FIELD ASSESSMENT OF ACID-MINE DRAINAGE CONTAMINATION IN SURFACE AND GROUND-WATER

Both sulfate and conductivity are useful indicators of acid mine drain age (AMD) contamination. Unlike pH, they are both extremely sensitive to AMD even where large dilutions have occurred. The advantage of usin g sulfate to trace AMD is that unlike other ions it is not removed to any great extent by sorption or precipitation processes, being unaffec ted by fluctuations in pH. These two parameters are also closely assoc iated as would be expected, as conductivity is especially sensitive to sulfate ions. Therefore, as sulfate analysis is difficult in the fiel d, conductivity can be used to predict sulfate concentration in both A MD and contaminated surface waters using regression analysis. Most acc urate predictions are achieved by using equations given for specific c onductivity ranges or AMD sources. There is also potential to use cond uctivity to predict approximate concentrations of key metals when the pH of the water is within their respective solubility ranges.