Release of a “forever material” from end-of-life boats and glass-reinforced composite boats is pervasive and entering food chains

Abstract

Fine strings of silica glass in various configurations in a matrix of plastics provide the strength for now ubiquitous glass-reinforced plastic (GRP). Over the past 80 years, GRP boats have become a mainstay of the boating industry while little attention has been given to the consequences of GRP degradation or boat disposal. Its importance is highlighted by the recent discovery of high levels of glass particles in mussels and oysters using Raman spectroscopy (Ciocan et al., 2024). Recent studies reveal widespread glass fiber pollution in heavily trafficked coastal waterways, while research and policy lag behind (Ciocan et al., 2024; Galimany et al., 2009; Lekshmi et al., 2023). With over one million GRP boats reaching the end of their life each year, disposal and recycling solutions that protect aquatic life and human health are necessary.

Building boats of sufficient strength and durability to withstand the harsh water environment has always been a challenge. Composites, particularly GRP, historically provided one of the best low maintenance solutions (Rubino et al., 2020). The Global GRP Boats market is anticipated to grow in the forthcoming years at a rate of 13.2% per year in North America (Fortune Business Insight, Transportation and logistics, 2024). As the marine industry continues to push for advanced electronics and luxury furnishing on board, hulls are becoming thinner and this, in turn, affects the boat's lifetime expectancy (IMO report, 2019). Exposure to environmental conditions degrades GRP chemically and physically over time: the resin will plasticize, swell, and microcrack, exposing the glass fibers, suggesting that marine craft are additional sources of microparticulate (MP) in the environment (Hopkinson et al., 2021).

Indeed, the marine (shipping)-based sources or ship-related skid marks (similar to road tire wear) are now considered an underestimated source of marine MPs (Dibke et al., 2021). High levels of MPs associated with polymeric paints and/or alkyd resins within GRP have been reported worldwide (Pothiraj et al., 2023); in contrast, records of thin hygroscopic silica fibers, sometimes referred to as “asbestos like fibers” (Galimany et al., 2009; Hopkinson et al., 2021), are scarce. Thousands of glass fiber particles have been isolated from bivalves in SE England (Ciocan et al., 2024) and widespread contamination has been detected in coastal sediments, suggesting a significant presence of composite-derived MPs in the aquatic environment and potential trophic transfer (Ciocan et al., 2020). Elsewhere, unpublished results (Kozloski, unpublished data) reveal clumps of glass fibers and free-floating shards as a dominant component of MP pollution in the Mekong River, Cambodia (Figure 1).

The common use of techniques designed for microplastics is poorly suited to identifying microparticles of glass and may have hidden the problem. Alternative methods, such as stainless steel filters and a combination of ID methods (Raman and infrared spectroscopy coupled with light microscopy), are now revealing the extent of the glass fiber presence in the environment.

The lack of landfill spaces and difficulty of recycling composite materials led to concerns surrounding the disposal and/or recycling of GRP boats (IMO report, 2019). Around 55,000 tones/year of GRP waste are generated by the marine industry in the United Kingdom (National Composite Centre news, 2022). There are approx. 12 million recreational boats in the United States (Global Market Insights, 2020) and more than 6 million in Europe—10% of these reach the end of their active life every year (IMO report, 2019). Decaying boats are a common site in coastal areas around the world and expensive to remove: 5649 abandoned boats (of which 88% as recreational vessels) were reported in three US states in 2017; the removal of 54% of these came at a taxpayer's expense of more than $15 mil (GAO, 2017).

The issue of end-of-life GRP boats was brought into sharper focus by the Pacific Small Island states due to their limited infrastructure for disposal (landfill and/or scuttling; IMO report, 2019). The problem is also exacerbated by the extreme weather events and the glut of wrecked GRP boats left after hurricane damage. With no viable market for damaged boats, thousands of vessels end up in landfill (Flannery, 2016) or may be scuttled offshore after being stripped of recyclable items (Fain, 2018).

Hurricane frequency is increasing, with wider reports of damage to island communities and marine habitats. In 2017, hurricane Irma hit the Florida Keys and left 1671 damaged boat, many of them later wrecked on the coast with an excavator (Herrald, 2018). Locals expressed concerns over the resulting MP dust, with some justification, as dermatitis, diagnosed as “fibreglass dermatitis,” caused by fine, sharp glass particles (>5 μm in diameter) are well-documented events in industrial environments (Park et al., 2018). Additionally, even working for a short period at GRP boat–building facilities is linked to an increased risk of early death from respiratory disease (Nett et al., 2017).

New techniques of analysis are now showing high levels of microparticles of glass entering aquatic food chains (Ciocan et al., 2024). The emerging evidence suggests that minimizing the impacts of GRP will require a multisectoral and multidisciplinary approach. Prospective legal and policy measures are necessary to reduce the environmental presence of GRP and thus manage risks to human and marine life. In the international context, end-of-life vessels are understood as carriers of hazardous waste such as asbestos; if GRP poses analogous risks, then both international and domestic law should unambiguously reflect these risks (Moen, 2008). A vessel itself may be waste, though various sources of international law diverge on this point (UNEP, 2005). Within the regime controlling the movement of hazardous waste across state borders (Moen, 2008), GRP's demonstrable ecotoxicity meets the criteria for hazardous waste and vessels should be classified on this basis.

Corina Ciocan: Conceptualization; funding acquisition; investigation; supervision; writing – original draft; writing – review and editing. Kethan Jha: Writing – original draft. Claude Annels: Investigation. Rachel Kozloski: Writing – review and editing. Ilse Steyl: Visualization; writing – review and editing. Simon Bray: Writing – review and editing.

The authors declare that they have no conflict of interest.