Quantitative analysis of iron and manganese distribution in surface waters of the Jewish Autonomous Region

The article presents the results of a quantitative analysis of the distribution of iron and manganese in surface watercourses of the Jewish Autonomous Region (JAR) belonging to the Bira River basin. The materials for the study were obtained during expeditionary trips in the autumn of 2018 and the summer of 2019. The conducted sampling of river waters made it possible to identify the distribution contour of iron and manganese levels in the Bira River basin, which was statistically confirmed by correlation and cluster analysis. Based on the cluster analysis, the authors identified three groups of rivers that differ in the concentrations of the studied elements. In the rivers of the first group, originating from the southern spurs of the Bureinsky ridge, no excess of the MAC for iron and manganese was found. In the waters of the rivers of the second group, flowing through the northwestern part of the region and draining the foothills of the Maly Khingan, traces of ferromanganese ore content are clearly visible. The rivers of the third group are characterized by a noticeable content of metals, including due to the influx of soluble humic acids of iron and manganese from the swamp catchment. It is shown that, despite the difference in natural conditions in the fall of 2018 and summer of 2019, the distribution of Mn concentration by rivers is preserved to some extent, which is confirmed by a noticeable correlation between the total Mn content in these periods. High values of the correlation coefficients between water temperature and the content of Mn and Fe may indicate the influence of the hydrothermal factor on their concentration in surface waters.