Serum dioxin levels in residents of Calcasieu and Lafayette parishes, Louisiana with comparison to the US population.

The Agency for Toxic Substances and Disease Registry (ATSDR) used a cross-sectional study to compare the serum dioxin toxic equivalent (TEQ) levels of a population-based representative sample of Calcasieu Parish residents aged 15 years and older to a similar group of residents of Lafayette Parish with less industrial facilities. Serum dioxins consisted of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls. Overall, the mean and distribution of serum dioxin TEQ level in residents of both parishes were similar by age groups (15-29 years, 30-44 years, 45-59 years, and 60 year and older). When the Calcasieu Parish area was further divided based on distance to three industrial areas, the mean dioxin TEQ levels were similar. Serum dioxin TEQ levels in residents of both parishes increased with age. Calcasieu Parish residents who reported having eaten locally caught fish, smoked cigarettes, worked in an occupation with potential exposure, or used pesticides had dioxin levels similar to Lafayette Parish residents who reported these activities. African Americans had higher dioxin levels than Caucasians in Lafayette Parish and both races in Calcasieu Parish. The congener profiles were similar in residents of both parishes. When the combined Calcasieu and Lafayette Parish data were compared by age group to the National Health and Nutrition Examination Survey (NHANES) 2001-2002 data, the geometric means for the dioxin levels in the combined Parish data set were significantly lower than the NHANES data in all age groups (all P-values <0.0001), except the oldest age group where the significance level is marginal (P=0.067). The various percentiles of the youngest age group of the combined parish data were also significantly lower than those in NHANES. Since the combined parish dioxin levels were below a representative sampling of the US population, there is no increase in serum dioxin concentrations in both the parishes.