Relationship Analysis between Pesticide Monitoring Plan and Their Detection at Waterworks throughout Japan

Abstract

The relationship between the monitoring plan and the detection of pesticides in raw water at waterworks throughout Japan in fi scal years 2009-2011 was investigated. For analysis, monitoring data of pesticides in the statistics on water supply were used. The number of waterworks at which pesticides monitored were was about 650 and the percentage of waterworks at which pesticides detected were was about 20%. For the waterworks that acquire raw water from surface water, a higher percentage of waterworks detected pesticides in the group of waterworks that frequently monitored many pesticides than in other groups. Additionally, in the group of waterworks that carried out monitoring once a year, a few waterworks detetcted pesticides. Furthermore, most of them detected one pesticide once in the three years. For waterworks that acquire raw water from groundwater, the detection rates of pesticides were low regardless of the monitoring frequency. The number of pesticides detected was 77 among the 102 pesticides listed in the guidelines. However, the pesticieds detected at relatively many waterworks more than 10 was only about 10. Thus, it was considered that several pesticides might be detected at many waterworks throughout Japan, although many pesticides detected showed regional diversity.