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

Abstract

The contamination of aquatic sediments by metals is a worldwide phenomenon and its assessment is a fairly complex issue, as numerous factors affect the distribution of particular contaminants in the environment, as well as their bioavailability. Wigry Lake, as the object of this study, is almost a perfect water body for such considerations. It has been well investigated and densely sampled (up to 459 sediment samples). The quantities of seven metals were determined using the atomic absorption spectrometry (AAS) or inductively coupled plasma (ICP)-MS methods, following previous extraction in a microwave oven. The levels of concentration of the examined elements were as follows (min–max (mg·kg−1)): Cd—0.003–3.060; Cr—0.20–22.61; Cu—0.02–59.70; Fe—80–32,857; Mn—18–1698; Pb—7.0–107.5; Zn—3.1–632.1. Significant differences were also registered in terms of particular metal concentrations in different sediment types found at the lake bottom. Five different geochemical backgrounds and sediment quality guidelines implemented in the study enabled a very scrupulous contamination assessment of the lake sediments’ condition, as well as the evaluation of the natural and anthropogenic contribution to the enrichment of examined sediments in metals. Although Wigry Lake is situated in a pristine region, it is still subject to anthropopressure, which seems to be the lowest in respect to Cr and Mn, while the highest in the case of Pb. The chemoecological state of the lake was ultimately assessed as good. The study highlighted the necessity of an integrated approach to the assessment of contamination or pollution in the course of an environmental research.

Geochemical State of Wilga River Environment in Kraków (Poland)—Historical Aspects and Existing Issues

“…One of the most important roles in water environments is performed by sediments, as they are usually the main collector of contaminants and pollutants introduced into water systems-substances dissolved in water are bonded on the solid particles over time and finally trapped in bottom deposits [24]. Aquatic sediments are also a very dynamic component, in which physico-chemical processes such as transport, diagenesis, bioturbation, remobilization or bioaccumulation, constantly take place [25].…”

“…The physicochemical composition of river sediments in non-industrialised areas depends mainly on the geological structure of the catchment, the dynamics of weathering processes, the morphological structure of the river bed and on the surrounding vegetation [26,27], while in the case of densely populated, urbanised or industrialised catchments, the chemical composition of river sediments reflects the local anthropopressure [28], which may lead to the contamination or pollution of sediments with various substances. Contamination is understood as the increased concentration level of a given chemical in relation to the geochemical background, while pollution means that this concentration poses a threat to biota [24,29]. A distinct, and quite complicated issue, is the appropriate determination of the geochemical background used in environmental risk assessment [30], which may significantly affect the data analysis results [31].…”

History of Environmental and Climatic Changes Recorded in Lacustrine Sediments—A Wigry Lake Case Study

“…It is worth noting, however, that these sediments are more finegrained and lighter in color (which is related to the organic matter content). Additionally, research related to seven metals (Cd, Cr, Cu, Fe, Mn, Pb, and Zn) present in Wigry Lake sediments [41,42,64,102,151] has revealed that mean element concentrations in organic gyttja and carbonate gyttja do not differ significantly (except for iron, and to a lesser extent manganese). This may suggest that organic gyttja is genetically more related to carbonate gyttja than to fluvial-lacustrine sediment, although the small amount of organic gyttja samples being studied prevents an unambiguous conclusion.…”

“…More contemporary adverse changes in the Wigry Lake environment are a result of the urban and industrial development of the nearby city of Suwałki (which held the status of the voivodeship capital in the years 1974-1999) [16,173], the development of tourism [16,174], and the relatively large load of nutrients (especially phosphorus) carried by the Czarna Ha ńcza River [37,91,164,[175][176][177][178], as well as some other contaminants like polynuclear aromatic hydrocarbons [179] or metals, which have been extensively studied [41,42,64,102,147,[149][150][151]163,[180][181][182][183][184][185][186][187]. The analysis of long sediment cores [150,186] revealed that relatively high metal concentrations in the bottom part of profiles originate from crystalline rocks derived from glacial sediments, whereas the middle parts of cores are very pure, and the concentration of metals is higher in the upper part of the profiles.…”

Editorial for Special Issue “Elemental Concentration and Pollution in Soil, Water, and Sediment”

“…Several studies were focused on the anthropopressure on sediments; Warta River studied by Jaskuła and co-authors [10] and Wigry Lake surveyed by Kostka and Leśniak [11], both located in Poland, showed signs of heavy metal pollution. In Warta River, the thirdlongest river in Poland, heavy metal contaminated sediments can act as point sources in urbanized areas and fluvial processes.…”