Toxicity Weighting for Human Biomonitoring Mixture Risk Assessment: A Proof of Concept.

Area of Science:

• Environmental Health Sciences
• Toxicology
• Biomonitoring

Background:

• Traditional chemical risk assessment relies on external exposure data.
• Human biomonitoring (HBM) offers insights into internal chemical concentrations and derived doses.
• Assessing health risks from chemical mixtures requires novel approaches.

Purpose of the Study:

• To develop and demonstrate a proof of concept for mixture risk assessment using HBM data.
• To identify groups of correlated biomarkers (chemical communities) in a population.
• To evaluate potential health concerns arising from co-occurring chemical exposures.

Main Methods:

• Network analysis was used to identify biomarker communities from 51 chemical substances in urine from the German Environmental Survey (GerES) V (n=515).
• A biomonitoring hazard index was developed by summing hazard quotients for each biomarker, weighted by HBM health-based guidance values (HBM-HBGVs).
• Communities with a hazard index > 1 were flagged for potential health concern.

Main Results:

• Seven biomarker communities were identified in the GerES V data.
• For five communities with available HBM-HBGVs, one showed concerning levels of phthalate metabolites (mono-isobutyl phthalate and mono-n-butyl phthalate).
• Hazard indices exceeded 1 in 5.8% of participants for the phthalate metabolite community.

Conclusions:

• The developed biomonitoring hazard index method effectively identifies chemical co-occurrence patterns of potential health concern at a population level.
• Further toxicological and health effects studies are warranted for identified chemical communities.
• Future research should focus on expanding HBM-HBGVs and incorporating diverse biomonitoring matrices for comprehensive risk assessment.