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Oscrept.bac Page 16 9 air pollutants . According to the local APCD, the level of pollution was lower than Fresno readings in the winter when residents burn wood in fireplaces . The CARB Emergency Response Report and START' s summary of air data are in appendices 3 and 4 . 3 . Soil and Water Contamination On May 28, 1996, START collected four samples to determine the contaminant levels in the ash and underlying soil and compare them to EPA' s Preliminary Remediation Goals (PRGs) and background levels . Due to the fires up canyon, sampling was restricted to the retention basin where the soils had cooled. The area was primarily impacted by pyrolytic oil runoff and was nearly void of a tire ash layer. Visual soil contamination was apparent only in the upper few inches of soil . This contamination was mostly a thin black crust composed of burnt ash, wire and carbon residue . The soil beneath the crust layer appeared to be unaffected. The samples were analyzed for Total Metals (EPA Method 6010) , Total Recoverable Petroleum Hydrocarbons (EPA Method 418 . 1) , Volatile Organic Compounds (EPA Method 8260) and Semivolatile Compounds (EPA Method 8270) . The soil samples were collected as follows : Sample No. 1 - Background sample collected on a slope upwind of the fire . Sample No. 2 - Background sample collected in the drainage channel downstream from the existing dam near the entrance to the canyon. Sample No. 3 - Sample collected in the retention basin. This sample was taken to determine extent of contaminant migration into the soil . The surface residue was scrapped away and only the underlying soil was sampled. Sample No. 4 - Sample collected in the retention basin. This sample was taken to determine the level of contamination in the surficial crust layer. The laboratory results indicated that only sample No. 4 , the surficial crust layer, contained elevated contaminant levels . The contaminants were zinc and petroleum hydrocarbons . Maximum concentrations were 32 , 000 mg/kg zinc and 25, 000 mg/kg TRPH. EPA' s PRG for zinc was 23 , 000 mg/kg (residential areas) and 100, 000 mg/kg (industrial areas) . The State ' s Total Threshold Limit Concentration (TTLC) for hazardous waste determination was 5, 000 mg/kg. Additional ash samples were taken by START on September 7, 1996 and analyzed using the field portable X-Ray Fluorescence Spectrometer (XRF) . The samples were collected from the sides and bottom of the canyon. The ash layer was very deep in some areas and had the consistency of talcum powder. The depth of the ash layer ranged from 3 to 4 feet on the bottom to 1 to 2 feet on the