Apples are at the top of the list of produce most contaminated with pesticides in a report published today by the Environmental Working Group (EWG), a public health advocacy group. Its seventh annual report analyzed government data on 53 fruits and vegetables, identifying which have the most and least pesticides after washing and peeling. For produce found to be highest in pesticides, the group recommends buying organic. Apples moved up three spots from last year, replacing celery at the top of the most-contaminated list; 92% of apples contained two or more pesticides. \"We think what\'s happening to apples is more pesticides and fungicides are being applied after the harvest so the fruit can have a longer shelf life,\" says EWG analyst Sonya Lunder. \"Pesticides might be in small amounts, but we don\'t know what the subtle, long-term effects of many of these pesticides are yet.\" The worst offenders also include strawberries (No. 3) and imported grapes (No. 7). Onions top the \"clean\" list, found to be lowest in pesticides. By choosing five servings of fruit and vegetables a day from the clean list, most people can lower the volume of pesticides they consume daily by 92%, the report says.