Abstract
This study focuses on the Dombrovska pit lake, near the city of Kalush in Ukraine, which is a former potassium salt mine filled with brine and freshwater. The water level is still increasing and as a result the salinity is decreasing. We analyzed the benthic fauna communities and the genome instability by assessing the rearrangements in the polytene chromosomes of Chironomus salinarius and the physicochemical parameters of the near-bottom water (pH, conductivity, mineralization, major ions, NO3−, NH4+, metals Cd, Pb, Cu, Mn, and Fe) and sediment (pH, organic matter and metals Cd, Pb, Cu, Zn, Mn, and Fe) at four sites. The water mineralization ranged from 17.3 to 26.2 g dm−3 which are classified as mesohaline and polyhaline waters, respectively. The biodiversity of the benthic fauna was low, and the dominant species was C. salinarius. The density of C. salinarius varied spatially and changed from 637 ind./m2 at a depth of 5 m to 8167 ind./m2 at a depth of 2.5 m. The genome instability was analyzed by examining the structural and functional changes in the salivary gland chromosomes of C. salinarius. The exposure of C. salinarius damaged the chromosomes and the activities of key structures, such as the Balbiani ring and nucleolar organizer, were partially or completely suppressed.
Highlights
The chemistry of water reservoirs that are created in former mine excavations usually lead to unique living conditions for biota
The aim of the study is to determine the physicochemical parameters of the Dombrovska pit lake and the communities of the benthic fauna and to track the response of the C. salinarius genome to stress conditions of decreasing salinity and increasing water levels
In terms of salinity (17.3–26.2 g dm−3), the studied water of the Dombrovska pit lake may be classified as mesohaline at site 1 and polyhaline at sites 2–4
Summary
The chemistry of water reservoirs that are created in former mine excavations usually lead to unique living conditions for biota. The Dombrovska pit lake near the city of Kalush in Ukraine is one of the most saline inland water bodies in the Responsible editor: Philippe Garrigues. Environ Sci Pollut Res (2021) 28:446–458 pit lake creates unsuitable conditions for most biota, regarding zooplankton only three living taxa have been found: the rotifer Brachionus plicatilis and the ciliates Paradileptus elephantinus and Tindinnidium. In the littoral part of the pit lake diatoms that are resistant to high salinity, such as Nitzschia pusilla, Halamphora borealis, H. tenerrima, and H. acutiuscula, have been found. The pit lake is not yet completely filled with water and the final state of water quality has not been reached (Zurek et al 2018)
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