Bromophenols, pentachlorophenol, and chlorinated benzenes in pooled human serum samples from Australia

Through various routes humans are constantly exposed to polyhalogenated compounds which are ubiquitous in the environment. Evidence of their harmful environmental and toxic properties led to many of them being classified and regulated as persistent organic pollutants (POPs) under the Stockholm Convention. The analysis of human serum samples enables the assessment of human exposure to these compounds. However, such biomonitoring should not only cover POPs but also halogenated natural products (HNPs) which have very similar structures, and can also be present in humans. The marine environment of Australia is known for its high abundance of HNPs including bromophenols. To consider and compare both classes of polyhalogenated compounds, human serum samples from three general areas in Australia were purposefully pooled using de-identified surplus pathology samples as well as pooled de-identified samples from an occupational cohort (typically 25 donors), i.e. urban areas, coastal areas as well as islands. Overall, 26 serum pools were analyzed for three bromophenols as well as chlorinated phenols, penta- (PeCB) and hexachlorobenzene (HCB). Pentachlorophenol (PCP) showed the highest levels in all serum pools. One serum sample with donors from a remote island showed exceptionally high levels of PCP (10,500 pg/mL serum) and 2,6-dibromophenol (2,6-DBP, 1,500 pg/mL serum). Typically, 2,4,6-tribromophenol was the 2^nd most abundant analyte (up to 140 pg/mL serum). However, the determined wide ranges of concentrations in the pools from the three general areas were overlapping. Significant differences between urban-dominated regions and islands as well as the coast were only found for 2,4-DBP, 2,6-DBP and HCB.