Trash is toxic. Just because you don’t toss your refuse into a red haz-mat bag every day, doesn’t mean hazardous substances aren’t there. Paper, metal and plastic items contain toxic chemicals and dyes, while things like batteries and small electronics feature an even more deadly cocktail, including beryllium, lead, chromium, and mercury compounds, all of which are toxic or carcinogenic to humans. Even food waste takes its own array of chemical pesticides and fertilizers with it to the grave.
A small percentage of these things get recycled, which ensures that they never spend a day leaking their toxic inside into the soil and water, but most head straight to the landfill. Now it seems that the lowly earthworm may be key in the bio-remediation of landfills and similarly contaminated sites throughout the world. Researchers at Pondicherry University, in Puducherry, India, say three species of this pink wrigglers could be used to extract toxic heavy metals, including cadmium and lead, from solid waste from domestic refuse collection and waste from vegetable and flower markets.
According to Swati Pattnaik and M. Vikram Reddy of Pondicherry’s Department of Ecology and Environmental Sciences, waste, especially food waste, are currently dumped on the outskirts of many towns and cities in the developing world, causing serious pollution, disease risk and general ecological harm.
Earthworms are like tiny bio-remediation machines, eating through dirt and waste, producing compost out the tailpipe. Eudrilus eugeniae, Eisenia fetida and Perionyx excavates earthworms appear to have digestive systems that are capable of detaching heavy metal ions from the complex aggregates between these ions and humic substances in organic waste as it rots. These substances are not released back into the soil as compost, but locked up in the worm’s tissues. “The separation of dead worms from compost is a relatively straightforward process allowing the heavy metal to be removed from the organic waste,” write the researchers.
What do you think? Should we turn waste dumps into giant vermicomposting operations?