Geochemistry of the Hyperalkaline Gorka Pit Lake (pH > 13) in the Chrzanow Region, Southern Poland

Abstract

The Gorka pit lake was formed in an inactive Jurassic limestone quarry after cessation of open-pit dewatering. The main problem of the water quality in this area is linked to a large volume of extremely alkaline leachate disposed in the flooded quarry. The lake is meromictic due to a large density contrast between shallow and deep water layers.Water in the lake is of the Na-CO 3 -OH type, pH is in the range from 11.5 to 13.3, and there are high concentrations of sulfate and several toxic elements (Al, As, Cr, Mo, P, and V). The chemical composition of the extremely alkaline leachate was formed as a result of the groundwater interaction with the industrial red mud wastes containing 5-10 wt.% of sodium carbonate. There is a trend of increasing concentrations and pH values with depth, mainly due to the ingassing of atmospheric CO 2 into the surface layer and due to density stratification in the water column. Similar stratification is observed in groundwater wells around the lake. High dissolved concentrations of oxyanionic contaminants such as As, Cr, and V are caused by their high mobility and desorption under extremely alkaline conditions. In spite of reducing conditions at the bottom of the lake, caused by high concentrations of dumped organic matter, sulfate behaves conservatively because sulfate reducing bacteria do not survive in this pH range.

Impact of Saline Mine Water: Development of a Meromictic Reservoir in Poland

“…It is often associated with closed pit lakes and with wastewater ponds of lignite (Dietz et al 2012;Jędrczak 1992), sulphur (Frankiewicz and Pucek 2006;Wilk-Woźniak and _ Zurek 2005;_ Zurek 2002), and gypsum (Madonia et al 2006) mines. Meromixis can also be caused by the inflow of highly saline mine waste water (Galas 2003;Molenda 2011;Motyka and Postawa 2000) or the inflow of leachate water from colliery waste tips (Czop et al 2011;Molenda 2005). This paper describes the characteristics of one such meromictic water body in the Gliniok reservoir.…”

Impact of landfilling of red mud waste on local environment – the case of Górka / Wpływ Składowania Odpadów Typu Red Mud Na Środowisko Lokalne Na Przykładzie „Górki“

“…Moreover, high mineralization (1600 mg/l) and exceeding of concentration limits of many indicators had been observed. The analysis confirmed that there is a trend of increasing concentration of pollutants and pH values with depth, mainly due to in-gassing of atmospheric CO 2 into the surface layer and due to density stratification in the water column (Czop et al 2011).…”

“…The volume of pH was in the 10.93-13.4 range (Czop et al 2002;Albinus et al 2004). The next analysis, which were conducted in 2000 and 2003 (Czop et al 2011) and in 2007 by local authority confirmed that the value of pH was greater than 13. Moreover, high mineralization (1600 mg/l) and exceeding of concentration limits of many indicators had been observed.…”

Main and Trace Element Distribution in Slag-Leachate-Tufa System Precipitate

“…For example, alkaline waters studied by [22] (generated by interaction of groundwater with aluminum production wastes) contained markedly higher As (up to 5.2 mg/l), Mo (up to 2.6 mg/l), and V (up to 5.4 mg/l) concentrations than the investigated slag leachate, and showed comparably high pH values. In the investigated system, the release of these trace elements is restricted by their low content in the slag rather than immobility in an alkaline environment.…”

“…Among the metals and metaloids analyzed in slag (Table 1), As, Sn, Zn, Cd, Cu, Ni, V, and Mo are potentially mobile at the extremely high pH by forming oxyanions [19,22]. For example, alkaline waters studied by [22] (generated by interaction of groundwater with aluminum production wastes) contained markedly higher As (up to 5.2 mg/l), Mo (up to 2.6 mg/l), and V (up to 5.4 mg/l) concentrations than the investigated slag leachate, and showed comparably high pH values.…”