Celery has no protective skin, which makes it almost impossible to wash off the chemicals that are used on conventional crops.
Can't find organic? Safer alternatives include broccoli, radishes and onions.
A perennial entrant on the Dirty Dozen list, 64 pesticides detected in residue on this veggie make celery rank No. 1 in the 2010 analysis, up from No. 4 in 2009.
Multiple pesticides are regularly applied to these delicately skinned fruits in conventional orchards.
Can't find organic? Safer alternatives include watermelon, tangerines, oranges and grapefruit.
Peaches, No. 1 on the Dirty Dozen list in 2009, rank No. 2 in 2010; 62 pesticides have been detected in residue on peaches.
If you buy strawberries out of season, they're most likely imported from countries that use less-stringent regulations for pesticide use.
Can't find organic? Safer alternatives include kiwi and pineapples.
Up from No. 6 in 2009, strawberries rank No. 3 on the 2010 Dirty Dozen list. Why? 59 pesticides have been detected in residue on strawberries.
Like peaches, apples are typically grown with the use of poisons to kill a variety of pests, from fungi to insects. Scrubbing and peeling doesn't eliminate chemical residue completely, so it's best to buy organic when it comes to apples. Peeling a fruit or vegetable also strips away many of their beneficial nutrients.
Can't find organic? Safer alternatives include watermelon, bananas and tangerines.
New on the Dirty Dozen list in 2010, blueberries are treated with as many as 52 pesticides, making them one of the dirtiest berries on the market.
With 33 different types of pesticides found on nectarines, they rank up there with apples and peaches among the dirtiest tree fruit.
Can't find organic? Safer alternatives include, watermelon, papaya and mango.
7. Bell Peppers
Peppers have thin skins that don't offer much of a barrier to pesticides. They're often heavily sprayed with insecticides.
Can't find organic? Safer alternatives include green peas, broccoli and cabbage.
Tests have found 49 different pesticides on sweet bell peppers.
New on the list for 2010, spinach can be laced with as many as 48 different pesticides, making it one of the most contaminated green leafy vegetable.
Traditionally kale is known as a hardier vegetable that rarely suffers from pests and disease, but it was found to have high amounts of pesticide residue when tested this year.
Can't find organic? Safer alternatives include cabbage, asparagus and broccoli.
Even locally grown cherries are not necessarily safe. In fact, in one survey in recent years, cherries grown in the
Can't find organic? Safer alternatives include raspberries and cranberries.
Government testing has found 42 different pesticides on cherries
Can't find organic? Safer alternatives include eggplant, cabbage and earthy mushrooms
Imported grapes run a much greater risk of contamination than those grown domestically only imported grapes make the 2010 Dirty Dozen list). Vineyards can be sprayed with different pesticides during different growth periods of the grape, and no amount of washing or peeling will eliminate contamination because of the grape's thin skin. Remember, wine is made from grapes, which testing shows can harbor as many as 34 different pesticides.Can't find organic? Safer alternatives include kiwi and raspberries.