Core Concept: Phytoremediation advances in the lab but lags in the field.

In the early 2000s, homeowners in Washington, DC’s leafy Spring Valley neighborhood received some unwelcome news. The Army Corps of Engineers had discovered that the soil on 177 of the Spring Valley properties contained unsafe levels of arsenic, a remnant of World War I-era weapons testing in the area (1). On highly contaminated properties, the Corps dug up yards and hauled soil away. On properties with lower arsenic levels, the Corps gave homeowners another option: the Edenfern. Edenfern is the trademarked name for the brake fern, a group of ferns in the genus Pteris that researchers discovered naturally draw arsenic from soil. Twenty-two homeowners chose these plants to clean up their properties. Edenspace Systems Corporation, the crop biotechnology company that markets the Edenfern, planted one fern for every square foot of contaminated space. The ferns extracted arsenic over the course of their growing season, about five months, and then Edenspace harvested the fronds, leaving purified soil in place. On 16 properties, remediation lasted a single growing season. Other more contaminated sites required repeat plantings and harvests, but all homeowners saw arsenic drop to safe levels within five years. “Wewere able to save a lot of money in restoration cost because we didn’t have to come back in and restore the landscape,” says Michael Blaylock, president and CEO of Edenspace. Removing arsenic with ferns is just one example of phytoremediation, using plants to purify land or water. By putting plants to work, remediation practitioners can save money on excavation costs and preserve soil structure.