A recent study from the United Kingdom Centre for Ecology & Hydrology shows how gas chromatography–mass spectrometry can be used to detect 6PPD, a common additive used in the production of car tires, in water environments to combat environmental pollution.
Environmental protection is an important topic for researchers. Because of climate change and the increased human production of waste, the health of the environment can suffer from a myriad of sources. As a result, finding new, innovative ways to monitor environmental pollutants is of utmost importance.
The United Kingdom Centre for Ecology & Hydrology is focusing on this very issue. The center is a not-for-profit research institute that is focused on environmental science research, primarily investigating the chemical behavior of polluting substances in freshwater and land environments (1).
Recently, scientists at the UK Centre for Ecology & Hydrology explored using gas chromatography–mass spectrometry (GC–MS) to measure the level of 6PPD in rivers, lakes, and streams. The research team chose 6PPD because it is a common additive used in the manufacture of car tires, and it is designed to prevent the degradation of the rubber (2). GC–MS is a well-known analytical technique that is often used in environmental applications to monitor environmental pollutants. Here, GC–MS was used to extract 6PPD from sediment samples taken from a transect in Wallingford where a busy road crosses the Thames River (2).
Using GC–MS allowed the research team to measure the chemical. The gas chromatograph separated each contaminant in the sediment sample, allowing the team to isolate 6PPD from the other contaminants (2). Then, the mass spectrometer analyzed 6PPD by its mass, and from that was able to determine how much of it was present in the sediment sample (2). By examining how each sediment sample location could influence the amount of 6PPD in the sample, the researchers proposed how their sampling method could be used in the future to quantify 6PPD’s presence in water (2).
This study was one of the more complicated ones the Centre has conducted, mostly because of the difficulty of investigating the chemicals in car tires.
“From a scientific perspective, car tires are a challenging material to investigate,” UKCEH pollution scientist Richard Cross said (2). “Every tire manufacturer uses a different formulation and can be quite closely guarded secrets.”
Tire manufacturers are particularly protective over how they construct their tires, and different specifications are often used to make the tires, even though the rubber appears to be identical (3). Despite this challenge though, Cross said that some similarities exist in tire production.
“A handful of additives are used in the production of almost all vehicle tires,” he said (2). “These have relatively consistent concentrations and aren’t really used in anything except tires. One of those is 6PPD and that’s why we decided to use it as the ‘red flag’ that told us tire rubber was in our sample.”
Several studies have explored the effect that road wear particles and additives have on the aquatic ecosystems (4–6). For example, fibers and black rubbery fragments that potentially originated from road wear particles and tires comprised of approximately 85% of particles found in stormwater runoff in the watersheds in the San Francisco Bay area (6). Several studies have documented how the toxic chemicals present in tires have been linked to the deaths of many water-based organisms, such as salmon and trout (4,5). Road runoff routinely ends up in water, creating an urbanized watershed that cases the toxic chemicals from tires to be exposed at great concentrations to the local inhabitants, dramatically decreasing their survival rate (4).
Aquatic ecosystems are important to preserve. They not only serve as the home for many living organisms, but we rely on these ecosystems to provide us with water for various purposes, including hydration and cleaning. Preserving the waterways is essential to ensure the flourishing of living organisms on earth. As this study concludes, GC–MS is a useful technique for the detection of microplastics in aquatic environments, especially when it comes to detecting road wear particles like 6PPD.
