Many of his cherry trees have not weathered the cold, wet spring well. Up the hill, Dr. Alex Liu, a University of Washington public-health researcher, helps two of his graduate students set up a laser device to measure how the cloud of pesticide drifts in the still, cool morning air. Soon the beams shoot across the hill and bounce back to produce spikes of light on a small field computer. Pesticides used on a huge variety of crops are under increasing scrutiny for their potential health effects, especially on children.
Scientists are concerned about children's exposures through food and through the environment.
Other common pesticides also are targeted for analysis. The agency took action against two organophosphates. It banned the use of methyl parathion on most tree fruits, grapes and a variety of vegetables. And it cut back on the amount farmers can use of another pesticide, azinphos methyl, which is widely used in orchards. Now nearly a year under way, the program is attempting to fill a huge void of information on the effects of pesticide exposure in children.