by Stephen K. Ritter, Chemical & Engineering News
As an organic analytical chemist, Ronald A. Hites of Indiana University has been taking the measure of persistent organic pollutants in the environment for decades. In a career spanning 50 years, Hites has watched some of these chemicals survive only a few days in the atmosphere. But to his surprise, they never seem to go away completely—some have stuck around as long as he has.
For example, traces of the infamous malaria-fighting insecticide DDT remain 40 years after it was banned in the U.S.—nearly everyone has tiny amounts in their blood. Hites knows firsthand of at least one place it originated.
“Growing up in Detroit in the 1950s, the streets were lined by big elm trees that formed a beautiful canopy,” Hites recalls. “In the summer, men wearing yellow rain slickers would come down the street following a truck and spraying DDT up into the trees to kill mosquitoes and other bugs.”
Hites is one of a persistent group of environmental scientists who develop testing methods and make long-term measurements to track the fate of DDT and other chemicals such as polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and brominated flame retardants. These compounds were once widely used for industrial and agricultural applications and as key components of consumer products. But scientists discovered that the properties that make them useful also make them stable to natural degradation. As a result, the chemicals accumulate globally in water, soil, plants, and animals. They accumulate in people too—in blood, fat tissues, and milk—where, in some cases, they can cause neurotoxic and other negative health effects. Read the entire story.