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vi <br /> consistently far below regulatory limits. The other four sites are affected to varying degrees by <br /> <br /> mine drainage. Mine drainage causes consistent exceedances of standards on upper Clear Creek <br /> and lower North Clear Creek. The amounts of metals transported in watersheds that are either <br /> affected or tm_affected by mine drainage far exceed the amounts that are added to roadways with <br /> magnesium chloride deicer. <br /> <br /> 18. Deicer contributed less than 5% to transport of phosphorus when no phosphorus- <br /> containing rust inhibitors were used. <br /> <br /> 19. Comparisons were made of algal communities at three locations receiving deicer and <br /> three locations not receiving deicer (controls). Analysis of the algal communities indicates no <br /> statistically significant difference in the algal communities of control and treatment sites. <br /> <br /> 20. During spring of 1998, samples were taken of runoff originating from portions of 1- <br /> 70 receiving magnesium chloride deicer. The samples were taken just following a storm during <br /> which deicer and salt with sand had been applied, and consisted of a series of transects beginning <br /> at the side of the highway and moving along drainage paths leading to the nearest large stream. <br /> The purpose of the sampling was to determine the degree and speed of dilution for deicers <br /> through chemical analysis ofrunoffwater. The results showed that dilutions were at a minimum <br /> 5000 fold and typically 10,000 fold or more at short distances from the roadway (e.g., 20 yds). <br /> <br /> 21. Water quality was studied in two wetlands, both of which support breeding <br />populations of the boreal toad. One wetland (the north wetland) does not receive hi'ghway <br />drainage because it is up slope of the highway, whereas a nearby wetland (south wetland) <br />receives highway drainage from 1-70. Studies of the concentrations of major ions, and especially <br />magnesium, indicate that the south wetland received concentrations of deicer not exceeding <br />0.002% during the toad breeding season (June to early July). Concentrations of metals and <br /> <br /> <br />