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.

3 comments

Dear Editor,
Whilst this document is technically correct in it’s referencing. It does fall down in key areas of critical thinking and comparison to the real world functions in public open space. Worthy of discussion “is a synthetic sports field?” A patch of fake grass or grass replacement, is it a manufactured playing surface like a tennis court, gymnasium or a park equipment play space. All of which have similar environment impacts.

High frequency playing surfaces are needed due to community demand and that sports turf managed surfaces are expensive, difficult to manage require skill professionals and tend not to meet the rigours of high frequency community sport. Plus these surfaces are managed grass; balanced between life and death and high performance by skilled horticultural professionals. Often, they are regularly treated with chemicals (fertilisers, herb and pesticides). They are manufactured nature not naturally occurring plant communities. They are far from “environmentally pristine” ecosystems. Any insect that eats the turf is killed by chemicals, fungi that naturally appear are sprayed with fungicide etc.

Typical, council style fields (community) often have sparse covers of grass with pot holes and dangerous impact zones and present risks to the public users. Line markings are usually a mix of Glyphosate and diesel (BaP’s that are toxic to human health even though they are in small deposits and below the EPA’s levels of acceptability like most of the chemical referenced in the document. These are fields with little maintenance and are cut regularly and often closed due to rain and poor drainage. Serviceability is poor on average compared to a synthetic field.

Also it is clear, that some synthetic field designs are poor in their design compared to others which have higher design expectations. Field designs have improved during the last twenty years. But there is considerable improvement needed with in this sector and professional bodies like the “Horticulturist” and Sports Turf Manager have considerable skill and with some new training to ensure that this “playing surface” is well implemented with minimal impacts on the environment.

Plus we also need to compare critically to the appropriate comparisons. My thoughts are Synthetic sports field should be compared with a concrete playing court or a gymnasium in heat island effects for which by comparison they perform well. It may look like a turf field but it really is not a naturally grown surface and should not be considered in the same space as most people would first think.

This is an area where in the institute could take strong leadership in and embrace the good and fix the bad. This will also broaden the skill of the modern day horticulturist and become the professional point of truth for the community.

Lauren Danecek

Thank you Colin for adding your voice to this conversation; I respect your experience and value added to this piece. I appreciate your time and comments.

Since the article was published, the Synthetic Turf Study in Public Open Space has been released by the NSW Government (link below). What is most rewarding for me, is that the report covers both your and my concerns, further confirming what we all want – usable, accessible, green public spaces. 

The report also points to areas we didn’t touch on, like community concern over access to green public space, restrictions surrounding informal access, grounds set up for specific codes, artificial light increases and noise abatement. There are some great and interesting case studies dotted throughout the report to further reflect on the ‘real’ aspects of turf installations and management – both natural, artificial and hybrid models.

The report kept highlighting the importance of soil construction and drainage, and the lack of knowledge and education that exists in these areas (Jonathan Garner wrote of educational bodies spending less time on a variety of important horticultural elements in the December 21′ issue of HortInsights). I believe from many of us this sounds like a call to reinstate more robust soil studies throughout all horticultural courses. I think we would all shout yes anyway, because soil is literally the beginning of everything. 

Nonetheless, a great place to start, and great that we can extend the knowledge and conversation (and word count!) in the comments. State Government recommendations are due in 2022, which I look forward to reading developed from this study.

NSW DPIE Synthetic Turf landing page
Synthetic Turf Study Report

Catriona Carver

Thank you Laura for this article, there is very little research on the effects of synthetic turf under Australian conditions, in particular the increased heat. The local park in our suburb, Gardiner Park, was recently converted to rubber filled synthetic and the heat and smell is noticeable. Using a IR temperature gun we measured over 90deg Celcius on the playing surface when the ambient temperature was 30degC
We question if Councils and sporting clubs are taking the temperature of these fields during summer soccer and early season training.
The Synthetic Turf Study does go towards the balance needed to make the decisions to install synthetic, however, the natural turf industry has made great leaps in playable hours that time-poor local councils are not taking advantage of and suburbs are losing their green spaces for toxic plastic parks.
For more information see https://savegardinerpark.wordpress.com/

Leave a Reply