The paper presents the results of monitoring observations (during 2002-2017 period) of the organochlorines levels and its distribution patterns in the bottom sediments of a small shallow low-flow lake in the south of the Arkhangelsk region, which is part of a complex lake-river system and hydrographically connected with the upstream Onega River (White Sea basin).
The industrial site of the shutdown timber mill is adjacent to the lake shore. In the past, the timber mill intensively and continuously used a wood-preservation commercial chemical (pentachlorophenol sodium salt, Na-PCP) for timber treatment, which contained pentachlorophenol (PCP) as the main component and hexachlorobenzene (HCB) as the impurity component. Also, one of the districts of a large local settlement is located in the vicinity of the timber mill industrial site.
In 2002, seven years after the termination of Na-PCP use at the timber mill, a survey of the lake was conducted. In the bottom sediments high levels of PCP and HCB (with predomination of the latter) were detected. It was found that the formation of sediment pollution by these toxic lipophilic organochlorines classified as persistent organic pollutants is caused by its transfer from the polluted soils of the nearby industrial site.
In lake sediments, fifteen years after the first research, PCP and HCB were still detected. This leads to the assumption that recent soils at the industrial site of a timber mill act as the currently active local source of these pollutants. The tendency to a general decrease in the concentrations of organochlorine pollutants with continuous dominance of HCB was revealed. In addition to PCP, other chlorophenolic compounds with various degrees of toxic level and lipophilic potential were detected and quantified in bottom sediments. It was found that the concentrations of toxic highly chlorinated methoxyphenols, which are derivatives of PCP, exceeded the concentrations of pentachlorophenol itself.
It is shown that the studied small lake is a holding reservoir of toxic organochlorines, including persistent organic pollutants, which can be transferred by waters further to the subarctic Onega River, which creates the threat of distribution of pollution in present and in future.
|Position of speaker||научный сотрудник|
|Affiliation of speaker||Федеральный исследовательский центр комплексного изучения Арктики|
|Publication||Публикация только в материалах конференции|