Managing the Risks of Soil Contamination
Rebecca Kessler is all too familiar with the difficulties and uncertainties of cleaning up dirty urban soil, having embarked on a multiyear project to convert a paved parking lot at her Providence, Rhode Island, home into a beautiful and fruitful garden.
n a bright late-September afternoon, Mary Bleach showed visitors around the community garden near her apartment in Boston’s Dorchester neighborhood. The sunflowers were nodding their heads in acquiescence to fall, but rust-colored marigolds, pink cosmos, and fuchsia morning glories were still abloom, and a few lazy bees hit them up for nectar. Kale, collards, okra, callaloo (a relative of spinach), tomatoes, onions, herbs, eggplants, beans, peanut plants, and a squash vine with leaves bigger than Bleach’s head entangling 15 feet of chain-link fence—all were still soaking up the fall sun’s rays. Bleach said she lives out of the garden in summer, and she freezes enough to eat well into winter, too.
All this vegetable profusion would soon be gone. Winter was coming, yes, but also heavy machinery to scrape the land level and to haul away the ramshackle chain-link fence and the timbers dividing one plot from another. After more than 25 years, the garden at the corner of Lucerne and Balsam streets was slated for a makeover: handicapped-accessible concrete paths, sturdy fencing, new water service, and reestablished plots with granite dividers.
Boston University toxicologist Wendy Heiger-Bernays and three students had come to check out the site in preparation for a detailed soil contaminant study that would inform the renovation. If the garden’s soil were anything like other Boston soils, it would contain elevated levels of lead—in Dorchester yards, 1,500 ppm of lead is common.1 In the worst-case scenario, much of the garden’s soil would have to be removed and clean topsoil and compost trucked in.