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8 <br />3.13 Groundwater Samples <br />Groundwater Wells. Both total and WAD ryanide concentrations were below detection (at <br />20 µg/1) in all groundwater samples. Well M-13, located downgradient from the tailings <br />pond, had a measured total cyanide concentration of 30 µg/1 for the November third-party <br />sampling. Both total and WAD cyanide concentrations in both M-13 samples (duplicates <br />were collected and analyzed) were below detection for this sampling. Total ryanide, WAD <br />cyanide and nitrate+nitrite values for all groundwater locations are from unfiltered samples, <br />while all metals values are from filtered samples (Table 3). Becau$e all cyanide <br />concentrations were below detection, only nitrate+nitrite and metals results ~+iill be discussed <br />below. <br />Ml9. M-9 had the lowest nitrate+nitrite and the highest calcium and sodium concentrations <br />of the three groundwater samples. Copper, iron and zinc concentrations, which were from <br />5ltered samples, were all below detection. Nitrate+nitrite and sodium concentrations were <br />nearly identical for this and the November sampling. Calcium conce~Ytrations were <br />somewhat lower in April than they were in November. <br />M-12. Nitrate+nitrite, calcium and sodium concentrations were very similar for both the <br />November and April thud-party monitoring samples. Dissolved copper, ,iron and zinc <br />concentrations were all below detection for the April sampling, as they were for the other <br />two groundwater wells. <br />M-l3. Duplicate samples were taken at well M-13. Total cyanide, WAD ryanide, copper, <br />iron and zinc concentrations in duplicate samples were all below detection. According to <br />TR-006, duplicate samples must agree within ± the detection limit if the analyzed value is <br />c 5 times the method detection limit and within 5 20% RPD if the analyzed value is > 5 <br />times the method detection limit Nitrate+nitrite, calcium and sodium values were all within <br />20% RPD. The largest RPD for duplicate analyses was for calcium, which had duplicate <br />results of ±11% RPD. <br />3.1.4 Quality Coptrol Samples <br />Field and Rinse Blank. The 5eld blank and rinse blank again used second-stage DI water <br />from the BMRI laboratory. Total ryanide, WAD cyanide, nitrate+nitrite, calcium and <br />copper concentrations were all below detection in the 5eld blank, and the zinc concentration <br />was at the detection limit Iron and sodium concentrations were somewhat elevated, <br />especially the uon concentration (280µg/1), which was higher than the rinse blank and higher <br />than the iron concentration in 5eld and rinse blanks from the earlier thud-party monitoring <br />trips. The sodium concentration in the rinse blank was somewhat elevated, but was lower <br />than that in the 5eld blank. <br />RCG/Hagler, liailty, lae <br />