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07:06
Continuous Flow Chemistry: Reaction of Diphenyldiazomethane with p-Nitrobenzoic Acid
Published on: November 15, 2017
Iodomethane human health risk characterization.
Beth E Mileson1, Lisa M Sweeney, Michael L Gargas
1Technology Sciences Group, Inc., Washington, DC 20036, USA. bmileson@tsgusa.com
Inhalation Toxicology
|June 13, 2009
Summary
Iodomethane, a new soil fumigant, poses inhalation risks. A health assessment using a PBPK model found nasal degeneration is the primary concern for acute exposure in humans.
Area of Science:
- Environmental toxicology
- Risk assessment
- Pharmacokinetics
Background:
- Iodomethane is a newly approved pre-plant soil fumigant in the US.
- High vapor pressure necessitates evaluating human inhalation exposure risks.
- Previous assessments identified fetal loss, nasal lesions, and neurotoxicity as critical effects.
Purpose of the Study:
- To conduct a quantitative human health risk assessment for iodomethane inhalation exposure.
- To develop a physiologically based pharmacokinetic (PBPK) model for iodomethane.
- To derive human equivalent concentrations (HECs) for workers and bystanders.
Main Methods:
- Developed a PBPK model for iodomethane to estimate internal dose.
- Calculated HECs from animal no-observed-adverse-effect levels (NOAELs) using chemical-specific parameters.
- Assessed acute exposure endpoints including developmental toxicity, nasal lesions, and neurotoxicity.
Main Results:
- Nasal olfactory degeneration identified as the primary endpoint for acute exposure risk assessment.
- HECs derived for developmental (7.4 ppm bystander), nasal (4.5 ppm), and neurotoxicity (10 ppm) endpoints.
- PBPK model incorporated species differences, showing humans are less sensitive to developmental toxicity.
Conclusions:
- Nasal degeneration is the critical effect for acute iodomethane inhalation risk.
- The PBPK model provides a refined approach to human health risk assessment for iodomethane.
- Derived HECs support risk management strategies for occupational and bystander exposure.
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