Abstract
The monitoring of 99 pesticides in drinking water from private wells in the Tama district in Tokyo was conducted from July 2004 to November 2005. Six pesticides (i.e., simazine, dichlorvos, bentazone, terbucarb, atrazine, and diuron) were detected in water samples. The frequencies of detecting bentazone, simazine, and the others were 5.2, 2.8, and less than 1%, respectively, in 250 water samples examined. The maximum concentration of each pesticide was less than 0.0001 mg · l-1 and was less than one-hundredth of maximum contaminant level. A degradation product of the herbicide chlorthal dimethyl (TCTP) was detected at a concentration of 0.0037 mg · l-1 in groundwater and at a concentration of 0.0008 mg · l-1 in tap water after disinfection using sodium hypochlorite.
