Organochlorine compounds in the bottom sediments of the meromictic Mogilnoe Lake (Kildin Island, Russia)

Abstract

The paper presents the results of a study of the behavior of organochlorine compounds (chlorinated benzenes and phenols) in the bottom sediments of Mogilnoe Lake (Kildin Island, Barents Sea). Mogilnoe Lake is a meromictic water reservoir located in the high latitudes of the Russian Arctic. A unique feature of the lake is its underground connection with the sea, which makes it similar to tropical anchialine lakes. Lake sediment samples were taken at three deep-water stations during complex expedition work in June 2019 by employees of the N. Laverov Federal Center for Integrated Arctic Research of the Ural Branch of the Russian Academy of Sciences (Arkhangelsk). Organochlorine compounds were extracted from air-dried samples of bottom sediments using accelerated flow-through solvent extraction with a hot mixture of organic solvents. Determination of the concentrations of chlorinated benzenes was carried out according to RD 52.24.417-2011 (RF), and the concentrations of chlorinated phenols and their derivatives – in accordance with the ISO 14154:2005. Quantification and identification of individual organochlorine compounds were carried out by capillary gas chromatography with electron capture detection. The presence of organochlorine compounds in sediments of the meromictic Mogilnoe Lake has been established. Concentrations of persistent organochlorine pollutants were assessed as high. Most likely, the component composition of organochlorine compounds and their detected levels (primarily pollutants) in the bottom sediments of the lake are due to the influence of various local anthropogenic sources, as well as atmospheric long-range transport from low/moderate latitudes and nearby regions.