl-N-methyl-
N-Cyclohexyl-N-methylcyclohexanamine
7560-83-0
Cyclohexane
110-82-7
Cyclohexane, isocyanato
Isocyanatocyclohexane
3173-53-3
Cyclohexane, isothiocyanato-
1122-82-3
Cyclohexanone
108-94-1
N-Cyclohexyl-2-benzothiazolesulfenamide (CBS)
N-Cyclohexyl-2-benzothiazolesulfenamide
95-33-0
n-Cyclohexyl-formamide
N-Cyclohexylformamide; Formamide, N-cyclohexyl
766-93-8
Cycloninasiloxane, octadecamethyl-
Octadecamethylcyclononasiloxane
556-71-8
Cyclopenta [cdjpyrene
27208-37-3
4H-cyclopenta[def]phenanthren-4-one
4H-Cyclopenta(def)phenanthren-4-one
5737-13-3
4H-cyclopenta[def]-phenanthrene
4-H-Cyclopenta(d,e,f)phenanthrene
203-64-5
Cyclopentane, methyl-
Methylcyclopentane
96-37-7
Decane
124-18-5
Diazoaminobenzenes
Dibenzo(a,h) anthracene
Dibenz(a,h)anthracene
53-70-3
Dibenzofurane
Dibenzofuran
132-64-9
Dibenzo(ae)pyrene
Naphtho(l,2,3,4-def)chrysene
192-65-4
Dibenzo(ai)pyrene
Dibenzo[a,i]pyrene
189-55-9
Dibenzo(ah)pyrene
Dibenzo[a,h]pyrene
189-64-0
Dibenzothiophene
132-65-0
Dibutyl phthalate
84-74-2
1,4-Dichlorobenzene
p-dichlorobenzene
106-46-7
Dichlorodifluoromethane
Freon 12
75-71-8
1,2-Dichloroethane
Ethylene dichloride
107-06-2
cis-l,2-Dichloroethene
(Z)-l,2-Dichloroethylene
156-59-2
1,2-Dichloropropane
78-87-5
N,N-Dicyclohexyl-2-benzothiazolesulfenamide (DCBS)
N,N-Dicyclohexyl-2-benzothiazolesulfenamide
4979-32-2
Dicyclohexylphthalate (DCHP)
Dicyclohexyl phthalate
84-61-7
1,3-Dicyclohexylurea
N,N'-Dicyclohexylurea
2387-23-7
Diethenylbenzene
Divinylbenzene
1321-74-0
Di(2-ethylhexyl) adipate
Hexanedioic acid, bis(2-ehtylhexyl); Bis(2-
ethylhexyl)hexanedioic acid
103-23-1
Diethyl phthalate
84-66-2
Diethylthiourea (DETU)
N,N'-Diethylthiourea
105-55-5
Dihydrocyclopentapyrene
2,3-Acepyrene
25732-74-5
Diisobutyl phthalate
84-69-5
Diisodecylphthalate
bis(8-Methylnonyl) phthalate
89-16-7
Diisononyl phthalate
DINP
28553-12-0
9,I0-Dimethyl-1,2-Benzanthracene
7,12-Dimethylbenz(a)anthracene
57-97-6
(N-l,3-dimethyl-butyl)-N'- phenyl-p-phenylenediamine
(6PPD)
N-(l/3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine
793-24-8
Dimethyldiphenylthiuram disulfide (MPTD)
Dimethyldiphenylthiuram disulfide
53880-86-7
2,6-Dimethylnaphthalene
581-42-0
2,4-Dimethylphenol
105-67-9
Dimethyl phthalate
131-11-3
Dinitroarenes
Di-n-octyl phthalate
Dioctyl phthalate
117-84-0
Di-ortho-tolylguanidine
97-39-2
128
-------
Dipentamethylenethiuramtetrasulfide (DPTT)
Bis(pentamethylenethiuram)tetrasulfide
120-54-7
Diphenylamine
122-39-4
N,N'-Diphenylguanidine (DPG)
1,3-Diphenylguanidine
102-06-7
N,N'-Diphenyl-p-phenylenediamine (DPPD)
N,N'-Diphenyl-p-phenylenediamine
74-31-7
Disulfides
Di-(2-ethyl)hexylphosphorylpolysulfide) (SDT)
Bis-(ethylhexylthiophosphoryl) polysulfide
3,5-Di-tert-Butyl-4-hydroxybenzaldehyde
1620-98-0
2,2'-Dithiobis(benzothiazole)
2,2'-Dithiobisbenzothiazole
120-78-5
Dithiocarbamates
Dithiomorpholine (DTDM)
4,4'-Dithiodimorpholine
103-34-4
Dithiophosphates
N,INT-Ditolyl-p-phenylenediamine (DTPD)
N,N'-Ditolyl-p-phenylenediamine
27417-40-9
Docosanoic acid
112-85-6
Dodecanoic acid
143-07-7
Dotriacontane
544-85-4
Drometrizol
2-(2H-Benzotriazol-2-yl)-4-methylphenol
2440-22-4
Eicosane
112-95-8
Erucylamide
Erucamide
112-84-5
Esters
Ethanol, 2-butoxy-
2-Butoxyethanol
111-76-2
Ethanol, l-(2-butoxyethoxy)
l-(2-Butoxyethoxy)ethanol
54446-78-5
Ethanone, l/l'-(l/3-phenylene)bis-
Benzene-l,3-bis(acetyl)
6781-42-6
Ethanone, l/l'-(l/4-phenylene)bis-
l,l-(l/4-Phenylene)bis-ethanone
1009-61-6
Ethanone, l-[4-(l-methylethenyl)phenyl]-
l-[4-(l-Methylethenyl)phenyl]ethanone
5359-04-6
Ethyl Acetate
141-78-6
Ethyl benzene
Ethylbenzene
100-41-4
Ethyl benzene aldehyde
Benzaldehyde, 2-ethyl-
22927-13-5
Ethylene thiourea (Ethylene thiourea)
96-45-7
2-Ethyl-l-hexanol
104-76-7
l-Ethyl-4-Methyl Benzene
4-Ethyltoluene
622-96-8
Fluoranthene
206-44-0
Fluorene
86-73-7
Formaldehyde
50-00-0
Furan, 2-methyl
2-Methylfuran
534-22-5
2(3H)-Furanone,dihydro-4-hydroxy-
Dihydro-4-hydroxy-2(3H)-furanone; beta-
Hydroxybutyrolactone
5469-16-9
Guanidines
Halocarbon 11
Trichlorofluoromethane, Trichloro-fluoromethane,
Freon 11
75-69-4
Hemeicosane
Heptadecane
629-78-7
Heptane
142-82-5
Heptanonitrile
Heptanenitrile
629-08-3
Hexacosane
630-01-3
Hexadecane
544-76-3
Hexa(methoxymethyl)melamine
N,N,N',N',N",N"-Hexakis(methoxymethyl)-l,3,5-
triazine-2/4/6-triamine
3089-11-0
Hexamethylenetetramine
Methenamine
100-97-0
Hexane
n-Hexane
110-54-3
Hexanedioic acid, methyl ester
Methyl hexanedioate
627-91-8
Hexanoic acid, 2-ethyl-
2-Ethylhexanoic acid
149-57-5
Hydrocarbon (olefin/aromatic)
7-Hydroxybenzo[f]flavone
7-Hydroxy-3-phenyl-lH-naphtho[2/l-b]pyran-l-one
86247-95-2
1-Hydroxypyrene
5315-79-7
lndeno[l,2,3-cd]pyrene
o-Phenylenepyrene
193-39-5
lH-isoindole-1,3 (2H)-dione
Phthalimide
85-41-6
iso-nonylphenol
3-Nonylphenol
11066-49-2
Isophorone
78-59-1
Isopropyl Alcohol
2-Propanol, Isopropanol
67-63-0
Isopropylbenzene
Cumene
98-82-8
129
-------
Isopropyltoluene
l-Methyl-2-(propan-2-yl)benzene
527-84-4
Ketones
Latex protein
Limonene
138-86-3
MEK
Methyl ethyl ketone
78-93-3
2-Mercaptobenzothiazole
149-30-4
Methane, diethoxy-cyclohexane
Diethoxycyclohexanemethane;
Bis(cyclohexyloxy)methane
1453-21-0
Methyl Alcohol
Methanol
67-56-1
2-Methylanthracene
613-12-7
2-Methyl-Butane
2-Methylbutane
78-78-4
2,2-Methylene-bis-(4-methyl-6-tert-butylphenol) (BPH)
119-47-1
Methylene Chloride
Dichloromethane
75-09-2
5-Methyl-2-hexanone
Methyl isoamyl ketone
110-12-3
1-Methylnaphthalene
90-12-0
2-Methylnaphthalene
91-57-6
3-Methyl-Pentane
3-Methylpentane
96-14-0
4-Methyl-2-pentanone
MIBK
108-10-1
1-Methylphenanthrene
1-Methyl phenanthrene
832-69-9
2-Methylphenanthrene
2531-84-2
3-Methylphenanthrene
832-71-3
9-Methylphenanthrene
883-20-5
2-Methylphenol
o-Cresol
95-48-7
4-Methylphenol
p-Cresol
106-44-5
MES (special purified aromatic oil)
2-(4-morpholino)benzothiazole
2-morpholinothio benzothiazole (MBS);
Morpholinothio-benzothiazole; N-
Oxydiethylenebenzothiazole-2-sulfenamide
102-77-2
2-Morpholinodithiobenzothiazole (MBSS)
2-(Morpholin-4-yldithio)-l,3-benzothiazole
95-32-9
Naphthalene
91-20-3
Naphthalene, 2-(bromomethyl)-
2-Bromomethylnaphthalene
939-26-4
Naphthalic Anhydride
lH,3H-Naphtho(l,8-cd)pyran-l,3-dione
81-84-5
Napthenic oil
Nitro compound (isomer of major peak)
Nitro compound (nitro-ether derivative)
Nitrogen containing substances
Nitrosodibutylamine (n-)
N-Nitrosodibutylamine
924-16-3
Nitrosodiethylamine (n-)
N-Nitrosodiethylamine
55-18-5
Nitrosodimethylamine (n-)
N-Nitrosodimethylamine
62-75-9
n-Nitrosodiphenylamine
N-Nitrosodiphenylamine
86-30-6
Nitrosodipropylamine (n-)
N-Nitrosodipropylamine
621-64-7
Nitrosomorpholine (n-)
N-Nitrosomorpholine
59-89-2
Nitrosopiperidine (n-)
N-Nitrosopiperidine
100-75-4
Nitrosopyrrolidine (n-)
N-Nitrosopyrrolidine
930-55-2
Nonadecane
629-92-5
Nonanale
Nonanal
124-19-6
Nonane
111-84-2
4-n-nonylphenol
4-Nonylphenol
104-40-5
Octadecanoic acid, methyl ester
Methyl stearate
112-61-8
Octane
111-65-9
4-t-octylphenol
4-(l,l,3,3-Tetramethylbutyl)phenol, 4-tert-(octyl)-
phenol
140-66-9
Optadecane
Organic thiola and sulfides
Orthocarbonate - Carboxy compound)
N-Oxydiethylenedithiocarbamyl-N"-
oxydiethylenesulfenamide (OTOS)
13752-51-7
PAHs
Polycyclic aromatic hydrocarbons
Parrafinic oils
Mineral oil
8012-95-1
PCB sum
130
-------
PCDD/F sum
Pentacosane
629-99-2
Pentane
109-66-0
Perylene
198-55-0
Petroleum Naphtha
Naphtha
8030-30-6
Phenalone
Phenalen-l-one
548-39-0
Phenanthrene
85-01-8
1-Phenanthrenecarboxylic acid, 1,2,3,4,4
1,2,3,4,4-1-Phenanthrene carboxylic acid;
Dehydroabietic acid
1740-19-8
Phenol
2,4-Di-tert-butylphenol
108-95-2
Phenolics
Phenol, 2,4-bis(l,l-dimethylethyl)-
96-76-4
Phenol, 2,4-bis(l-methyl-l-phenylethyl)-
2,4-Bis(l-methyl-l-phenylethyl)phenol
2772-45-4
Phenol, m-tert-butyl-
3-tert-Butylphenol
585-34-2
Phenylbenzimidazole
2-Phenylbenzimidazole
716-79-0
p-Phenylenediamines
Phenylenediamines
2-(l-phenylethyl)-phenol
2-(l-Phenylethyl)phenol
26857-99-8
3-Phenyl-2-propenal
3-Phenylprop-2-enal
104-55-2
Phthalates
PM 2.5
PM10
Poly-and di-nitrobenzenes
Poly-p-dinitrosobenzene
Propene
1-Propene; propylene
115-07-1
Propylbenzene
103-65-1
Pyrazole
288-13-1
Pyrene
129-00-0
Pyrimidine, 2-(4-pentylphenyl)-5-propyl-
94320-32-8
2-Pyrrolidinone. 1-methyl-
N-Methyl-2-pyrrolidone
872-50-4
Quinones
Resorcinol
108-46-3
Rethene
Siloxanes
Styrene
100-42-5
Styrene oligomers
Substituted p-Phenylenediamines
Sulfur containing organics
Sulfur Donors
Sulphenamides
TDAE (special purified aromatic oil)
Tertbutylacetophenone
3,3-dimethyl-l-phenylbutan-l-one
31366-07-1
N-tert-Butyl-2-benzothiazolesulfenamide (TBBS)
95-31-8
4-tert butylphenol
4-tert-Butylphenol
98-54-4
Tetraalkylthiuram disulfides
Tetrabenzylthiuram disulfide (TBZTD)
10591-85-2
Tetrabutylthiuram disulfide (TBTD)
1634-02-2
Tetrachloroethene
Tetrachloroethylene; perchloroethylene
127-18-4
Tetracosane
646-31-1
Tetraethylthiuram disulfide
Disulfiram
97-77-8
Tetrahydrofuran
109-99-9
Tetramethylthiuram disulfide
Thiram
137-26-8
