전국 하천수 중 잔류우려 농약 실태조사

우리나라 주요 하천수의 사용 중인 농약의 실태조사를 위해서 전국 50지점을 선정 후, 1차 (농약 사용 비성수기, 4/5월)및 2차(농약 사용 성수기, 8/9월)로 나누어 실시를 하였다. 하천수 모니터링 결과 농약 1차, 2차 때 각각 11, 28개의 농약이 검출되었다. 농약은 7월부터 기온이 올라가면서 병·해충 방제를 위해 농약사용량이 증가하기 때문에 2차시기에 농약검출량이 증가한 것으로 판단된다. 검출빈도 10회 이상의 농약은 1차 시기에는 butachlor, carbofuran, 2차 시기에는 tricyclazole, azoxystrobin, chlorantraniliprole, thiamethoxam, isoprothiolane 5종이었다. 검출농약은 대부분 수도용 농약으로 검출비율은 90%, 81%로 높게 나타났다. 이러한 이유는 하천수 중 잔류농약은 논에서 사용된 농약이 비산되어 직접적으로 하천수로 잔류되기도 하며 또는 토양에 잔류된 농약이 논물을 방류하면서 하천수로 이동하기 때문이다. 네 개의scenario를 이용하여 위해성 평가를 진행하였을 때, butachlor, carbofuran, carbendazim, chlorantranilprole 및 oxadiazon 에서 잠재위해성 및 위해성이 있는 것으로 평가되었다. 추후모니터링 연구와 수서생물에 위해성이 나타나지 않는 농도 이하로 잔류할 수 있도록 농약안전사용기준 설정연구가 필요 할 것으로 보인다. BACKGROUND: This study was carried out to investigate pesticide residues from fifty streams in Korea. Water samples were collected at two times. Thee first sampling was performed from april to may, which was the season for start of pesticide application and the second sampling event was from august to september, which was a period for spraying pesticides multiple times. METHODS AND RESULTS: The 136 pesticide residues were analyzed by LC-MS/MS and GC/ECD. As a result, eleven of the pesticide residues were detected at the first sampling. Twenty eight of the pesticide residues were detected at the second sampling. Seven pesticides were frequently detected from more than 10 water samples. Ecological risk assessment (ERA) was carried out by using residual and toxicological data. Four scenarios were applied for the ERA. Scenario 1 and 2 were performed using LC50 values and mean and maximum concentrations. Scenarios 3 and 4 were conducted by NOEC values and mean and maximum concentrations. CONCLUSION: Frequently detected pesticide residues tended to coincide with the period of preventing pathogen and pest at paddy rice. As a result of ERA, five pesticides (butachlor, carbendazim, carbofuran, chlorantranilprole, and oxadiazon) were assessed to be risks at scenario 4. However, only oxadiazon was assessed to be a risk at scenario 3 for the first sampling. Oxadiazon was not assessed to be a risk at the second sampling. It seems to be temporary phenomenon at the first sampling, because usage of herbicides such as oxadiazon increased from April to march for preventing weeds at paddy fields. However, this study suggested that five pesticides which were assessed to be risks need to be monitored continuously for the residues.