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ATTACHMENT H:OPERATING DATA Nature of the Annular Fluid The annular fluid in the STIG-1 well is fresh water containing corrosion inhibitor and algaecide. Both the LEC-1 and LEC-2 will use the same annular fluid. Geochemical Evaluation of the Injection Fluid The source and analysis of the chemical,physical,radiological, and biological characteristics,including density and corrosiveness, of injection fluids for the STIG-1 and LEC-1 wells are presented in this section. The injection fluid of the LEC-2 well will be dependent upon which well is being substituted and so would be as either the STIG-1 or LEC-1 wells or an intermediate condition. Water quality of the injected water at STIG-1 has been monitored since test injection began in the 1990s. LEC-1 projected water quality has been modeled to estimate individual parameters when the wastewater is injected. Both waste streams have undergone geochemical evaluation to assess the potential for interaction with the native Domengine Formation water.Water quality of each of these waste streams is discussed in the following. The data presented herein assumes that each well is injecting fluids only from the plant it supports. If one well is injecting supplemental fluids from the other plant,the water quality of the injectate will be somewhere between the conditions of the two water quality endpoints,STIG-1 or LEC-1. The quantity of fluids transferred between injection wells will be monitored as part of the monitoring program presented in Attachment P. It will also be reported on the quarterly reports to EPA. STIG-1 Prior to fluid being injected at the STIG-1 well,the geochemical evaluation of the Domengine groundwater and the STIG-1 injectate (Appendix 5) indicated that although there was some potential for minor precipitation of phosphate minerals, dispersion of the injectate within the Domengine injection zone was expected to reduce the potential for adversely affecting the interval. No other compatibility issues were identified (Don Michaels and Associates, 1994). Data collected with the quarterly sampling of the injectate between 2002 and 2008 (Figure H-3) indicates that the quality of the water is generally consistent and where variability exists,the parameters are favorable. The one exception to this is the most recent (June 2008) alkalinity measurement,which is significant different from any preceding analysis. NCPA will be tracking this parameter to determine if this was an anomalous situation or an indication of a change in source water conditions. In addition to the quarterly sampling, samples of the influent water received at STIG and of the injectate were collected and analyzed in 2006 for full Title 22 parameters (Appendix 6). These samples were collected and analyzed in response to a request by the Central Valley Regional Water Quality Control Board (CVRWQCB). These samples indicated that most constituents were lower in the injectate sample versus the influent sample,with the exception of 19 analytes (Table H-1). Copper and nitrate had the greatest increase in concentration,followed by mercury and phosphorous. SAC/371322/082550024(ATTACHMENT-H.DOC) H-3