[Image above] Screenshot from a video of a mussel filtering food. Bivalve mollusks such as mussels are stationary filter feeders, which makes them highly susceptible to accumulating microplastic particles. Credit: Ocean Wise, YouTube

 

In the August 2024 Bulletin, we took a deep dive into the deep seas to explore how human activities can affect the lives and habitats of animals that play crucial roles in aquatic ecosystems. Though the ramifications of deep-sea mining are currently a future worry, there are immediate threats to marine life closer to our shores.

Shellfish such as oysters and mussels are necessary components of global ocean health. These animals not only filter and clean the surrounding water, but they can also serve as barriers to storms and tides, preventing erosion and protecting productive coastal ecosystems.

Unfortunately, decades of overfishing, habitat loss, and disease have proved devasting for these bivalve mollusks, leaving oyster and mussel populations at historic lows. In response, governments, conservation groups, researchers, and mollusk growers in states along the U.S. Atlantic and Gulf coasts have launched initiatives, such as here, to help restore the population.

But rebuilding habitats and passing new fishing regulations is only part of the solution. Pollution also greatly affects mollusk populations, and a recent open-access study reveals the far-reaching extent of this contamination.

The study was a collaborative effort between researchers at the Universities of Brighton and Portsmouth in the U.K. They focused specifically on contamination from glass-reinforced plastics, which are used extensively in boat manufacturing.

Fiberglass boats became popular in the 1960s because they are much heavier than aluminum boats, which makes the ride more comfortable. But fiberglass boats are also less durable than aluminum boats, and their heavier weight makes proper disposal more expensive.

Because of the high disposal costs, some owners will choose to abandon their old fiberglass boats in public waters instead. The abandoned boats will eventually degrade, leaking microplastics and other toxic chemicals into the surrounding environment, as detailed in a January 2023 CTT.

In the recent study, the U.K. researchers aimed to gather more exact data on the levels of contamination resulting from this illegal dumping. To do so, they gathered oysters and mussels from several areas in Chichester Harbor, downstream of an active boatyard. They collected the mollusks during both the winter months (coinciding with seasonal boat maintenance) and in May (start of a busy schedule for water sport activities). They then used micro Raman spectroscopy to identify the chemical composition of glass fibers found in the mollusks.

Sample sites with key location points within the Chichester Harbor, south of England. Credit: Ciocan et al., Journal of Hazardous Materials (CC BY-NC-ND 4.0)

The researchers found the highest fiberglass concentrations during the winter months, with up to 11,220 fiberglass particles per kilogram in oysters and up to 2,740 particles per kilogram in mussels. This contamination can have severe consequences for the mollusks’ health, as explained in a University of Portsmouth press release.

“Bivalves, being stationary filter feeders, are highly susceptible to accumulating these particles, which can severely impact their health. The ingestion of GRP [glass-reinforced plastic] can interfere with their digestive systems, leading to physiological stress and even death,” the press release states.

Furthermore, “This [contamination] not only affects marine life but could also have significant implications for human health, given that these bivalves often end up on our plates,” the press release continues.

More research is needed to understand the full scope of effects resulting from this contamination. But regardless, “Creating a better ethos around end-of-life boat management is crucial to minimize further exposure and spread of these contaminants,” says first author Corina Ciocan, principal lecturer in marine biology at the University of Brighton, in the press release.

The open-access paper, published in Journal of Hazardous Materials, is “Glass reinforced plastic (GRP) boats and the impact on coastal environment—Evidence of fiberglass ingestion by marine bivalves from natural populations” (DOI: 10.1016/j.jhazmat.2024.134619).

Author

Lisa McDonald

CTT Categories

  • Environment