HOW HAZARDOUS ARE THE “GREEN” Artificial TurfS?
A small but growing number of school districts, municipalities, and universities in New Jersey and elsewhere are switching from traditional grass athletic fields to artificial turf. Changed considerably since 1960s AstroTurf, newer synthetic grass is touted for advantages like shock-absorption and durability in varied weather conditions. There is no need for mowing, watering, pesticides, or fertilizer and therefore the turf is advertised as environmentally friendly. While these advantages have powerful appeal, synthetic turf comes with an unfortunate host of established and potential health and environmental risks.
A modern artificial field surface has three layers – drainage, shock absorbing, and surface. The surface has polyethylene plastic blades that simulate grass and a several inch layer of “infill” that keeps the blades upright. The infill varies by manufacturer and may include ground-up recycled tires, ground-up soles of athletic shoes, silica sand, and/or new thermoplastic or rubber material. The silica sand contains crystalline silica, a proven human carcinogen that causes silicosis. This “crumb rubber” has been found to contain additional toxic materials such as:
• Toxic metals including zinc, lead, arsenic, cadmium, and chromium which have many harmful effects on humans and the environment.
• Carcinogens including polycyclic aromatic hydrocarbons (PAHs).
• Latex and other rubbers which can cause allergic reactions.
• Phthalates which have adverse effects on the reproductive organs, lungs, kidneys and liver.
Crumb rubber can degrade from weather and microbes, producing new chemicals. Toxic components can be breathed in, accidentally ingested, contact the skin, and leach into surface water and groundwater. Besides toxicity, other problems with artificial turf include:
• Crumb rubber doesn’t stay in place. It can move around on the field and sticks to the skin, shoes, and clothing of staff and students who use the fields. It can end up inside schools, vehicles, and homes.
• Excessive heat. Artificial surfaces are dramatically hotter than natural grass fields, reaching temperatures up to 150 degrees Fahrenheit and possibly contributing to burns, dehydration, and heat exhaustion. They may be too hot to play on at times. Watering cools them down but they heat back up quickly.
• High cost. Artificial fields cost in the range of one-half to two million dollars.
• Friction. Some types of artificial turf can cause skin abrasion to a greater extent than natural grass.
• Sanitation. Dog, goose, and other droppings do not decompose on artificial turf.
• Maintenance. The crumb rubber may need to be raked to maintain a uniform depth. Solvents and adhesives may be needed to repair seams. Leaves, gum, and other debris need to be regularly removed or they may clog the drainage system.
• Short Life. Artificial turf has a life expectancy, with proper maintenance, of five to ten years compared to at least 15 years for grass fields.
• Disposal. One football field contains approximately 120 tons of crumb rubber or 26,000 recycled tires. Crumb rubber takes more than 25 years to break down completely.
• Unpleasant odor. The odor is especially a problem in indoor installations.
• Loss of habitat. Artificial turf does not support birds, animals, or insects.
• Combustibility. While shredded tires will burn at a much lower rate than chunk tires, crumb rubber can certainly be made to burn by arson, producing smoke and toxic air, soil, and water pollutants.
A 2006 study by the Norwegian Institute of Public Health and the Radium Hospital, Artificial turf pitches – an assessment of the health risks for football players examined health risks on turf used in indoor halls, which consist of artificial turf fiber and rubber granulates. It looked at exposure via inhalation, skin contact and ingestion, concluding that that the granulate used in many types of artificial turf contains chemicals that could harm human health, but in extremely low concentrations, and these are leached from the granulate in very small quantities, and air concentrations are very low.
Total VOC were found at higher concentrations than generally found in homes, but the study concluded that the values found do not represent an elevated health risk, adding “… but our knowledge of this area is rather inadequate…”. Although there is some evidence of a link between phthalate exposure and development of asthma and/or allergies, at this point – due to a lack of knowledge – a risk assessment was not possible.
Environment & Human Health Inc.’s 2007 report Artificial Turfsummarized a study that looked at the leaching potential of metals from tire crumb samples, as well as chemicals released from the crumbs. In one experiment, 25 chemicals were identified (with 72-99% certainty) in tire crumbs, as were metals (mainly zinc, but also selenium, lead and cadmium). Among the report’s recommendations is to limit exposure to turf fields that contain rubber tire crumbs until more is known about human exposure issues, and that those allergic to latex should use caution when using fields or playgrounds that include these materials.
The Swedish Chemicals Agency reported that although synthetic turf contains recycled tire rubber that may cause local environmental risks, the amount of substances like zinc and phenols that leach from the rubber granulate is small, so any environmental effects would likely be local, i.e., they won’t reach watercourses. They recommend that water quality be analysed where the water is associated with these turf surfaces. They advise that the recycled tire rubber in the turf need not be replaced immediately, but should be replaced by alternatives, over the long term and where the material shows signs of breakdown (e.g., where it forms smaller particles, which are of greater risk).
The Connecticut Department of Public Health fact sheet, Lead in Artificial Turf states that the only way to determine if artificial turf contains lead is to have the turf tested. Lead chromate has been used in pigments to colour nylon-based turf. Children playing on the field may be exposed to lead dust from worn turf fibres that get onto their hands or toys, then is ingested when the children put these into their mouths.
