Abstract
In order to elucidate the behavior of the fungicide hexaconazole in soil and rice plants, rice plants were grown for 42 days in a microecosystem (pot) containing fresh and 28 day-aged soil residues of $[^{14}C]$hexaconazole. The amount of $^{14}CO_2$ evolved during 28 days of aging was 0.11 % of total $^{14}C$-radioactivity treated and the averaged weekly degradation rate was 0.03%. Mineralization rates for 42 days of rice cultivation on fresh and aged paddy soils were 0.67% of the total $^{14}C$ in case of non-rice planting on aged soil and 1.17% in case of rice planting on aged soil, whereas 1.25% in non-rice planting on fresh soil and 1.72% in case of rice planting on fresh soil, suggesting that the amounts of $^{14}CO_2$ were evolved higher from fresh soils than aged ones and from rice-planting soils than non-planting ones. The amounts of volatiles collected were very low as background levels. Most of $^{14}C$-Radioactivity was remained in soil after 42 days of rice cultivation and $^{14}C$ absorbed through rice roots was distributed more in shoots than roots and translocated into the edge of shoots of rice plants. Amounts of non-extractable $^{14}C$ in soils were higher in rice planted soil than in non-planting soil. The distribution of non-extractable $^{14}C$ was increased in the order of humin>fulvic acid>humic acid. The amounts of $^{14}C$ translocated into rotational crop Chinese cabbage were 2.36 and 3.69% of the total $^{14}C$ in case of rice planted soil containing fresh and aged residues, respectively, suggesting that small amounts of $[^{14}C]$hexaconazole and its metabolite(s) were absorbed and their bound residues were more available than their fresh ones to Chinese cabbage.
살균제 hexaconazole의 벼 및 토양 중 행적을 구명하기 위하여 $[^{14}C]$hexaconazole의 신생 및 숙성 토양 잔류물을 함유한 microecosystem(pot)에서 42일간 벼를 재배하였다. 28일간의 숙성기간중 방출된 $^{14}CO_2$의 양은 총처리방사능의 0.11%이고 주당 평균분해율은 0.03%이었다. 42일간의 벼 재배기간중 방출된 $^{14}CO_2$의 양은 숙성토양에 벼를 재배하지 않은 처리구와 벼를 재배한 처리구에서 각각 총처리방사능의 0.67%와 1.17%인 반면 숙성하지 않은 신생토양의 경우는 각각 1.25%와 1.72%로서 숙성토양보다는 신생토양에서, 벼를 재배하지 않은 경우보다는 재배한 경우에 무기화율이 더 높은 것으로 나타났으며. 휘발율은 미미하였다. 벼 재배 후 방사능은 주로 토양에 분포하였으며, 벼에 흡수된 방사능은 벼 지상부의 선단으로 집적되었다. 토양중 추출불가 결합잔류물의 양은 벼를 재배할 경우 증가하였으며, 그 분포양은 humin>fulvic acid>humic acid순이었다. 후작물인 배추에 흡수이행된 $^{14}C$는 hexaconazole의 신생 및 숙성잔류물을 함유한 벼 재배토양에서 각각 총처리 방사능의 2.36%와 3.69%로써 소량이 흡수이행되었으며, 신생잔류물보다 숙성잔류물의 이용률이 더 높았다.
