Influence of inter-annual variability of river runoff on the bottom sediments of the Razdolnaya River estuary, Primorye, Russia. V.M. SHULKIN

Abstract

Influence of inter-annual variability of river runoff on the bottom sediments of the Razdolnaya River estuary, Primorye, Russia. V.M. SHULKIN (Pacific Geographical Institute, FEB RAS, Vladivostok).

Grain size and chemical composition have been studied of the upper 2 cm layer of bottom sediments of the Razdolnaya River estuary sampled thrice in 2015–2019. It was a period when the river runoff increased by 2–3 and 5–6 times for the water and suspended solids, respectively, compared to 2014. It has been shown that significant subtraction of sedimentary material is accompanied by 10–20 % increase of pellite fractions (grain size <0.01 mm) in the deposits of the outer part of anestuary in the North part of the Amur Bay. Grain size composition is the main controlling factor determining 67 % of the total variability of the chemical composition of estuarine bottom sediments. Another 20 % of variability are due to the admix of polluted sediments of the Amur Bay, containing an increased concentration of Corg., Hg, Zn, Pb, Cd, Ag, Cu, Mo, V, as well as diagenesis, leading to depletion of sediments by the Mn and Co on a river-sea section. It is not possible to establish the influence of coagulation processes in the mixing zone on total concentration of trace elements in the bottom sediments of Razdolnaya River estuary.