Tetramethylthiuram monosulfide
97-74-5
Thiazoles
Thioureas
Thiurams
Thiuram sulfides
Toluene
108-88-3
Total petroleum hydrocarbons
Trans trans-muconic acid
(E,E)-Muconic acid
3588-17-8
131
-------
Trimethyl-l,2-dihydroquinoline (TMDQ)
l,2-Dihydro-2,2,4-trimethylquinoline, polymer
26780-96-1
1,1/1-Trichloroethane
71-55-6
Trichloroethylene
79-01-6
l,l,2-Trichloro-l,2,2-trifluoroethane
76-13-1
Trichloro-trifluoroethane
l,l,l-Trichloro-2,2,2-trifluoroethane
354-58-5
Tricosane
638-67-5
1,2,3-Trimethyl benzene
1,2,3-Trimethylbenzene
526-73-8
1,2,4-Trimethyl benzene
1,2,4-Trimethylbenzene
95-63-6
1,3,5-Trimethyl benzene
1,3,5-Trimethylbenzene
108-67-8
2,2,4-Trimethyl-l,2-dihydroquinoline (TMQ)
l,2-Dihydro-2,2,4-trimethylquinoline, polymer
26780-96-1
Vinyl Acetate
108-05-4
White gasoline
Natural gasoline
8006-61-9
o-Xylene
95-47-6
Xylenes
1330-20-7
Zn-Dibenzyldithiocarbamate (ZBEC)
136-23-2
Zn-Diethyldithiocarbamate (ZDEC)
Zinc diethyldithiocarbamate
14324-55-1
Zn-Dimethyldithiocarbamate (ZDMC)
Ziram
137-30-4
Zn-dibutyldithiocarbamate (ZDBC)
ZnO
Zinc Oxide
1314-13-2
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Appendix C- Data Collection for Synthetic Turf Fields/Summary of Activity to Date
The agencies finalized the "Federal Research Action Plan on Recycled Tire Crumb Used on
Playing Fields and Playgrounds" (referred to subsequently as the Federal Research Action Plan
or FRAP) in February 2016. EPA and CDC/ATSDR, in collaboration with CPSC, prepared a
research protocol to implement portions of the research activities outlined under the FRAP.
Specifically, the design of the research protocol implemented three of the research elements
described in the FRAP:
• conduct a Literature Review/Gaps Analysis,
• perform tire crumb rubber characterization research,
• perform human exposure characterization research.
Section B and Appendix B of this status report cover the Literature Review/Gaps Analysis.
Section C and this appendix update the two key data collection studies on synthetic turf fields.
One of the studies is an evaluation of tire crumb samples collected from tire crumb
manufacturing plants and from indoor and outdoor synthetic turf fields across the country. The
second is a pilot-scale exposure study that will gather activity data from people who regularly
perform activities on synthetic turf fields.
The protocol document received an external peer-review, as well as reviews by the CDC's IRB
and EPA's Human Subjects Research Review Official (HSRRO). The OMB conducted an ICR
review on the data collection components of the study, and, as part of that process, the agencies
received and addressed public comments. Comments and the agencies' responses are publicly
available on the OMB's website
(http://www.reginfo.gov/public/do/PRAViewDocument7ref nbr=201607-0923-001).
The study team obtained final approval to commence work on August 5, 2016. Field collections
began in mid-August. Collections for the tire crumb characterization component of the study is
complete as proposed. Analysis of the samples is in progress. Recruitment of fields and
participants for the exposure characterization also is in progress.
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Tire Crumb Rubber Characterization
Federal researchers have made substantial progress in developing a research protocol, recruiting
synthetic fields and recycling plants, sample collection, and sample analysis for the tire crumb
rubber characterization research.
1. A research protocol was
- developed by EPA and CDC/ATSDR with input and review by CPSC and the
U.S. Army Medical Command, Army Public Health Center (APHC);
- externally peer reviewed and revised;
- reviewed by the CDC IRB and approved following revision;
- reviewed and approved by the EPA HSRRO;
- reviewed by OMB as an ICR and approved following revision.
2. The study team prepared, reviewed, and approved quality assurance project plans, sample
collection and analysis standard operating procedures (SOPs).
3. The study team achieved recruitment and sample collection goals for recycling plants and
synthetic turf fields through
- field sample collection training provided to members of the APHC and their
subsequent collection of tire crumb rubber samples at 19 synthetic turf fields at
Army installations across the United States;
- recruitment and tire crumb rubber sample collection successfully completed by
CDC/ATSDR and EPA for nine tire recycling facilities across the United States;
- recruitment and tire crumb rubber sample collection successfully completed by
CDC/ATSDR and EPA for 21 "community" synthetic turf fields across the
United States.
4. Laboratory analyses for chemicals, physical properties, and microbes associated with tire
crumb rubber are underway or in preparation at several EPA and CDC laboratories.
An overview of the tire crumb rubber characterization research effort and accomplishments and
additional details regarding the procedures and status are provided below.
Overview
The tire crumb rubber characterization research is intended to characterize a wide range of
chemical, physical, and microbiological constituents and properties for tire crumb rubber infill
material collected from tire recycling plants and synthetic turf fields around the United States
and to assess factors that may affect exposures to these constituents by field users. Substantial
progress has been made in the tire crumb rubber characterization research. Collection of samples
at tire recycling plants and synthetic turf fields has been completed, meeting the research
objectives of collecting tire crumb rubber samples from nine tire recycling plants and 40
synthetic turf fields across the four U.S. census regions. Chemical and microbiological analyses
of the collected tire crumb rubber are underway at several EPA and CDC laboratories.
The tire crumb rubber characterization involves the collection of crumb rubber material from tire
recycling plants and synthetic turf fields around the United States, with laboratory analysis for a
wide range of metals, VOCs, and SVOCs. Laboratory analyses include dynamic emission
chamber measurements for VOCs and SVOCs under different temperature conditions and
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bioaccessibility measurements for metals and SVOCs. The emissions and bioaccessibility
experiments will provide important information about the types and amounts of tire crumb
rubber chemical constituents available for human exposure through inhalation, dermal, and
inhalation pathways. In addition to quantitative target chemical analyses, suspect screening and
nontargeted analysis methods are being applied for VOCs and SVOCs in an attempt to identify
whether there may be potential chemicals of interest that have not been identified or widely
reported in previous research. The study also includes collection of tire crumb rubber infill from
synthetic turf fields to assess microbial populations; however, microbial assessments will not be
conducted for tire crumb rubber collected at tire recycling plants.
IRB/OMB Process and Approvals
As required by the Paperwork Reduction Act, agency researchers submitted the activities under
the FRAP requiring contact with participants to the OMB for review and approval. As part of the
OMB review process, the agencies posted a 60-day FR notice describing the activities on
February 17, 2016. Prior to the end of the 60-day public comment period, the public requested
additional time to submit comments for the 60-day FR notice. A 2-week extension period was
granted, and the public comment period ended on May 2, 2016.
The agencies submitted the Research Protocol to the CDC's IRB for accelerated review on June
17, 2016, and received IRB approval on July 6, 2016. EPA's HSRRO approved the IRB Reliance
on July 6, 2016. On July 11, 2016, ATSDR submitted an emergency request, along with the data
collection package, "Collections Related to Synthetic Turf Fields with Crumb Rubber Infill," to
OMB for review and approval. Agency researchers received final OMB approval on August 5,
2016 and initiated recruitment of community fields August 8, 2016.
Recycling Plant Selection and Recruitment
Researchers aimed to recruit and consent nine tire recycling plants producing tire crumb rubber
for use as synthetic turf infill. The researchers had a second goal of recruiting five plants using
the ambient production process and four plants using the cryogenic production process. ATSDR
and EPA contacted seven companies operating tire recycling plants producing tire crumb rubber
for synthetic turf infill. ATSDR and EPA reached sample collection agreements with six
companies, resulting in successful sample collection at nine recycling plants operated by those
companies around the United States. Six recycling plants used the ambient process, and three
used the cryogenic process.
