[jfengel]

The ground is actually pretty dirty -- by definition. And since you don't cook lettuce, you risk eating whatever was on the ground (and the hands of the picker, and everybody else along the line).

You usually don't drink water the way we pull it out of the ground, either.

That doesn't automatically make the chemicals safe. But it highlights that there is a tradeoff. The environment is full of things that make you sick.