“…Metal concentrations in the bottom sediments of the affected rivers are elevated a hundred meters below the inflow point of drainage from the waste piles. These sediments become a source of secondary contamination (Salomons 1995;Nordstrom et al 2000;Dinelly et al 2001;Lei and Watkins 2005;Audry, Blanc, and Schafer 2005;Freire et al 2005;Bortnikova, Gas'kova, and Ayriyants 2003;Bortnikova, Gas'kova, and Bessonova 2006;Lu ıs et al 2011;Bortnikova et al 2010).…”