Synthetic Turf Field Selection and Recruitment
Field Selection Criteria - Researchers aimed to recruit and consent 40 synthetic turf fields with
recycled tire crumb rubber infill, 10 fields in each of the four U.S. census regions. However, if
the study team could not obtain the maximum sample size in a specific U.S. census region by the
end of the recruitment period, researchers enabled a previously consented field in a different
census region to be eligible to participate. The study team defined the target "population" for the
community fields as synthetic turf fields with recycled tire crumb rubber infill and defined the
recycled tire crumb rubber infill as either manufactured with a cryogenic process or an ambient
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process. There were no restrictions on field age, "grass blade" composition or color, or field type
(i.e., soccer, baseball). Researchers requested field size, but that was not a specific exclusion
criterion. The study team excluded synthetic turf fields with encapsulated or colored or painted
crumb rubber from the study and limited participation to two outdoor fields per facility;
however, the fields must meet one of two criteria: (1) the fields must be of different ages, or (2)
the fields must be installed by different manufacturers if the same age. Indoor fields co-located
with outdoor fields were permitted.
U.S. Army Installation Synthetic Turf Fields - The U.S. Army has constructed athletic and physical
training synthetic turf fields at many of its installations. The APHC collaborated in the research
effort through identification of eligible synthetic turf fields at Army installations in the United
States and by collecting tire crumb rubber samples at synthetic turf fields. Following training by
EPA and ATSDR researchers, APHC personnel collected samples at 16 outdoor and 3 indoor
synthetic turf fields between August and September 2016.
Community Synthetic Turf Fields - ATSDR recruited the remaining 21 synthetic turf fields, and
they were sampled by trained ATSDR or EPA staff members. The term "community fields" is
used to represent fields not on military installations (i.e., at parks, schools, etc.). ATSDR/EPA
used a convenience sampling approach for the recruitment and consent of facilities with
synthetic turf fields. Researchers found prospective facilities using the search engine website
Google and the following key search terms: "recreational fields," "sports training facilities,"
"sports training," "sport fields," "sporting fields," "soccer fields," "baseball fields," "football
fields," and "parks and recreation." The researchers followed these key search terms by the state
or area of focus. For example, a search would be "recreational fields in Georgia." Often, these
searches provided the address, contact information, and website about the prospective facilities
in the target area. Additionally, the study team allowed self-identification of facilities with
synthetic turf fields. For inclusion in the study, agency researchers required agreement to
recycled tire crumb rubber sample collection and answering a questionnaire on field maintenance
procedures and field use.
Researchers initiated contact with potential facilities and fields on August 8, 2016 and classified
responses to initial contacts in six categories: (1) no answer (a voicemail was left if applicable);
(2) incorrect contact person (correct contact information was requested); (3) immediate
declination; (4) requested additional information; (5) noneligible (i.e., grass field); and (6) verbal
consent. The researchers limited contact with facilities to five times for those in categories 1 and
2. For those requesting additional information, the researchers sent a fact sheet describing the
study and the facility agreement form via email. For those agreeing, researchers administered the
eligibility screening and sent the agreement form to those facilities deemed eligible. The
researchers categorized eligible fields as indoor or outdoor and by age (2008 or older, 2009 to
2012, and 2013 to 2016). The researchers contacted weekly the facilities verbally agreeing to
participate until (1) obtaining written consent, (2) the maximum number of facilities consented
for census region, or (3) the project recruitment period ended.
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Once written consent was obtained from the field owner, the research team scheduled a date and
time for sample collection. The study team provided a questionnaire regarding facility
installation, use, and maintenance to each facility or field prior to computer-assisted
administration via telephone.
Between August and November 2016, the researchers contacted a total of 306 community field
owners (Table C-l). The researchers obtained participation agreement and completed sample
collection at 21 fields, including 9 outdoor fields and 12 indoor fields (Tables C-2 and C-3).
For those immediately declining participation in the study, researchers requested information
regarding the declination. In general, those declining to participate gave reasons that were
limited to three main issues.
• Liability: Many field owners and managers expressed concern about the potential liability
associated with sampling their fields. Specifically, the concerns centered around the potential for
specific actions that would need to be taken based on the outcome of the study.
• Confidentiality: As expressed in the agreement forms, EPA/ATSDR will not be releasing
individual facility names or results in the public reports; EPA/ATSDR will release the number of
fields sampled per U.S. census region. However, EPA/ATSDR could not assure the facility of
complete anonymity or confidentiality.
• Not at this time: Although many field owners and managers were interested in the study, they
declined participation in the current study.
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Table C-l. Community field recruitment efforts
Region
Contacted21
Ineligible
Refusedb
Participated
Northeast
118
22
20
5
Midwest
96
10
9
8
South
40
11
13
2
West
52
8
9
6
Total
306
51
51
21
facilities with more than one field were only counted as n=l.
facilities that did not return phone calls or other attempts (i.e., email) at recruiting are not
included in the number of refusals; however, the majority of fields contacted that were not
included in the ineligible column, the refused column, or the participated column were facilities
that failed to respond to recruitment attempts.
Table C-2. Synthetic Turf Field Final Recruitment and Sampling Status
U.S. Army Total
Community Fields Fields (Army and Community)
Region Consented/Sampled Sampled Fields Sampled
Northeast 4 5 9
Midwest 8 0 8
South 5 8 13
West 4 6 10
Total 21 19 40
Table C-3. Outdoor and Indoor Synthetic Turf Field Final Sampling Status
Region
Outdoor Fields
Indoor Fields
Total
Fields Sampled
Northeast
5
4
9
Midwest
2
6
8
South
11
2
13
West
7
3
10
Total
25
15
40
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Recycling Plant Sample Collection
Researchers collected recycled tire crumb rubber samples of the size category used in synthetic
turf fields (typically 10 to 20 mesh) from nine tire recycling plants around the United States. The
samples collected were from three different storage containers at each plant. For each storage
container, the study team filled two 1-1 high-density polyethylene (HPDE) jars for metals
analysis, two 1-1 amber glass jars for organic chemical analysis, and one 1-1 HPDE jar for
particle characterization. At most plants, the study team used precleaned stainless steel scoops to
gather tire crumb rubber into precleaned and certified 1-1 amber glass wide-mouth jars with
Teflon-lined lids for organics analysis. Researchers used precleaned plastic scoops to gather tire
crumb rubber into precleaned and certified 1-1 polyethylene wide-mouth jars for metals analysis
and particle characterization. At one plant, researchers collected samples from storage bags using
a stainless steel sampling spike designed to include material from multiple levels of the storage
bag in the vertical and horizontal dimensions using that plant's established equipment and
protocol.
The study team enrolled nine plants located across all four census regions. Three of the plants
used a cryogenic process for creating tire crumb rubber, whereas the remaining six plants used
the ambient process. Researchers generated a total of 27 samples for organic chemical analysis
(including emissions testing and bioaccessibility analysis), 27 samples for metals analysis
(including bioaccessibility analysis), and 27 samples for particle characterization.
Synthetic Turf Field Sample Collection
Researchers collected tire crumb rubber samples from 40 synthetic turf fields to support
characterization of chemical constituents and to examine microbial species. Chemical
characterization includes analysis of SVOC and metal analytes in tire crumb rubber,
bioaccessibility analysis of SVOCs and metals from tire crumb rubber, and emissions testing of
VOCs and SVOCs from tire crumb rubber.
Substantial variability in tire crumb rubber chemical concentrations have been reported;
therefore, researchers used a composite sample collection approach at synthetic turf fields.
Researchers collected individual samples from seven locations at each field separately for
SVOC, metal, microbial, and particle characterization analyses. Researchers used specified
sampling locations for different types of fields (e.g., rectangular fields and baseball fields). To
support between-field assessments, the study team returned the individual location samples to the
laboratory where a composite sample was created from the seven individual location samples. To
support within-field variability assessment of chemical constituents, researchers identified some
of the individual location samples from a subset of five fields for separate analyses. For
microbial analyses, the study team scheduled all seven of the individual location samples from
each field for separate analyses.
Information about the synthetic turf field locations in the four U.S. census regions and the
number of outdoor and indoor fields in each region is shown in Table C-4. Researchers collected
samples from between 8 and 13 fields in each census region and from 25 outdoor fields and 15
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indoor fields. One field was a baseball/softball field, three were Army physical training fields,
and the remainder were soccer/football-type playing fields. Field installation dates ranged from
2004 to 2016.
Table C-4. Samples Collected for Analyses at Synthetic Turf Fields
Individual Location Samples Collected Across 40 Fieldsa
Total
Composite
Samples
Prepared0
Region
For Organic
Chemical
Analysis
For Metals
Analysis
For Particle
Characterization
For
Microbial
Analysis
Northeast
63
63
63
63
18
Midwest
56
56
56
56
16
South
91
91
91
91
26
West
70
70
69b
70
20
Total
280
280
279
280
80
aAt each field, samples were collected from seven individual locations.
bThe cap came off of one sample collection container during transport.
Tor each synthetic turf field, one composite sample was prepared in the laboratory from the
seven individual location samples for organic chemical analyses and one composite sample was
prepared for metals analyses.
The study team collected tire crumb rubber samples for SVOC samples using a small handheld
metal rake to pull tire crumb rubber from the field at each location. The collection depth in the
field was no more than about 3 cm from the surface. Researchers placed collected tire crumb
rubber into certified precleaed 250-ml amber glass wide-mouth containers with Teflon-lined lids.
For metals samples, researchers used a small handheld plastic rake to pull tire crumb rubber from
the field at each location, with the collection depth no more than about 3 cm from the surface.
The study team placed collected tire crumb rubber into certified precleaned 250-ml polyethylene
wide-mouth containers. For samples to be used for particle characterization, researchers used a
small handheld plastic rake to pull tire crumb rubber from the field at each location, with the
collection depth no more than about 3 cm from the surface and placed collected tire crumb
rubber into certified precleaned 250-ml polyethylene wide-mouth containers. Researchers
incorporated an alternate tire crumb rubber collection technique using spatulas as required at
some fields, particularly older fields with greater wear and higher blade and rubber compression.
The study team prepared a single composite sample from the seven SVOC samples for each field
at a central processing laboratory. Researchers added a weighed amount (approximately 35 g) of
the tire crumb rubber material from each of the seven individual location samples to a single
certified precleaned 500-ml amber wide-mouth glass container with Teflon-lined lid and mixed
the composite sample thoroughly. Researchers then removed subsamples of the composite
sample and added them to smaller precleaned and certified amber glass containers to distribute to
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the analysis laboratories. Researchers retained the remaining individual samples in their sealed
containers and stored all samples in a freezer at -20 °C. Researchers used the same procedure to
prepare composite samples for metals analysis using certified precleaned HPDE containers.
Researchers also prepared subsamples for analysis from individual field locations to support
analyses from individual field locations for a subset of five fields. For particle characterization
analysis, the study team combined the entire contents from each 25-ml individual location
container prior to analysis.
