Laserfiche WebLink
A total of two samples from two sites had cadmium values that were less <br />than an elevated detection limit (30 ug /l vs. a normal detection limit <br />of 3 ug /1) , which was higher than the CDPHE standard of 10 ug /1. <br />Likewise, the same samples had lead values that were less than an <br />elevated detection limit (200 ug /l vs. a normal detection limit of 20 <br />ug /1), which was higher than the CDPHE standard of 100 ug /1. The cause <br />of these elevated detection limits was a decision by the laboratory to <br />dilute the samples prior to analyses in order to reduce the effects of <br />interferences (primarily, high salinity). <br />Elevated levels of iron (i.e., greater than 5 mg /1) may be attributed to <br />natural (i.e., not mining related) conditions, since the highest level <br />of iron found in spoil springs at this mine this year was 3.71 mg /l. The <br />one bedrock well (WW14) that often exhibit high levels may have higher <br />than usual concentrations of iron pyrite in the rock. The high levels of <br />iron displayed in the alluvial well this year may be the result of <br />organic matter and plant debris present in the alluvium (Hem, 1989, pg. <br />77) . <br />High manganese values may, in part, be due to recharge from the spoil <br />aquifer, although high values are often common due to naturally <br />occurring geochemical conditions, especially in alluvial material (Hem, <br />1989, pgs. 86 -89). This standard is used to protect crops grown in soils <br />with a pH value lower than 6.0. In January 2008, CDPHE revised their <br />ground water agricultural standard to reflect this pH qualifier. In <br />soils with a higher pH (as are found in the Seneca II -W region), a more <br />appropriate standard would be 10 mg /l (EPA, 1976). This year, none of <br />the Seneca II -W wells displayed a value higher than 1.73 mg /1. <br />At the Seneca II -W shop well, Well 201TC, CDPHE drinking water standards <br />were used to determine its suitability. No human health standards were <br />exceeded. The secondary standard for iron (0.3 mg /1) was exceeded with a <br />value of 5.69 mg /1. The secondary standard for manganese (0.05 mg /1) was <br />exceeded with a value of 0.076 mg /1. However, bottled water is consumed <br />at Seneca II -W. Also, since the aquifer for the shop well (Trout Creek <br />Sandstone) starts at 280 feet below the Wadge Coal and is separated by <br />7 <br />