Diazinon is rapidly excreted from the bodies of animals. Studies have reported blood half-lives for diazinon ranging from
2.5–5.0 hours.10
• Fifty percent of single 4 mg/kg oral doses of radio-labeled diazinon given to rats were excreted within 12 hours. Most (69-
80%) of the metabolites were found in the urine, and 18-25% were excreted in the feces.12
• In another study of rats orally exposed to radio-labeled diazinon, most diazinon was metabolized and excreted in the
urine (58.2% of dose in females and 93.3% in males) within 24 hours and small amounts (less than 2.5%) were excreted in
the feces. After seven days, less than 1% of the labeled dose remained in the tissues, with the highest levels found in the
blood.14
• Human volunteers who ate diazinon excreted 60% of the applied dose as urinary metabolites within two hours of the
exposure.36
• In one study, human volunteers were exposed dermally to diazinon for eight hours. After eight hours, most of the applied
diazinon (90%) was recovered from the application site with only 1% of the applied dose being recovered in the urine.36
Another human study found that dermal exposure to radio-labeled diazinon for 24 hours resulted in 3-4% of the administered
dose being excreted in the urine over seven days following the exposure.12