Researchers also collected tire crumb rubber samples from synthetic turf fields to support
microbiome analysis but did not analyze samples collected from tire recycling plants for
microbes. Researchers collected individual samples from each field at all seven locations that
were also used for metals and organic analysis sample collections. The study team employed
aseptic techniques while collecting and handling samples and sampling equipment by wearing
clean nitrile gloves at all times and donning new gloves at each of the seven field locations to
handle the sample collection container and sampling equipment. The researchers wore a new
disposable lab coat during sample collection and used a sterile polypropylene spatula to collect
each sample and used a new spatula at each of the seven locations. The researchers inserted the
sterile spatula into the athletic field surface to maximum depth of about 3 cm from the surface
and moved it forward to collect tire crumb material. The researchers added the tire crumb rubber
to a new sterile 50 ml polypropylene container with volumetric lines at each of the seven
locations. The researchers filled the containers with tire crumb rubber material to the 25-ml line.
Once samples were collected, the study team placed them immediately into a cooler with ice
packs and shipped the samples the same day they were collected in a container with ice packs to
the appropriate laboratory by overnight shipment. The study team kept the samples separate for
analysis of all individual location samples collected at all fields.
Table C-5 shows the total number of samples and subsamples prepared for the range of analyses
to be applied. This table includes the totals from both tire recycling plants and synthetic turf
fields. The table does not include quality control samples and analyses.
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Table C-5. Number of Recycling Plant and Synthetic Turf Field Tire Crumb Rubber
Samples Prepared for Analysesa,b
Number
Number of
of
Total
Composite
Individual
Number of
Sample Type
Samples
Samples
Samples
Direct Constituent Analysis
Samples for metals constituent ICP/MS analyses
40
60
100
Samples for metals constituent XRF analyses
40
60
100
Samples for targeted SVOC constituent LC/MS analyses0
40
62
102
Samples for targeted SVOC constituent GC/MS analyses0
40
62
102
Dynamic Chamber Emissions Experiments
Chamber experiments for VOCs at 25 °C
40
42
82
Chamber experiments for VOCs at 60 °C
40
42
82
Chamber experiments for SVOCs at 25 °C
40
42
82
Chamber experiments for SVOCs at 60 °C
40
42
82
Emissions Sample Analyses
Samples for targeted VOC emissions analyses0
80
84
164
Samples for formaldehyde emissions analyses
80
84
164
Samples for targeted SVOC emissions LC/MS analyses0
80
84
164
Samples for targeted SVOC emissions GC/MS analyses0
80
84
164
Particle Characterization Analysis
Particle size characteristics
40
27
67
Scanning electron microscopy
40
27
67
Microbial Sample Analysis
Samples for microbial analyses - targeted
0
280
280
Samples for microbial analyses - non-targeted
0
280
280
Bioaccessibilitv Analysis
Samples for metals bioaccessibility - simulated saliva
40
42
82
Samples for metals bioaccessibility - simulated gastric
40
42
82
Samples for metals bioaccessibility - simulated sweat
40
42
82
Samples for SVOC bioaccessibility analyses - simulated saliva
40
42
82
Samples for SVOC bioaccessibility analyses - simulated gastric
40
42
82
Samples for SVOC bioaccessibility analyses - simulated sweat
40
42
82
aDoes not include quality control/quality assurance samples or analyses; does not include chamber background samples.
bThe total numbers of samples are based on 40 synthetic turf field composite samples, 15 to 35 synthetic turf field individual
location samples, and 27 individual recycling plant samples from 9 recycling plants; except for microbial analysis where all 280
individual synthetic turf field location samples are scheduled for analysis.
cIn addition to analysis for target analytes, 12 of the samples will be selected for non-targeted analysis.
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Tire Crumb Rubber Characterization Sample Analyses
Laboratory analyses for a wide range of chemical, physical, and microbiological constituents and
properties for tire crumb rubber infill material collected from tire recycling plants and synthetic
turf fields around the United States is in progress or in preparation to begin. Although other
research studies have examined crumb rubber constituents, most studies have been relatively
small, restricted to a few fields or material sources, and measured a limited number of
constituents. In this study, tire crumb rubber samples collected directly from tire recycling plants
will provide information on constituents in unused material, and samples collected from outdoor
and indoor synthetic turf fields will provide a better understanding of constituents potentially
available for exposure under different conditions of weathering and facility type.
Characterization will include direct measurement of metal and SVOC constituents of tire crumb
rubber, studies of VOC and SVOC emissions and emission rates from tire crumb rubber, and
bioaccessibility testing of metal and SVOC constituents. Multiple analytical methods will be
used to provide information on a wide range of metals and organic chemicals. A combination of
targeted quantitative analysis, suspect screening, and nontargeted approaches will be applied for
VOCs and SVOCs. The research will help fill data gaps regarding the types and concentrations
of the chemical constituents in crumb rubber material and their potential availability for human
exposure. Physical characteristics, such as particle size, will be examined to better understand
potential exposures. The research also will address gaps in the knowledge regarding microbial
pathogens associated with tire crumb rubber on synthetic turf fields.
Table C-6 shows the status of the laboratory analyses. Researchers are performing direct
constituent analyses for metals by inductively coupled plasma mass spectrometry (ICP/MS) and
x-ray fluorescence (XRF) analyses. Researchers also are extracting tire crumb rubber samples for
quantitative and suspect screening analyses for many SVOCs by both gas chromatography/mass
spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS) methods
(including LC/MS in both positive and negative ion modes). In addition to direct constituent
analyses, emissions testing and bioaccessibility experiments will provide important information
about the types and amounts of tire crumb rubber chemical constituents available for human
exposure through inhalation, dermal, and inhalation pathways. Researchers also are performing
dynamic emission chamber measurements for SVOCs using microchambers and for VOCs
(including formaldehyde) using small chambers at both 25 °C and 60 °C. In addition to
quantitative target chemical analyses, the study team will apply suspect screening and
nontargeted analysis methods for VOCs and SVOCs in an attempt to identify whether there may
be potential chemicals of interest that have not been identified or widely reported in previous
research. Preparation is underway for bioaccessibility measurements for metals and SVOCs
using simulated saliva, gastric, and sweat fluids. Researchers are assessing tire crumb rubber
particle size using separation and gravimetric approaches and particle morphology using
scanning electron microscopy. Researchers are using both nontargeted (polymerase chain
reaction [PCR]) and targeted (droplet digital polymerase chain reaction [ddPCR]) DNA testing to
characterize microbial species on tire crumb rubber infill collected from synthetic turf fields.
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Table C-6. Status of Laboratory Analyses for Tire Crumb Rubber Characterization
Sample Type Status
Direct Constituent Analysis
Metals constituent ICP/MS analyses
Metals constituent XRF analyses
SVOC constituent LC/MS analyses
SVOC constituent GC/MS analyses
In progress
In progress
In preparation
In preparation
Dynamic Chamber Emissions Experiments
Chamber experiments for VOCs in TCC at 25 °C
Chamber experiments for VOCs in TC at 60 °C
Chamber experiments for SVOCs in TC at 25 °C
Chamber experiments for SVOCs in TC at 60 °C
Completed
Completed
Completed
Completed
Emissions Sample Analyses
VOC emissions analyses
Formaldehyde emissions analyses
SVOC emissions LC/MS analyses
SVOC emissions GC/MS analyses
Particle Characterization Analysis
Particle size characteristics
Scanning electron microscopy
In progress
In progress
In progress
In progress
In progress
In preparation
Microbial Sample Analysis
Microbial analyses - targeted
Microbial analyses - nontargeted
Bioaccessibilitv Analysis
Metals bioaccessibility analyses
SVOC bioaccessibility analyses
In progress
In progress
In preparation
In preparation
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Exposure Characterization
Researchers have made progress in several exposure characterization research activities.
• As described in Section C. 1, a research protocol was developed, reviewed, and approved,
which included the exposure characterization research elements.
• Quality assurance project plans and activity data collection and sample collection SOPs
were prepared.
• Exposure and activity assessment questionnaires were developed for adult and child
synthetic turf field users.
• Identification of extant public video data collection for synthetic turf field users is in
progress.
• Preparation of sampling equipment and materials for the exposure measurement study is
in progress.
• Recruitment of exposure study research participants is in progress.
An overview of the exposure characterization study and additional details regarding the
procedures and status are provided below.
Overview
The tire crumb rubber characterization research activities described in the Tire Crumb Rubber
Characterization Section are important and necessary to reduce gaps in the understanding of
what chemical, physical, and microbial constituents and properties may be of interest or concern.
However, that information cannot be put into proper context with regard to potential impacts on
human health without understanding exposure. The exposure characterization study component
is a pilot-scale effort to collect information on human activity parameters for synthetic turf field
users that affect potential exposures to tire crumb rubber constituents and to implement a human
exposure measurement study to further develop and deploy appropriate sample collection
methods and to generate data for improved exposure characterization.
There are important data gaps in human activity parameters for various synthetic turf field users
that are needed for estimating exposures and evaluating risks from contact with tire crumb rubber
constituents. Although the potential for inhalation exposures has been characterized for some
constituents, there is far less information for characterizing dermal and ingestion exposure
pathways. Improved exposure factor information is needed for estimating and modeling
exposures from the inhalation, dermal, and ingestion pathways. Goals for this research include
collecting information using questionnaires from adults and youth who use synthetic turf fields
with crumb rubber infill for several types of active uses. Video data collection for a subset of
participants engaged in activity on synthetic fields is intended to obtain objective information
about important dermal and ingestion contact rates. Extant videography of users engaged in
activities on synthetic fields is intended to provide additional data on contact rates for people
using synthetic turf fields that are difficult to capture consistently using questionnaires. The pilot
exposure study is intended to develop and assess questionnaire and video approaches for activity
data collection.
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Human exposure measurement data for synthetic turf field users are also limited. Important data
gaps exist, particularly for potential dermal and ingestion exposures to synthetic turf field and
tire crumb rubber chemical constituents. There are also important limitations in the types of
methods that have been developed and used for human exposure measurements during activities
on synthetic fields. Challenges include collecting relevant surface, dust, and personal air
samples. Few studies have performed measurements of dermal exposures. In addition, few
studies have collected urine or blood samples that might be used for measuring biomarkers of
exposures to chemicals in crumb rubber infill. As a pilot-scale effort, this study is intended to
implement a human exposure measurement study to further develop, deploy, and assess
appropriate sample collection methods and to generate data for improved exposure
characterization.
Activity Questionnaire
Researchers have developed two questionnaires to collect activity information from synthetic
turf field users, one for adults and one for children (to be completed by an adult parent or
caregiver). Researchers designed the questionnaire to collect information about characteristics
and activity parameters that may affect the magnitude, frequency, and duration of exposure to
tire crumb rubber infill constituents, including
• frequency of field use across a range of activity types,
• duration of field use across a range of activity types,
• levels of physical exertion that affect breathing rates,
• contact rates for different types of activities,
• clothing types and uses,
• demographic characteristics.
