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%W we Wright Environmental Services, Inc. 2. Reconnaissance groundwater samples will be collected in the field in temporarily cased exploratory boreholes using clean Teflon® or disposal bailers. The samples will be collected from excavations or temporarily cased exploratory boreholes and poured into the properly prepared laboratory containers with minimum cavitation. All sample containers will be properly sealed with minimum headspace, labeled, and identified. Label information will include the date, sampler name, sampling time, and identification number, and the project name and number and chain -of custody. If groundwater recharge is slow, sampling will begin within 24 hours following temporary well development, following the procedures detailed below for monitoring well sampling. Depth to water measurements will be made to the nearest 0.01 foot to existing grade (or surveyed datum if possible) for estimates of depth to water in pits/excavations, and triangulation in temporary boreholes. All borings/pits/excavations are also checked for presence of separate phase product. Following water sampling all temporary casing or sampling tools are removed and boreholes are sealed with cement grout from the bottom to top, or by the regulatory approved method of sealing. 2. The sample will be delivered to a State Certified Laboratory. Samples will be kept on ice and/or refrigerated continuously for shipment to the Laboratory under chain -of -custody. The sealed sample will only be opened by Laboratory personnel who will perform the chemical analysis. The samples will be analyzed according to the approved EPA Method and storage for that requested analysis. Monitoring Well Construction 1. The proper permits will be obtained from the appropriate agency or water district, scheduling a Well Inspector as required to be present to witness the installation of the annular seal. Soil borings will be drilled with a continuous -flight hollow -stem auger of nominal S inches outside. diameter (to leave 2 - inch annular space for well construction). All augers will be thoroughly steam -cleaned prior to arriving at the site. The augers will be steamed cleaned between borings at a location well away from the proposed borings or adequate clean auger will be available to complete all of the wells without reusing auger sections. 2. The borings will be advanced to the uppermost water bearing zone (or a depth of 45 feet if a saturated zone is not encountered and in absence of other exploration depth specifications). If a saturated zone is encountered, the boring will advance no further than 15 feet below first encountered groundwater or 5 feet into the underlying clay aquitard. If entered, a seal will be placed in the overdrilled portion of the aquitard. 3. During the drilling operations, 55 -gallon drums will be on site to contain potentially contaminated soils, drilling muck and rinse water to minimize surface contamination. 4. Where borings are completed as groundwater monitoring wells, 2 -inch ID schedule 40 PVC blank pipe will be used. Well screen selection will be 2 inch ID Schedule 40 PVC pipe with 0.020 inch machine slot (in absence of other specifications). Sections will be threaded and screwed flush together; glues will not be used. Screens will extend 3-5 feet above first encountered groundwater. The annulus of the perforated section will be packed with clean #3 or #4 Monterey Sand, Lonestar 2/12 Sand or equivalent, to a level about 2 -feet above the screen interval (field experience has shown this monitoring well design has worked well in stratified alluvial and fine grained environments; if special well designs supersede this design, a specification will be attached). Wes Sampling Protocols last rev. 2/96 Page