Tire permeation is the process by which tire-derived chemicals can enter the environment. These chemicals can come from various sources, including the production and use of tires, and can pose risks to human health and the environment.
There are several ways in which tire-derived chemicals can enter the environment, including through:
- The leaching of chemicals from tires into soil and water;
- The release of chemicals into the air during tire use; and
- The disposal of waste tires in landfill sites.
Tire-derived chemicals are persistent, bioaccumulative, and toxic (PBT). This means that they can remain in the environment for long periods, build up in the bodies of animals and humans, and cause adverse health effects.
The most well-known tire-derived chemical is 6PPD, used as an antiozonant and antioxidant in tires. 6PPD is harmful to human health and the environment and is classified as a probable human carcinogen by the International Agency for Research on Cancer (IARC).
Other tire-derived chemicals of concern include:
- Butylated hydroxytoluene (BHT) – a synthetic antioxidant that is used in tires;
- Naphthalene – a volatile organic compound that can be released from tires during use;
- Benzothiazole – a chemical used in the vulcanization process of tires; and
- Phenol – a chemical used in the production of synthetic rubber.
Tire permeation is a complex issue, and there is still much to learn about the risks of tire-derived chemicals on human health and the environment. However, it is clear that these chemicals can have harmful effects and that further research is needed to understand the risks they pose.