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510 /L. The dissolved-metals concentrations measured at the adit mouth exceeded <br /> the table-value standards for the reach of the Swan River adjacent to the site. <br /> 7.3 Surface Water and Sediments <br /> i <br /> CDPHE collected a total of 7 surface-water and 8 sediment samples during the 2000 <br /> investigation. Locations of the samples are shown on Figure 2. ABC collected surface- <br /> water samples upstream and downstream of the IXURoyal Tiger in 1998, 1999, and <br /> 2000. Aqueous samples collected by CDPHE and ABC were analyzed for dissolved <br /> metals. CDPHE also had aqueous samples analyzed for total metals. Sediment <br /> samples collected by CDPHE were analyzed for metals. Analytical results are presented <br /> in Table 8 to Table 10. <br /> 7.3.1 Surface Water <br /> CDPHE Investigation { <br /> Samples collected by CDPHE from a ditch along the south side of the Swan River valley <br /> downgradient from the IXURoyal Tiger site indicated an increase in some dissolved <br /> metals compared to samples collected from the ditch upgradient of the site. Dissolved <br /> cadmium was measured at a concentration of 21 ug/L in a sample (RT-SW-04)collected <br /> from the point of entry of the adit flow into the ditch;dissolved manganese at a i <br /> concentration of 630 ug1L;and dissolved zinc at a concentration of 3,700 ug/L(CDPHE, <br /> 2002). At a point 420 feet downgradient of the point of entry into the ditch(RT-SW-05), <br /> dissolved cadmium had dropped to 10 ug/L;dissolved manganese had dropped to 80 <br /> ug/L; and dissolved zinc had dropped to 1,900 ug/L. <br /> Dissolved cadmium,magnesium, and zinc were not detected in a water sample(RT-SW- <br /> 02) collected by CDPHE in the main channel of the Swan River along the north side of <br /> the valley adjacent to the IXURoyal Tiger site. Analytical results from a sample collected <br /> approximately%2 mile downstream of the site in the main channel of the Swan River(RT- <br /> SW-03)indicated no detectable dissolved cadmium or manganese, and dissolved zinc at <br /> a concentration of 9 ug/L. These values are within the table-value standards for the <br /> reach of the Swan River adjacent to and downstream of the IXURoyal Tiger site,which <br /> are expressed in terms of dissolved concentrations. <br /> CDPHE (2002)indicates that total manganese and total zinc were measured at <br /> concentrations significantly above background levels in samples RT-SW-02 and RT-SW- <br /> 03. Total manganese was measured in sample RT-SW-02 at a concentration of 8 ug/L, y <br /> and in sample RT-SW-03 at a concentration of 18 ug/L. These values can be compared <br /> to non-detectable total manganese at a quantification limit of 5 ug/L in sample RT-SW- <br /> 01. Total zinc was measured in sample RT-SW-02 at a concentration of 7.0 ug/L and in <br /> sample RT-SW-03 at a concentration of 15 ug/L_ These values can be compared to <br /> non-detectable zinc at a quantification limit of 5 ug/L in sample RT-SW-01. Although the <br /> total concentrations of these two metals can be considered above background levels, <br /> the values remain below the applicable dissolved concentration limits for the Swan River <br /> adjacent to and downstream of the IXURoyal Tiger site. <br /> ABC Investigation <br /> Dissolved cadmium measured in samples collected by ABC in 1998, 1999. and 2000 at <br /> a point in the ditch along the south side of the Swan River valley downgradient of the <br /> IXURoyal Tiger site(Tiger-4)ranged from non-detectable to 1.2 ug/L. Dissolved <br /> manganese concentrations in samples from this point ranged from 47 ug/L to 447 ug/L. <br /> t XVRoyai Tiger VCUP Apptication­ Page 18 of 33 I <br /> I <br />