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i § 4.0 EVALUATION OF PAST AND CURRENT SOURCES OF CONTAMINATION IDENTIFIED AT OR NEAR THE SITE AND RECOMMENDATIONS FOR FURTHER ACTION § 4.1 Evaluation of each potential and/or known source of contamination identified in the above Sections have been discussed in the respective Sections to facilitate the transfer of information to the reader. Based upon the State Water Resources Control Board - GeoTracker System, there are records of Leaking Underground Fuel Tanks (LUFTs)well over a mile to the east of the property, along the Interstate 5 corridor. This is illustrated on the attached GeoTracker Site Map. It is impossible for these LUFTs to adversely impact groundwater under the property due.to.the distances involved. The Inactive UST Facility Inventory List and the Underground Storage Tank Site Mitigation Database List,both from EHD,.are found in Appendix C. The Lists show that there is no reference for Noceti,Noceti Farms, or for the property address. Potential environmental.impacts from past, present or future facilities within a one mile radius of the property are unknown at this time. From the USGS Topa Map, it noted there is agricultural production land to the east, residential structures to the west and a chicken layer ranch with waste holding ponds further to the west. Since the precise groundwater directional flow cannot be determined due to proximity to the San Joaquin River, it is unknown what effect these waste holding ponds may have on the groundwater under the subject property. The science of pesticide residues in soil, air, surface water and groundwater is extremely complex and variable. Environmental models that attempt to predict pesticide behavior and transport in the environment are beyond the scope of this investigation. However, pesticides with long half-lives that may have been used or drifted onto the property decades ago, primarily DDT, may be of an extremely slight concern. DDT was used extensively throughout the agricultural fields of the San Joaquin Valley and degradates of DDT can be found in nearly all these soils. Previous Exposure Assessments made on typical San Joaquin Valley soils suggest an extremely low probability of adverse health effects from soil DDT/DDD and DDE concentrations (if the concentrations even exist). The environmental fate data are presented below for DDT, and its degradates DDD and DDE. DDT. Common name:Agritan,Anofex,Azotox, et al. Half-lives in the environment: l Air: 17.7-177 h. Surface water: 73.9 h for a pond 1 m deep. Degradation half-life of about 10 yr-average from loss rates determined in Lake Michigan. Groundwater: 16 d to 31.3 yr. Sediment: 3 to 5 yr Soil: 2-15.6 yrs based on observed rates of biodegradation in aerobic soils under field conditions. Avg.half life of--12 yrs in 3 different soils for -50 ppm in soil.(conversion of p,p'-DDT to p,p'-DDE). Environmental Fate Rate Constants or Half-Lives: Volatilization: Half-life of 3.7 d for water depth of 1 m,from soil w/h-1 of 578 h #. Oxidation: Photooxidation half-life of 168-8400 h in water, 17.7-177 h in air Hydrolysis: Estimated first-order half life of 22 yr Biodegradation: Aqueous aerobic half-life of 2-15.6 yrs Page -5- t Chesney Consulting