Why it's risky: Grown for months, celery is subjected to more pesticides over a long period of time. Unlike broccoli, which is sheltered by big leaves on big bushes, celery is not protected from pesticides.
How to lower your exposure: Buy organic or frequent farmers' markets with small growers who can't afford or choose not to use expensive pesticides, says Lu. (Don't be afraid to ask the sellers about their use of pesticides.) Or try a cleaner green veggie alternative, like avocado or asparagus, both of which have low exposure to pesticides, according to the Environmental Working Group (EWG).