We bury them underground, drown them in lagoons, or shove them out to sea—no matter how remote a site, it may be full of the toxic by-products of modern life. Nuclear waste and heavy metals are just some of the noxious residue of our everyday existence. To reverse the damage, scientists turn to both innovative technologies and peculiar organisms.
If they make their way into the groundwater, chlorinated wastes, like those found in dry-cleaning fluids and paint thinner, can cause liver problems and cancer in people. But some bacteria find these chemicals quite palatable: When Dehalococcoides ethenogenes comes in contact with the chemicals, it feasts on chlorinated compounds, converting them into harmless gases.
Fly Ash Bricks
In the process of generating electricity, U.S. coal plants spew more than 70 million tons a year of a radioactive waste called fly ash. Now a Missouri company has found a way to turn the ash into bricks, an innovation that reduces fly ash while providing an extra benefit: The bricks soak up toxic mercury from the air.
White rot fungi, common in the forests of North America, use special enzymes to convert the carbon in trees to energy. These same enzymes can oxidize environmental pollutants such as pesticides and PCBs, rendering them benign.
Metal toxins commonly found at mining sites could be treated with the stinky remains of human wastewater. The human waste, rife with iron, would be especially useful if dumped at sites loaded with cadmium, lead, and arsenic. The iron would readily react with the other metals and keep them from dissolving into nearby groundwater.
Hematite, a shiny black mineral sometimes used to make jewelry, can soak up plutonium and uranium waste from nuclear plants. Scientists recently found that hematite crystals placed in acid grow pyramid-like structures on their surface. As the structures form, contaminants can settle into tiny pockets in the hematite crystal, where they could remain stable for hundreds of years.