Without realizing it, we are exposed to them every day. These plastic particles are released into the air and fall back as a fine plastic dust, invisible to the naked eye. Because of their microscopic size, these particles can spread by the billions in nature.
Scientists working on the St. Lawrence Action Plan are trying to understand the impact of nanoplastics on the health of aquatic species.
Unlike macroplastics or microplastics, which have direct effects on an animal when ingested (obstruction of the digestive tract, for example), nanoplastics have more subtle effects.
To better understand these effects, St. Lawrence Action Plan scientists installed cages of mussels in urban contaminated sites downstream from the Montréal metropolitan area, and then analyzed their tissues. Because mussels are permeable, meaning that they have a high capacity to absorb contaminants, nanoplastics penetrate their cells more easily.
Using electron microscopes and techniques such as liquid chromatography to separate the various components of a sample, the scientists found accumulations of nanoplastics in the mussels’ digestive glands. The presence of nanoparticles in the body can interfere with the body’s internal processes, both with metabolism (poor energy intake) and the immune system. The researchers also detected abnormal accumulations of damaged proteins in the mussels that they studied; these damaged proteins can lead to cell degeneration and compromise mussel health.
Although the long-term health effects of nanoplastics are still being studied, St. Lawrence Action Plan scientists continue to advance scientific knowledge by developing innovative detection and toxicological analysis techniques for aquatic species.
As this project continues, they plan on studying the sources of nanoparticles in the environment (urban waste, solid waste, tire wear) and the impacts of heavy rainfall within the context of climate change.