In the mind of an ecotoxicologist

Re:Bounce went to meet Ragn-Sells’ ecotoxicologist, Sara Stiernström, who dedicates a lot of her working week to checking and quality-assuring material from used tyres. ”This is a highly usable and diverse material with a number of different uses, which can also make an important contribution to the circular economy,” says Sara.

”Monitoring what’s going on the world is part of my job, and I follow any study within this field with great interest,” says Sara Stiernström, who joined Ragn-Sells in 2014. Previously, she had researched within environmental science and graduated from Stockholm University in the autumn of 2013. ”In principle, I am a biologist, but have read a lot of chemistry and law. I met the team from Ragn-Sells during a break at a conference. They were looking for someone with my qualifications, and that’s how it happened.”

Health and the environment in focus

Sara’s responsibilities include legal issues and contact with the authorities, and via Svensk Däckåtervinning (SDAB) she enjoys close collaboration with the European tyre manufacturer’s association, ETRMA.

”My title is Material Distribution Manager, which means that when we find a new use for recycled materials, it’s my job to ensure the quality whilst ensuring we meet the requirements of customers and the authorities. The same applies to existing uses. My job also includes risk assessment with regards to health and the environment.”

Regular analyses

Ragn-Sells collects and recycles all worn-out tyres in Sweden on behalf of SDAB. The tyres are processed in special facilities, and are used for both recycling and energy production. Some are exported or retreaded, others are used for swings, gymnastic mats, fenders and buffers. A large number of tyres are shredded, granulated and used for such purposes as athletic tracks, asphalt and all-weather pitches. The rest goes to the cement industry and power plants. No tyres are dumped.

”To ensure the quality of the material, may team and I perform regular tests and analyses according to a number of predetermined parameters. We take samples every month, and after six months they are combined into a single collective sample sent for analysis.”

Participation in several studies

Sara tells us that right now, there is a debate in the media on microplastics in the sea. It originates from a report by the Swedish Environmental Research Institute (IVL), which alleged that rubber granulate from artificial grass was the next biggest source of this.

”All the indications we have say the opposite - that granulate does not spread into the sea. Ragn-Sells and I follow and participate in several studies looking at how we can ensure that granulate does not end up outside football pitches. Several tests have been run using particle traps in the drain system near artificial pitches, which have shown very little granulate in the water analysed.

They don’t factor in the disappearance of granulate within a few hundred metres. It’s not that easy,” believes Sara.

Part of the sustainable society

Sara emphasises that the reason we use recycled tyre rubber in the community is that we cannot afford to exhaust the world’s resources. This material is highly useful, whilst no research exists that proves it is hazardous.

”Obviously, we need to work towards a non-toxic environment, and need to increase recycling to save the world’s resources. To make the equation work, we have to permit a certain amount of the substance in what we recycle, just as we do for virgin material, but there always has to be an acceptable risk,” concludes Sara.