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r- F Manteca Unified School District tt�[,, Subsurface Soil &Groundwater InVgation N.J document the above information and other significant data, such as names of on- site personnel, sampling methods, date and time of sampling, the number of well volumes removed before sampling, preservatives added, and any filtration performed on samples. The samples will be refrigerated immediately for delivery to the laboratory and will under no circumstances be opened by anyone other than laboratory personnel. Chain of Custody records will be maintained at all times. 2.4 Soil Sampling All soil sampling equipment will be thoroughly steam-cleaned before and between sampling to prevent cross contamination. Relatively undisturbed soil samples will be taken at intervals of not more than 5 feet in order to evaluate the subsurface materials, however, this sampling interval may be waived in saturated sands in which sample recovery is not possible. Soil samples will be taken using a California Modified Split Spoon sampler with brass liners. The sampler will be driven by a 140 pound hammer repeatedly falling 30 inches. The blow counts necessary to drive the sampler will be recorded for each 6-inch interval to help evaluate the consistencies of the materials. The laboratory samples will not have head space and will be immediately sealed in their liners using aluminum foil lined plastic caps. The remaining sample will be removed from its liner to be used as an aide to the on-site geologist in logging the material at that depth. The samples shall be analyzed for Total Petroleum Hydrocarbons (diesel) by 3550 Luft. BTX&E (Benzene, Toluene, Xylene, and Ethyl Benzene) by method 8020. The minimum detection limits used for each analyte will be .005 mg/kg for BTX&E and 1.0 mg/Kg for diesel. Analyses are to be conducted by GeoAnalytical Laboratories, Inc., in Modesto, California. 2.5 Groundwater Sampling A travel blank provided by the laboratory will accompany the sample vials from the time they are picked up from the lab to the time they are delivered to the lab. This travel blank should be listed on the Chain of Custody but will be analyzed only if all samples contain the same contaminants. All sampling equipment including the pump, bailer, and cables, used by sampling personnel, will be disassembled, if appropriate, and steam-cleaned prior to commencement of sampling. These procedures will also be followed between each well, sampling point and at the end of the sampling day. De-ionized or organic-free water (also provided by the laboratory) will then be introduced into the pump or bailer as a final stage of cleaning. This water will then be pumped or gently poured into sample vials to be used as pump or bailer blanks. These blanks 5