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upon site - specific characteristics. <br />The greatest changes were noted in the pH, conductivity, <br />alkalinity, and concentration of some metals (zinc, nickel, <br />chromium, strontium, iron, manganese). Table IV identifies the <br />standards, and upstream and downstream concentrations for those <br />parameters which violate standards at the Sacramento site. <br />The increase in the sulfate concentration of the stream is <br />most likely due to the oxidation of pyrites as a result of a <br />change in the redox potential (Eh) of the soil after drainage. <br />This is known to occur in areas with high concentrations of <br />ferric sulfide compounds in the soil. Associated with the <br />increased sulfate concentration is a drop in the pH, which also <br />causes the alkalinity to decrease. A decrease in the pH, along <br />with changes in the Eh causes some metals to become more soluble <br />and increases their concentration in the water. <br />Literature reviews conducted by the Minnesota Dept. of <br />Natural Resources (MDNR 1978) pointed to the potential of <br />peatland excavations to increase concentrations of metals and <br />humic acids to the point where they are deleterious to aquatic <br />organisms. The USFWS (1981) has noted that without mitigation, <br />the loadings of phosphorus, nitrogen, suspended sediment, <br />dissolved organics, and color to receiving waters would likely <br />increase. Owens (personal communication 1989), in his studies of <br />the uranium concentrating effect of peat, has found very high <br />concentrations of a wide range of metals and notes that any <br />method that utilizes drainage of the peatland would likely <br />• 43 <br />