“Given their pervasive and persistent nature, microplastics have become a global environmental concern and a potential risk to human populations,” said Rachel Hurley from the University of Manchester and colleagues in their report, published in Nature Geoscience.
“Microplastics have been found in mussels everywhere scientists have looked,” she said.
More than five trillion pieces of plastic are estimated floating on the surface of the world’s oceans. It has been claimed that there is now enough plastic to form a permanent layer in the fossil record.
“… plastic debris is often contaminated with toxic chemicals. Plastics can absorb and concentrate toxic pollutants present at trace levels in seawater, and some of the chemical additives mixed in during the manufacturing process can be toxic as well. When marine organisms ingest chemical-laden plastic pieces, some of the pollutants may be released within the gut of the animal and absorbed into body tissue. Although it is uncertain how much of these harmful chemicals enter marine animals due to ingestion of plastic debris in the ocean, laboratory experiments suggest there may be reason for concern.”
The researchers then observed the oysters’ physiological responses to ingesting the microplastics. The most obvious effect was on reproduction. Oysters that were exposed to microplastics produced fewer and smaller egg cells and slower sperm. Exposed oysters also produced fewer larvae and their offspring tended to grow more slowly.
But ocean plastics pose a threat to a wide variety of marine animals, and their risk is determined by the amount of debris an animal encounters, as well as the size and shape of the debris.
Plastic waste causes $13 billion in damage to marine ecosystems each year, according to the UN Environment Program. California and cities including Chicago, Seattle and Portland have banned single-use plastic bags.