Paraquat 토양 잔류량을 사과원, 배원, 포도원 및 복숭아원을 대상으로 조사하였다. 대상 과수원은 각 과수별 주산 단지에서 15개소씩을 선정하였다. 한편 과수원별 토양의 paraquat 흡착능을 밀 뿌리 생육 50%를 저해하는 농도(Strong adsorption capacity measured using wheat bioassay, SAC-WB)로 산출하고, 총 SAC-WB (SAC-WB값+paraquat 잔류량)에 대한 paraquat 잔류 수준을 조사하였다. 우리나라 과수원 토양 60개소의 paraquat 결합성 잔류량은 평균 6.9 ppm이었다. 잔류량이 가장 높았던 토양은 사과원 토양의 20.2 ppm이었으며, 사과원 토양의 paraquat 평균 잔류량은 다른 과원 토양의 거의 두 배 정도의 높은 경향을 보였다. 잔류량이 높았던 상위 5개소 양에 대한 치환성 잔류량은 0.5 ppm 검출한계 미만이었다. SAC-WB 값은 평균 276.1 ppm이었으며, SAC-WB 값과 점토 함량, 유기물 함량 및 양이온 치환 용량간에는 상관관계를 인정할 수 없었다. 한편 우리나라 과수원 토양의 총 SAC-WB 값 대비 paraquat 잔류 수준은 평균 2.43%이었다.
Soil residues of paraquat (1,1-dimethyl-4,4-dipyridinium dichloride) were determined in apple, pear, grape, and peach orchards for which 15 sites each were selected randomly from the corresponding large-scale production area throughout the country. Strong adsorption capacity measured using wheat bioassay (paraquat concentration required to reduce 50% root growth of wheat, SAC-WB) was also investigated on the orchard soils and the paraquat residue level was calculated against total SAC-WB values (SAC-WB value + paraquat residue). Average bound residue of paraquat on the 60 sites was 6.9 ppm, while paraquat residue in apple orchard reached 20.2 ppm which was the highest among the orchards and was almost double as compared with those in the other three orchards. Loosely bound residue of paraquat determined on the bound residue high top five soils occurred less than 0.5 ppm detection limit. Average SAC-WB value was 276.1 ppm and there were no any correlations between the SAC-WB value and clay content, organic matter content, and cation exchange capacity of the orchard soils. Paraquat residue level of the orchard soils against total SAC-WB recorded 2.43%.
