Researchers have a cheap, easy way for cleaning up oil spills: letting plants do the work.

Why isn’t it used more often?

Imagine a field contaminated by an oil spill. The toxins have reached deposits of water, and fumes have overtaken the air. Unfortunately, situations like these are common all over the world, presenting hazards to both the environment and to human health. Cleaning up such toxic sites can be very expensive and dangerous, but, in the last three decades, researchers have been working on a new technique: letting plants do the work for us.

Bioremediation, the microbiologist Carol Litchfield wrote in BioScience, is “any use of living organisms to degrade wastes .” Phytoremediation, the use of plants for these purposes, is a part of the larger field of bioremediation. In a sense, people have been using the technique through all of human history, but bioremediation first became a field of scientific study in the 1970s. At first, researchers focused more on microorganisms, either adding nutrients to facilitate the growth of microorganisms at the contaminated site or transporting the contaminated soil or water to bioreactors, where decontamination occurred.

It wasn’t until the 1980s that plants were included in the roster of organisms used in bioremediation, mainly to restore fields contaminated with agrochemicals. Soon after, researchers started to explore a wider range of compounds that could be cleaned from the environment, including petroleum derivatives, heavy metals, TNT, and volatile compounds from paints and refrigerants.

Finding the right plant to use for this purpose is not easy. Most plants cannot grow on contaminated soil or water and, even if they can, most will simply avoid absorbing toxins, leaving them in the soil. Crops used in agriculture also are not ideal, since they have been selected for yield, not remediation. But when the right plant is found, it can pay off.