The researchers have coded the questionnaires into EpiSuite software for computer-assisted
interviewing and will administer at fields the questionnaires to synthetic turf field users who
engage in a sport or activity that brings them into contact with field materials. Researchers will
recruit participants at community fields that took part in the tire crumb rubber characterization
study. Participant recruitment is in process.
Extant Publicly-Available Video Activity Data Collection
The study team is identifying publicly available videos (e.g., YouTube) for collection of activity
pattern data for adults, adolescents, youth, and children playing and practicing on artificial turf
fields that contain tire crumb rubber infill at athletic facilities. Researchers are collecting the
extant videography to provide an objective assessment of user activity patterns potentially
impacting exposure to chemicals found in tire crumb rubber infill that are difficult to capture
consistently using questionnaires. Researchers also are collecting the videography to record
specific types of activity data, including type of activity or sport; type of field (e.g., indoor or
outdoor); participant's age group; durations of rest or low, moderate, and high activity; and hand-
to-mouth, object-to-mouth, and skin-to-surface contact rates on turf. Researchers have identified
approximately 45 of the goal of 60 activity videos to date, with between 30 and 60 minutes of
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videotaped footage of discrete individuals engaged in sporting activities on artificial turf fields.
The study team will complete video identification and perform a structured extraction of the
specified activity data elements.
Videography of Exposure Measurement Study Participants
Researchers will use videography to collect activity pattern data on a subset of exposure
measurement study participants who routinely play on artificial turf fields that contain tire crumb
rubber infill at athletic facilities. The purpose of the video data collection is to supplement the
information obtained from the facility user questionnaire on the participants' activity patterns
that may impact the magnitude and frequency of their exposures to chemicals found in tire
crumb rubber infill. The study team will videotape participant's activities for up to 1 hour while
playing or practicing sports at the facilities. Researchers have prepared equipment and SOPs for
collecting video from synthetic turf field users who agree to participate in the exposure
measurement study (see below).
Exposure Measurement Pilot Study
The study team will recruit adults and youth who use synthetic turf fields with tire crumb rubber
infill for participation in an exposure measurement pilot study. Researchers will collect a set of
personal, biological, and field environment samples around a sport or training activity performed
on a synthetic turf field. Researchers will analyze personal and environmental samples for metal,
VOC, and SVOC analytes and subject a subset of SVOC samples to suspect screening and
nontargeted analysis. Researchers will hold biological samples in a biorepository for future
analysis once potential biomarker chemicals of interest are identified based on the tire crumb
rubber and exposure characterization studies. As noted above, the researchers also will ask a
subset of participants to allow videography of their on-field activities. The study team has
prepared equipment, materials, and SOPs for collecting most of the proposed sample types (see
Table C-7). Researchers also have performed several on-field method assessment experiments
toward development of a synthetic field vacuum dust collection method; however, we have not
yet finalized a suitable method.
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Table C-7. Types of Samples for Exposure Characterization Measurements
Number of
Samples Per Person or
Sample Type Locations Per Field Analytes
Personal Samples
Air
Dermal
Dermal
Urine
Urine
Urine
1
3
3
2
2
2
VOCs
SVOCs
Metals
PAH metabolites
Metals
Creatinine
Blood
Serum
2
2
Metals
Metals
Facility Samples
Air
Air
Air
Surface wipe (drag sled)
Surface wipe (by hand)
Surface wipe (by hand)
Dustb
Dustb
Dustb
3a
3a
3a
3
3
3
3
3
3
VOCs
SVOCs
Particulates/Metals
SVOCs
SVOCs
Metals
SVOCs
Metals
Characterization
includes one off-field background location for each field and two on-field locations.
bAdditional dust sample collection method development is required.
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Appendix D - Playground Surfaces with Recycled Tire Materials
The U.S. Consumer Product Safety Commission (CPSC) is an independent federal agency
charged with protecting the public from unreasonable risks of injury and death associated with
the use of the thousands of types of consumer products under the agency's jurisdiction. The
Federal Research Action Plan on Recycled Tire Crumb Used on Playing Fields and Playgrounds
identifies the CPSC as a partner in the research activities conducted by the EPA and ATSDR.
The CPSC's role in the Federal Research Action Plan is to assess the risks associated with the
use of recycled tire crumb rubber in playground surfaces, while the EPA and ATSDR investigate
tire crumb rubber and its uses on synthetic turf athletic fields.
The Federal Research Action Plan differentiates playing fields from playgrounds without
defining these terms. The CPSC has not published an official definition of a "playground." For
this research activity, the CPSC staff has interpreted a "playground" to be a designated area
intended for recreational play that includes engineered recreational equipment including, but not
limited to, climbing structures, swings, slides, seesaws. Many modern playgrounds have
structures that integrate multiple pieces of playground equipment. A "use zone" as defined in the
CPSC's Public Playground Safety Handbook,15 is the surface under and around a piece of
equipment onto which a child falling from or exiting from the equipment would be expected to
land (CPSC, 2010). The scope of the CPSC's review of playground surfacing made from
recycled tire materials includes the surfaces found in the use zone and extending to the
playground border.
Playground surfaces differ from synthetic turf fields in their construction and purpose. Synthetic
turf fields are intended to be lower-maintenance and reduce certain injuries sustained while
playing field sports, in comparison to natural turf. Modern playground surfaces are intended to
reduce the risk of injury and death from vertical falls from playground equipment, compared to
harder surfaces. A recent study of 2,691 playground equipment-related incidents reported to the
CPSC from 2001 to 2008 indicated that falls are the most common hazard (44% of injuries) on
playgrounds (O'Brien, et al., 2009). The CPSC has periodically published and revised the Public
Playground Safety Handbook since 1981, to promote safety awareness to those who purchase,
install, and maintain public playground equipment used by children ages 6 months through 12
years. The current version of the handbook was published in 2010 (CPSC, 2010). The handbook
includes guidelines on playground surfacing. A "public" playground refers to the playground
areas of commercial (non-residential) child care facilities, institutions, multiple family dwellings,
such as apartments and condominium buildings, parks (city, state and community maintained),
restaurants, resorts and recreational developments, schools, and other areas of public use (CPSC,
2010). The CPSC (2005) also published the Outdoor Home Playground Safety Handbook16 to
provide similar guidance for playgrounds at homes and residential child care facilities.
The recommendations in the Public Playground Safety Handbook are intended as guidelines and
are not mandatory rules. However, many state and local jurisdictions adopt the recommendations
in the Public Playground Safety Handbook as enforceable rules for public playgrounds. In
15 The Public Playground Safety Handbook is available at https://www.cpsc.gov/s3fs-pnblic/325.pclf
16 The Outdoor Home Playground Safety Handbook is available at httpsi//www.cpsc.gov/s3fs-public/324.pdf.
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addition to addressing hazards such as sharp edges and strangulation, the recommendations
include those that address the potential for falls from, and impact with, equipment as well as the
need for impact-attenuating protective surfacing under and around equipment. In December
2015, the CPSC attached an addendum to the front of the Public Playground Safety Handbook to
clarify that "... Section 2.4 of the Handbook identifies shredded/recycled rubber mulch as an
'Appropriate Surfacing' product, given that this product can meet the impact attenuation
requirements of ASTM F1292, as long as minimum depths of the material are maintained, as
specified in Table 2 of Section 2.5. This notation is solely focused on the impact attenuation to
minimize serious head injuries and not on other aspects that may pose other risks, such as
chemical exposure or ingestion" (CPSC 2010). The CPSC's studies of recycled tire materials
used in playground surfacing per the Federal Research Action Plan seek to improve
understanding of potential chemical hazards to children using playgrounds.
CPSC Activities Supporting the Federal Research Action Plan
In 2016, the CPSC began several activities to gather information about the chemical safety of
recycled tire materials in playground surfacing. As described in the Federal Research Action
Plan, the CPSC joined its partner agencies, EPA and ATSDR, in the general activities of the
recycled tire crumb rubber research effort, which include:
• conducting data knowledge gap analysis
• reaching out to key stakeholders
• characterizing the chemical composition of recycled tire crumb rubber,
• characterizing human exposures to recycled tire crumb rubber.
The Federal Research Action Plan includes data collection efforts by the federal partners, which
would support future risk assessments of recycled tire crumb rubber used in fields and
playgrounds. However, the partner agencies have not yet determined whether comprehensive
risk assessments of recycled tire crumb rubber used in fields and playgrounds will be needed to
determine if there are human health risks.
Playground Surface Types
While recycled tire crumb rubber is used with few variations as infill on synthetic turf athletic
fields, a wider variety of options for recycled tire materials of various sizes and shapes is
marketed for use as playground surfacing. CPSC staff used a combination of resources to gather
information about how recycled tire materials are used in playground surfacing. These resources
included ASTM voluntary standards regarding playground surfacing, online marketing websites
for playground surfacing manufacturers and installers, in-person tours of tire recycling facilities,
public meetings with representatives of the Synthetic Turf Council and the Recycled Rubber
Council, research on playground surface installation and rubber tile production, and visits to
public playgrounds in the Washington, D.C., metropolitan area. In addition, CPSC staff reviewed
a guide for choosing playground surfaces for compliance with the Americans with Disabilities
Act, published by the International Playground Equipment Manufacturers Association17
(IPEMA, 2013). Based on these resources, meetings and observations, CPSC staff identified five
general types of playground surfaces that are made with recycled tire materials: (1) loose-fill
17 Choosing IPEMA-Certified Playground Surfacing to Meet ADA Requirements, A Resource is available at
http://www.ipema.org/docnments/IPEMA%20InstaHation%20Gnide Final.pdf.
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rubber, (2) rubber tiles, (3) poured-in-place, (4) bonded rubber, and (5) synthetic turf. Other non-
rubber surfacing types commonly found on playgrounds include loose-fill wood products (e.g.,
mulch, chips, and engineered wood fiber), sand, and pea gravel. These non-rubber options are
not addressed in the Federal Research Action Plan. Additionally, this review does not include the
use of playground equipment (e.g., tire swings or climbing structures) made from whole or
partial tires. The Public Playground Safety Handbook describes that appropriate playground
surfacing should be designed and tested to comply with ASTM F1292-13, Standard
Specification for Impact Attenuation of Surfacing Materials Within the Use Zone of Playground
Equipment18 (CPSC, 2010; ASTM International, 2013b).
Playground surfaces can be divided into two main categories: loose-fill systems and unitary
systems. A loose-fill system consists of small, independent, moveable components, such as sand,
gravel, wood chips, engineered wood fiber, rubber particles, and similar materials (ASTM
International, 2015a). A unitary system consists of one or more components bound together, such
as foam composites, urethane/rubber systems, like prefabricated blocks, tiles, or mats, or as
poured-in-place and similar materials (ASTM International, 2015a).
