Distribution of Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn in dissolved and particulate solids from two streams in Tennessee

Abstract

In order to study metal distribution in streams, four water samples were taken from two streams in northeast Tennessee. One drains an area of exposed minor zinc mineralization. Three classes of solids were extracted from the water: coarse particulates ( > 1500 A ̊ ), colloidal particulates ( < 1500 A ̊ , > 100 A ̊ ) and dissolved solids. Each particulate fraction was extracted by continuous flow ultracentrifugation. The dissolved solids in the remaining effluent were recovered by evaporation. Of the total solid, the dissolved fraction accounts for over 95%; collids make up less than 1%. The three solid fractions were totally dissolved and analyzed for Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn. The dissolved solids always contain the lowest concentrations of metal (ppm metal in solid); the colloids have the highest, typically more than 10 times that of the dissolved material. The coarse particulates occupy an intermediate position. Despite its low concentration, generally over 90% of each metal occurs in the dissolved state. Less than 10% occurs with the coarse particulates, less than 1% as colloids.