Measurement of DDTs Fluxes from a Recently Dicofol-Treated Cotton Field with Relaxed Eddy Accumulation Technique

Dicofol is a current source of DDT in China, while how do the DDT related compounds (DDTs) in dicofol enter into environment, especially into atmosphere, is not well known. To examine the emission of DDTs to the atmosphere with the application of dicofol, relaxed eddy accumulation (REA) method was applied to measure the fluxes of DDTs over a dicofol treated cotton field during 8 consecutive days in August, 2003. The maximum volatilization fluxes of o,p'-DDE, p,p'-Cl-DDT, o,p'-DDD, and o,p'-DDT at the day after dicofol treatment were 0.34±0.01, 0.55±0.003, 0.58±0.00, and 1.01±0.03 ng m^-2 s^-1 , respectively. The estimated cumulative evaporative losses during the first week after dicofol was applied were 270, 330, 150, and 660 mg ha^-1,which were 0.79, 2.4, 2.4, and 0.95% of application amount, for o,p'-DDE, p,p'-Cl-DDT, o,p'-DDD, and o,p'-DDT, respectively.