Serum PCB concentrations in residents of Calcasieu and Lafayette Parishes, Louisiana with comparison to the U.S. population

•The percentiles of serum total PCB concentrations were similar in both Parishes.•The adjusted GM of total serum PCBs was higher in residents in Lafayette than in Calcasieu Parish.•Serum total PCB levels in residents of both parishes increased linearly with age.•The PCB congener profiles were similar in residents of both parishes.