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The second source of information can be found on USGS maps. Unfortunately, the subject property is on the border of the Lathrop Quadrangle map. Found in the Appendix are the four surrounding USGS maps which document surrounding land use. Since the subject property has been in pasture, and the fact that according to Ms. Prouty,no agrichemicals have been applied to the property, an evaluation of environmental fate data for agrichemical residues as a nonpoint source of potential contamination was not done. She also stated that when she was a little girl, a few of the neighbors around the property applied DDT, but due to her father's philosophy of environmental stewardship, no DDT was applied to their 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 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 may 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). It can be reasonably concluded that any DDT, DDE and DDD concentrations will continue to degrade as reported in the published environmental fate data. The environmental fate data for DDT and its degradates DDD and DDE are illustrated below: DDT. Common name: Agritan, Anofex, Azotox, et al. Half-lives in the environment: Air: 17.7 -177 h. Surface water: 73.9 h for a pond 1 in 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 in, 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 L[DDED . Common name: DDE (p,p'-DDE; o,p'-DDE), product of DDT degradation. Half-lives in the environment: Air: Atmos. transformation lifetime est. to be Surface water: Hydrolytic half-life of >120 yr, est. half-life>300 d in lakes. Groundwater: N/A Sediment: N/A Soil: Field half life of 1000 d Page -4- Ckesney Consulting