Abstract: For protection of aquatic organisms in the Yangtze River Delta Basin, it is essential to define principles for screening out pesticides for priority control. Based on the prediction with models, pesticides commonly used in the region were screened in light of their predicated risks to aquatic organisms, and a pesticide priority control list involving 15 pesticide active ingredients was worked out. The list could provide a priority list for formulating a national surface water ecological criteria for pesticides, and also serve as guidance for control of pesticide pollution in surface water bodies in the Yangtze River Delta Basin.

Key words: Yangtze River Delta Basin, aquatic organism, priority, pesticide, screening