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concentrations at GW-52W-150V), ne long term tare nds are apparent. There are inadequate •
<br />winter and spring water quality samples in the Wadge Overburden data base to perform a
<br />definitive analysis of seasonal variability, but summer and fall major ion concentrations
<br />are more concentrated than winter values (Figure 7-3).
<br />Wadge Coal Aquifer. Water chemistry has been monitored at eight wells completed in the
<br />Wadge Coal aquifer: GW-52W-1W, -2W, -3W, -4W, -SW, -15W, -17W, and -16W. Water quality
<br />monitoring at Wells GW-S2W-1W through -SW was iii scontinued by the end of 1986. Although
<br />Wells GW-52W-14W and -16W are scheduled to be monitored, they have never produced
<br />sufficient water for sampling.
<br />As discussed in the "Ground Water levels" section of Tab 7, Wells CW-S2W-1W, -2W, and -SW
<br />are suspected to have failed, and data from these wells were not incorporated in ground
<br />water level analyses of the Wadge Coal aquifer. Therefore, water quality data from these
<br />wells are also suspect, and chemical data for Wells GW-52W-1W and -SW have not been used
<br />in this hydrochemical assessment of the Wadge Coal. However, careful inspection of water
<br />quality data for Well GW-52W-2W indicates that there are no significant differences in
<br />water quality data collected before and after suspected failure of this well, which is •
<br />though to have occurred in late December, 1981. Consequently, all water chemistry data
<br />collected at CW-52W-2W are included in the analyses below.
<br />As can be seen in Table 7-16, mean aquifer millieq uivalent values for the Wadge Coal
<br />indicate that it has a mixed ion water type. Individual wells, however, have water
<br />chemistries that are predominantly bicarbonate or sulfate waters, with the exception of
<br />CW-52W-15W which has mixed anions. Most wells have mixed cations, but the water chemistry
<br />at GW-52W-1SW and -17W is strongly sodi c.
<br />With an average field pM of 7.40 (range: 6.80 to 10.69), Wadge Coal waters are slightly
<br />alkaline (Table 7-17). TDS values for the Wadge Coal aquifer range from 341 to 6,376
<br />mg/l, with a mean of 884 mg/1. With an average hardness of 478.60 mg/1, the Wadge Coal
<br />contains water that is classified as very hard. Detectable concentrations of the
<br />following trace elements have been measured: A1, As, Ba, B, Cd, Cr, Cu, F, Fe, Pb, Mn,
<br />Mg, Mo, Ni, Se, and Zn. With the exception of F, Fe, and 2n, all trace element
<br />concentrations are less than 1.0 mgll.
<br />•
<br />The Wadge Coal aquifer shows little evidence of long term changes in water chemistry.
<br />4B
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