Hydrodynamic Controls of Particulate Metals Partitioning Along the Lower Selenga River—Main Tributary of The Lake Baikal

Abstract

In this study, the downstream effects of pollutants spreading due to hydromorphological gradients and associated changes in sediment transport conditions along the braided-meandering and deltaic distributary reach of a large river downstream section are discussed. We demonstrate the significance of hydrodynamic control for sediment-associated metal partitioning along the river. Typically, the downward decline of the sediment and metals spreading towards Lake Baikal is observed due to buffer effects in the delta. During peak flow, the longitudinal gradients in heavy metal concentration along the distributary delta reach are neglected due to higher concentrations delivered from the upper parts of the river. In particular, significant variations of heavy metal concentrations associated with the river depth are related to sediment concentration and flow velocity profiles. Various particulate metal behavior in silt-sand delta channels and the sand–gravel Selenga main stem emphasize the importance of near-bottom exchange for particles spreading with the river flow. Using empirically derived Rouse numbers, we found quantitative relationships between the ratio of particulate metals sorting throughout depth in a single river channel and the hydrodynamic conditions of sediment transport.

Exchangeable form of potentially toxic elements in floodplain soils along the river-marine systems of Southern Russia

“…ecosystems, but the accumulation of pollutants in deltaic landscapes aggravates their degradation (Lychagin et al, 2015;Kasimov et al, 2020a,b;Chalov et al, 2020). Thus, delta geochemistry studies are very informative for tracking anthropogenic activities within the entire river basin, since various components of such systems provide information on both current and historic pollution (Beltrame et al, 2009;Loureiro et al, 2009;Uluturhan et al, 2011;Dhanakumar et al, 2015;Birch et al, 2015;Buscaroli et al, 2021).…”

River Water Quality of the Selenga-Baikal Basin: Part II—Metal Partitioning under Different Hydroclimatic Conditions

“…Previous research on metal partitioning in the Selenga River basin was based mostly on single-season sampling campaigns and included heavy metal transport along the Mongolian part of the Selenga River watercourse [27], sediment-associated metal partitioning along the Selenga lowermost reach [28] and its delta [29], as well as metal spreading in the Selenga tributaries [30,31]. In this study, we present an extensive, novel dataset for the Selenga River basin-the largest tributary of Lake Baikal [32]-which is based on spatially distributed sampling locations that were visited during field campaigns over six years, from 2011 to 2016, to assess different hydrological seasons.…”