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5. CONCLUSIONS AND RECOMMENDATIONS § 5.1, § 5.2. From visual observations, no surface contamination from hazardous materials or hazardous environmental conditions exists on the surface of the subject property. Section 9-905.12 of San Joaquin County Development Title states"Corrective Action: If the report indicates there are surface and subsurface contamination, corrective action shall be recommended in the report and concurred with by Environmental Health prior to the issuance of the building permit." Therefore, it/ is recommended that no corrective action is required on the proposed six Parcels composing the subject property, other than removing the aforementioned tires. Given that the property adjacent to the south was a landing strip for the Mosquito Abatement District, any potential adverse environmental concerns from this activity which may affect the subject property, or underlying groundwater is unknown. As noted o e Lines of Equal Depth groundwater map, the static groundwater depth is approximat ly 90 fee . The lines of Equal Elevation map shows the groundwater directional flow to be in a nort westerl direction. This places the only nearby site of the Geotracker system (Raymond eer s' a crossgradient from the subject property) over 2.5 miles from the property. This contamin site could not affect the subject property. The dirt roads around and through the property should continue to be patrolled on a regular basis to," ensure there is no trespassing, or the dumping of hazardous materials, especially from drug manufacturing chemicals. Private homesites surrounding the subject Parcels may contain lead paint, asbestos or hazardous materials that may or may not be typical. Typical household"hazardous materials" include pesticide sprays, gasoline, paint thinners, used motor oil, antifreeze, etc. The ASTM E-1527-00 Document referenced above refers to de minimus environmental conditions. De minimus conditions generally do not present a material risk to public health or to the environment and generally would not include an enforcement action if observed by the appropriate governmental agencies. Household hazardous materials may be considered de minimus concerns if there has been no spillage or dumping. This also applies to the surrounding septic systems that serve residential structures. The septic system density in this locale is very sparse. The soils under the subject Parcels have limited percolation. Therefore, sumps and seepage pits must be installed to manage septic effluent. Given the low density of septic system in this locale, and the clay soil structures, there may be a comparatively lower nitrate impact from existing and future septic systems. Given that agricultural irrigation recharge is the largest single contributor to groundwater nitrate concentrations, and since the surrounding land has been farmed for several decades, it is assumed that the nitrate concentrations in the underlying groundwater would be much higher than the 11.8 j ppm referenced in this report. Consequently, attenuating factors may be significant. As referenced, it is unlikely there is nitrate formation under the rice paddies during the growing season due to anaerobic conditions. 6 Chesney Consulting