Laserfiche WebLink
Mx. Thomas Schreitler <br />Aivision of Reclamation, Mining and Safety <br />Adequacy Review Comments TR-OS <br />4/10/2007 <br />Page 2 of S <br />Pursuant to Colorado Water Quality Contml Commission (CWQCC) regulations', the <br />baselixle water quality standards shall be the greater ot~; <br />1. Background concentration computed fot each species, determined as the 99% <br />upper confidence liluit from the first flue quarterly readings taken frum the <br />monitoring well prior to start of MRV production mining operations at the site. <br />2. Agticulttutal groundwater quality litnilts, based on the most likely use of <br />groundwater in the area (as the natural TDS and sulfate concentrations exceed <br />drinkiog water standards). The Agricultural limits are presented in Table 1. <br />Table 1-Colorado Agricultural Groundwater Standards <br />Parameter Standard <br />Aluminum (AI) 5 Mg/L <br />Arsenic (As) 0.1 MgJL <br />Aeryllium (Ae} 0.1 MP~L <br />Boron (B) 0.75 Mg/L <br />Cadmium {Cd) 0.01 MP/I, <br />Chromium (Cr) o.l M L <br />Cobalt {Co 0.45 Mg/L <br />Copper {Cu 0.2 Mg/L <br />Fluoride (F) 2 MdlL <br />Iron (Fe) 5 Mg/L <br />Lead (Pb) 0.1 Mg1L <br />Lithltmt (Li) 2,5 Mg/L <br />Manganese (Mn) 0.2 M <br />Mercury (11) 0.01 M <br />Nickel t1Vi}, 0,2 M L <br />Nitrite (N02-H) 10 Mg/L <br />Nitrlte&Nitrate (N02+NQ3-N) 100 M <br />Selenium (Se) 0.42 Mg/L <br />Vanadium 0.1 Mg/L <br />Zinc (Zn) 2 Mg1L <br />H 6.5-ti.5 <br />Swxce: CWQCC, 2005. Rcguluioe. No. at, Table 3 <br />,Colorado Water l]uality Control Commission, 5 CCR 1002-41: Regulation No. 41-The Basic <br />Standards for Ground Water, March 22, 2005. <br />' CWdCC provide guidance for selection of a groundwater standard as follows: 'For ground water <br />classified "Domestic Use -Quality" or "Agricultural Use - Lluaiity,' where a table value is <br />exceeded by the background level, the applicable standard for that parameter shall be either 1) <br />the table value or 2) the background Ievei for that parameter. This determination shall be made <br />considering the increased risk to public health, crops, or livestock associated with the background <br />levels, the extent of the exceedance above the table value, the degree to which the pollution is <br />deemed correctable and subject to treatment; and the economic reasonableness of such <br />treatment requirements.' [CWQCC, 2006, 41.5(6)(5)] <br />