For many years, an abandoned Coast Guard base along the Pasquotank River in northeast North Carolina leaked fuel into the soil and groundwater, an environmental legacy left over from when the military stored aircraft fuels there from 1942 to 1991.

Now 3,000 hybrid poplar and willow trees planted on the five-acre site may be the answer to cleaning up the pollution in this sensitive watershed.

With $255,000 in grants from the federal government and British Petroleum, the military, industry, state and federal environmental officials and researchers at N.C. State University are collaborating on a project to show that green technology can deal with the pollution more effectively than conventional remediation practices.

Planted in 2006 and 2007, the trees help clean groundwater through phytoremediation, a process by which root systems absorbthink of them as living vacuum cleanersand break down the pollutants. The degraded contaminants are then released into the air through leaves and stems. Trees also phytoremediate by introducing microorganisms into the soil that break down the pollutants.

Standard methods of remediation, such as the use of “oil skimmers,” which extract leaked fuel from contaminated soil, were tried but proved ineffective. Phytoremediation was chosen because it could help slow the movement of polluted groundwater to the Pasquotank River.

And because nothing is ever as good as it seems, a word of caution: According to the Environmental Protection Agency, scientists are studying whether insects and animals that eat the leaves or other parts of the trees could be harmed from the absorbed pollution.