New artificial turf products that contain fewer toxic chemicals are being developed. For example, Ecofillis advertised as being free from heavy metals, polycyclic aromatic hydrocarbons, and as emitting much less heat than rubber-based products. GeoTurf apparently uses materials that are organic or 100% recyclable, and are lead-free and non-toxic.
What about UofT’s artificial turf? UofT has posted general information about the turf it plans to use, noting that the fields will not contain any fill (including crumb rubber infill) or lead as a stabilizer for pigment (it’s not clear if lead will be present for any other purpose). The turf appears likely to result in increased water runoff– a drainage system will divert regular runoff into the City’s sewer system and a large cistern will be located beneath the field to handle excess stormwater.
According to the UofT Project Planning Report, the turf material will be composed of knitted or tufted nylon, polypropylene or polyethylene, with a granular porous asphalt as sub-base and a shock pad under the turf. To meet world field hockey requirements, the turf surface will need to be watered during the Games – allowing for reduced friction and faster ball speed.
What are the issues [and what did we find]?
Many types of artificial turf contain rubber materials, which may contain toxic chemicals, although generally at very low concentrations. Much of the literature relating to environmental and health impacts of artificial turf relates to the rubber component. We won’t get into how much the artificial versus natural turf fields cost – both on a short-term and long-term basis. There are many analyses published, with a huge lack of consistency. Environmental concerns raised about artificial turf include:
· Unlike with soil, which soaks up rainwater, turf will divert the water into runoff, which could reach groundwater and drinking water [natural surfaces absorb and use much of the precipitation; however, projects UofT’s include extensive planning for dealing with stormwater drainage]
· Real grass provides a cooling surface (so important in climate change); artificial turf heats up in sunlight and can contribute to increase in urban temperatures [this is a significant concern; in one study, the surface temperature of an artificial soccer and football field averaged 117 °F, with a high of 156-157 °F, while a nearby natural grass field’s surface temperature averaged 78 °F (high 89 °F). The temperature of concrete was 94 °F and asphalt 110°F. Irrigation of artificial fields significantly decreased surface temperatures, but only for a few minutes]
· It may be contaminated with harmful chemicals, including metals like lead [this depends on the turf type –e.g., rubber crumb turf may contain many chemicals; however the concentrations that leach out are not believed to be significant risks to the environment ….but there are gaps in the science]
· Natural fields filter air/water pollutants; artificial ones don’t. Artificial fields have a high net carbon loss, while a natural grass field typically has a net carbon gain.
And health concerns include:
· Artificial turf heats up, contributing to heat stress [watering the turf can reduce the temperature for a short time, but athletes should be advised to stay hydrated]
· There are more injuries on artificial turf [differences in injury rates in athletes playing on natural surfaces and crumb-rubber turf have not been consistently shown; artificial turf proponents argue that turf surfaces are more uniform than natural fields, and offer better traction and proper hardness levels ]
· It may be a breeding ground for bacteria (e.g., methicillin resistant Staphylococcus aureus), as it cannot get rid of bacteria from sweat, blood, skin cells deposited during play [A causal relationship between artificial turf and staph infections has not been shown. Contact with either natural or artificial turf is an infection risk; the usual precautions for dealing with wounds and skin abrasions should be followed]
· People allergic to latex (i.e., from rubber crumb) are at risk [There have been no reports of such allergy from contact with artificial turf]
· Users are exposed to harmful chemicals [Data are lacking, but the low concentrations of these toxins is not believed to be a threat to human health]
Caution Advised
Although the desire to improve access to sports fields is clearly well-intentioned, the risks that accompany synthetic turf need to be carefully considered. Issues of toxicity, movement, heat, cost, friction, sanitation, lifespan, maintenance, warranty, disposal costs, odor, loss of habitat, combustibility, should be thoroughly addressed before any decision to purchase is made. The community should carefully consider all the options including natural grass.
There are many manufacturers of artificial turf with different products and advertising claims. It is reasonable to expect vendors to identify the chemical ingredients of all turf components and provide a Material Safety Data Sheet on each component, especially the crumb rubber. If the crumb rubber is of unknown composition, that should raise a serious warning.
Tires are known to contain over 60 different substances. Typically, forty-five percent is vulcanized or cross-linked polymer, forty-five percent is carbon black, and the rest is dispersing oil, sulfur, synthetic fibers, pigments, processing chemicals and steel or fiberglass. Tire manufacturers use a variety of formulation recipes and Ingredients are often kept secret. Therefore the company that produces the crumb rubber will most likely have to analyze its composition on a regular basis to provide accurate information on ingredients, since different batches can be expected to vary in content.
When it comes to synthetic turf, the most sensible approach may be to follow the precautionary principle of assuming something involving chemicals is hazardous until scientific evidence proves that it is not. Some public health professionals are calling for a moratorium on installing any new fields that use ground-up rubber tires until the hazards are better understood. Some are also recommending that exposures to already installed fields that contain rubber-tires should be limited.
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