Humans, fish and other animals are consuming microfibers in our food and water.
Jul 11, 2018 at 1:00pm
By Mary Catherine O'Connor, Ensia
As tiny fibers shed from synthetic textiles invade our bodies, researchers scramble to identify potential threats.
To date, laboratory studies have largely looked at microplastics as a whole rather than specifically at microfibers. However, since microfibers are a primary constituent of microplastics, such research can provide useful insights.
Lab studies have found that microplastics can harm small aquatic organisms that eat them — including plankton, a hugely important food source for aquatic organisms. These harms include decreased ability to feed and reproduce. Zooplankton given food laced with microplastics in a lab had decreased nutrition and poorer health than the control group. And pearl oysters fed polystyrene microbeads had less energy.
Microfiber researcher Chelsea Rochman, assistant professor in the Department of Ecology & Evolutionary Biology at the University of Toronto, and other researchers, including Matthew Cole, a research scientist at Plymouth Marine Laboratory, hypothesize that the physical shape of synthetic fibers might affect organisms. For example, they could increase the likeliness of blockages in the digestive tracts of some organisms that consume them, depending on the fiber’s size and the animal’s size, they say.
A small number of lab studies have sought to analyze how ingesting fibrous microplastics affects aquatic organisms. For a 2015 study, European researchers embedded 1- to 5-millimeter (0.04- to 0.2- inch) microfibers from polypropylene rope in food given to crabs for four weeks. The crabs that were fed the fiber-laced food ate less overall than the control group and had less energy available for growth. After moving through the digestive tracts, the fibers were balled up, so they did not seem to cause physical blockages.
Cole also has shown that copepods — crustaceans that are found in marine and nearly all types of freshwater and serve as a key food source for small fish — readily ingest the fibers.
There is concern about impacts due to chemicals that attach themselves to microfibers, too. Rochman fed fish microplastic pellets that had absorbed toxins via prolonged exposure to seawater near San Diego. The fish accumulated the chemicals — which included polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs), all known carcinogens — and suffered liver toxicity and other pathological changes.
Advocacy groups such as 5 Gyres pointed to Rochman’s study, and to concern that microplastics, including microfibers, could cause large-scale harm by introducing toxins found in waterways (including the legacy industrial contaminants PCB and DDT) into the food chain, to successfully lobby for a U.S. ban on the sale of soaps and cosmetics with added plastic microbeads. (Canada and the United Kingdom have followed suit.)
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