Loose-Fill Rubber is a loose-fill system consisting of rubber nuggets or buffings and is
sometimes described as rubber mulch. Nuggets are rubber granules, irregular in shape, with a
maximum dimension of approximately 3/8 in. to 7/8 in. (9.5 mm to 22.2 mm) (ASTM
International, 2014a). Buffings are elongated rubber strands with approximate dimensions of
0.039 in. to 0.375 in. thick (1 mm to 9.5 mm), 0.039 to 0.50 in. (1 mm to 12.7 mm) wide, and
0.079 in. to 3.0 in. (2 mm to 76.2 mm) long (ASTM International, 2014a). The nuggets or
buffings are typically created from recycled tires. Rubber mulch intended or marketed for
landscaping or gardening uses may not be appropriate for use as a playground surfacing;
consumers should verify on the packaging or product label that it is safe for use on playgrounds.
All playground surfacing should comply with the impact attenuation standards per ASTM
F1292-13 (ASTM International, 2013). The Public Playground Safety Handbook describes that a
6-inch depth of loose-fill rubber protects to a fall height of 10 feet (CPSC, 2010). ASTM F3012-
14 describes specifications for loose-fill rubber as a playground surface and includes standards
for rubber particle size, hazardous metal content, total lead content, tramp metal content, and
sharp tramp metal content (ASTM International, 2014a). Loose-fill surfacing requires frequent
maintenance to ensure surfacing levels never drop below the minimum depth. Areas under
swings and at slide exits are more susceptible to displacement; special attention must be paid to
maintenance in these areas. In addition, wear mats can be installed in these areas to reduce
displacement. The Public Playground Safety Handbook notes that loose-fill systems should be
avoided for playgrounds intended for toddlers (CPSC, 2010).
Rubber Tiles provide a unitary system consisting of factory-formed tiles, mats, or pavers made
of an energy-absorbing material, such as recycled tire rubber. Rubber pieces of varying sizes are
formed into solid design shapes with pressure and heat and/or a binder such as polyurethane.
Tiles are considered low maintenance. Some manufacturers produce tiles with surface coatings
to provide color options and/or durability from wear. The Public Playground Safety Handbook
and ASTM standards do not provide specific recommendations for rubber tile playground
18 All ASTM standards can be found at: Mte
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surfacing, except that all playground surfacing should comply with the impact attenuation
standards per ASTM F1292-13 (CPSC, 2010; ASTM International, 2013).
Poured-in-Place (PIP) describes a unitary system that consists of a combination of rubber
crumb, chips, or rubber buffing, or all three, with a polymer binder in specific percentages
determined by the manufacturer/installer that is mixed proximate to the playground and poured
in one or more layers on a prepared base to provide a smooth and seamless surface. The poured-
in-place surface is generally installed in two layers, with the lower layer being a cushioning layer
and the top being a wearing course (ASTM International, 2012). The wear-coarse layer usually
consists of ethylene propylene diene monomer (EPDM) or thermoplastic vulcanizate (TPV)
particles mixed with a polymer binder. Polyurethane is commonly used as the polymer binder.
The wear-coarse layer may be colored for cosmetic effect and provides a durable contact surface
to protect the cushioning rubber crumb layer from wear and erosion. ASTM F2479-12 describes
the standards for specification, installation, and maintenance of PIP surfacing (ASTM
International, 2012). All playground surfacing should comply with the impact attenuation
standards per ASTM F1292-13 (ASTM International, 2013).
Bonded Rubber describes a type of PIP system that is typically made with a single layer of
buffing-size rubber particles mixed with a polymer binder and less densely applied than the two-
layer PIP systems described above. Bonded rubber often provides a lower-cost option than other
unitary surfaces, and it is porous, allowing water to flow through it. Bonded rubber surfacing is
not specifically described in the Public Playground Safety Handbook or ASTM standards
(CPSC, 2010). Because it is a type of PIP surfacing, ASTM F2479-12 standards should apply, as
well as the impact attenuation standards per ASTM F1292-13 (ASTM International, 2012;
ASTM International, 2013).
Synthetic Turf is an engineered artificial grass product that gives a playground surface the
appearance of natural grass but offers impact attenuation protection. Less information is
available on synthetic turf as a playground surface type than for the loose-fill and PIP surfaces.
Synthetic turf used on playgrounds appears to differ from the synthetic turf used on athletic
fields. A review of the marketing material {i.e., websites) for synthetic turf on playgrounds
indicates that it consists of an artificial grass "carpet" installed over a PIP unitary system
(buffing or crumb-size rubber) or a layer of porous closed-cell composite or other cushioning
material. Synthetic turf on playgrounds may include an infill material to support the artificial
grass blades. However, CPSC staff was unable to find any installers that advertise the use of
recycled tire crumb rubber as an infill as it is used in athletic fields. Sand with or without a
polymer coating appears to be the most common infill material used on playground turf. The
Public Playground Safety Handbook does not address synthetic or artificial turf as a playground
surfacing material (CPSC, 2010). The published ASTM standards for synthetic turf appear to be
specific to turf used on athletic fields and not playgrounds (ASTM International, 2009a, 2009b,
2015b, 2014b, 2011, 2015c, 2016). However, because the sub-turf layer appears to be a type of
PIP surfacing, ASTM F2479-12 standards should apply, as well as the impact attenuation
standards per ASTM F1292-13 (ASTM International, 2012; ASTM International, 2013).
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Distribution of Playgrounds in the U.S.
No information was found regarding the total number of public playgrounds in the U.S. One
survey reports that there are 13,486 public park playgrounds in the 75 largest cities in the U.S.,
with a median value of 2.3 playgrounds per 10,000 residents of those cities (The Trust for Public
Land, 2016). CPSC staff presumes the actual count of public playgrounds would be several-fold
higher, because large regions of the country are not captured in the Trust for Public Land survey.
The survey does not capture public/private schools, child care facilities, restaurants, or
residential housing developments. Additionally, CPSC staff did not find information about
whether there are regional variations or preferences for any of the five playground surface types
described above.
Literature Review/Gaps Analysis for Playgrounds
The interagency Literature Review/Gaps Analysis (LRGA) report is presented in Appendix B of
this status report. Thorough searches of scientific literature databases for studies of recycled tire
crumb rubber and its uses on athletic fields and playgrounds identified 95 references for
consideration. Seven of these were not included in the final analysis because they were not
directly related to the scope of the project. Of the remaining 88 relevant references, eight were
identified by the LRGA team that specifically examined "playground" environments with
recycled tire surfacing. Descriptions of these references and others identified by CPSC staff are
provided below. Some references identified in the literature searches use the term "playground"
to describe playing fields or athletic fields and do not refer to children's playgrounds as
recognized by the CPSC. These studies (Bocca, et al., 2009; Kim, et al., 2012b; Menichini, et al.,
2011) were included in the LRGA review for recycled tire crumb rubber on fields, but they were
excluded from the CPSC's specific review of playgrounds.
Two reports described original laboratory studies of direct health effects of playground surfacing
made of recycled tire rubber.
Birkholz, et al. (2003) tested a dimethyl sulfoxide (DMSO) extract of tire crumb rubber in a
series of three in vitro screening assays for genetic toxicity. No signs of mutagenicity or other
genetic toxicity, with or without metabolic activation, were reported. The researchers also
performed a battery of aquatic toxicity assays using bacteria, invertebrates, fish and algae. The
test materials were water leachates of both new tire crumb rubber and samples of tire crumb
rubber collected from a playground 3 months after application on the playground (the
playground surface type was not specified). All leachate samples were found to be toxic to all
test species; but when potency was quantified, the aqueous leachate from 3-month-old tire crumb
rubber collected at a playground was 59 percent less potent than leachate from unused tire
crumb. The authors concluded: "the use of tire crumb in playgrounds results in minimal hazard
to children and the receiving environment. " Limitations of this study for evaluating the potential
health effects of recycled tire material on playgrounds include: (1) the genetic toxicity assays
reported only address one possible health effect pathway (mutagenicity and carcinogenicity); (2)
DMSO extraction may not be representative of the bioavailability of tire crumb rubber
constituents in a playground exposure scenario; (3) no information was available about the
chemical composition or concentrations of the extract or aqueous leachate.
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California's Office of Environmental Health Hazard Assessment (OEHHA, 2007) conducted a
skin sensitization assay of three recycled rubber playground surfaces. The researchers used a
modified Buehler method for solid materials according to testing guidelines (US EPA, 1998) and
in accordance with Good Laboratory Practices at Product Safety Laboratories. Guinea pigs were
the test animals. The three test materials included loose crumb rubber made from recycled tires,
tiles molded from tire shreds mixed with a binder, and tiles molded from particles of the
synthetic rubber EPDM mixed with a binder. Appropriate positive and negative controls were
included in the study design for induction and challenge phases. None of the components of
rubberized playground surfaces caused any skin sensitization, while the positive control
substance (alpha-Hexylcinnamaldehyde) produced positive reactions in 40 percent to 50 percent
of the animals. The researchers concluded that "playground surfaces made of recycled tires do
not constitute a skin sensitization risk to children."
Five reports described laboratory analyses of extractable organic compounds and metals from
recycled rubber playground surfacing, and two of these used exposure modeling to estimate risk
of adverse health effects.
Llompart, et al. (2013) analyzed the chemical composition of recycled tire playground surfacing
and pavers. Loose-fill rubber mulch made from recycled tires was collected from nine
playgrounds. Pavers (rubber tiles) made from recycled tires were purchased new from a retail
source. Heated (120 °C) ethyl acetate extractions were analyzed by gas chromatography-mass
spectrometry (GC-MS). The researchers concluded that"[t]he analysis confirmed the presence
of a large number of hazardous substances including polyaromatic hydrocarbons (PAHs),
phthalates, antioxidants, benzothiazole and derivatives, among other chemicals. The study
evidences the high content of toxic chemicals in these recycled materials. The concentration of
PAHs in the commercial pavers was extremely high, reaching values up to 1%. " Limitations of
this study for evaluating the potential health effects of recycled tire material on playgrounds
include: (1) the ethyl acetate extraction is not representative of the bioavailability of the analytes
in a realistic exposure scenario, and (2) the study was apparently conducted in Spain, so the
recycled tires in the products analyzed may not be representative of recycled tires in the U.S..
Celeiro, et al. (2014) analyzed samples of recycled tire playground surface material (from an
indoor playground) for the presence of PAHs and other organic compounds. Samples of a
poured-in-place indoor playground surface with a green wear-course layer were cut into small
pieces and extracted with ultrasound assistance in ethyl acetate. The lower black tire crumb
rubber layer was analyzed separately from the green upper wear-course layer (possibly made of
EPDM or TPV). The solvent extractions were analyzed by GC-MS to identify and quantify
PAHs and other target compounds. The analyses found that the solvent extracts contained 14
PAHs and other compounds of concern including phthalates, adipates, antioxidants and
benzothiazole. Total PAH concentrations were 170 |ig/g and 295 |ig/g in the green and black
layers, respectively. Diethylhexyl phthalate (DEHP) was found at concentrations greater than
3000 |ig/g in the green wear course layer. In the black recycled tire layer, concentrations of
DEHP at more than 4,500 |ig/g were found. An additional aqueous leaching study of the rubber
playground surface found a concentration of 2223 ng/mL total PAHs (nine PAH substances) in
the water leachate. The researchers concluded that"/t]he presence and the high concentrations
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of these chemical compounds in playgrounds should be a matter of concern owing to their high
toxicity."
