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• end sodium adsorption ratio (SAR) for each geologic unit. The Lennox overburden has a very high salinity ha:erd, while ell other units have a high salinity hazard. All units, based on mean sAR values, have low sodium haxerds. Excepting the Lennox overburden, ground water from ell other geologic units et the Yoast mining area would generally have adverse effects on many crops and would require careful irrigation practices on tolerant species if applied. use of Lennox overburden ground water would be unsuitable for most irrigation uses. Livestock Veter Suitability. Table 7-23 presents a compilation of livestock drinking water standards developed by several agencies including the CDOH (1994). The livestock standards were compared against sample constituent concentrations measured in each Yoest monitoring well. Table 7-24 presents the results of the comparisons in an identical format to Table 7-20. Table 7-24 shows chat several monitoring wells exhibited exceedentes of the livestock standard for aluminum (5 mg/l). Xowever, in all cases, the ezeeedences of Al were measured by the USGS prior to 7982, end review of subsequent analyses for aluminum in ell Yoast wells collected from 1991 through 1993 show that aluminum measurements have been well below 5 mg/l (see Appendix 7-4). PWCC believes early (1980 to 1983) analyses for aluminum in Yoast monitoring wells ere suspect end not representative. The one analysis for arsenic that exeeeded the livestock standard (250 ug/l - Yw2) is considered suspect, as subsequent As values measured et this well have been undecteble. The one lead exceedence noted for Yell YLOV3 is also considered suspect, es five subsequent samples collected et this well were below 20 ug/l for dissolved lead. Measurements of pH (at 25°C) in several Yoas[ monitoring wells have occasionally been in excess of the alkaline end of the pH standard range (B.5 S.U.). The high pH value range listed for Wedge coal Well YW7 (see Appendix 7-4) ere not representative of the wedge coal seem due to monitoring well construction problems. Excepting Yell TW7, pH measurements in the alluvium in all three drainages, Wedge coal end overburden units, end Yadge underburden have not exceeded 8.7 S.U., end not more then 28 percent of all pH values collected at each well (see Appendix 7-4) have exceeded the livestock pN stenderd range. The Lennox overburden Vell YLOV3 has shown more than one exceedence of both the sulfate • end TDS livestock stenderd, end at least one exceedence of the lead stenderd. Excepting the early aluminum values, only the Lennox coal seem showed no exceedences of any other livestock standard. 69