Laserfiche WebLink
suspected that the high fluoride values are related to this type of <br />water chemistry (Hem, 1989, pg. 121). Several wells at SCC's Seneca II <br />Mine with high fluoride values also exhibit this type water. <br />Elevated levels of iron may be attributed to natural (i.e., not mining <br />related) conditions, since elevated levels for this parameter are not <br />found in the adjacent Seneca II spoil wells. The high levels of iron <br />displayed in the one alluvial well (YGAL15) may be the result of organic <br />matter and plant debris present in the alluvium (Hem, 1989, pg. 77), <br />This well displayed high levels of iron prior to mining. <br />High manganese values may, in part, be due to recharge from the spoil <br />aquifer, although high values are often common, especially in alluvial <br />material (Hem, 1989, pgs. 86-89). The wells displaying high manganese <br />values this year also did so prior to mining. It should be noted that, <br />while the CDOx uses a standard of 0.2 mg/1, the EPA states that this <br />standard is used to protect crops grown in soils with a pH value lower <br />than 6.0. The CDOH has recently revised their surface water agricultural <br />standard to reflect this pH qualifier. In soils with a higher pH (as are <br />found in the Yoast region), a more appropriate standard would be 10 mg/1 <br />(EPA, 1976). This year, no well displayed a value higher than 1.12 mg/1. <br />Well YSAL1 experienced a high selenium value, 24.8 ug/1, in May 2006, <br />This may be an anomaly or lab error. Previous selenium values at this <br />well were normally below the detection limit, but never greater than 6 <br />ug/1, The November 2006 value was back down to 2 ug/1. <br />Ground Water Summary <br />TDS trends are decreasing at one well, stable at four wells, and <br />increasing at twelve wells. CDOH agricultural ground water standards for <br />fluoride, iron and manganese were exceeded at certain monitoring wells. <br /> In the area surrounding Yoast, ground water is not being pumped for <br /> irrigation or livestock watering purposes, nor has the CDOH classified <br />• any aquifer in this region for any use. The above discussion is provided <br /> only to serve as a comparative basis to judge ground water quality. <br />7 <br />