Heavy metal content in ice in the lower Amur River

Abstract

For the first time, the content of heavy metals in the river ice in the lower Amur River has been analyzed, taking into account the stratigraphic heterogeneity of the ice structure in the river channel. According to the conditions of origin and duration of formation, the main varieties of ice were identified – layered frozen ice, naled-type (icing) ice, and hummocky ice. The most widespread in the Amur ice cover is ice consisting of layers forming hummocky-frozen, hummocky-naled and homogeneous frozen ice sequences. The aim of the study was to determine the content of heavy metals in different ice varieties and the possibility of using this data to assess river pollution during the winter period. The highest content of heavy metals was found in the naled ice, which is due to its formation on the ice surface contaminated during the winter. The minimum content was found in the layered frozen ice, which is formed throughout the winter due to accretion from below. In the layers of hummocked ice formed for several days during the autumn ice drift, metals have average content and uniform distribution within the entire thickness. Influence of Khabarovsk city in winter period is most noticeable by the content of metals in the frozen variety of Amur river ice near its right bank, where the city is located. High concentrations were noted for Pb and Zn, and less pronounced for Cu and Ni. Ice is more informative object than water under the ice, and its chemical composition can serve as an indicator of the ecological state of the river during the freezing period.