Tracing the source of methomyl using stable isotope analysis.

Area of Science:

• Forensic Chemistry
• Environmental Science
• Toxicology

Background:

• Pesticide self-poisoning is a significant cause of suicide globally, particularly in agricultural regions.
• Methomyl, a highly toxic and prohibited insecticide in South Korea, is frequently implicated in self-poisoning incidents and criminal harm.
• Investigating the origin of such substances is crucial for legal and public health purposes.

Purpose of the Study:

• To determine the specific source of methomyl used in a fatal poisoning case in South Korea.
• To evaluate the efficacy of stable isotope ratio analysis in tracing insecticide origins.

Main Methods:

• Analysis of methomyl from seized Soju bottles, gastric contents, and an energy drink from the victim.
• Collection and analysis of nine different methomyl brands from the vicinity.
• Stable isotope ratio analysis (carbon and nitrogen) using Gas Chromatography/Isolink/Isotope Ratio Mass Spectrometry (GC/Isolink/IRMS).
• Verification of results using linear discriminant analysis.

Main Results:

• Isotope ratio analysis revealed similarities between the methomyl found in the victim's samples (Soju, gastric contents, energy drink) and a specific seized product, Samgong methomyl 2011 (SG11).
• The findings strongly suggest that SG11 was the methomyl used in the fatal poisoning incident.

Conclusions:

• Stable isotope ratio analysis is a viable and powerful tool for identifying the origin of insecticides in fatal poisoning cases.
• This technique can provide critical evidence in forensic investigations involving pesticide-related deaths.