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dilute the samples prior to analyses in order to reduce the effects of • <br />interferences (primarily, high salinity). <br />Ammonia values require extra calculations to determine exceedences. The <br />standard is 0.02 mg/1 un-ionized NH3, while the method detects both un- <br />ionized NH3 and ionized NH4. The following table calculates the actual <br />un-ionized NH3 concentration of the exceedences reported on Table 12. <br />Ammonia values were calculated from the Internet site <br />http://aquanic.org/images/tools/ammonia.htm. <br />Site Date NH3+NH4,mg/1 ~ Temp,C $NH3 NH3 conc., mg/1 <br />No samples exceeded the ammonia standard this year. <br />Sulfide values also require extra calculations. The standard is 0.002 <br />mg/1 un-ionized H2S, while the method detects for un-ionized H2S and <br />ionized HS. The following table calculates the actual un-ionized H2S <br />concentration of the exceedences reported on Table 12. Sulfide values <br />were calculated from a table found on page 5 of the Internet site <br />http://www:cpda.co.uk/techn/clay/w2253,pdf. <br />Site Date H2S+H5,mg/1 pH $H2S H2S concentration, mg/1 <br />No samples experienced exceedences of the sulfide standard this year. <br />Two samples (from SSF11 and 13) had values that were less than elevated <br />detection limits. Any sulfides present in surface water should <br />eventually oxidize to sulfates. <br />Finally, all mercury values reported were less than the most sensitive <br />available detection limit, 0.2 ug/1. The standard for mercury is 0.01 <br />ug/1. <br />In September 2003 (effective January 2004), the CDOH resegmented Grassy <br />Creek from Yampa Segment 12 to Segment 13e. Table 13 shows the new CDOH <br />receiving stream standards for Grassy Creek. Table 14 provides a <br />comparison of those standards to water quality data collected this year <br />22 <br />