• Watercourses of the protected area were studied as the background, so it makes sense to compare the concentrations of metals in the bottom sediments of these streams to the approximate permissible concentrations in soils (close to neutral and neutral (loam and clay) pHKCl > 5.5). As shown in Table 1, the threshold background concentrations of Zn and Cd in the bottom sediments of the streams to the north-east of Sikhote-Alin are slightly higher than the approximate permissible concentrations for soils. In particular, the concentrations of Zn are increased in the bottom sediments of rivers Dzhigitovka and Zabolochennaya, and the concentrations of Cd are elevated in the bottom sediments of rivers Zabolochennaya and Yasnaya compared to the approximate permissible concentrations. Elevated concentrations of Zn in the bottom sediments of a number of streams in the reserve are confirmed by the results obtained during the analysis of the heavy metal content in water moss and periphyton (Chernova et al., 2013).