Abstract
Indoor exposure to chlorpyrifos (an organophosphorus termiticide) and S-421 (an organochlorine synergist) of residents was investigated by examining the residual levels of the termiticides in polished rice stored in houses for a week. The survey covered 244 ordinary families in the Kansai area from 2007 to 2016. Diazinon and fenitrothion in the rice was analyzed at the same time.
The polished rice was homogenized with acetone • hexane and then purified by silica gel column. Quantitative analysis for chlorpyrifos, diazinon and fenitrothion were performed by GC-FPD, and for S-421 was performed by GC-ECD. The detection frequency of organophosphorus termiticide was 9/244 for chlorpyrifos, no diazinon was detected, and fenitrothion was 12/244. The highest value was 35 ng/g (2008) for chlorpyrifos and 4.3 ng/g (2016) for fenitrothion. In 6 out of 9 cases where chlorpyrifos were detected, they were carrying out termite control before 2003. In July 2003, chlorpyrifos was banned from use as termite control application of houses in Japan. S-421 was detected from 214 out of 216 samples, the highest value was 29 ng/g (2008). Although the detection frequency of S-421 was high, it turned out that the concentration level decreased during the surveillance period.
