Hydrochemical Indicators of Water Quality in the Norilsk–Pyasino Lake–River System after a Diesel Fuel Spill at Norilsk Heat and Power Plant 3 in 2020

The results of a hydrochemical analysis of the consequences of an accidental fuel release in the Norilsk–Pyasino water system are presented. The pollution of watercourses in the catchment of Lake Pyasino (a nameless (Nadezhdinsky) creek, the Daldykan River, and the Ambarnaya River) with oil products, phenols, easily oxidizable and hard to oxidize organic matter (COD, PO, and BOD₅), suspended solids, inorganic salts, and heavy metals at concentrations exceeding the background levels and MPC for fishery water bodies, as well as a temperature rise in waters of the nameless creek near Norilsk Heat and Power Plant 3 (CHPP-3), have been revealed. The contamination of the surface water decreases downstream in ascending order: nameless creek–Daldykan River–Ambarnaya River. The occurrence of oil products, phenols, and organic substances in the surface waters 2 months after the fuel spill is obviously due to their diffusion from the river bottom sediments, which accumulated a considerable quantity of heavy fractions of diesel fuel after the accident. Increased concentrations of Ca, Cu, Zn, Mn, Co, and Ni in the waters of the studied tributaries of Lake Pyasino are not directly related to the accident; they result from the general technogenic pollution of the territory and the increased geochemical background for these elements. Water contamination with oil products and phenols in the studied areas of Lake Pyasino (its central and northern parts) and the Pyasino River has not been detected. However, Pb concentrations exceed the MPC and Cd is recorded in the water, which is probably due to pollutants that accumulated in previous years.