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1.0 INTRODUCTION On behalf of Nutrien Ag Solutions, Inc. (Nutrien), Rubik developed this Pilot Test Work Plan for the Nutrien facility located at 35100 South Highway 33 in Vernalis, California (site, Figure 1). 1.1 Objective The objectives of this project are to: • Reduce nitrate in concentrations in the groundwater at well MW-3 through enhanced in- situ bioremediation (EISB); • Evaluate groundwater at the northern corner of the site following the installation of a new monitoring well; and • Possibly reduce 1,2,3-trichloropropane (1,2,3-TCP) concentrations with EISB near the northern corner of the site, depending the data from the new monitoring well. 1.2 Chemicals of Concern The primary chemicals of concern (COCs) are nitrate and 1,2,3-TCP. Ammonia, 1,2- Dichloropropane (1,2-DCP), 1,2-Dibromo-3-Chloropropane (DBCP) and ethylene dibromide (EDB) are also monitored in groundwater. 2.0 SITE DESCRIPTION The Site is used for retail sales of bulk liquid and dry fertilizers and pre-packaged fertilizers and pesticides. The current and former site features are depicted on Figure 2. 3.0 GEOLOGY AND HYDROGEOLOGY 3.1 Geology The soil beneath the site consists primarily of clay from the ground surface between approximately 15 to 25 feet below the ground surface (bgs). The clay is underlain by discontinuous layers of sand, silt, and clay to at least 70 feet bgs. 3.2 Hydrogeology In August 2023, average depth to water in the site monitoring wells was approximately 52 feet bgs. Groundwater elevations have declined approximately 21 feet since 2013. Groundwater predominantly flows to the east at an average gradient of 0.0009 feet per foot (ft/ft). Monitoring well construction details are presented in Table 1 and historical groundwater elevations are summarized on Table 2. Graphs showing the depth to groundwater over time for the monitoring wells are presented as Appendix A. 4.0 ENVIRONMENTAL BACKGROUND In 2002, a pilot test was conducted to evaluate the feasibility of using EISB to reduce nitrate and chlorinated hydrocarbons concentration in groundwater. Hydrogen Release Compound (HRC°) Nutrien Vernalis, California 1 7ut)1f2 / / Pilot Test Work Plan