Pesticides: Now More Than Ever

How quickly we forget.

After the publication of “Silent Spring,” 50 years ago, we (scientists, environmental and health advocates, birdwatchers, citizens) managed to curb the use of pesticides and our exposure to them — only to see their application grow and grow to the point where American agriculture uses more of them than ever before.

And the threat is more acute than ever. While Rachel Carson focused on their effect on “nature,” it’s become obvious that farmworkers need protection from direct exposure while applying chemicals to crops. Less well known are the recent studies showing that routine, casual, continuing — what you might call chronic — exposure to pesticides is damaging not only to flora but to all creatures, including the one that habitually considers itself above it all: us.

As usual, there are catalysts for this column; in this case they number three.

I was impressed by a statement by the American Association of Pediatrics — not exactly a radical organization — warning parents of the dangers of pesticide and recommending that they try to reduce contact with them. The accompanying report calls the evidence “robust” for associations between pesticide exposure and cancer (specifically brain tumors and leukemia) and “adverse” neurodevelopment, including lowered I.Q., autism, and attention disorders and hyperactivity. (Alzheimer’s, obviously not a pediatric concern, has also been linked to pesticide exposure.)

This reminded me of recently disclosed evidence showing that pesticide exposure in pregnant women may be obesogenic — that is, it may cause their children to tend to become obese. The mechanism for this is beginning to be understood, and it’s not entirely shocking, because many pesticides have been shown to be endocrine disruptors, changing gene expression patterns and causing unforeseen harm to health.

And that in turn prompted me to recall that genetically engineered crops, ostensibly designed in part to reduce the need for pesticides, have — thanks to pesticide-resistant “superweeds” — actually increased our pesticide use steadily over the last decade or so. (In general, fields growing crops using genetically engineered seeds use 24 percent more chemicals than those grown with conventional seeds.)

Although these all caught my attention, the most striking non-event of the last year — decade, generation — is how asleep at the wheel we have all been regarding pesticides. Because every human tested is found to have pesticides in his or her body fat. And because pesticides are found in nearly every stream in the United States, over 90 percent of wells, and — in urban and agricultural areas — over half the groundwater. So Department of Agriculture data show that the average American is exposed to 10 or more pesticides every day, via diet and drinking water.