Highsmith, et al. (2009) conducted a scoping-level field monitoring study of synthetic turf and
playgrounds in the U.S. Air samples were collected 1 m above a loose-fill rubber playground
surface, and loose-fill rubber samples were collected at the same playground. The report
described the playground surface as "tire crumb"; but based on the report's description of the
rubber (i.e., "pieces were larger than 1 g"), it appears that the surface was loose-fill rubber
"mulch"-sized pieces, rather than the "crumb size" particles used as synthetic turf infill. Air and
rubber samples were analyzed. Concentrations of PMio particles and metals at the playground
site with high play activity were higher than background levels. All PMio air concentrations were
well below the National Ambient Air Quality Standards (NAAQS) for PMio (150 |ig/m3). All air
concentrations for lead (Pb) were well below the NAAQS for Pb (150 ng/m3). The researchers
concluded: "concentrations of components monitored in this study were below levels of concern;
however, given the very limited nature of this study (i.e., limited number of components
monitored, samples sites, and samples taken at each site) and the wide diversity of tire crumb
material, it is not possible to reach any more comprehensive conclusions without the
consideration of additional data. " This was a limited scoping-level study designed to evaluate
the methods for generating quality environmental data for selected tire crumb rubber constituents
and for understanding potential exposure routes and pathways. The study was not designed to
provide representative U.S. environmental measurement data for all tire crumb rubber
constituents or applications. The researchers intended to collect samples at more playgrounds,
but they experienced difficulty gaining permission to collect samples.
OEHHA (2007) used a wipe sampling method to estimate the chemicals that might be transferred
to a child's hand through contact with a unitary playground surface made of recycled waste tires.
The protocol was modified from the US EPA (2003) protocol used to wipe-sample arsenic from
CCA-treated wood using 9-inch-by 9-inch square polyester wipes. Field control wipes were
performed on nearby sections of cement sidewalk. See OEHHA (2007) for sampling and
analytical method details. One metal (zinc) and four PAHs (chrysene, fluoranthene,
phenanthrene, and pyrene) were measured at levels that were at least three times background. No
semi-volatile organic compounds (SVOCs) were detected in any wipe sample. The researchers
used exposure factor values found in the literature to estimate the chronic hand-to-mouth contact
exposure to selected chemicals playing at a playground with a unitary recycled tire surface by a
15-kg 3-year-old child. Assuming ingestion of the above five chemicals via chronic hand-to-
mouth contact, exposures were below the corresponding chronic screening values, suggesting a
low risk of adverse non-cancer health effects. Of the five substances, only chrysene was
identified as a carcinogen by California. Assuming playground use from 1 through 12 years of
age, an increased cancer risk of 2.9 x 10"6 was calculated, due to the chronic hand-to-mouth
ingestion of chrysene. This risk is slightly lower than the di minimis risk level of 1 x 10"6,
generally considered an acceptable cancer risk because of its small magnitude compared to the
overall cancer rate (OEHHA, 2007). Therefore, none of the chemical exposures from hand-to-
mouth contact from recycled tire playground surfacing raised concerns about health effects in
children. The authors acknowledge that many of the uncertainties in the assumptions used in
their modeling could overestimate or underestimate actual health risk.
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OEHHA (2007) also exposed shredded tire rubber to simulated gastric fluid to simulate the
release of constituent chemicals that would occur in the stomach after a child swallowed a rubber
nugget or buffing. Twenty-two chemicals, including metals and organic compounds, were
released from tire shreds during a 21-hour incubation period at 37°C. The researchers used an
exposure model for a 15-kg child ingesting 10 g of tire rubber to estimate the bioavailable oral
dose. All of the calculated exposure-dose levels were at or below the corresponding screening
value, suggesting a low risk of adverse non-cancer health effects. Five of the leaching chemicals
were currently listed by California as carcinogens by the oral route, but the experimental
concentrations applied to the model were associated with a 3.7 x 10"8 increased risk of cancer,
lower than the di minimis risk level of 1 x 10"6. Therefore, a low risk adverse health effects was
predicted from this model of a 15-kg child ingesting 10 g of tire rubber.
CPSC staff identified six literature reviews and other assessments of the health and ecological
risks associated with the use of recycled tire rubber in consumer applications and that
specifically address recycled rubber on playgrounds. These reviews and assessments do not
report any original data or specific exposure modeling, and the references cited in these reports
that would be of interest to the Federal Research Action Plan have been captured in the LRGA
document in Appendix B of this status report. The conclusion of these reviews varies; some
support the relative safety of tire crumb rubber playground surfaces (Simon, 2010; Cardno Chem
Risk, 2013; LeDoux, 2007; Anderson, et al., 2006), while others expressed concerns about
hazards to children's health (Sullivan, 2006; Environmental and Human Health, Inc., 2007). The
authors of many of these reviews discuss the limitations of the available data and indicate that
additional studies are needed to support the safety of recycled tire rubber in playground
surfacing.
The LRGA report notes that data gaps were more pronounced for recycled tire crumb rubber on
playgrounds and indoor fields than for outdoor synthetic turf fields. CPSC staff and the
interagency LRGA team did not identify any epidemiological studies on any of the topics
included in the Federal Research Action Plan.
Exposure Characterization for Recycled Tire Materials on Playgrounds
The Federal Research Action Plan includes an objective that the federal partners will
"characterize exposures, or how people are exposed to these chemical compounds based on their
activities on the fields." CPSC staff interprets this objective also to include activities on
playgrounds.
No studies identified by CPSC staff or the LRGA team have measured children's exposure to
chemicals from playing on recycled tire rubber playground surfaces. The OEHHA (2007) studies
used exposure models to estimate children's oral exposure to selected substances in rubber
playground surfaces from hand-to-mouth contact and direct ingestion of rubber pieces. These
appear to be quality laboratory studies, and the modeling methods used may be useful for
CPSC's work, but they are limited in scope because the studies assessed only oral exposures.
Children on playgrounds can be exposed to playground surfacing materials by oral, dermal, and
inhalation routes. Oral exposure can occur by directly mouthing the surface materials,
ingestion/swallowing of loose materials, hand-to-mouth contact, object-to-mouth contact, and by
eating food or drinking beverages while on the playground surface. Direct dermal contact with
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surface materials can lead to transdermal absorption of certain substances while children touch or
carry surfacing with their hands, walk barefoot, or wear short pants or sleeves that allow a larger
surface area of exposed skin. Some activities, such as burying in or throwing loose-fill materials
can add to dermal exposure. Volatile compounds released from rubber and fine particles
suspended in the air by disturbing the surface can be inhaled.
Performing experimental studies of children's exposure to chemicals would be complicated by
ethical and practical challenges. No epidemiological or bio-monitoring studies of children on
rubber playground surfaces are available. The next best method to estimate exposure, without
doing direct measurements in children, is to use mathematical models. Modeling allows
researchers to estimate chemical exposure by using quantitative exposure factors and activity
patterns in combination with experimentally measured chemical concentration and
bioavailability data. For example, OEHHA (2007) used a simple hand-to-mouth exposure model
to estimate oral mass exposure rate (using zinc as an example):
Hand-loaded zinc concentration ([j,g/cm2) x hand surface area transferring zinc to mouth
(cm2/hand-to-mouth event) x total events (hand-to-mouth events/day) x hand-to-mouth transfer
efficiency (dimensionless) = oral mass exposure rate ([j,g/day)
In this model, the hand-loaded zinc concentration was determined by analysis of wipe samples
collected at a playground. The other variables are examples of exposure factors and represent
behavioral (hand-to-mouth events/day), anatomical (hand surface area), and physico-chemical
(hand-to-mouth transfer efficiency) factors found in the literature to develop its exposure
estimates (OEHHA, 2007). Dividing the daily oral mass exposure rate by the child's body weight
(in kg) will provide a daily oral dose of the chemical in units of [j,g/kg-day. An oral dose value
can then be compared to a toxicological reference value, such as a reference dose (RfD) or
cancer slope factor (CSF), to predict the risk of specific health effects.
Exposure models can be simple or complex, depending on the variables the modelers have
available and/or the specific questions being addressed by the model. Modeling can also
demonstrate the impact of changes to a single variable on the output figure. Some exposure
factor data can be found in the scientific literature, but the scenarios of children playing on each
of the types of playground surfacing are too specific to be represented accurately by generic
playground activity data. At a minimum, CPSC staff will need certain data describing children's
behaviors and activities on playground surfaces, frequency and duration of playground visits,
how children are dressed on playgrounds, and more. Certain anatomic and physiological factors,
such as skin surface area of hands, body weights at various ages, and respiratory rates during
active play can be acquired from the literature.
To estimate the exposure of children to recycled tire rubber constituents on playgrounds, the
CPSC will require the chemical characterization and bioavailability results that are currently
being collected by the EPA and ATSDR under the Federal Research Action Plan. No exposure
modeling for playgrounds can be completed until these data are available. Meanwhile, the CPSC
is gathering data that will inform the behavioral exposure factors and activity patterns.
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National Survey of Parents and Supporting Data Collection Activities
The Federal Research Action Plan notes that the "CPSC is exploring conducting a survey of
parents to get first-hand perspectives on potential exposures from playground surface materials."
A survey of parents could provide valuable information on the behavioral exposure factors that
will be specific to the playground surface types of interest. However, to ensure that the survey
conducted with parents asks the correct questions and asks the questions in an efficient manner
that is not too burdensome on those being surveyed, CPSC initiated preliminary data collection
activities that will inform development of the survey. These activities included field observations
of children at a limited number of public playgrounds and focus groups of people who visit and
work at playgrounds. The subsections below describe the CPSC's data collection activities.
Playground Field Observations
CPSC staff conducted limited scoping playground field observations of children playing on
playgrounds with different types of surfacing. The purpose of the scoping observations was to
gain first-hand observations of how toddlers and young children interact with unitary and loose-
fill playground surfacing. The behaviors observed will be considered while developing the
national survey to be distributed to parents and child caretakers. This observational activity is
very limited in scope and is not intended to produce statistically representative data on any
population.
CPSC staff gained permission from local public parks officials in a limited region of Maryland to
conduct the observations. The agreement with the playground owners included anonymity of the
playground sites in reporting.
