Pumpkins become one of the most popular plants this week, with many people carving Jack-o-lanterns in honor of Halloween. But Canadian scientists have another purpose for the orange fruit in mind: cleaning up pollution. According to a recent study, pumpkins can cheaply remove DDT from contaminated soil.
Before it was banned in 1972, DDT was used widely as an insecticide. A type of persistant organic pollutant, its hydrophobic, or water-fearing, characteristics make it difficult to remove from soil. Often large swathes of land must be removed and either buried in a specially designed landfill or burned in a high-temperature incinerator. Ken Reimer of the Royal Military College of Canada and his colleagues studied a number of plant species to determine whether they are viable candidates for DDT phytoremediation (the use of vegetation for treating contaminated soils). The researchers grew zucchini, tall fescue, alfalfa, rye grass and pumpkins in a greenhouse using soil imported from the Canadian Artic that had been treated with DDT. “The cold temperatures meant that the contamination was virtually identical to the technical grade DDT mixture that had originally been used,” Reimer says. “We could therefore examine the ability of [the plants] to suck the DDT out of the soil that had been contaminated with DDT for several decades.”