Persistent halogenated pollutants in mothers´ milk

University dissertation from Stockholm : Department of Materials and Environmental Chemistry (MMK), Stockholm University

Abstract: Persistent organic pollutants (POPs) are substances that degrade slowly, are distributed wotldwide, bioaccumulate and are harmful to both animals and humans. The release of POPs to the environment was the preamble to human background contamination. In the mid-20th century it became clear to scientists and policy makers that even the mothers´ milk was contaminated by POPs. This led to national and global monitoring programs to assess the extent of contamination and subsequently to ban several POPs via the Stockholm Convention.The concentrations of dioxin, polychlorinated dibenzodioxins (PCDD), -furans (PCDF) and dioxin like polychlorinated biphenyls (DL-PCB) is analysed in a retrospektive time trend study. The findings show a faster decrease of dioxin concentrations 2002-2011, compared to the whole series, 1972-2011. The transfer of polybrominated diphenyl ethers from mother to child via the milk is investigated and a relationship between both the PBDE molecule’s size and time post partum of the sampling and the ability to transfer to the milk is found. A literature review concerning the POPs in human milk finds, in addition to accounting for POP concentrations; that some substances are investigated more thoroughly than others; DDT and PCB compared to Aldrine and Toxaphene and that certain geographical areas are more well-studied than others, e.g. Europe compared to Africa. The study also shows a strong over all need for better reporting protocols. To understand the current and emerging POPs present in mothers´ milk screening of a larger than normal sample of mothers´ milk can give new insights. The development of a method designed to tackle the problems of large fat rich sample and still to be as benign as possible to the analytes was undertaken. The method is subsequently applied to a both Swedish and Chinese pooled sample to show the differences in POP exposure between countries.