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FDDTwas used extensively throughout the agricultural fields of the San Joaquin Valley and degradates T can be found in nearly all these soils. Previous Exposure Assessments made on typical San in 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 that may be present on the property will continue to degrade as reported in the published environmental fate data, which is 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 DDE. 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< 1 d. Surface water: Hydrolytic half-life of >120 yr, est. half-life>300 d in lakes. Groundwater: NIA Sediment: NIA Soil: Field half life of 1000 d Biota: Elimination half-life of 340 d(rainbow trout), 300 d for birds. Environmental Fate Rate Constants or Half-Lives: Volatilization: NIA Oxidation: NIA DDD. Common name: DDD, TDE (tetrachlorodiphenylethane), product of DDT deg. Half-lives in the environment: Air: 17.7-177 h Surface water: 2-15.6 yr. Groundwater: 1680-270,000 h based on anaerobic soil study data Sediment: NIA Soil: Field half life of 2-15.6 yrs based on observed rates of biodeg. of DDT Biota: 119 hr in mussels. Environmental Fate Rate Constants or Half-Lives: Volatilization: Aquatic approx. 1 mo. Oxidation: Aquatic half-life approx. 22 yr Hydrolysis: half-life of 570 d @ pH 9 and 190 yr @ pH 5 Biodegradation: Aqueous aerobic half-life of 2-15.6 yr Page -4- Chesney Consulting