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8 <br />3.13 Groundwater Samples <br />C.roundwate~r Wells. Both total and WAD cyanide cona:ntrations 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 collecl.ed and analyzed) were below ietection for this sampling. Total cyanide, WAD <br />cyanide and nitrate+nitrite values for all groundwater locations are from unfiltered samples, <br />while all metals value;s are from filtered samples (Table 3). Because all cyanide <br />concentrations were below detection, only nitrate+t»trite: and metals results will bc: discussed <br />below. <br />M_9. M-9 had the lowest nitrate+nitrate and the highest calcium and sodium concentrations <br />of the three groundwater samples. Coppc;r, iron and zinc concentrations, which were from <br />filtered samples, were all below detection. Nitrate+nitrite and sodium concentrations were <br />nearly identical for this and the November sampling. Calcium concentrations were <br />somewhat lower in April than they were :in November. <br />M_12• Nitrate+nitrite, calcium and sodircm concx:ntrations were very similar for both the <br />November and April third-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_13. Duplicate samples were taken at well M-13. Total cyanide, WAD cyanide, copper, <br />iron and zinc concentrations in duplicate samples were all below detection. According to <br />'[R-006, duplicate samples must agree within ± the detection limit if the analyzed value is <br />5 times the method detection limit and within :; 20°o RPD if the analyzed v;jlue is > 5 <br />times the method detection limit Nitrate-~rritrite, 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 duality Control Samples <br />Field and Rinse Blank. The 5eld blank and rinse blank again used second-stage D1 water <br />from the BMRI laboratory. Total cyarude, WA.D c}~anide, 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 iron concentration (280µg/1), which was higher than the rinse blank: and higher <br />than the iron concentration in Seld and rinse blanks from the earlier third-parry monitoring <br />trips. The sodium concentration in the rinse blank was somewhat elevated, but was lower <br />than chat in the field blank. <br />RCGJHagler. Badly, Iac <br />