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non -corrected conductivity data may be found in the 1990 through 1992 <br />AHRs. <br />In 1995, Peabody instituted a new monitoring site numbering system for <br />its new ParadoxTM water quality database. This revised system is <br />detailed in Table A. For convenience sake, this table has been placed at <br />the end of the Table of Contents. In addition, Table 3, Summary of <br />Ground Water Monitoring Wells; Table 8, Summary of Surface Water <br />Monitoring Sites; and the Table of Contents of Appendices B through D <br />have all been revised to correlate the old site (and map) name to the <br />new (Paradox) computer name. The revised computer name will be used <br />throughout the following text. <br />On September 12, 2012, the CDPHE issued a Notice of Violation #I0- <br />120912-1 to the PSCM for the selenium exceedances that occurred in 2011 <br />and 2012. The PSCM is working with the CDPHE to resolve this issue. <br />Possible remedies to the situation include (but are not limited to); <br />identifying and isolating the source(s) of selenium, using downstream <br />wetlands as a treatment method, utilizing other treatment methods, <br />and/or developing a site-specific selenium standard for the respective <br />receiving streams. <br />In the 2013 water year, PSCM completed an extensive, enhanced monitoring <br />effort to determine the sources of selenium in mine discharges, as well <br />as within the region generally. Monitoring consisted of sampling at the <br />outfalls, at stream monitoring locations, spoil springs, spoil wells and <br />natural springs. In addition, biological monitoring at multiple sites <br />was initiated in the spring of 2012 and continued into the fall of 2012. <br />Further, seasonal biological surveys were completed during 2013. These <br />surveys included sampling of fish and invertebrate populations, habitat <br />quality, and tissue sampling for selenium. PSCM collected additional <br />data from 2014 through 2018. This AHR will only discuss data from those <br />sites that are required in the CDRMS permit. <br />The monitoring data collected are currently being assessed to better <br />understand the source and fate of selenium to evaluate potential <br />2 <br />