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TABLE 4 PARAMETERS FOR PILOT TEST PERFORMANCE MONITORING Nutrien Ag Solutions, Inc. 12325 North Dos Palos Road Firebaugh, California Parameter Method Rationale/Notes Laboratory Analysis Nitrate as Nitrogen (-N) EPA 353.2 Generally, when nitrate-N concentrations are less than 1 mg/L, manganese will become the preferred electron acceptor(AFCEE, 2004). However, manganese can begin being utilized as an electron acceptor at nitrate concentrations greater than 10 mg/L. When manganese (Mn4+) is used as the electron acceptor during anaerobic microbial metabolism it is reduced to manganese (Mn2+). The Mn2+ Dissolved Manganese EPA 200.7 concentrations can be used to indicate that the system is becoming more anaerobic. During or after Mn4+ is depleted, ferric iron (Fe3+) can be utilized for microbial metabolism. When Fe3+ is utilized as the electron acceptor, it is reduced to ferrous iron (Fe2+). Elevated levels of Fe2+ can be used to indicate if the ORP and DO in the Dissolved Iron EPA 200.7 groundwater are low enough to support anaerobic dechlorination. Fe2+ concentrations greater than 1.0 mg/L are indicative of favorable reducing conditions for dechlorination (AFCEE, 2004). Sulfate EPA 300.0 Decreasing sulfate concentrations (<20 mg/L) may indicate an environment suitable for reductive dechlorination, although there cases in the literature where dechlorination occurred at elevated dissolved sulfate levels (2,600 to 5,400 mg/L). (AFCEE, 2004) Total Organic Carbon (TOC) EPA 415.1 TOC is an indicator that sufficient carbon is available in the groundwater to support biological activity(biodegradation). TOC concentrations greater than 20 mg/L are indicative of favorable reducing conditions (AFCEE, 2004). Volatile Organic Compounds (VOCs) EPA 8260 Full VOC scan, including Site chemicals of concern (1,2-DCP)and (1,2,3-TCP). 1,2,3-Trichloropropane (1,2,3-TCP) SRL 524 Low level analysis for Site chemical of concern. Chloride EPA 300.0 During reductive dechlorination, chloride is released into the groundwater. Because of the neutral chemical behavior of chloride, it can be used as a conservative tracer to estimate biodegradation rates. Field Measurements Dissolved Oxygen (DO) Field Probe Denitrification will typically begin as DO decreases to less than 1 mg/L. Oxidation Reduction The ORP is a measure of electron activity and an indicator of the relative tendency of a solution to accept or transfer electrons. Reducing conditions are Potential (ORP) Field Probe required for anaerobic dechlorination to occur, and the ORP should remain less than -100 millivolts (mV)within the treatment zone for anaerobic dechlorination to occur(AFCEE, 2014) Conductivity is a measure of the capability of solution to conduct electricity. The conductivity of groundwater is directly related to the concentration of ions in Conductivity Field Probe solution. Specifically, conductivity will increase as hydrogen ion concentrations increase during the controlled release of 3DME and then will decrease as anaerobic degradation of available carbon proceeds towards and during reductive dechlorination. pH Field Probe The pH of groundwater influences the presence and activity of microbial populations in the groundwater. Microbes capable of conducting reductive dechlorination prefer pH values varying from 5 to 9 standard units (AFCEE, 2004). Notes: mg/L = milligrams per liter References: Air Force Center for Environmental Excellence (AFCEE). August 2004. Principles and Practices of Enhanced Anaerobic Bioremediation of Chlorinated Solvents. Page 17 of 17