Removal of endocrine disruptors by selective sorption method using polydimethylsiloxane membranes

Abstract

Human milk has unique nutritional and immunological properties and is the most natural and important food source for infants. However, human milk often contains trace amounts of chemical contaminants known as endocrine disruptors, e.g. DDT, hexachlorocyclohexane (HCH), polychlorinated biphenyls (PCBs), and polychlorinated dibenzo- p-dioxin. The concentrations of PCBs and dioxins in human milk in some countries are so high that the breast-fed infant’s intake exceeds the tolerable daily intake (TDI). The goal of this study was the removal of endocrine disruptors from milk without any decomposition nor denaturation of the milk components by a sorption method using hydrophobic polydimethylsiloxane (PDMS) membranes. Endocrine disruptors, e.g. 1,2-dibromo-3-chloropropane, dibenzo- p-dioxin, and hexachlorocyclohexane could be removed efficiently from aqueous solution or milk by the sorption method using hydrophobic PDMS membranes. The removal ratio was high for endocrine disruptors having high octanol–water distribution coefficients. It is possible to estimate the removal ratio of other endocrine disruptors in the sorption experiments using PDMS membranes, if their octanol–water distribution coefficients are known. Sorption of γ-globulin and casein in the PDMS membranes was extremely low, because protein molecules are too large to be sorbed into the PDMS membranes. Other nutrients of water-soluble vitamins, such as Vitamins B 2 and B 12, and niacin, were also not sorbed into the PDMS membranes.