Residue Of Octachlorodipropyl Ether(S-421) In Tea And Main Environmental Influence Factors

Octachlorodipropyl ether (S-421, S-2), as an effective, cheapest synergist, was used widely in pyrethroid, carbamate, organophosphorus and organchlorine pesticides, and also used widely in mosquito coils. It is carcinogenic mutagenic and macrocephalic,which was also supported by the results of a survey of lung cancer for the workers in the S-421 manufactory. The new limited value of S-421(0.01 mg kg^-1) in imported tea regulated by European Union, have beening one of the important obstacles for Chinese tea exportation. There is no any available data on the residue of S-421 in tea and tea garden environment, even in total agro-ecosystem. Therefore, the residues of S-421 in Chinese teas and in soils from teagarden were investigated, and the possible role of mosquito coils on the contaminated of S-421 in tea was also discussed.The results of investigation of S-421 in tea showed that the residues of S-421 in tea are very popular, and were in the range of 0.027 mg kg^-1 to 0.265 mg kg^-1. All tea samples include the famous quality teas, and common teas, were polluted by S-421. The average values of S-421 residues were higher in green tea and oolong tea than in scented teas, black teas and Pu'er teas. The S-421 contents in fresh leaves were higher than that in maked tea.The contents of S-421 in tea garden soil ranged from 0.021 mg kg^-1 to 0.163 mg kg^-1 and its average value 0.0481 mg kg^-1. It was also detected in other farmland soils that were in the range of 0.011 mg kg^-1 -0.049 mg kg^-1 and its average value was 0.022 mg kg^-1.The residue of S-421 was also detected in agricultural products, such as grain and vegetable. The content of S-421 in rice was 0.146 mg kg^-1 and higher than that in wheat and corn. The residues of S-421 were obviously higher in leaf-vegetables than in root-vegetables. The order of S-421 residues in leaf-vegetables follows: Maomao(0.282 mg kg^-1) > celery (0.164 mg kg^-1) > cabbage (0.136 mg kg^-1). The results indicated that the amount of pesticides was used in vegetable growing.There are higher S-421 values in mosquito coil samples purchased in market. The S-421 volatilized with smog during combustion and no S-421 was detected in coil ash. The maked Tea could absorb S-421 in air which came from mosquito coil combustion or from other sources. These results showed thatair pollution due to application of mosquito coils in the ambience of tea manufactories also resulted in tea contaminated by S-421 except for the application of pesticide in tea garden.