Comparability and precision of serum PCB measurements

Area of Science:

• Environmental Chemistry
• Toxicology
• Occupational Health

Background:

• Polychlorinated biphenyls (PCBs) are persistent organic pollutants with known health risks.
• Commercial Aroclor mixtures have been widely used, leading to occupational and environmental exposure.
• Accurate measurement of serum PCB levels is crucial for assessing human exposure and health impacts.

Purpose of the Study:

• To evaluate the variability in serum PCB measurements using different analytical approaches.
• To determine the range of reportable PCB levels in occupationally exposed individuals.
• To investigate the relationship between analytical methods, PCB isomer distribution, and clearance patterns.

Main Methods:

• Analysis of serum samples from capacitor workers with documented exposure to Aroclors 1016, 1242, and 1254.
• Application of multiple quantification methods: sum-of-the-peak-heights, most persistent peaks, total PCBs present, and the NHMP procedure.
• Assessment of the 95% prediction interval for single serum Aroclor measurements from a commercial laboratory.

Main Results:

• Single serum Aroclor measurements exhibited a wide 95% prediction interval of approximately +/- 42%.
• Serum PCB levels in exposed workers varied significantly depending on the calculation method, ranging from 19 ppb ('human PCB') to 1905 ppb (minimum initial PCBs).
• The observed variability in reported values was linked to PCB isomer profiles and individual clearance rates.

Conclusions:

• Standard analytical methods for serum PCBs can yield substantially different results.
• The wide prediction interval underscores the inherent uncertainty in single PCB measurements.
• Understanding PCB isomer distribution and pharmacokinetics is essential for accurate exposure assessment in occupational settings.