Historical (or legacy) contaminants, such as metals and persistent organic pollutants (POPs; e.g., polychlorinated biphenyls) have been measured in circumpolar subpopulations of polar bears, especially from Hudson Bay, East Greenland and Svalbard, but substantially less is currently known about new and/or emerging contaminants such as polychlorinated naphthalenes, current-use pesticides, organotins, and polycyclic aromatic compounds. The polar bear is an apex Arctic predator that accumulates high levels of POPs and mercury, but there is currently no comprehensive profiling of the present knowledge on contaminants in tissue and body compartment in polar bears. Based on current literature reports and data, and including archived museum samples (as far back as the 1300s) and up to 2018, the aim of this review is to use available data to examine the comparative distribution and burden of mainly lipophilic contaminants in kidney, liver, fat, and other body compartments, such as milk, blood, and brain. Highlights from this review include the following: 1) the kidneys are one of the most important tissue depots of contaminants in polar bears; 2) there is a critical lack of data concerning the presence of metals of concern (other than mercury); and 3) there currently are no data available on the concentrations of many newer and emerging contaminants, which is especially relevant given the increasing oil and gas development in regions such as the Beaufort Sea (Canada). Additionally, given the vulnerability of polar bear populations worldwide, there is a need to develop non-invasive approaches to monitor contaminant exposure in polar bears.

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