Reviving prospects for lake restoration - investigating the geochemistry of lake Alūksne sediments

Abstract

Lake sediments have a broad range of elementary and organic substance content. Bottom sediments collect decaying organic debris of aquatic plants and animals mixed by water drift with mineral constituents-deposited in the bottom of the lake in anoxic conditions. Lake Alūksne is situated in Northeast Latvia and is of glacial origin. Its water and bottom sediments chemical content depends on formation conditions-influenced also by anthropogenic activities. In order to determine environmental quality for restoration purposes and sediment recovery, geochemical research is needed. This paper aims to study bottom sediments-texture, ash part, organic compounds and metals to pinpoint necessary steps that are crucial for distinguishing environmental quality of the lake through geochemistry research. Bottom sediments contain sapropel with large admixture of organic compounds and microelements that may significantly influence biota and human health if concentration exceeds natural background levels. When bottom sediments are recovered, it may improve oxygene conditions in the lake, extracted sapropel can be used as a fertilizer, therapeutic agents, supplements for farm foods. Generally, sapropel is improving the structure of agricultural soils, increasing the cation exchange capacity and serving as binding material for complexes formation; thus diminishing ecotoxicological exposure threats of heavy metals, increasing yields and albumen and protein quantity in plants cultivation products. As these sediments can be used for soil fertilizing and crop production improvement in agriculture, mechanisms of ecotoxicological impact to various soil types and agricultural plant ecology should be researched.

Ecological quality of freshwater lakes and their management applications in urban territory

“…To better describe processes in studied lakes, also sediment analyses were done, including N, P concentrations in the upper sediment layer (Table 3). Upper layers of studied lakes indicate a strong impact of human actions in watershed basin and in coastal area of lakes with significantly increased proportion of allochthonous material (Purmalis et al, 2017). High N:P ratios typically are associated with agricultural runoff (Lanza-Espino et al, 2015), which correlates very well also with Lake Balvu and Pērkonu and their location in the studied hydrological cycle and catchment area.…”

Composition and Quality of Freshwater Lake Sediments (Balvu and Pērkonu Lakes)

“…Although accelerated eutrophication and requirements of the Water Framework Directive impose searching for effective restoration methods [11], sediment removal is not used frequently [14], [15] due to the different quality of sediments [16] and environmental risks which include influencing and destroying water ecosystem in the particular area [5]. Nevertheless, the applied recultivation actions have been studied and show different success rates and activity costs, most of the studies show necessity to continue activities for several years [11].…”