Troubled Waters: Salmon, Fishing, and a Chemical Threat

California is anticipating another disappointing salmon season, leaving fishers and tribes who rely on salmon for their livelihoods concerned about the future of one of the most important fish species in the Pacific Northwest. The decline in salmon populations is due to several factors, including habitat loss, dams, and drought. However, a toxic chemical found in tires, called 6PPD, has recently emerged as another significant threat to salmon populations. 6PPD is a chemical added to tire treads to prevent tread separation, and it is released into nearby waterways as tires wear down.

Environmental advocates, lawmakers, and the tire manufacturing industry are concerned that 6PPD poses a risk to salmon and other fish species. Scientists have found that the chemical can thicken fish blood, leading to brain damage and death in salmon. Washington state studies found that up to 90% of salmon died from 6PPD in some waterways. Dianne Patterson, an assemblymember from San Mateo, introduced a bill that would require Caltrans to create pilot projects to rid waterways of 6PPD by using green infrastructure solutions. While there is hope that the chemical could be removed, it will take considerable time and effort to mitigate the threat of 6PPD, as millions of cars in California alone have tires with this chemical.

This story sheds light on how human actions, from tire manufacturing to driving, can have unintended consequences for fragile ecosystems and the efforts underway to address these impacts.