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July 19,2019 18107649 <br /> i <br /> A similar trend was observed in 1999 and 2000 samples for MW-4 following installation for constituents such as <br /> chloride and TDS. This stabilization process may indicate the initial influence of drilling water on water quality. <br /> 4.2 Comparison to Interim Narrative Standards <br /> A comparison of water quality results to the Regulation 41 Interim narrative standards is provided on Table 2 <br /> through Table 8. A visual comparison to the standards (broken out by group) is provided for most analytes on <br /> Figure 9 through Figure 11. Figure 9 though Figure 11 show the minimum, average, and maximum concentration <br /> for each well group for each consituent for three different time periods. Additionally the ratio of the Synthetic <br /> Precipitation Leaching Procedure(SPLP)test results for CKD materials to native material is shown on the <br /> ' figures. Each constituent has exceeded the interim narrative standard in at least one sample in downgradient <br /> (Group 2 or Group 3)wells as discussed below. <br /> Arsenic: When detected, arsenic concentrations are greater in the Group 3 versus Group 2 wells. <br /> Exceedances of the interim narrative standard occurred in 1999-2000 and 2010-2011. Between 2011 and <br /> 2010, concentrations where lower and there were only two exceedances of the interim narrative standards <br /> (both in well MW-7). Arsenic was not monitored from 2015-2017. Arsenic concentrations were below the <br /> interim narrative standard in 2018 sampling. Concentrations of arsenic in SPLP leachate are approximately <br /> two orders of magnitude greater for CKD samples than for samples of native materials. <br /> Boron: Boron concentrations are slightly greater in the Group 2 versus Group 3 wells. Exceedances of the <br /> interim narrative standard have inconsistently occurred in the Group 2 and Group 3 wells. Concentrations of <br /> boron in SPLP leachate are approximately one order of magnitude greater for CKD samples than samples of <br /> native materials. <br /> Barium: Barium concentrations are greater in the Group 3 versus Group 2 wells. Exceedances of the interim <br /> narrative standard have consistently occurred in the Group 2 and Group 3 wells(less in often in MW-2). In <br /> the Group 3 wells, barium concentrations generally showed increasing trends in the initial sampling events <br /> for each well. Concentrations of barium in SPLP leachate are less than one order of magnitude greater for <br /> CKD samples than for samples of native materials. <br /> 111 Lithium: There has been one detection of lithium above the interim narrative standard. The sample was <br /> collected in July from well MW-4. Concentrations of lithium in SPLP leachate are less than one order of <br /> magnitude greater for CKD samples than for samples of native materials. <br /> Iron: Iron concentrations are slightly greater in the Group 3 versus Group 2 wells. Exceedances of the interim <br /> narrative standard have consistently occurred in MW-5, the Group 2 wells, and occasionally in the Group 3 <br /> wells. Iron concentrations in site wells vary more between sampling events than other metals, but do not <br /> generally exhibit long term trends. Concentrations of iron in SPLP leachate are approximately equal in CKD <br /> and native material samples. <br /> 0 Manganese: Manganese concentrations are slightly greater in the Group 3 versus Group 2 wells. <br /> Exceedances of the interim narrative standard have consistently occurred in the Group 1, Group 2, and <br /> Group 3 wells. In the Group 2 and Group 3 wells manganese concentrations were generally higher in the <br /> earlier sampling for each well and decreased with time. Concentrations of manganese in SPLP leachate are <br /> approximately equal in CKD and native material samples. <br /> GOLDER 6 <br />