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As one would expect the total recoverable method to result in the same, <br />or higher, value than the potentially dissolved method (the former <br />involves a hot acid digestion, while the later involves a cold acid <br />digestion), we suspect that three of the four selenium excursions noted <br />above at NPDES sites to be in error. This may be due to matrix <br />interference in the sample that displays itself in the potentially <br />dissolved ICP -MS method, but not with the total recoverable and AA- <br />Hydride methods. <br />Selenium excursions recently began occurring at these two outfalls in <br />2011. In the previous three years (2008 - 2010), Outfall 004 never <br />exceeded the 4.6 ug /1 selenium standard. Outfall 002 last exceeded the <br />selenium standard in 1998. However, there was no selenium limit in the <br />NPDES permit until May 2010. It is unknown as to why these recent <br />exceedances occurred, although we suspect it may be due to the record <br />snowfall and rainfall, and near - record snowmelt runoff that occurred in <br />Routt County in 2011. Perhaps that unusually high runoff somehow <br />mobilized the selenium, and the excursions noted in 2012 were on the <br />tail end of that event. No excursions of selenium have occurred at these <br />two outfalls from July 2012 to January 2013. <br />On September 12, 2012, the CDPHE issued Notice of Violation #I0- 120912 -1 <br />to the PSCM for the selenium exceedances that occurred in 2011 and 2012. <br />The PSCM is working with the CDPHE to resolve this issue. Possible <br />remedies to the situation include (but are not limited to); indentifying <br />and isolating the source(s) of selenium, using downstream wetlands as a <br />treatment method, utilizing other treatment methods, and /or developing a <br />site- specific selenium standard. The PSCM is going to be performing an <br />extensive monitoring program in 2013 to help identify the sources of <br />selenium. <br />Surface Water Summary. Water discharged from the PSCM is not used <br />directly for irrigation. No irrigation exists on Grassy Creek or Cow <br />Camp Creek below the PSCM. Indirectly, although, water discharged from <br />the mine is significantly diluted by water from either Fish Creek or the <br />Yampa River before it is diverted and used for irrigation. Due to the <br />20 <br />