COMPARISON STUDY ON THE TOXICITY OF TEN ORGANOPHOSPHORUS PESTICIDES TO PLATYMONAS SP.
十种有机磷农药对扁藻的毒性

The EC_(50) values of ten organophosphorus pesticides to platymonas sp. were studied. According to EC_(50), these pesticides can be divided into four groups. Only phoxim belongs to the first group, its EC_(50) is 0. 76 mg/L. The second group includes isodenphos-methyl, parathion ,parathion-methyl, their EC_(50) are 1. 07 mg/L, 1. 90 mg/L, and 1. 69 mg/L, respectively.The third group includes dichlorvos, omethoate, methamidophos, with EC_(50) of 2. 56 mg/L ,5. 26 mg/L, 2. 61 mg/L and 3. 66 mg/L, 3. 00 mg/L, respectively. The fourth group has the lowest toxicity and includes moncrotophos and malthion, their EC_(50) are 6. 31 mg/L and 10. 47 mg/L, respectively. The relationship between the structure of organophosphorus pesticides and its toxicity is discussed.