“…In both otters and beavers, the focus of research has been on tissue and body burdens as a result of mercury exposure in river otters and cadmium exposure in beavers due to their food preferences. Accumulation of metals (arsenic, cadmium, lead, mercury, selenium, copper, manganese, and zinc) and PCBs in both species can be age‐specific (Fimreite et al ; Giżejewska et al ; Hillis and Parker ), sex‐specific (Walker et al ), and tissue‐dependent (Chadwick ; Kang et al ; Wren ; Zalewski et al ).…”