The playgrounds to which CPSC staff was granted permission to make observations included
playgrounds with PIP, bonded rubber, loose-fill rubber, and engineered wood fiber (EWF)
surfaces. Although EWF is not made from recycled tires, it was included for reference as a non-
tire surface and as a surrogate for loose-fill rubber because permission was granted for only one
loose-fill rubber playground. The playground owners who agreed to the field observations do not
have playgrounds with rubber tile or synthetic turf surfaces. Therefore, these surface types are
not represented in this data collection activity. However, the PIP and bonded rubber can serve as
surrogates for all of the unitary surface types.
The behaviors of interest were:
• hand contact with surface material;
• picking up or throwing surface material;
• playing with surface material for more than 30 seconds;
• playing with a toy on the playground surface for more than 30 seconds;
• barefoot contact with surface;
• face or mouth contact with surface material
• contact of other exposed body parts with surface material;
• falling onto surface;
• crawling on surface for more than 30 seconds;
• eating food or drinking a beverage while on playground surface.
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Playing with toys or other objects and eating food or drinking a beverage while on the
playground surface is considered secondary contact, while the remaining behaviors listed above
describe primary contacts with the surfacing materials.
Other information recorded for each 20-minute observation session included the number of
children on the playground who appear to be? 6 months to 5 years old; the playground surfacing
type; the names of the observers (two or three observers per session); date, starting time, ambient
temperature in °F; and whether the playground surface was wet or dry.
Observations were made passively with two or three CPSC staff members sitting at a bench or
picnic table near the playground and with a clear view of most of the playground area. One or
two observers reported when the behaviors of interest were observed; and one recorded making a
mark next to that behavior on the data collection form. Notations were made each time a child
arrived or exited the playground during the 20-minute observation period. No photos or videos or
any identifying information about the children was collected. Observers did not interact with the
children or anyone else at the playgrounds. Knowing that parents and child care providers are
sensitive to strangers at a playground, observers were prepared to explain what they were doing,
if approached and asked; no one approached the observers with questions. Children who were
estimated to be between 6 months and 5 years old were included in the study. Children's ages
were estimated by appearances for inclusion, based on observers' experience; however,
information on individual children was not recorded. No contact was made with anyone to verify
age estimations.
Observations were made at one playground per surface type (PIP, bonded rubber, loose-fill
rubber, and EWF); and 20-minute observation sessions were conducted at each playground four
times. Observation sessions occurred over approximately 2 weeks in October 2016, and the
sessions included different times of the day between 10:00 a.m. and 5:00 p.m. to observe
different children.
Each of the behaviors of interest listed above was observed at least once for unitary and once for
loose-fill surfaces. A more thorough analysis of data collected during the scoping observations
was not completed by the writing of this status report. The behaviors observed will be considered
while developing the national survey planned for distribution to parents and child caretakers in
different regions of the U.S. in 2017.
Focus Groups
A focus group is a collection of people assembled for a "carefully planned series of discussions
designed to obtain perceptions on a defined area of interest in a permissive, nonthreatening
environment" (Krueger & Casey, 2015). It is a method for gathering qualitative information on a
topic, using a semi-structured discussion among a small group of participants. The discussion is
guided by a moderator to keep the conversation on topic and to ensure specific questions are
addressed by the group. This method is used to gather information about participants'
experiences and thoughts on the topic of interest. The CPSC chose focus groups to collect
information to develop the national survey of parents. CPSC contracted with an Arlington, VA-
based contractor with experience in conducting behavioral research for government agencies to
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execute the focus groups and subsequently, the national survey (Contract No. CPSC-D-16-0002;
Solicitation No. CPSC-Q-16-0031).
CPSC staff worked with the contractor to develop the focus group plan and instructions for
moderators. CPSC staff and the contractor have prepared the necessary paperwork for Office of
Management and Budget (OMB) review package, as required under the Paperwork Reduction
Act. The contractor has arranged for review of the survey plan by an institutional review board
(IRB), to ensure that the proposed methods are appropriate and ethical. The IRB service selected
is experienced in performing reviews for healthcare and government research efforts. No
recruitment of survey participants will begin until IRB and OMB are obtained.
The focus groups will include three sets of participants: 1) parents of children between 1 and 3
years of age; 2) childcare providers of children between 1 and 3 years of age, and 3) playground
inspectors. Participants of the first two groups (10 parents and 10 childcare providers) will have
or care for at least one child who is over one year of age and under three years of age and who
supervises this child or children in playgrounds at least three times a week. The contractor will
attempt to recruit an accurate representation of the U.S. population and to include a range of
demographic and socioeconomic groups. The participants of the third group will be 10 parks
professionals who hold a current Certified Playground Safety Inspector (CPSI) certification and
who inspect and maintain playgrounds regularly at least once per month. The park personnel will
be employed at a diverse range of playgrounds in terms of playground size, materials, and
equipment, and who also work in a diverse range of neighborhoods {i.e., urban vs. rural,
socioeconomic attributes of the area).
To recruit parents and childcare givers, the contractor will send an e-mail to an existing pool of
participants asking for parents and childcare providers of toddlers in the Washington, D.C.,
metropolitan area for participation in a focus group. If the e-mails to parents do not yield enough
responses, the contractor will then reach out to local parent groups online and through message
boards in common areas where these parents are likely to frequent. Similarly, if the e-mails to
childcare providers do not yield enough responses, the contractor will reach out to local childcare
provider groups or businesses, either online, or through message boards in common areas where
these childcare providers are likely to frequent. To recruit parks and recreation employees, the
contractor will initially send invitations to the focus group to the e-mail addresses of CPSI
certified individuals located within a 25-mile radius of the contractor's offices in Arlington, VA.
Potential participants will be identified by a public CPSI registry maintained by the National
Recreation and Park Association.
Focus groups will take place at the contractor's offices in Arlington, VA. Because participants
often have competing demands for their time, incentives are used to encourage participation in
research. Participants will receive nominal compensation for participating. This compensation
value will be determined per IRB and OMB recommendations, after these organizations' review
of the research plan.
After participants have been identified, but before they report to the contractor's office for
scheduled focus groups, the participants will be asked to take a picture of the playground
surface(s) at the playground(s) they visit most regularly, and e-mail it to the contractor. The
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photographs will not be a prerequisite for participation, but they will help with identifying the
playground surface types (e.g., loose-fill rubber, PIP, bonded rubber).
The three focus groups (parents, caregivers, parks employees) will be conducted separately.
When participants report to the contractor's offices for the focus group, the moderator will
introduce him/herself and have brief introductions among the participants. The moderator will
then lead an informal, but structured, discussion within each group, to address a list of questions
regarding playground visitation habits, children's activities and behaviors observed on
playgrounds, clothing worn by children on playgrounds, snacks and refreshments consumed at
playgrounds, hand-washing habits, and more. Visual aids will be provided to clarify
understanding of the different types of playground surfaces. Each focus group is expected to take
up to 120 minutes, including opportunities for breaks and refreshments.
The focus group discussions will be video and audio recorded and observed by a one-way glass
window by contractor personnel and CPSC staff for data-collection purposes. A data coding
scheme will be developed by the contractor and CPSC staff to emphasize organization of
qualitative data. The contractor will assign a data manager to maintain quality control of the data
collected. The contractor will provide to CPSC a written summary of the data collected in each
focus group. Participant confidentiality will be protected by the contractor, and no personally
identifiable information will be permanently recorded or reported to the CPSC.
National Survey
CPSC staff will work with the contractor to develop a national survey that will be distributed to
parents and child caregivers in various regions of the U.S. The survey questions will be
developed based on information collected in the focus groups, playground field observations, and
other research studies. The contractor will ensure that the survey promotes comprehension and
thoughtful responding, and meanwhile, reduce survey fatigue and its consequences (e.g., non-
response, invariant responding).
The contractor will develop and propose sampling and data collection plan options necessary to
obtain a nationally representative sample of households with children of ages 0-5. The
contractors will outline tradeoffs between the different approaches and will address key sources
of survey error, including coverage, nonresponse, sampling, and/or measurement error. CPSC
staff will review the options for recruiting strategies and inform the contractor of the choice
selected.
The contractor will arrange for review of the survey plan by an IRB to ensure that the proposed
methods are ethical. The IRB service selected is experienced in performing reviews for
healthcare and government research efforts. CPSC staff and the contractor will prepare the
necessary paperwork for internal CPSC clearance and OMB review package, as required under
the Paperwork Reduction Act.
The contractor will begin recruitment of survey participants following the finalization of the
questionnaire and after receiving OMB and IRB approval to administer the survey. Participants
will be recruited by re-contacting and interviewing respondents of the Social Sciences Research
Solutions (SSRS) Omnibus, which is a national, weekly, dual-frame bilingual RDD (random
digit dialing) telephone survey designed to meet standards of quality associated with custom
research studies. The contractor will use this sample source to pre-screen individuals in the target
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population {i.e., individuals with children ages 0-5). The targeted households will be re-contacted
to administer the full survey.
The time of delivery of survey results will depend on the preceding steps required before
recruitment of participants can begin. CPSC staff intends to submit the OMB package for
approval in early calendar year 2017. Because this survey will require a full OMB review and the
publication of Federal Register notices, it could take 12 months or more to obtain approval. Data
collection will be completed within 12 weeks of receipt of OMB approval. A draft report will be
submitted by the contractor to CPSC for review and approval within four (4) weeks of
conclusion of data collection.
Findings of the national survey will be used to clarify and improve the CPSC's understanding of
how children less than 5 years of age interact with various types of playground surfacing.
Qualitative and quantitative data obtained in the survey will be used to inform development of
exposure scenarios and exposure factors that can be used to estimate children's exposure to
substances of concern in playground surfaces made with recycles tires.
Subsequent Research Considerations
The CPSC's strategy for understanding the chemical composition of rubber products derived
from recycled tires is to review the results of the tire crumb rubber characterization and exposure
characterization studies conducted by the US EPA and ATSDR conducted under the Federal
Research Action Plan when those data are available. These new data will be considered with
published scientific literature on tire rubber composition, bioavailability, and exposure. The
CPSC will use exposure modeling to determine whether any of the bioavailable substances may
pose a health hazard to children using playgrounds. Oral, dermal, and inhalation routes of
exposure will be considered individually and in combination. Specific risk assessment strategies
will be determined based on review of the new data and will likely focus on substances of
highest concern.
CPSC staff might find that the data for tire crumb rubber and its use on synthetic turf fields
cannot be used to estimate adequately exposure for children on playgrounds. In this case, the
CPSC staff will explore initiating collection of samples at playgrounds with recycled tire
surfaces for chemical analysis and bioavailability characterization. This type of data collection
endeavor will be contingent on overcoming several challenges, including (1) acquiring funding
(CPSC has requested FY 2017 funding for this and related work); (2) identification of
playgrounds across the country with each of the different types of recycled tire rubber surfacing;
and (3) gaining permission from playground owners to collect samples. A previous attempt by
the EPA to collect samples of rubber playground surfacing was hindered by denial of
permissions for access to collect samples (Highsmith, et al., 2009).
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&EPA
United States
Environmental Protection
Agency
Office of Research and Development (8101R)
Washington, DC 20460
Official Business
Penalty for Private Use
$300
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