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3.3.10 Surface Water Unionized Ammonia <br />Chart 15 shows unionized ammonia concentrations for monitoring sites TR-A, TR-B, TR-C and <br />TR-D for the period of record. Unionized ammonia concentrations have been consistently below <br />detection limits. The unionized ammonia concentration appeared to drop for the 1997 through <br />1999 monitoring periods due to the laboratory lowering the detection limit from 0.05 ppm to 0.01 <br />ppm. In 2000, the laboratory raised the detection limit for unionized ammonia back to 0.05 ppm, <br />then lowered the detection back to 0.01 ppm in 2001. The 2009 sampling period shows <br />detections in April at monitoring sites TR-B, TR-C and TR-D. The high was recorded at <br />monitoring site TR-C in April with a value of 0.06 mg/L. Unionized ammonia concentrations <br />were below the detection limit of <0.02 mg/L at all sites for the August 2009 sampling date. <br />3.3.11 Surface Water Nitrite <br />Chart 16 shows nitrite concentrations for monitoring sites TR-A, TR-B, TR-C and TR-D for the <br />' period of record. Nitrite concentrations have been consistently below detection limits with few <br />exceptions. Nitrite was elevated at site TR-D with a value 0.32 mg/L in April 1999. This value <br />is not consistent with historical data or the other monitoring sites during the April 1999 <br />' monitoring event. The April 1999 TR-D value is considered to be a sampling/laboratory error. <br />The nitrite concentration upstream of the mine at TR-A was 0.06 ppm in the July 2001 sample. <br />The concentration decreased as it passed by the mine site as a result of dilution. Samples <br />collected in May and October 2001 show nitrite levels at TR-A below the detection limit. The <br />2009 sampling period shows consistent sampling results compared to all previous events. Nitrite <br />concentrations were below the detection limit of <0.01 mg/L at all sites for all sampling dates of <br />2009. <br />3.3.12 Surface Water Orthophosphate <br />¦ Chart 17 shows orthophosphate concentrations for monitoring sites TR-A, TR-B, TR-C and TR- <br />D for the period of record. Values obtained for orthophosphate have been low with most being <br />below detection limits throughout the duration of monitoring. Orthophosphate showed some <br />perturbation during the 2001 sampling period at TR-B. However, concentrations downstream of <br />TR-B are consistent with previous sampling results. Therefore, either sample contamination or <br />' laboratory error is suspected. The 2009 sampling period shows slightly elevated sampling results <br />compared to the period of record. The lowest orthophosphate concentration in 2009 was the <br />lower detection limit of <0.01 mg/L recorded at all sites in April and the high was recorded at all <br />' monitoring site TR-C in August with a value of 0.04 mg/L. <br />' 3.3.13 Surface Water Chloride, Potassium and Iron <br />' Charts 18, 19 and 20 show chloride, potassium and iron concentrations for monitoring sites TR- <br />'161-1-wWCHNG ....NG Page 9