Concentrations of organochlorine pesticides and polychlorinated biphenyls in human serum and adipose tissue from Bolivia.

Organochlorine pesticides and polychlorinated biphenyls (PCBs) are synthetic chemicals that are highly resistant to biodegradation and have proven adverse health effects. The objectives of this study were to determine concentrations of three selected organochlorine pesticides (p,p'-DDT, p,p'-DDE, HCB) and three specific PCB congeners (PCB 138, 153, 180) in adipose tissue and serum samples from an urban adult population (n=112) in the city of Santa Cruz de la Sierra, Bolivia, and to investigate their relationships within and between the two matrices and with selected socio-demographic characteristics. The percentages of samples positive for these compounds ranged from 40% for PCB 180 to 100% for p,p'-DDE in adipose tissue, and from 21% for HCB to 93% for p,p'-DDE in serum. Median number of residues per sample was five for adipose tissue and three for serum. Geometric mean concentrations indicate a considerable historical and recent exposure to organochlorine pesticides and PCBs in this population. Adipose tissue:serum ratios ranged from 149.3 to 590.3 (wet basis) and from 0.9 to 3.5 (lipid basis). We found positive and statistically significant correlations between adipose tissue and serum concentrations only in p,p'-DDE and HCB. This novel study in Bolivia underlines the need for human biomonitoring to assess exposure to environmental pollutants in South America.

Factors influencing combined exposure to three indicator polychlorinated biphenyls in an adult cohort from Bolivia.

Polychlorinated biphenyls are persistent organic pollutants that have been used for decades in several industrial applications. Although production of polychlorinated biphenyls was restricted from the 1970s in most countries, substantial amounts remain in old equipment and buildings and they have been detected in various environmental and biological matrices. The main objective of this study was to analyze predictors of the combined exposure to three non-dioxin-like polychlorinated biphenyls (congeners 138, 153 and 180) in serum and adipose tissue from an adult cohort (n=112) living in the city of Santa Cruz de la Sierra (Bolivia) and surrounding towns/villages. A second aim was to identify modifiers that might influence the statistical associations found, using crude, partially-adjusted, and global multiple linear regression models. Main predictors of serum concentrations were occupation and fatty food consumption, while those for adipose tissue concentrations included age, smoking habit, fatty food consumption, and residence. The differences between the two matrices might be derived from their biological meaning, given that adipose tissue concentrations are an indicator of chronic exposure to polychlorinated biphenyls while serum levels are a good predictor of ongoing exposure and the mobilization of polychlorinated biphenyls stored in fatty tissues. Body mass index was found to be an important modifier of these associations.