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Soil Suitability/ Nitrate Loading Study Lease Property ■ Acampo, California December 17, 2021 Terracon Project No. NA217090 Ircerr on of fertilizers, livestock waste, and untreated septic tank waste. Nitrate is mobile and often accumulates in the shallow groundwater zones. In the early 1900s, natural levels of nitrate in groundwater were measured in forty-three (43) wells throughout the Sacramento Valley by Kirk Bryan (1923). It was thought that groundwater at that time was close to " natural" conditions. Based on the work by Bryan, it is estimated that under " natural" conditions, groundwater concentration containing nitrate is no more than about 13.5 milligrams per liter (mg/L) nitrate (NO3)or (3 mg/L-N). Areas having 24.75 mg/L-NO3 (5.5 mg/L- N) or more, are those in which nitrate concentrations may be increasing (Hull, 1984). DBCP (dibromo chloropropane) is a nematocide and soil fumigant for vegetables and grapes. It is thought to cause health problems consisting of kidney damage, liver damage, and cancer. The use of DBCP was discontinued in 1979. Based on the historical information, the past agricultural land use and septic systems in the area should be considered potential groundwater contamination sources. According to the State Water Resources Control Board website, there were no nitrate impacted wells reported within 2,000 feet of the site. 1.4.3 Water Sample Location A domestic groundwater well is currently located on the eastern portion of the site northeast of the residence (Exhibit 2). On December 7, 2021 two groundwater samples (GW -1 and GW -2) were collected from a faucet located on the south side of the residence. The water faucet was allowed to run for approximately 5 minutes. 1.4.4 Groundwater Sample Analysis Sample GW -1 was collected into a clean unpreserved plastic 125 milliliter (ml) bottle and analyzed for nitrate as N by EPA Extraction Method E300.1. Sample GW -2 was collected into two clean glass 40 ml VOAs preserved with ascorbic and maleic acid and analyzed for DBCP (1,2-Dibromo- 3-chloropropane) by EPA Extraction Method E524.3. 1.4.5 Groundwater Sample Handling The groundwater samples were immediately placed on ice and submitted to McCampbell Analytical Inc. for analysis. Nitrate as N was reported at 3.5 milligrams per liter (mg/L) in groundwater sample GW -1, below the Maximum Contaminant Level (MCL) of 10 mg/L-N. DBCP was reported below laboratory reporting limits of 0.010 micrograms per liter (pg/L) in groundwater sample GW -2, below the MCL of 0.2 pg/L. Responsive ■ Resourceful ■ Reliable 8