Plants have long been known as air purifiers, but now Paul Jackson, a microbiologist at Los Alamos National Laboratory, is using plant cells to purify liquids contaminated with heavy metals like barium and uranium, and with the residue of explosives like TNT.

Jackson's "green filter" consists of a silica-based powder mixed with cells from various plants such as corn and citrus. Different plants prefer different minerals, so when the contaminated liquid is passed through the filter, microscopic hooks located on the outside of the plant cells snatch their preferred toxins from it. Lab studies show that contaminant levels are reduced to below accepted standards at a rate of 3.78 litres every 3 minutes.