Monitoring of Tunnel Water Quality Sample Clauses

Monitoring of Tunnel Water Quality. Tunnel dewatering operations began in November 2006. At the present time only water infiltrating into the tunnels is pumped into the water treatment system. Table 4.7 summarizes the concentrations of select water quality parameters for MP1, untreated tunnel water, and MP4, treated discharge from the DEVCO settling pond to Schooner Pond Cove during this period. It indicates that the maximum concentrations for each of the parameters, except cadmium, were less than the CCME Freshwater Aquatic Life (“FWAL”) Guidelines prior to being discharged to Schooner Pond Cove. Graphs depicting the incidence of pH, iron, zinc and TSS over the monitoring period indicate the effectiveness of the water treatment system as the water travelled from sampling point MP1 through the system to MP4 (see Appendix F). Water Quality Parameter Statistical Parameter MP1 (ug/L) MP4 (ug/L) CCME Freshwater Aquatic Life1 FWAL MAL pH Max 8.2 8.0 Min 7.3 7.1 Average 7.9 7.6 6.5-9.0 7.9-8.7 Total Suspended Solids (“TSS”) Max 320 45 - Min 2 <2 Average 40 4.5 Arsenic Max 10 1.8 Min 0.3 0.3 Average 2.4 0.9 5 ug/L 12.5 ug/L Cadmium Max 0.76 0.085 Min 0.0085 0.0085 Average 0.19 0.02 0.017 ug/L 0.12 ug/L Copper Max 10 4.8 Min 1 1 Average 3.9 1.4 2-4 ug/L - Iron Max 9700 550 Min 220 50 Average 3165 237 300 ug/L - Lead Max 5.4 0.5 Min 0.5 0.25 Average 1.9 0.5 1-7 ug/L - Nickel Max 15 1.5 Min 1.5 1 Average 4.6 1.5 25-150 ug/L - Zinc Max 690 93 Min 45 1 Average 232 12 30 ug/L - 1 Marine Aquatic Life The data for the ongoing monitoring shows the same drop in metal concentrations through the flow path as the baseline samples, from the inlet to the serpentine pond to the discharge from the DEVCO settling pond. The ongoing monitoring program has shown that the existing wastewater treatment system is very effective in treating the tunnel water and protecting the surrounding water environment. This monitoring program will be kept in place throughout the execution of the Project. There have been a number of peaks in the MP1 iron concentrations through the monitoring period. These spikes, samples with iron concentration greater than 6,000 µg/L, correspond to operational events within the tunnels, primarily during cleaning activities to remove sediment buildup on the bottom of the tunnels to make a safer environment for the underground miners. The data indicates that the wastewater treatment system was very effective in reducing the iron concentrations following these events.