Biomonitoring Equivalents for triclosan

Area of Science:

• Environmental Health
• Toxicology
• Biomonitoring

Background:

• Growing biomonitoring data requires tools for health risk interpretation.
• Biomonitoring Equivalents (BEs) bridge exposure guidelines and measured concentrations.
• Triclosan is a widely used chemical with increasing population exposure data.

Purpose of the Study:

• To derive Biomonitoring Equivalents (BEs) for triclosan.
• To establish reference values for interpreting human biomonitoring data for triclosan.
• To integrate pharmacokinetic data with existing health-based guidance values.

Main Methods:

• Reviewed health-based guidance values from US EPA, EC SCCP, and NICNAS for triclosan.
• Derived BE values using pharmacokinetic data (urinary excretion, plasma clearance) and risk assessment targets (RfD, MOS).
• Utilized human pharmacokinetic data and animal blood concentration data.

Main Results:

• Estimated urinary BE for triclosan corresponding to US EPA RfD: 6.4 mg/L (8.3 mg/g creatinine).
• Estimated urinary BE for triclosan corresponding to EC MOS target: 2.6 mg/L (3.3 mg/g creatinine).
• Estimated plasma BE values for triclosan: 0.3 mg/L (US EPA), 0.9 mg/L (EC), and 0.4 mg/L (NICNAS).

Conclusions:

• Derived BE values offer a screening tool for triclosan biomonitoring data.
• These BEs facilitate the interpretation of triclosan body burdens in a health risk context.
• Supports public health risk assessment by contextualizing measured triclosan levels.