The Impact of Pesticides - Academy Publish

Fig. 11 Detection of herbicides in River (2) flowing into Seta River and western areaof Lake Biwaof pesticides in Lake Biwa and Seta River water from 2000 to 2009Materials and MethodsWater samples were collected from Lake Biwa (17A, 17C’, 13A, 13C, 9B, 8C, 6B,4A) and Seta River (2) (Fig. 1) once in August from 2000 to 2009. Water sampleswere analyzed immediately after sample collection.A measured volume (500 mL) of water sample was passed through 3M EmporeExtraction Disk (C18) after washing with 10 mL of acetone and 10 mL ofdichloromethane and conditioning with 10 mL of methanol and 3×10 mL of distilledwater. The disk was washed with 10 mL of water, dried 15 min under air stream atroom temperature and eluted with 2 mL of acetone, 4 mL, 2 mL and 2mL ofdichloromethane. The eluate was mixed with 20 mL of hexane, dehydrated withanhydrous Na 2 SO 4 and rotary-vacuum evaporated nearly to 1 mL at 40℃. Thesolution was transferred to 5 mL graduated test tube by rinsing with hexane andevaporated to 0.5 mL under N 2 gas stream. Determination of 13 pesticides(dichlorvos, fenobucarb, simazine, diazinon, propyzamide, chlorothalonil,iprobenfos, fenitrothion, thiobencarb, isoprothiolane, isoxathion, chlornitrofen andEPN) in the hexane solution was performed using SIM by GC/MS (Nakamura et al.2008). Average recoveries (n=3) were 71-132% at a spiked level of 0.1 μg/L andquantification limits were 0.01-0.02 μg/L for the 13 pesticides.AcademyPublish.org - The Impact of Pesticides272