Artificial Turf: Rubber and Sand

Ok, here we go. I know I have been promising to write about the chemicals for awhile. But there are just so many chemicals it’s hard to know where to start. Of course there are the chemicals and carcinogens in the turf material itself. And then there are the chemicals required for maintenance, to wash down the synthetic material in the attempt to keep it free of bacteria.

So I thought I would start with just what the artificial turf is made of. Most basic question: What is it?

Let’s start with what the synthetic material is made out of. According to FieldTurfTarkett, the primary materials in their product are sand, and rubber.

One square foot contains seven pounds of ‘silica sand’ and three pounds of ‘cryogenic’ rubber. We can contrast that with natural turf, which contains ‘grass.’

The synthetic material is ‘layered’ to provide ‘grass like stability.’ Again, to compare with natural turf, grass provides ‘grass stability,’ which, based on the text from the commercial website is exactly what artificial turf manufacturers are striving for.

Again according to the website, “A base layer of silica sand is followed by up to 21 individual layers of mixed silica sand and cryogenic rubber and then topped with a final layer of specially graded cryogenic rubber which stays on the top of the infill system.”

And, again to contrast, natural turf pretty much is just one layer of ‘grass,’ underlain by ‘soil.’

Sand

The website states carefully that ‘washed silica sand does not break down from use or heavy traffic.’ So, my interpretation only, sand does not break down. As many of us know, sand in fact is eroded rock, eroded to its finest stage, and so wouldn’t break down, including at the desert, or at the beach, which is probably where most of this sand comes from. That is what sand is. It is made of silica (Silicon Dioxide, or Sio2). Pretty much a no-brainer. They are using sand that they washed.

Rubber

The website doesn’t have a similar statement for the rubber. From this let’s assume that the rubber does break down. Of course I could be wrong.

So, what is in the rubber? According to the Rubber Manufacturer’s Association, this is the “Typical Composition of a Tire”

Synthetic Rubber
Natural Rubber Sulfur and sulfur compounds
SilicaPhenolic resin
Oil: aromatic, naphthenic, paraffinic
Fabric: Polyester, Nylon, Etc.
Petroleum waxes
Pigments: zinc oxide, titanium dioxide, etc.
Carbon black
Fatty acids
Inert materials
Steel Wire

What is ‘synthetic rubber,’ exactly?

According to the journal, Environmental Health Perspectives,

“The most common types of synthetic rubber used in tires are composed of ethylene–propylene and styrene–butadiene combined with vulcanizing agents, fillers, plasticizers, and antioxidants in different quantities, depending on the manufacturer. Tire rubber also contains polyaromatic hydrocarbons (PAHs), phthalates, and volatile organic compounds (VOCs).”

and,

“According to the Rubber Manufacturers Association, only 8 states have no restrictions on placing tires in landfills. Most of these restrictions have to do with preventing pest problems and tire fires, which release toxicants such as arsenic, cadmium, lead, nickel, PAHs, and VOCs.”

Ok. Whoa, whoops. Zinc? Arsenic? PAHs? What is that stuff? And that’s before its ground down and has to be reconstituted as artificial turf.

To manufacture artificial turf, used tires and other products are ground into small particles, called ground rubber tire, or GRT. According to the New Jersey Work Environment Council, one football field contains 26,000 recycled tires, or 120 tons of crumb rubber.

Ok, well, this is probably all you can read in one day, and definitely all I can write! So more on what is GRT made of, next time…

Do you have a story or tip for us? Send it to artificialturftips@yahoo.com.