The western portion of Pond #1 has been treated and capped and the 

 process of establishing vegetation on the capped surface begun. 

 Future water levels in the eastern portion of Pond #1 may be 

 manipulated to retain reducing conditions in wetland sediments. 



Water chemistry. At the time of sampling, the WET77 site exhibited 

 dilute, moderately alkaline calcium-bicarbonate/sulfate water. 

 Dissolved solids, pH and proportional sulfate concentrations were 

 lower than at WET76. Mineral equilibria indicate slight 

 oversaturation with calcium carbonate phases . In contrast to 

 WET77, nitrate and ammonium concentrations were comparatively high. 

 Phosphorous concentrations (total and orthophosphorous ) ranked mid- 

 range with respect to sample sites of the intermontane valleys, and 

 the total organic carbon concentration was near the low end of the 

 range for the site class. 



Water-column concentrations of arsenic, iron, copper and zinc rank 

 mid-range among sites of the intermontane valleys and are of 

 similar magnitude to WET76 concentrations. Most other trace 

 element concentrations were below reporting limits. 



Chemical history. Seasonal time-series water chemistry data are 

 presented in DHES documents referenced in the site bibliography. 



Sediments. Extractable calcium concentrations in the WET77 

 sediment sample are high, reflecting liming of the pond saturation 

 of the water column with calciiim carbonate. Extractable 

 concentrations of trace elements are generally much lower than at 

 either WET76 or WET78. Arsenic, copper and zinc concentrations 

 exceed geometric means of soils concentrations in the western 

 United States by factors of 2.7, 1.4 and 1.7 respectively. 



