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Cal-Farm facility where 4-4'-DDT concentrations exceeded 1,000 ug/Kg <br /> were delineated for excavation. <br /> Post-excavation Soil <br /> Following excavation, composite soil samples were collected from the <br /> excavated areas for laboratory analysis. The results of those analyses <br /> are presented in Table 5 of this report. The results from the <br /> confirmation samples and the results from previous analyses conducted on <br /> samples outside of the excavated areas were used to estimate potential <br /> risks remaining at the site. This is considered a conservative approach <br /> based on the fact that the excavated areas were backfilled with clean <br /> material , thereby minimizing the potential exposure to underlying soil . <br /> The ranges and average concentrations of pesticides remaining in soil <br /> and provided in Table B-5. Averages were calculated using one-half the <br /> detection limit when the chemical was not detected in a sample. This is <br /> also considered conservative because the detection limits were <br /> frequently elevated due to laboratory dilution of the extract <br /> Ingestion of Soil . A comparison of the range of concentrations of <br /> pesticides and their average concentrations with the potentially <br /> relevant soil criteria for the ingestion exposure pathway is provided in <br /> Table B-5. All average and maximum concentrations of pesticides in soil <br /> at the site are below the RCRA criteria for systematic toxicants and <br /> carcinogens. <br /> The average concentration of the pesticides in soil was used to <br /> calculate the hazard indexes. The results of the HI calculations are. <br /> Systematic Toxicants: Liver HIT = 0.014 <br /> Kidney HIT = 0.012 <br /> Carcinogens HIC = 0.98 <br /> The systematic toxicants and carcinogens present in surface soil do not <br /> exceed EPA-established health-based action levels. In addition, the <br /> calculated hazard indices do not exceed one. Therefore, consideration <br /> of additional corrective measures are not deemed necessary for <br /> pesticides remaining in surface soil at the site based on exposure by <br /> soil ingestion. <br /> Inhalation of Airborne Dust The calculated airborne concentration of <br /> pesticides and the available RCRA RSDs and criteria for systematic <br /> toxicants are provided in Table B-6. The airborne chemical <br /> concentrations were calculated by multiplying the average concentrations <br /> in site soil by the State annual average dust (PM10 standard) <br /> concentration. The airborne concentrations calculated for the site were <br /> below the applicable RCRA criteria for all pesticides detected <br /> . Hazard indices were calculated for carcinogens and systematic toxicants <br /> using the assumptions described above. The calculated HIs are: <br /> WPI13 B-5 882526 01 <br /> i <br />