The salad bowl sounds healthy enough, but fill it with chemical-laden greens, and some people would call it a poisoning waiting to happen. Insects, worms and slugs love the tender leaves of spinach and lettuce just as much as we do. Some of the most potent pesticides in use are sprayed right on the leaves we crunch on in our chef's salad. Spinach had the highest number of pesticides of any vegetable tested in the Environmental Working Group's study [source: EWG]. Organic growers use traps, nontoxic repellents and mesh nets to keep the insects at bay.
Greens such as kale, mustard greens, turnip greens and collards are also at high risk of pesticide contamination. Purchase organic versions of these hearty greens if they're available.