Hydrogeochemical characteristics of interstitial water and overlying water in the lacustrine environment

Abstract

This research was conducted in the lacustrine environment of Lake Wigry, one of the largest and deepest lakes in Poland. The main objective was to determine the relationship between the chemical composition of interstitial water, overlying water and bottom sediment in the different sedimentation conditions. Therefore, seven research positions were selected, taking into account different zones of lake and lithological type of deposits. Overlying water samples taken from zones with carbonate type of sediment (lacustrine chalk or calcareous gyttja) were characterized by slightly alkaline pH, similar hydrogeochemical type (HCO 3 -Ca-Mg, HCO 3 -SO 4 -Ca-Mg), low values of mineralization and low metal concentrations. The situation is different with the water taken from the zone of organic: detritus gyttja or dy deposits. Overlying water collected from the Hańczańska Bay (estuary of Czarna Hańcza River) had the highest mineralization 552 mg/L, HCO 3 -Ca type and low metal concentrations, while water collected from the dystrophic lake was SO 4 -Ca-Mg type, low mineralized and acidic type. Studies of interstitial solutions collected from different lithological type of sediments showed noticeable chemical composition differences, both between the carbonate and organic sediments in the same reservoir, as well as in the same kind of sediment but exposed to different external conditions. The highest mineralization (2032 mg/L) was generally found in the interstitial water obtained from the detritus gyttja localized in the shallow positions, which are more exposed to pollution. The highest trace metals and nutrients content in the sediment and interstitial water found in the Czarna Hańcza River estuary were a result of the input from increasing industrial wastewater, domestic sewage discharge and runoff from agricultural soil. A greater resistance to adsorption of contaminants characterizes sediments composed of the lacustrine chalk; mineralization of their pore solutions was significantly lower. This fact is probably also affected by very low mineralization and chemical composition of overlying water and sediment.

Hydrochemistry of sediment pore water in the Bratsk reservoir (Baikal region, Russia)

“…The terrigenous material, entering the reservoir due to the destruction of rocks and abrasions of shores, and transported with water ow, plays an important role in the genesis of pore water. As was shown earlier, the pore water chemistry is greatly in uenced by the chemical and mineralogical composition of bottom sediments [36].…”

Natural and Anthropogenic Origin of Metals in Lacustrine Sediments; Assessment and Consequences—A Case Study of Wigry Lake (Poland)

“…For example, calcium carbonate, which makes up lacustrine chalk, is partly precipitated with the participation of Charophyta (a group of algae), which leads to the formation of calcite tubes of even more than 1 cm in length, and it was found that those tubes are made of almost pure CaCO 3 [98]. Moreover, research on pore water mineralization of Wigry Lake sediments has revealed that it is relatively low in the case of lacustrine chalk (544.5 mg/L) when compared to other types of deposits (e.g., carbonate gyttja-717.7 mg/L; fluvial-lacustrine sediment-1670.9 mg/L) [120]. Con-sequently, apart from lacustrine chalk, clastic sediment, as the most coarse-grained, is also the least enriched with metals.…”

Hydrochemistry of sediment pore water in the Bratsk reservoir (Baikal region, Russia)

“…The pore water chemistry is greatly influenced by the chemical composition of bottom sediments. It was earlier shown that pore water contained in sediments have higher CaCO 3 (> 90%) contents, demonstrated pH values ranging between 7.7 and 8.2, relatively low TDS values and represented HCO 3 –Ca, HCO 3 –Ca–Mg or HCO 3 –SO 4 –Ca–Mg hydrochemical water types 36 .…”