Source Evaluation of Diazinon Using Stable Carbon Isotope Ratio

Soil samples were collected between May 27 and October 28, 2005, at sites in Yurihonjo City, Akita Prefecture, Japan. Diazinon, an extensively used organophosphate insecticide, was detected in high concentrations. Recent advances in analytical techniques enabled identification of the source of the high levels of diazinon by measuring the 13C isotope ratio of diazinon. Eight diazinon products primarily used in Akita Prefecture were analyzed. The results show that the isotope ratio of the diazinon products ranged from −31.25 ± 4.07½ to −21.67 ± 2.91½, and the isotope ratio of the diazinon in the soil samples was −24.20 ± 1.23½.