5종(種)의 농약(農藥)(butachlor, isoprothiolane, probenazole carbofuran, cartap)에 대하여 잉어를 대상으로 하여 급성어독성(急性魚毒性)값인 96시간 $LC_{50}$값을 평가(評價)하였고, 또 합리적인 급성어독성(急性魚毒性) 실험(實驗)을 위한 기초자료(基礎資料)로 처리시문(處理時問)및 처리방법(處理方法)에 따른 급성어독성(急性魚毒性)값의 변화(變化)와 수조내(水槽內) 용존산소(溶存酸素)의 농도(濃度)를 측정(測定)한 바, 그 결과(結果)는 다음과 같다. 1) 각(各) 농약(農藥)의 96시간 $LC_{50}$값은 butachlor 0.25 ppm, isoprothiolane 10.0 ppm, probenazole 6.2 ppm, carbofuran 1.40 ppm, cartap 0.64 ppm이었다. 2) 각(各) 농약(農藥) 모두 처리시간(處理時間)이 길어짐에 따라 $LC_{50}$값 이 낮아지는 경향을 나타내었다.
This study was performed to evaluate the aquatoxicity of 5 chemicals (butachlor, isoprothiolane, probenazole, carbofuran, and cartap) to carp (Cyprinus carpio), discuss the impact on the $96 hr-LC_{50}$ values of the chemicals with the exposure time. In butachlor, we also compared the acute toxicity values between two exposure system, the continuous flow system and static state system, and measured the dissolved oxygen concentrations in the two systems. The acute toxicity values (96 hr-LC50 values) of the 5 chemicals were 0.25 ppm in butachlor, 10.0 ppm in isoprothiolane, 6.2 ppm in probenazole, 1.40 ppm in carbofuran, and 0.64 ppm in cartap, respectively. We also found that the $LC_{50}$ values were downed with increase of the exposure time.
