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25 Changes in Soii and Vegetation Chemical Constituents Between 1976 and 1985 Sore chemical constituents changed in soil and vegetation between 1976 and 1985. There was a significant increase in soil pH, electrical conductivity (EC), nitrate-nitrogen (NQl-N), calcium (Ca), magnesium (Mg), sodium (Na), irgn (Fe), manganese (Mn), copper (Cu), and fluoride (F) between 1976 and 1979 (Table 6). However, all of these differences had disaF~peared, or were even less than 1976 values, by 1985. Mast of these differences were probably not related to MoSl production at the mill as discussed in tlhe previous section. Both copper and molybdenum in herbaceous samples showed a 3- to 4-titres increase between 1976 and 1979 and remained high in 1985. Fluoride, copper, and molybdenum were all more ccaicentrated in tailing than in soil, so this difference aright be related to tailing or ore processing dust that had acctitantlated on foliage. Since soil levels of these chemical constituents were low, fugitive dust is more likely the reason for elevated levels in foliage rather than plant uptake through the root system. Copper levels in herbaceous vegetation were not different among the six sattpling locations (Table 7). Molybdentm concentrations ammig samples from the six locations were similar in 1976, but in 1979 molybdenum concentrations in samples taken fran locations Number 6 (coattrol) and Number 4 were ]Ligher than from any other locations. Herbaceous vegetation at the control location (No. 6) still had somewhat higher molybdenum levels in 1985, but difference were no longer statistically significant. In addition, both copper azid molybdenum were mare concentrated in 1979 and 1985 samples of herbaceous vegetation than in vegetation samples collected in 1976. Samples of 1.odgepole pine showed simdlaz trends for copper and molybdenum levels, evert thrntgh