Regional Variation in Human Exposure to Persistent Organic Pollutants in the United States, NHANES

Table 5

Geometric means and selected percentiles of the sum of 35 PCBs concentrations and total TEQ in ng/g of lipid or parts per billion on a lipid weight basis for the US population by geographic area, NHANES 2003-2004.

	Ages of 20 years and older
	Geometric mean (95% CI)	Percentile (95% CI)
		50th	90th
Sum of 35 PCBs
Northeast	189 (173–204)	187 (138–250)	534 (346–929)
Midwest	144 (114–175)	142 (85–213)	405 (270–713)
South	152 (123–182)	156 (122–206)	430 (358–484)
West	141 (99–182)	138 (94–208)	406 (287–508)
Total TEQ
Northeast	—	—	35.5 (30.6–41.9)
Midwest	—	—	35.3 (22.7–59.0)
South	—	—	29.7 (25.5–36.4)
West	—	—	28.2 (24.1–32.6)

Regional means with the same letter superscript are not significantly different from each other based on analysis of covariance adjusting for age, smoking status, gender, and race/ethnicity.
For TEQ estimates, we present only the 90th percentile because the detection frequency was less than 40% for some congeners included in the calculation.