Chemical Mixtures in the EU Population: Composition and Potential Risks.

Area of Science:

• Environmental Health Sciences
• Toxicology
• Risk Assessment

Background:

• Chemical mixture regulation is complex, requiring assessment of combined exposures.
• Human biomonitoring (HBM) data provides insights into internal exposure levels.
• Previous risk assessments often focused on external exposure or single substances.

Purpose of the Study:

• To investigate typical chemical mixtures and their potential risks in the European population based on internal exposure.
• To derive representative mixtures for median (P50) and worst-case (P95) scenarios in adults and children.
• To inform potential mixture assessment factors (MAFs) for single substance risk assessment.

Main Methods:

• Utilized HBM data from the HBM4EU project to define generic mixtures.
• Performed mixture risk assessment using HBM concentrations and health-based guidance values (HBGVs).
• Applied the concentration addition model and calculated Maximum Cumulative Ratios (MCRs).

Main Results:

• Mixture risk assessment covered subsets of available biomarkers due to limited HBGVs.
• The mixture hazard index ranged from 2.8 (P50, children) to 9.2 (P95, adults).
• Six to seven substances significantly contributed to the overall mixture risk; MCR values were between 2.6 and 5.5.

Conclusions:

• The study highlights potential risks from chemical mixtures based on internal exposure.
• Results suggest that MCR and MAF_ceiling analyses can inform mixture assessment factors.
• Caution is advised in interpreting results due to limited substance coverage and hazard index application across endpoints.