Modelling past human internal exposure to lower chlorinated indicator PCBs using proxies - A calculation based on...

Area of Science:

• Environmental Health
• Toxicology
• Biomonitoring

Background:

• Polychlorinated biphenyls (PCBs) are persistent organic pollutants with diverse industrial applications.
• Assessing past exposure to lower chlorinated PCBs (e.g., PCB 28, 52, 101) is difficult due to their short biological half-lives.
• Accurate historical exposure assessment is crucial for understanding long-term health effects.

Purpose of the Study:

• To identify suitable PCB congeners as proxies for estimating past plasma levels of lower chlorinated PCBs.
• To develop and validate a model for backward estimation of historical PCB exposure.
• To assess the feasibility of using current biomonitoring data to infer past exposure levels.

Main Methods:

• Utilized longitudinal biomonitoring data from the German HELPcB cohort.
• Identified PCB 66, 74, and 99 as potential proxies based on biological half-lives and correlations.
• Validated the estimation model using internal (HELPcB cohort) and external (two other cohorts) data.

Main Results:

• PCB 74 demonstrated good correlation (ICC3=0.682, rho=0.724) for estimating past PCB 28 levels within the HELPcB cohort.
• External validation confirmed PCB 74's utility for PCB 28 estimation (ICC3=0.723, rho=0.654).
• External validation for PCB 101 was feasible but less accurate (ICC3=0.460, rho=0.516); PCB 52 estimation was unsuccessful.

Conclusions:

• Current PCB 74 levels can provide a rough estimation of former PCB 28 plasma levels years after exposure cessation.
• PCB 74 serves as a valuable proxy for retrospective assessment of lower chlorinated PCB exposure.
• The model's success varies for different congeners, highlighting the need for congener-specific validation.