2010-07-30_HYDROLOGY - M1977526 (4)

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Sampling of the groundwater will be done quarterly for the first eight quarters and then be reduced to semi-annual. Semi-annual sampling for detection monitoring will be done throughout the operating life of the facility unless reduced with the approval from CDPHE and Adams County. Detection monitoring may likely be reduced to annual sampling in post-closure with prior approval of CDPHE. Low flow sampling of the wells may be utilized considering the depth to groundwater. Low flow sampling minimizes the volume of purge water, and takes less time for sample collection without compromising the sample, has the least tendency to stress the well during purging, minimizes turbidity, and provides a higher quality sample. The initial sampling at the site will likely be done using conventional bailing methods. Low flow sampling may be utilized in the future is deemed appropriate by the operator. Prior to sampling the depth to groundwater will be measured. Using conventional sampling, the samples will be taken from the wells after a minimum of three boring well volumes have been purged from the well. Periodic field analysis of pH, temperature, and specific conductance will be taken and recorded prior to collecting the sample. Purging will continue until these parameters have stabilized to within 0.2 pH units, 2 degrees C or F, and 10 percent of the specific conductance reading. Samples will then be collected as soon as possible after purging, but no longer than 24 hours after purging. Purge waters will be disposed of on the ground by the well from which the fluid was purged. If dedicated pumps or peristaltic pumps are used, the wells will be purged of three pump and tubing volumes at a flow rate of 100 milliliters per minute or less and sampled immediately after purging, the flow rate during sampling will also be 100 milliliters per minute or less. Samples will be transferred directly from the bailers or pump discharge tubing into sample bottles provided by the laboratory. Sample bottles and preservation will be as specified in the analytical methods employed, except that VOC samples will be chilled but otherwise unpreserved (consistent with CDPHE policy). Sample bottles will be placed in a cooler or other shipping container and chilled as soon as possible after collection. 6.2.1 Chain of Custody Chain-of-custody procedures will be used to track the sample from the time of collection until it, or its derived data, is used. A chain-of-custody form will be initiated at the time that the samples leave the site. Field personnel will complete all applicable sections of the form. The chain-of-custody forms will be protected from moisture by encasing them in plastic (e.g., Ziplock plastic bags) and placed inside the shipping containers. The chain-of-custody forms will accompany the containers during shipment to the laboratory. The shipping containers will be sealed with custody seals. • AFS Frei-Henderson Inert Fill Page 18 of 23 MOLEN & ASSOCIATES, LLC