The dynamics of the human contaminants cocktail: Employing longitudinal POPs data from Northern Norway (1979-2007) and mechanistic models

Humans are continuously exposed to a substantial number of contaminants, and no study can capture the overall complexity. The present work has summarized the time trends across almost thirty years for 24 polychlorinated biphenyls (PCBs), 17 organochlorine pesticides including metabolites (OCPs), 3 polybrominated diphenyl ethers (PBDEs), and 10 per- and polyfluoroalkyl substances (PFASs) in a set of persons. These trends were based on analyses of serum sampled from
53 men in Northern Norway in 1979, 1986, 1994, 2001, and 2007. DDTs decreased from 1979, many PCBs from 1986 whereas PBDEs were low throughout and PFASs increased until 2001 and decreased thereafter. The compositional patterns changed according to the trends yet PFASs were dominant in most years. Based on these results, the understanding of temporal aspects of human concentrations can provide a holistic view on human exposure to contaminants in terms of complexity and dynamics. A close resemblance could be observed between human concentrations and the overall global emission estimates for the different compound groups. Also, emission-based environmental and human accumulation modeling could reproduce temporal trends for PCBs and the age group patterns observed in measurements. Predicting individual PCB concentrations in two cross-sectional studies including
pregnant and postmenopausal women displayed realistic concentrations compared to measurements. Predicting concentrations previous in their life course revealed temporal aspects providing valuable illustrations of
variation over time in PCB concentrations within and between
individuals. In the longitudinal study, the time trends were specific to the different compound groups and the diverging changes likely largely relate to different production and use histories along with environmental and human persistence. These perspectives clearly show the close
relation between use and concentrations and have implications for considerations of human exposure.