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y 4 2 3 5 Monitoring Program 4 2 3 5 1 Sampling Method Currently over 40 wells are being sampled every 6 months Sampling requires about 3-4 weeks to complete Because of the distance to the water table, and purging requirements, it usually takes about a half a day to sample one well Use of diffusion groundwater sampling devices would eliminate the need to purge wells during sampling, and should be considered Diffusion samplers are generally polyethylene bags filled with de-ionized water and lowered into the screened interval by inert rope or wire Contaminants diffuse through the polyethylene into the bags and over time concentrations inside and outside of the bag equilibrate After some period of time the bags are retrieved, water is decanted into vials, packaged for shipment, and sent for standard chemical analysis Studies by Vroblesky and Hyde ("Diffusion Samplers as an Inexpensive Approach to Monitoring VOCs in Ground Water," Ground Water Monitoring and Remediation, Summer 1997, p 177-184) have indicated that the recoveries of typical VOCs, including TCE, are very good and compare to the best of the traditional sampling methods Assuming a reduction of three hours in sampling time per well, a two-person crew, and semiannual sampling of 45 wells, this would translate into a potential saving of 540 person-hours per year Initially, however, a couple of studies may be required, including a study to determine the length of time needed to reach equilibrium (2-4 weeks) and a comparability study that would allow the determination of the changes in concentration due to the change in sampling method Possibly, a study to determine precision using this sampling method should also be undertaken The use of diffusion samplers will undoubtedly require regulatory approval 4 2 3 5 2 Analytical Suite Currently, the ground water and influent/effluent samples are being analyzed for the full analyte list by USEPA methods 8010 and 8020 A reduction in the suite of parameters being tested in groundwater samples should reduce analytical costs, and is strongly encouraged Given the five years worth of sampling results now available, the site contaminants are well characterized and consist of only five parameters of interest, TCE, carbon tetrachloride, 1,1, DCA, and some detections of 1,2 DCE and chloroform Some savings in costs (perhaps as much as 15-20%) particularly for validating the analytical results and for managing the data could be achieved if only these parameters were quantified Methods 8010 and 8020 are now outdated The use of method 8021 or 8260 should be considered Replacing the 8010/8020 combination with a single method such as 8021 would cut costs by 15% These would translate into total potential analytical savings of approximately $4,500 per year or more Note that certain wells can be analyzed for the full list of VOCs at some interval 4 2 3 5 3 Electronic Data Transfer for Analytical Data Currently laboratory data must be manually entered into a database by the Operations staff Since there are a considerable number of monitoring wells, it would save time if the contract included a requirement for the laboratory to provide the analytical data in a format compatible with that used by the Operations staff This would result in a Y reauction in labor costs 4 2 3 5 4 Regulatory Acceptance The RSE team recognizes the difficulties in implementing changes to the permit under which the system operates and the costs for obtaining regulatory acceptance If the changes to the monitoring program could be proposed as a package to the State of Utah, then some cost efficiency could be achieved • 06/07/99 Page 12 of 14