RECOVERY OF DNA FROM EXHIBITS CONTAMINATED WITH CHEMICAL WARFARE AGENTS: A PRELIMINARY STUDY OF THE EFFECT OF DECONTAMINATION AGENTS AND CHEMICAL WARFARE AGENTS ON DNA

Bloodstains were exposed to chemical warfare agents and then to decontamination agents to evaluate the effect on DNA extraction and profiling for human identification. DNA profiles were not obtained from blood dilution samples exposed to the decontamination agents CASCAD (R) and the American equivalent, MDF LSA-100, even when quantifiable DNA was extracted. Fresh and aged bloodstains were exposed to nine chemical warfare agents: hydrogen cyanide, phosgene, chlorine, dimethyl sulfate, sodium fluoroacetate, diazinon (R), sulfur mustard, lewisite I, and sarin in gaseous and/or liquid form. In general, following exposure to chemical warfare agents, most bloodstains gave lower concentrations of DNA relative to controls. Full DNA profiles were obtained from bloodstains exposed to sarin, diazinon (R), sodium fluoroacetate, and hydrogen cyanide. During exposure to chlorine, phosgene, lewisite I, and dimethyl sulfate, the bloodstains changed colour from red to brown. These four chemical warfare agents were shown to inhibit the recovery of DNA. Although samples exposed to sulfur mustard did not exhibit any colour changes, recovery of DNA was inhibited in some samples exposed to sulfur mustard.