Scientists in South America are exploring the use of common earthworms to clean contaminated soil and liquids at former industrial sites and landfills. According to a study published in the International Journal of Global Environmental Issues, earthworms, which process waste and soil in gardens, have the 
potential to safely — and cheaply — remove toxic metals including lead and mercury from contaminated materials. In one study, researchers at the Universidad Centro Occidental Lisandro Alvarado in Venezuela found that in just two weeks earthworms were able to remove arsenic levels from soil with 42 to 72 percent efficiency, and reduce mercury content with 7.5 to 30.2 percent efficiency. In addition, they found that compost produced by worms worked as an effective absorbent substrate for cleaning wastewater contaminated with metals such as nickel, chromium, and lead.
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