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PACIFIC ENVIRONMENTAL MANAGEMENT, INC. Attachment A Sampling Methods Proper sampling methods must be followed 10 assure that samples represent actual field conditions and that samples are labeled, preserved, and transported properly to retain sample integrity. This attachment describes procedures to be followed by Pacific Environmental Management, Inc. (PEM), during collection of samples of subsurface soil and ground water. Sampling procedures will be based on sampling guidance documents from the American Society of Testing and Materials (ASTM), U.S. Environmental Protection Agency (EPA), and California Department of Health Services(DHS). Actual sampling procedures to be employed will be based on field conditions and may differ from those described here. A. EXPLORATION BORING/SOIL SAMPLING PROCEDURES Soil borings and soil sampling will be performed under the direction of a PEM geologist. The soil borings will be advanced using drilling techniques appropriate for each project, as specified in the project work plan. Soil samples will be collected at maximum intervals of 5 feet. Soil sampling will be done in accordance with ASTM 1586- 84. Using this procedure, three 1.06-to 2-inch-diameter, 6-inch-length, brass or stainless steel tubes are placed in a California-type split-barrel sampler. The sampler is driven into the soil either by using a drilling rig sampling device, consisting of a 40-pound weight falling 30 inches or a manual impact sampler. If a drilling rig sampling device is used, the sampling assembly will initially be set 6 inches,then the number-of blows required to drive the sampler an additional 12 inches is known as penetration resistance, or the"N"value. The"N"value is used as an empirical measure of the relative density of cohesionless soils and the consistency of cohesive soils. Upon recovery of the split-barrel sampler,the brass or stainless steel tubes containing' the soil will be removed. One of the three tubes will be sealed at the ends with plastic end caps. The end caps will be secured to the ends of the tube to prevent loss of volatile constituents. The sample will be labeled with an identification number, time, date, location, and requested laboratory analysis. The sample will then be placed in a plastic bag and stored at approximately 4° Celsius © in an ice chest for transport to the laboratory. Sample custody procedures outlined in Section E of this attachment will be followed. This will be performed for each sample collected. If proposed in an approved work plan, soil in one of the brass or stainless steel tubes will be extracted upon recovery, placed in a plastic bag, and sealed for later screening for organic vapors using a photoionization detector(PID)or a flame ionization detector(FID). The remaining portion of the soil sample will be examined and a complete log of soil conditions will be recorded on a soil boring log (Enclosure A) using the Unified Soil Classification System (Enclosure B). The soil will be examined for grain size, color, and moisture content. The soil sampling assembly will be cleaned to prevent contamination across sampling intervals using procedures described in Section C. Soil generated from the soil borings will be stored in 55-gallon drums(unless otherwise directed by agencies or the client) and labeled with the corresponding boring number, date,.and address of the facility. B. DECONTAMINATION AND DISPOSAL PROCEDURES All equipment that comes into contact with potentially contaminated soil, drilling fluid, air,or water will be decontaminated before each use. Decontamination will consist of steam-cleaning, a high-pressure, hot-water rinse, or trisodium i phosphate(TSP)wash and freshwater rinse, as appropriate. Drilling and sampling equipment will be decontaminated as follows: 1. Drill rig augers, drill rods, and drill bits will be steam-clearied prior to use and between borings. Visible soil, grease, and other impurities will be removed. 2. Soil sampling equipment will be steam-cleaned prior to use and between each boring. Prior to individual sample collection,any sampling device will also be cleaned in a TSP solution and rinsed twice in clean water. Any visible soil residue will be removed. 3. It is anticipated that disposable equipment will be used to collect water samples. If disposable equipment is not used, water sampling equipment will be decontaminated using methods described in Item 2 above for soil sampling equipment.