Developing Farmland Can Release Contaminants

Disturbing old farmland can release pesticides applied more than 100 years ago, contaminating surface water, according to Dartmouth researchers. The researchers found that lead and arsenic, widely applied as lead arsenate pesticide on orchards in the late 1800s and well into the 1900s, have become part of the fine silt and organic matter in the top 10 inches (25 cm) of soil, making the contaminants susceptible to erosion. “While the arsenic and lead in the soils of old orchards is essentially immobile as long as the land is not disturbed, our work suggests that the development of these lands can inadvertently mobilize these metals toward bodies of water,” says Carl Renshaw, associate professor of earth sciences. The study was published in the January/February 2006 issue of the

Journal of Environmental Quality.