From roads to oceans: Pollution pathways of end-of-life tires in coastal and marine environments

The use and disposal of end-of-life tires (ELTs) in coastal and marine environments has emerged as a form of pollution that is largely absent from existing regulatory frameworks. Originally engineered for strength, durability, and resistance to environmental stress, tires are increasingly repurposed in informal coastal infrastructure such as erosion control structures, ramps, walkways, and artificial reefs. However, these uses have resulted in significant negative environmental consequences, including chemical leaching, microplastic release, and tire wear particle release, physical habitat degradation, localized thermal stress, public health risks, among others. Despite these impacts, tires remain absent from most marine pollution frameworks and coastal adaptation strategies. This paper provides the first global review of ELT use in coastal contexts, presenting a typology of informal applications, analyzing their environmental consequences, and identifying the key motivations behind their continued deployment. The review highlights critical gaps in national regulations, a lack of coastal-specific prohibitions, and the lack of formal integration ELTs into marine litter action plans. Case studies from both developed and developing countries illustrate the widespread nature of this issue and its socioecological implications. A comprehensive management framework emphasizing regulatory bans, safer alternatives, inland recycling innovations, and targeted monitoring and remediation is presented. Emphasis is placed on the need for integrated governance, environmental justice, and alignment with global sustainability targets. Addressing the risks posed by end-of-life tires in coastal systems requires urgent attention, informed policymaking, and coordinated action across sectors to prevent further degradation of nearshore ecosystems and human well-being.