Heavy Metal Contamination in the Surface Layer of Bottom Sediments in a Flow-Through Lake: A Case Study of Lake Symsar in Northern Poland

Abstract

River-lake systems most often behave as hydrographic units, which undergo complex interactions, especially in the contact zone. One such interaction pertains to the role of a river in the dispersal of trace elements carried into and out of a lake. In this study, we aimed to assess the impact of rivers on the accumulation of heavy metals in bottom sediments of natural lakes comprised in postglacial river-lake systems. The results showed that a river flowing through a lake is a key factor responsible for the input of the majority of available fraction of heavy metals (Zn, Mn, Cd and Ni) into the water body and for their accumulation along the flow of river water in the lake. The origin of other accumulated elements were the linear and point sources in catchments. In turn, the Pb content was associated with the location of roads in the direct catchment, while the sediment structure (especially size of fraction and density) could have affected the accumulation of Cr and Zn, which indicated correlations between these metals and fine fraction. Our results suggest that lakes act as filters and contribute to the self-purification of water that flows through them. As a result, the content of most metals in lake sediments showed a decrease by approx. 75% between the upstream (inflow) and downstream (outflow) sections. The increased content of two metals only, such as chromium and cadmium (higher by 2.0 and 2.5 times, respectively, after passing through the lake), was due to the correlation of the metals with fine sand. Both the content and distribution pattern of heavy metals in lake sediments are indicative of the natural response of aquatic ecosystems to environmental stressors, such as pollutant import with river water or climate change. The complex elements creating the water ecosystem of each lake can counteract stress by temporarily removing pollutants such as toxic metals form circulation and depositing them mostly around the delta.

Lake Restoration and Management in a Climate Change Perspective: An Introduction

“…Finally, the impact was assessed of rivers on the accumulation of heavy metals in bottom sediments of natural lakes comprised in postglacial river-lake systems [36]. The results obtained showed that a river flowing through a lake is a key factor determining the input/accumulation of the majority of the occurring fractions of heavy metals (Zn, Mn, Cd, and Ni).…”

Seasonal Evolution and Depth Variability of Heavy Metal Concentrations in the Water of Firiza-Strîmtori Lake, NW of Romania

“…The last years have shown a trend of enhancement in pollution by heavy metals present in the sediments of surface water [8,14]. In this context, the distribution pattern of contaminants across the water column could provide some useful information on the environmetal characteristics of heavy metals such as their transformation and migration [9].…”

“…Fe, for example, prevents anaemia, and Zn is a cofactor in over 100 enzyme reactions [7]. In the aquatic environment, metals undergo chemical and biogeochemical processes that control their solubility, mobility, bioavailability and toxicity [14]. It is important to know the distribution of contaminants in lake water because it provides information about their origin, transformation and migration that are useful in water reservoir management [9,[15][16].…”

The occurrence of heavy metals and metal-resistant bacteria in water and bottom sediments of the Straszyn reservoir (Poland)

“…They cause the environmental pollution from sources such as industrial effluents, mine tailings, land application of fertilizers, atmospheric deposition and leaching of metal ions from the soil into lakes and rivers by acid rain [1][2][3]. The authors of many papers report the impact of heavy metals on aquatic communities including bottom sediments of rivers and lakes [4][5][6][7][8][9]. Numerous natural and anthropogenic factors affect the chemical composition of surface water sediments [10][11][12].…”

“…Numerous natural and anthropogenic factors affect the chemical composition of surface water sediments [10][11][12]. In the case of flow-through lakes often the most important material is the suspended and dissolved one, transported by supplying river, especially passing through urban, rural or agricultural areas [9]. The composition of sediments depends on geological structures, geomorphology and weathering process, so the background values of individual compounds are characteristic for each region.…”