During the past two decades human exposure to bisphenol A (BPA) and phthalates such as di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), butylbenzyl phthalate (BBzP) and di-(2-ethyl-hexyl) phthalate (DEHP) has received substantial interest due to widespread population exposures and potential endocrine disrupting effects. Therefore, these chemicals have gradually been restricted and phased out through legislation. However, humans are still exposed to a wide range of other less studied phthalates, phthalate substitutes and BPA analogues as well as other polychlorinated and phenolic substances. In this study, we investigated human exposure to these chemicals over the past decade. Three hundred urine samples collected in 2009, 2013 and 2017 (100 samples each year) from young Danish men of the general population, participating in a large on-going cross-sectional study, were selected for the present time trend study. The urinary concentration of metabolites of 15 phthalates, di-2-ethylhexyl terephthalate (DEHTP) and di-iso-nonyl-cyclohexane-1,2-dicarboxylate (DINCH), seven bisphenols including BPA, bisphenol S (BPS) and bisphenol F (BPF), as well as triclosan, triclocarban, benzophenone-3, three chlorophenols and two phenylphenols were analyzed by two new sensitive LC-MS/MS methods developed and validated for the present study. A significant decrease in urinary concentrations over time was observed for the majority of the chemicals. Median concentrations of BPA and the metabolites of DiBP, DnBP, BBzP and DEHP were more than halved from 2009 to 2017. Similar decreases were observed for triclosan and the chloro- and phenylphenols. In contrast, metabolites of the two phthalate substitutes DEHTP and DINCH increased more than 20 and 2 times, respectively. The potential BPA substitutes; BPS and BPF also increased, but only slightly. Despite these new exposure patterns, the exposure to the old well-known chemicals, such as DiBP, DnBP, BBzP, DEHP and BPA was still higher in 2017 compared to the exposure level of the new substitutes such as DEHTP, DINCH, BPS and BPF. A significant decrease in internal exposure to most of the common phthalates and BPA over the past decade was observed, reflecting market changes and regulatory measures implemented in EU. Despite increasing exposures to some of the known phthalate substitutes and BPA analogues, the total amount of each measured chemical group (original and substitute analytes combined) was lower in the more recently collected samples. This indicates only partial direct substitution or substitution by chemicals not covered in this approach, or a general decline in the exposure to these chemical/product groups over the last decade.
Keywords: DINCH; Di-2-ethylhexyl terephthalate (DEHTP); Endocrine disruptor; Human biomonitoring; Phenol; Phthalate.
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