Running Hot: Synthetic Turf

By Lauren Danecek, AIH Horticulture Student of the Year 2020.

This topic is getting political, and the environmental impacts are stacking up.

The integration of synthetic turf into both public and private spaces has, of late, become often political and has layers of complexity. My assumptions were that green plastic carpet was a thing of the past. An environmental nightmare that leached into the waterways, added to the ever-building horrors of microplastics, filled the surrounding air with volatile organic compounds (VOCs) and contributed to the urban heat island effect.

There are research and data sets available, that highlight a variety of depressing issues: the original, recycled tyre, crumb-filled turf was not the greatest stuff; for us or the environment. There are new synthetic turf alternatives around that utilise cork or sand as in-fill, but it’s not still not ‘grass’ in the traditional sense. And so, many of the same concerns still apply, but the data from research is still being unearthed.

Considering many gardeners, horticulturists and landscapers are now taking climate change into consideration in their design and plantings to future-proof gardens, avoiding the above horrors should be at the top of the list when it comes to creating clean, cool and safe environments for our clients (and, our children’s children). But it is still being laid, it’s readily available and I’ve even seen it on residential council verges. So, is it really that menacing?

As a student of sustainability and environmental science, anthropogenic activities lead our studies. ‘Humans did A! Now we have to deal with B’. The major environmental concerns surrounding the installation of synthetic turf include:

 

A simple diagram from the Celeiro et al. (2021) study to demonstrate their review of how elements of the turf were leached into the waterways, reviewed by both sports field and comparable in-lab results.

 

Leaching of Chemicals

Synthetic turf is often filled with recycled tyre crumb, that can leach chemicals into the surrounding environment, including polycyclic aromatic hydrocarbons (PAH’s, generated by the incomplete combustion of organic materials like oil and petrol), VOCs and phthalates (‘plasticers’ if you will, they keep things flexible and soft).

A Portuguese study released this year reviewed 40 chemicals in synthetic pitches and found continual leaching of PAHs into the surrounding environment (Celeiro et al. 2021).

 

 

Low use, artificial turf fraying at the edges with loose plastic blades in a local garden centre. Image/ Lauren Danecek.

 

Microplastics

These are pieces of broken-down plastic that have degraded in the environment to less than 5mm in size. Less than 1mm (down to 1μm (0.0001mm)), we generally class as a “nanoplastic”.

The synthetic blades (usually polyethylene or polypropylene) and the infill crumb break down over time loosening their hold, the blades, and tiny particles now freely available to move through the ecosystem. In a council-run field or professional playing field, they know about this and often (though, not always) have installed purpose-made ‘sieves’ in the drains to catch debris as the fields degrade over time through use and environmental factors.

However, for the neighbour who has run a roll to the gutter near the storm water drain, that catch is missing. The story then tells itself.

 

 

 

West Beach Parks Football Centre in Adelaide, showing a clear temperature difference between natural grass and synthetic turf (Government of South Australia 2021).

Adding to the Urban Heat Island Effect

The concept of the urban heat island (UHI) effect is localised warming created by anthropogenic means: our dark coloured surfaces like roads, roofs and carparks, removal of greenery, car engines and air conditioners, to name a few things. Summer days are hotter, and the infrastructure holds heat so it doesn’t cool at night. The science on heat associated concerns with synthetic turf is not good, as seen in an Australian study from Twomey et al. (2014).

Results clearly demonstrated that synthetic turf temperatures were significantly hotter (mean = 46.3°C) than irrigated natural grass (mean = 24.1°C). Would it be safe to assume that the installation of this product can contribute to the UHI, warming our suburbs and decreasing thermal comfort? Amusingly, that study calls for more data surrounding the ‘comfort’ of the athletes’ feet, but what else are we cooking at that temperature?

 

 

Which leads to a concern about the soil; our most precious commodity of all. Let us consider the solitary bees, insects and ‘microfauna’ that call the soil home. They must be being solarised under this artificial blanket, yet there is no data to back my claim. No studies that I can find detail what happens to the soil underneath, if the soil communities are functioning, and if there are reverberations beyond the artificial carpet.

Once you really get into the data, then you start to learn about other things that maybe you wouldn’t normally consider, like that synthetic fields have their own microbial communities that are different to natural turf (Valeriani et al. 2019) and MRSA has the ability to hang out in infill and on turf fibres (Keller et al. 2020). It’s this kind of new data that will help those in management and policy-making positions create synthetic turf guidelines and frameworks for installation and where it should and should not be used.

There are huge knowledge gaps across all stakeholders: professional football teams, councils, horticulturists and landscapers, right down to the home gardener. So much so that in NSW, planning minister Rob Stokes has commissioned a ‘Synthetic Turf Study’ (NSW Government 2021), to review synthetic turf options as replacements for natural grass. That review is due to be published mid-2021, and there will be a lot of people keen to read it.

No matter the side you’re on – natural or artificial – people want lush, good-looking, green turf. Our goals are the same, there just doesn’t seem to be the education about what to use when, we don’t have the knowledge about alternatives, or the data and science to back it up (more importantly, solid science for the Australian landscape). Synthetic turf looks great the first day it’s laid, and then it declines to the end of its life, where it’s rolled up and sent to landfill. Natural grass can be regenerated, and something has to be said for that. Mother Nature usually does it best, after all.

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