A Study on the Biodegradability of Some Pesticides in Water

물 중에서 일부 농약의 생분해성에 환한 연구

The present study was conducted to investigate biological degradability of phosphamidon and profenfos. In the biodegradation test of two pesticides by the modified river die-away method from May 20 to July 29, 1999, the biodegradation rate was determined in Nakdong (A) and Kumho(B) River. The residual percentages of phosphamidon were 74.9%, 68.8% and 62.7% in control, A and B samples 7 days after applicaton, respectively. Biodegradation constants and half-lives of phosphamidon were 25.1%, 21.9% and 11.9% in control, A and B samples 7 days after application. Biodegradation constants and half-lives of profenofos were 0.0005 and 58.4 days in A, 0.0013 and 21.6 days in B, respectively. The biodegradation rates of phosphamidon and profenofos were higher in the Kumho River (B) than in the Nackdong River(A). The strains of microorganisms for the degradation of phosphamidon and profenofos were identified as Klebsiella pneumoniae, Aeromonas hydrophila and Acinetobacter calcoaceticus, all Gram-negative bacteria. In order to identify biodegradate products, the extracts of cultivates were analyzed by GC/MS. The mass spectra of biodegradate roducts of phosphamidon were at m/z 153 and 149, those of the profenofos were at m/z 208 and 240, respectively. It was suggested that the biodegradate metabolites of phosphamidon were O, O-dimethyl phosphate(DMP) and N, N-diethylchloroacetamide, those of profenofos were 4-bromo-2-chlorophenol and O-ethyl-S-propyl phosphate.

Modified river die-away 법으로 1999년 5월 20일부터 7월 29일 까지 낙동강 (A)과 금호강(B)에서 채수한 강물로 phosphamidon과 profenofos의 생분해 시험을 한 곁과는 다음과 같다. Phosphamidon의 경우 배양 7일 경과 후 최초처리량 대비 잔류량은 대조군에서 74.9%, A 실험군에서는 68.8%, B 실험군에서는 62.7%가 잔류하였으며, profenofos의 경우 배양 7일 경과 후 대조군에서 25.1%, A 실험군에서는 21.9%. B 실헌군에서는 11.9%가 잔류하였다. Phosphamidon과 profenofos의 생분해는 배양시간이 경과할수록 수질오염이 높을수록 생분해율이 높았다. 채취한 하천수에서 phosphamidon과 profenofos의 분해균주는 모두 그람 음성균으로 Klebsiella pneumoniae, Aeyomonas hydrophila 및 Acinetobacter calcoaceticus의 3종임이 확인되었다. 생분해에 의한 분해산물을 확인하고자 GC/MS분석을 한 결과 phosphamidon의 분해생성물은 m/z=153의 O, O-dimethyl phosphate(DMP)와 m/z=149의 N, N-diethylchloro acetamide로 추정된다. Profenofos의 분해생성물은 m/z=208로 4-bromo 2-chloro phenol과 m/z=240으로 O-ethyl S-propyl phosphate로 추정된다.