(Anaconda Creek and Swamp Gulch) suffer serious mining or mineral 

 processing impacts. The Swamp Gulch wetland has functioned as a 

 physical and geochemical sink for some of the mine wastes 

 transported out of these drainages. 



Water chemistry. The water sampled at the WET64 site is dilute, 

 mildly acidic, calcium-sulfate in composition, and heavily impacted 

 by acid mine drainage (AMD) from the Carbonate Mine in lower Swamp 

 Gulch. Equilibrium calculations indicate highly undersaturated 

 conditions with respect to carbonate minerals. Nitrate and 

 ammonium concentrations were below detection limits, and 

 orthophosphate and total organic carbon concentrations were near 

 the lower end of the ranges shown for the sample set. 



Copper, iron, lead and zinc concentrations were near the upper end 

 of the ranges shown for Rocky Mountain sites, and were generally 

 exceeded only at other sites exhibiting impacts from mining or 

 mineral processing. The arsenic concentration was comparatively 

 low, cadmium occurred at the reporting limit, and other trace 

 elements analyzed were below reporting limits. 



Chemical history. The development of the Carbonate Mine predates 

 1933, and mine drainage has presumably been impacting the WET64 

 site since that era. Detailed data collection on this site was 

 conducted as part of a 1987 investigation into the AMD-treatment 

 capability of the wetland (see Dollhopf et al in the WET64 site 

 bibliography). None of the sampling sites used in the 1987 study 

 correspond to the WET64 site; the 1987 sampling sites show 

 considerable spatial variability within the general area receiving 

 inflow from Swamp Gulch. pH values below 3, sulfate concentrations 

 in excess of 400 mg/1, and cadmium concentrations in the mg/1 range 

 were reported for sampling points near the Swamp Gulch outfall. 

 In contrast to the DHES sample, measurable nitrate concentrations 

 were reported for almost all of the samples analyzed in 1987 and 

 1988, with concentrations in the mg/1 range at several sites. 



Sediments. The Swamp Gulch sediment sample was heavily 

 contaminated with metals precipitated from AMD inflow to the 

 wetland. Extractable iron accounted for approximately a third of 

 the sample. Boron, copper, cadmium, cobalt, nickel, vanadium and 

 zinc concentrations were the maximum reported for Rocky Mountain 

 sites and in many cases for the entire data set. Extractable 

 boron, cadmium, iron, and zinc concentrations exceeded those for 

 all other sample sites by several hundred percent. Most trace 

 elements with reportable concentrations exceeded mean soil 

 concentrations for the western United States, in the case of boron, 

 copper and zinc by more than an order of magnitude. 



