the Warm Springs Pond treatment system, but when Silver Bow 

 Creek bypasses the ponds during high runoff events, it is 

 clearly a significant source of metals to the mainstem Clark 

 Fork. 



Aquatic life toxicity criteria for copper and zinc (EPA 

 1985a, 87a) were exceeded in all samples from Silver Bow 

 Creek, and annual average concentrations were ten to more 

 than 20 times the threshold levels. Arsenic concentrations 

 were commonly an order of magnitude less than either copper 

 or zinc. Aquatic life criteria for arsenic were not exceeded 

 in Silver Bow Creek or the mainstem Clark Fork during FY 

 1985-87 WQB sampling. 



Figure 3-16 shows FY 1985-87 total recoverable copper 

 concentrations at stations 1-3 above the Warm Springs Ponds 

 and at the Pond 2 discharge (station 4) . Stations 1-3 had 

 very high concentrations with the median values about ten 

 times higher than the chronic copper criteria for aquatic 

 life. Station 4 values illustrate the dramatic decrease in 

 copper concentrations due to attenuation by the Warm Springs 

 Ponds, with a median value right at the chronic copper 

 criterion. 



Warm Springs Ponds . As mentioned previously, the Warm 

 Springs Ponds were constructed by the Anaconda Company in an 

 attempt to limit the downstream effects of mining. A number 

 of investigations have addressed the pond system and its 

 effect on the water quality of the Clark Fork, including: 

 Casne et al. 1975; Botz and Karp 1979; Hydrometrics 1983c; 

 and others. However, these studies do not reflect current 

 conditions, and very few of them collected samples from 

 enough stations to identify contaminant sources or to 

 complete a mass balance analysis of the pond system 

 (MultiTech 1987a) . 



Data on the Warm Springs Ponds were collected for the 

 Phase I RI Superfund investigation from November 1984 to 

 September 1985. Additional, but limited surface water 

 quality data were collected above and below the pond system 

 in 1986. Field data collected included pH, temperature, 

 conductivity, and flow (where appropriate) . Water and bottom 

 sediment samples were analyzed for major cations, major 

 anions, and selected trace elements. Meteorological data 

 were collected and surveys of the pond bottoms were performed 

 to aid in volumetric calculations. 



The Warm Springs Ponds generally act as a sink for 

 sediment, total metals, dissolved metals, and nutrients. 

 However, the ponds are not 100 percent efficient in trapping 

 metals delivered by Silver Bow Creek and the Opportunity 



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