More dangerous than microplastics! A hook shrimp can break down microplastics into fragments smaller than cells in 4 days

One study showed that a small crustacean was able to break down microplastics into fragments smaller than cells within 96 hours.

Until now, plastic fragmentation has been largely attributed to slow physical processes such as sunlight and the action of waves, which can take years or even decades.

Environmental scientists at University College Cork (UCC) in Ireland studied the 2-centimeter-long Gammarus duebeni and found that microplastics are not only swallowed into the body, but also break down into nanoplastics at an incredible rate.

Because these fragments are small enough to pass through cell membranes, it is thought that they may be more potentially harmful to wildlife than 5-millimeter-sized microplastics.

The study, published in Scientific Reports, said the paper's lead author, Dr. Alicia Mateos-Cardenas, said her findings were "completely unexpected."

"When I started working on this problem three years ago, it sounded crazy that such a small animal could break down plastic, but our study showed that 66% of all the microplastics observed in the intestines of these animals were plastic fragments."

Mateos-Cardenas uses spherical microbeads from polyethylene, a common polymer found in plastic bottles. Each bead is labeled with a fluorescent dye so that its feeding and fragmentation can be tracked with a microscope.

Studies have shown that these microbeads are broken down by the Dick's hook shrimp into nanoplastics smaller than 1 micron or one thousandth of a millimeter. More debris was found when The Hook Shrimp was exposed to high concentrations of microplastics for 4 days.

In the presence of its food (a plant substance), the smaller proportion of plastic fragments is highest after being purified in pure water, suggesting that plastic fragmentation may be closely related to the feeding process.

Hook shrimp is an aquatic arthropod that mostly inhabits benthic life, both crawling and swimming. The food of benthic species is mainly zooplankton food such as animal and plant fragments, algae and animal carcasses, and there are also a few benthic species that hunt for life, often with developed compound eyes, which is conducive to finding predatory objects.

Hook shrimp is one of the largest groups of crustaceans, they are small, diverse, fast reproduction, widely distributed, in different water depths, different geographical locations, different water quality conditions are distributed.

"We've seen The Hook Shrimp swallow these plastic particles, chew them with their jaws, and then pass them on to the digestive system, but we don't yet know how these animals break down the plastic. We need to investigate the actual mechanisms of this biological fragmentation," Mateos-Cardenas said.

The study has broader implications because the crustacean is one of more than 200 species of hook shrimp found in rivers, estuaries and oceans around the world.

"This undoubtedly increases our understanding of the fate of plastics in the environment," Mateos-Cardenas said.

"Once the plastic gets into the rivers and oceans, we really don't know what to expect. If animals devour and break them down, the problem widens. ”

Not only is this biological fragmentation a global problem, but the harmful effects of plastic contaminants may increase as particle size decreases.

"If nanoplastics can pass through cells (membranes), they may accumulate in animals and plants, with unknown potential negative effects, so the plastic pollution problem becomes more complex and more worrisome," Mateos-Cardenas said, adding that "nutrient transfer" occurs when predators such as birds and fish feed on the crustacean.

This means that nanoplastics may accumulate in the upper layers of the food chain, including possibly in humans, while toxic chemicals may attach to the surfaces of these nanoplastics.

Compilation/Prospective Economist APP Information Group

Original source:

https://www.theguardian.com/environment/2020/jul/30/small-crustacean-can-fragment-microplastics-in-four-days-study-finds