Biomonitoring-based risk assessment for hexabromocyclododecane (HBCD)

Area of Science:

• Environmental Science
• Toxicology
• Human Health Risk Assessment

Background:

• Hexabromocyclododecane (HBCD) is a flame retardant detected in environmental and human samples.
• Exposure pathways for HBCD are diverse, making external exposure estimation challenging.
• Human biomonitoring offers a more certain method for assessing integrated HBCD exposure.

Purpose of the Study:

• To evaluate human exposure to HBCD using biomonitoring data.
• To compare human HBCD tissue concentrations with established toxicological reference points.
• To determine the margin of exposure (MOE) for HBCD in the human population.

Main Methods:

• Analysis of lipid-adjusted serum and human milk concentrations from biomonitoring studies.
• Comparison of human biomonitoring data with points of departure from animal studies (rats).
• Calculation of margins of exposure (MOEs) based on internal dose measures.

Main Results:

• Central tendency of lipid-adjusted HBCD concentrations in humans is approximately 1 ng/g lipid.
• Upper bound HBCD levels in humans are around 20 ng/g lipid.
• Margins of exposure (MOEs) in humans range from 6,000 to over 100,000, exceeding target values.

Conclusions:

• Human biomonitoring indicates current HBCD exposure levels are well below those associated with adverse effects.
• Internal dose measures from biomonitoring provide reliable data for risk management.
• The high MOEs suggest a low risk from current HBCD exposures in the general population.