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irrigation dissolved manganese standard of 0.2 mg/l. This standard applies to crops grown • <br />in soils with pH values lower than 6.0. In soils with a higher pH (as is found in <br />agricultural soils surrounding the Seneca II area), a more realistic standard would be 10 <br />mg/l (EPA, 1976). <br />The irrigation dissolved iron standard of 5.0 mg/l was exceeded at alluvial Wells 32-A <br />and 33-A. Water with this iron concentration will precipitate iron oxides on the leaves <br />when the crop is spray-irrigated, but should not be a problem for flood irrigation (EPA, <br />1976). <br />Wedge Underburden Wells 8P1-U and 11-U and Wedge Coal Welt 19-W exceeded the irrigation <br />fluoride standard of 2.0 mg/l. Those same three wells also exceeded the irrigation pH <br />standard of 6.5 to 8.5. <br />Well 17-W exceeded the zinc standard of 2.0 mg/l with a value of 2.89 mg/l on November 12, <br />1991. At this time, this well was bailed while a metal monitoring pump was stuck at the <br />bottom of the well (the pump was removed the following day). The historic range of zinc <br />values prior to this sample (and also subsequent samples taken in Nay end November, 1992) • <br />was <0.01 to 0.03 mg/l. <br />Finally, water quality analyses performed on samples obtained at the Seneca II production <br />well (GW-SS-TC) during 1992 were compared against both primary and secondary drinking <br />water standards developed for ground water by the CDOH (CDOH, 1986). Sulfates (secondary <br />standard, 250 mg/l) were higher than the CDOH standard: 410 mg/l, November 20, 1991; and <br />360 mg/l, November 24, 1992 Csee Appendix D). Nell GY-SS-TC has historically exh(bi tad <br />higher sulfate concentrations then the secondary drinking water standard for this <br />parameter. Also, the November 24, 1992 sample exceeded the secondary standard for iron <br />(0.3 mg/l) with a value of 0.41 mg/l. <br />Ground Water ouality Summary. TDS values et Wells 69-A, 19-W, 8-U, 11-U, 5-TC and 27-5 <br />have increased the past year. These increases may be the result of the effects of six <br />years of below normal snowmelt runoff and/or increased TDS concentrations in the spoils <br />aquifers. CDOH agricultural ground water standards for manganese, iron, fluoride, zinc <br />and pH were exceeded at certain monitoring wells. <br />In the area surrounding Seneca I1, ground water is not being pumped for irrigation or • <br />10 <br />