Distribution of blood concentrations of persistent organic pollutants in a representative sample of the population of Catalonia
Background: Although virtually all populations worldwide are commonly exposed to numerous persistent organic pollutants (POPs) and human concentrations vary widely, only a few countries conduct nationwide surveillance programs of POP concentrations in representative samples of the general population. Objective: To evaluate the distribution of serum concentrations of nineteen POPs and their main predictors in a representative sample of the general population of Catalonia. Methods: Participants in the Catalan Health Interview Survey aged 18-74years were interviewed face-to-face, gave blood, and underwent a physical exam. Graphs (including ''POP Geoffrey Rose curves'') were used to represent the full population distribution of each POP in the 919 participants. Through multivariate statistical models we analyzed the influence on POP concentrations of sex, age, body mass index (BMI), socioeconomic status and, in women, parity. Results: We detected dichlorodiphenyltrichloroethane (p,p'-DDT), dichlorodiphenyldichloroethane (p,p'-DDE), polychlorinated biphenyls (PCBs) congeners 118, 138, 153 and 180, hexachlorobenzene (HCB) and @b-hexachlorocyclohexane (@b-HCH) in more than 85% of the subjects. p,p'-DDE, HCB and @b-HCH showed the highest concentrations (median=399, 159 and 92ng/g lipid, respectively). Distributions were highly skewed and interindividual differences were up to 7700-fold. POP levels differed significantly by gender, age, BMI, educational level, and parity. Conclusions: In Catalonia, an advanced European society, exposure to POPs remains common, a vast majority of the population has much lower blood concentrations than a relative minority, and the population distributions of POP are hence highly skewed to the right. Shifting distributions towards lower concentrations requires more energetic policies and population strategies.