Organophosphate (OP) pesticides are a class of chemicals that are typically derived from phosphoric, phosphonic, and phosphinic acids, and are commonly used in agriculture[1]. China is the largest producer of pesticides and one of the most intensive pesticide users in crop production in the world. Pesticide poisoning has been shown to be an important public health problem among Chinese farm workers[2]. Multiple routes of exposure to OP pesticides occur through food contamination, environmental and household pollution, proximity to agricultural fields, and agricultural work[3].