From the ACS Press Room Earthworms like to Eat Some Plastics, but Side Effects of Their Digestion are Unclear “Earthworms’ Degradable Bioplastic Diet of Polylactic Acid: Easy to Break and Slow to Excrete”
that earthworms will ingest these synthetic particles, even breaking them apart into smaller pieces. But during the digestion process, animals could potentially be harmed by Environmental Science & Technology the microplastics themselves or by the toxic .Earthworms are a welcome sight for garden- substances they carry. Currently, companies ers and farmers because the wriggling inver- are producing alternatives to petroleumtebrates recycle nutrients from soil, making based plastics that are derived from plants, them more accessible to plants. As worms are biodegradable or both. Just like traditionburrow, they consume almost everything in al plastics, these “bioplastics” can also fragtheir path, including microscopic plastic pol- ment into microscopic particles, but there is lution. Now, researchers reporting in limited information on whether earthworms ACS’ Environmental Science & Technolo- will also ingest and decompose these materigy have observed that earthworms actually als. So, Lei Wang and colleagues wanted to prefer soil with some types of microplastics compare the willingness of earthworms to but digest the polymers differently, which the consume soil laced with microscopic pieces team suggests could impact the animals’ of bioplastic and petroleum-derived plastic, health and the ecosystem. studying the in vitro digestion and excretion of the particles. By placing earthworms in chambers with different types of plastics in certain locations in the soil, the researchers found that worms preferred soils with bio-based polylactic acid (PLA) particles or petroleum-derived polyethylene terephthalate (PET) particles but actively avoided some semi-synthetic plastics. When lactic acid and terephthalic acid, soursmelling monomers that make up PLA and PET, respectively, were spiked into soil, the worms were also attracted, suggesting that Soil is becoming increasingly contaminated the animals were drawn in by the odors as by fragments of plastic – especially micro- potential cues for food. In another experiplastics less than 5 mm wide – that have bro- ment, the researchers put earthworms in soil ken off of larger plastic waste or have been directly released from products as small particles. Previously, researchers have shown Continued on page 15 May 2022
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