Statistical Evaluation of Dependence Between pH, Metal Contaminants, and Flow Rate in the AMD-Affected Smolnik Creek

Acid mine drainage (AMD) with a pH of 3.7–4.1 seeps from an abandoned sulphide mine in Smolnik, Slovakia at a flow rate of 5–10 L/s. Metals precipitate as the AMD mixes with the higher pH Smolnik Creek, adversely affecting the stream’s water quality and ecology. Multivariate statistics were used to interpret surface water and sediment quality effects. Factor analysis generated three significant factors that explained 79.9 % of the variance in the data: the pH is indirectly proportional to the concentration of dissolved metals; Fe precipitation is associated with a decrease in Al in the sediment; and increased Cu concentrations are associated with more Zn in the sediment. High rainfall events increase the flow of Smolnik Creek, which ranges from 0.3 to 2.0 m 3 /s (monitored 2000–2012). Increased flow is associated with a pH increase and precipitation of metals (Fe, Al, Cu, and Zn). The dependence of pH on flow in Smolnik Creek was evaluated using regression analysis, which confirmed the significance of the exponential relationship between pH and flow rate.