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Musco Family Olive Company - 11 - 12 December 2006 Well ID TDS Cl Na HCO3 (mg/L) (mg/L) (mg/L m /L Shallow Well ID MW-1 (S) 1,600 448 580 355 W-2 (1985)(S)*" 1,375 330 335 348 MW-3 (S) 2,675 730 985 1,350 MW-5 (S) 2,950 605 895 1,500 MW-6 (S)** 2,600 830 780 1,000 MW-10 (S)** 2,375 1,095 700 537 MW-11 (S)** 2,050 673 635 448 MW-13 (S)*' 2,475 1,175 599 675 MW-14 (S) 3,025 870 985 432.5 MW-15 (S) 1,525 525 435 900 MW-16 (S) 2,700 533 638 1,600 MW-17 (S) 1,975 610 610 600 Regional Well 1,225 240 325 280 Well K-1 1,050 225 308 283 Deep Well ID MW-4 (D) -1,425 210 335 355 MW-7 (D) 2,100 405 475 238 MW-8 (D) 1,400 293 280 250 MW-9 (D)** NS NS NS NS MW-12 (D) 2,325 603 530 390 MW-18 (D) 1,675 520 505 530 Well MW-2 MW-2 10,000 4,500 2,400 104 i 'Refer to Table 6. "* - Denotes wells that are currently dry Based upon a simple comparison between the interim background groundwater concentrations and the existing wells, the majority average concentrations of the shallow wells exceed the interim limits for TDS, chloride, and sodium. Musco has been land applying high strength wastewater to Field 55 East and West since 1991 and likely before that time based on records of spreading pond silt on the Park West field. Reviewing the limited data set from 2002 to 2006 for the existing wells indicates that elevated levels of constituents of concern (COC's) (TDS, chloride, and sodium) are detected in all shallow wells. This strongly suggests that wastewater applied to the land has impacted groundwater prior to 2002. When the data set is compared to the offsite Hanson Well (Regional), which is located in the. same alluvial fan environment but outside the spray irrigation areas or impact zone, it is evident that TDS, chloride, and sodium concentrations are elevated in the Musco monitoring wells and it can be concluded that groundwater beneath the spray fields has been impacted by wastewater. Table 8 above presents the average of the last four available sampling events collected from the Regional Well for TDS, chloride, sodium, and bicarbonate.