Research of Biogenic Substances Concentrations and their Connection With Runoff of the Siverskiy Donets River in the Borders of the Kharkiv Area

Abstract

Purpose. The purpose is to investigate the spatial-temporal change in the runoff of water, concentration of nutrients in water and establishment of communication between them, on the river Seversky Donets. Methods. Statistical analysis was used as a key method. Results. For the study of water flow and changes in average annual concentrations of nutrients in the Seversky Donets River, selected posts are located: on the border with the Russian Federation (Ogurtsovo village); Pechenezh reservoir; Chuguev city; city of Zmiev. To identify cyclical patterns in runoff fluctuations, chronological and smoothed, using a linear filter, time series for the periods 1923-2016 are used. To identify cyclical patterns in runoff fluctuations, chronological and smoothed, using a linear filter, time series for the periods 1923-2016 are used. The frequency of phases of water content is on average 3-5 years. The average perennial phosphate concentrations in posts are in the range of 0.65-1.96 mg/dm³, and the coefficient of variation is 0.2, that is, the variability of phosphates is negligible. The average concentration of nitrites by posts, for the entire observation period, varies in the range of 0.046-0.26 mg/dm³, and the coefficient of variation of nitrites varies in the range of 0.6-0.9, which indicates a significant variability of the indicator over time. The average annual concentrations of nitrates in the posts vary in the range of 0.71–4.96 mg/dm³, and the coefficient of variation of nitrates is 0.9. Conclusions.  The average annual concentration of biogenic substances at the indicated positions has no relation to the cyclicity of the water content of the river, except for the Pechenezh reservoir, where the concentration of nitrites and phosphates changes in synchrony with the average annual water consumption.