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<br /> compound concentrations from the solid-phase analysis conducted at part of the Golder program are detailed in '
<br /> Table 12. Additionally, samples of the CKD materials were analyzed for total metals once in 1991 and then
<br /> quarterly beginning in the first quarter of 1993 through the first quarter of 2002, with the exception of 1994.
<br /> Summary statistics of these results are provided in Table 13. Schoeller diagrams are provided in Figure 7 and '
<br /> Figure 8.
<br /> Concentrations reported for the CKD testing conducted by Golder and the quarterly testing by Holcim are within
<br /> the same range of values. The CKD material has elemental compounds that are higher than the native materials, ,
<br /> including: boron, calcium, lead, potassium, selenium, thallium, and zinc. The lead, selenium, and thallium
<br /> concentrations are elevated by at least a full order of magnitude. The CKD materials exhibited concentrations of '
<br /> arsenic, barium, chromium, and manganese that were similar to or less than the native materials. The
<br /> concentrations of arsenic, barium, copper, manganese, thallium, uranium and zinc are greater in the CKD and
<br /> native materials than in published concentrations for carbonates and sandstones (Price 1997).
<br /> 5.2 Synthetic Precipitation Leaching Procedure
<br /> The SPLP is a test where material such as soil or rock is saturated with a solution designed to mimic meteoric '
<br /> water or natural weathering solutions. The materials undergo grain size reduction such that all components pass a
<br /> 0.375" sieve. The solution to rock ratio is 20 to 1, and the test concludes after 18 hours, at which point the
<br /> leachate is collected. The chemical composition of the leachate is analyzed for the constituents of interest. Metals '
<br /> are generally analyzed by US EPA Methods 200.7 or 200.8 by ICP or ICP-MS, respectively. The leachate solution
<br /> has a weakly acidic pH of 5.0 to approximate rainfall (extraction fluid #2 in US EPA Method 1312). The test is not
<br /> designed to definitively predict long term water quality associated a material, as this is complicated by a number '
<br /> of variables such as surface area exposure, weathering rates, flow rates, and actual water to rock ratios.
<br /> SPLP testing was performed as part of the Golder and Secor programs. The SPLP testing conducted under the '
<br /> Golder program was conducted on four samples of CKD, one sample of silt, four samples of limestone and two
<br /> samples of sandstone. The analytical results for the SPLP leachate analysis are tabulated in Table 14. Schoeller
<br /> diagrams are provided in Figure 9 through Figure 10. '
<br /> The SPLP leachate pH values are greater than 12 for the CKD material and between 7 and 10 for the native
<br /> materials. Groundwater pH values in Site wells are between 7 and 9. These values are similar to values observed
<br /> in the wells prior to CKD placement in area A2, and do not show an increase over time that would be expected if '
<br /> the waters were being influenced by CKD. In addition, the SPLP leachate concentrations were at least an order of
<br /> magnitude higher for the CKD material than for the native materials for: arsenic, barium, chromium, lead, lithium,
<br /> selenium, and thallium, and the majority of major ions. Upward trending concentrations would be expected if CKD '
<br /> was influencing groundwater concentrations in the Site wells. For example, potassium concentrations measured
<br /> in the CKD leachate of approximately 500 mg/L are two orders of magnitude greater than that of the native '
<br /> materials. In contract, concentrations of potassium in groundwater from all wells are typically less than 20 mg/L,
<br /> and show no consistent increasing trends in concentrations.
<br /> 5.3 Sequential Batch Testing '
<br /> Secor performed sequential batch testing on the leachates produced by the SPLP tests as part of their 1998
<br /> hydrogeologic and geochemical assessment. The analytical methodology and results for the sequential batch '
<br /> testing are detailed in Secor(1998). The purpose of the sequential batch testing was to evaluate the attenuation
<br /> capacity of the bedrock materials. The assessment looked at the behavior of arsenic, barium, chromium, lead,
<br /> selenium and thallium. Secor reported that barium, lead and thallium from CKD leachate would sorb to the native '
<br /> 4 GOLDER 8 ,
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