| dc.description.abstract | Road salt, commonly comprised of sodium chloride, is utilized to mitigate winter road icing by augmenting friction between car tires and asphalt (Norrström, 2005). Upon dissolution in water, NaCl dissociates into free Na+ and Cl- ions, which are subsequently mobilized by rainfall and replace naturally occurring ions within soils and aquatic environments. Concurrently, heavy metals originating from vehicle abrasion are adsorbed to diluted salts and colloids, subsequently entering nearby
aquatic systems during precipitation events. The principal objective of this study was to ascertain the stratification status of Kutjern and evaluate the extent of heavy metal accumulation within its water column.
Throughout this master's thesis, monitoring in Kutjern was conducted from May 25th to August 31st, 2023. Measurements were taken at one-meter intervals to assess parameters including oxygen concentration, pH, redox conditions, specific conductivity, and temperature. Additionally, weekly water sampling was performed to analyze nutrient and heavy metal content by using techniques such as filtration, color reactions, chromatography, and spectrometry. Comparative analysis with previous
studies was undertaken, revealing if congruent metal concentrations and stratification patterns were present. The findings unequivocally indicated meromixis in lake Kutjern, with a discernible chemocline forming around a depth of 4 meters. The lake retained a distinct temperature and saline stratification, impeding seasonal mixing during spring and fall.
Notable deviations in physical parameters were observed, due to variations in precipitation and air temperature, during the summer of 2023. Anoxic conditions prevailing in the hypolimnion fostered reducing environments, facilitating release of heavy metals from the sediment surface, with elevated concentrations of Fe, S, and
Zn in epilimnion. Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb had admittedly concentrations below toxic levels. This research serves to elucidate the repercussions of road salt application on proximate water bodies, elucidating salt stratification dynamics and the accumulation
of heavy metals. Moreover, it furnishes a foundational framework for subsequent investigations concerning the ecological ramifications of salt intrusion in roadside lakes. | |
