Concentration of Organic Phosphorus Pesticides in the Atmosphere above the Dogo Plain and Ozu Basin

Abstract

The distribution of organic phosphorus pesticides in the atmosphere above the Dogo plain and Ozu basin was measured: The pesticides (IBP, MEP, Diazinon) were highly concentrated in the atmosphere in July, August, and September, 1976, corresponding to a large amount of pesticides added to the rice fields during these periods. The residual index in the atmosphere (concentration of perticides/amount of the used pesticides) was smaller than that of BHC and that of Diazinon, IBP, or MEP changed in this order. The fluctuation coefficient changed in the order of IBP, MEP or Diazinon, and the difference in concentrations in the atmosphere above the measured areas was significant. The coefficient of correlation between Diazinon and IBP was 0.73 as these pesticides were apt to spray at the same time.
When the concentration correlation matrixes were made, Ehime University, Matsuyama Technical High School, and Hojo City were found highly to correlate to these pesticides and the concentrations of pesticides in the atmosphere above these areas were smaller than those of Kawauchi Town and Iyo City. Therefore the pesticides in the atmosphere above these areas would come from other places. The IBP concentration in the atmosphere after a spray reached 37.3μg/m³ and it decreased to 61ng/m³ after about 100h.