Study Warns Composting Food Waste Could Add 20,000 Tonnes of Microplastics to US Soil
Updated
Updated · The Guardian · Aug 9
Study Warns Composting Food Waste Could Add 20,000 Tonnes of Microplastics to US Soil
3 articles · Updated · The Guardian · Aug 9
Summary
A Nature Food study found compost made from diverted food waste could leave about 20,000 tonnes of microplastics in US agricultural soils each year, even as it cuts landfill-related emissions.
Life-cycle modeling showed sending food waste to composting or anaerobic digestion instead of landfill would reduce climate impacts by 89% to 99% and also curb nutrient pollution in waterways.
Researchers said the tradeoff stems from plastic-packed food entering waste streams: even 99%-efficient separation systems still raised soil microplastic pollution by an order of magnitude because neither people nor machines remove all packaging.
The findings matter as states such as Vermont enforce organics-diversion laws that ban food scraps from trash, suggesting plastic controls need to be built into any national expansion of food-waste recycling.
The study adds a new constraint to a large climate problem: roughly one-third of food is wasted globally, and 40% of US food waste now goes to landfill, generating 30 million metric tonnes of CO2 equivalent a year.