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ADVISORY - ACTIVE SOIL GAS INVESTIGATIONS <br />Glass syringes and bulbs may be decontaminated by disassembling and <br />heating them. Some components of the syringes and glass bulbs, such as the <br />syringe barrel and bulb stopcock, cannot be heated and should be <br />decontaminated by other methods such as rinsing with methanol and/or <br />expunging with nitrogen or clean air. If a syringe is reused, it should be blank <br />tested; <br />Passivated stainless steel canisters should be decontaminated as specified in <br />USEPA Method TO-15, either batch or individually certified, according to <br />project DQ0s; <br />Polymer gas sampling bags should not be reused; and <br />Equipment blanks should be analyzed to verify and evaluate the effectiveness <br />of decontamination procedures for recycled or reused containers, except for <br />certified containers. At a minimum, one equipment blank should be run per 20 <br />sample containers cleaned, or at least one per day. <br />5.5 CHAIN OF CUSTODY RECORDS <br />The chain of custody documents the identity and integrity of the sample from the time of <br />collection through receipt at the laboratory. <br />A chain of custody form should be completed in the field and include any relevant <br />problems encountered during sample collection. The starting and ending pressures for <br />passivated stainless steel canisters should be recorded on the chain of custody form. <br />USEPA provides a complete description of chain of custody protocols and records <br />management (USEPA, 1998, 2000b). To avoid loss or damage, the chain of custody <br />forms should be placed into a sealable bag and attached to the inside of the shipping <br />container. <br />6.0 ANALYSIS OF SOIL GAS SAMPLES <br />The sections below summarize analytical methods, QA/QC, holding times, reporting and <br />laboratory certification. Additional details are provided in Appendices F and H. <br />6.1 TARGET COMPOUNDS <br />Target compounds are chemicals believed to be present, used, or released at the site. <br />Common target compounds are listed below. Compounds may be added or excluded <br />from the list below based on site history and DQ0s. A vapor intrusion-specific list can <br />be found in DTSC's Vapor Intrusion Guidance (DTSC, 2011). <br />6.1.1 Common Organic Compounds <br />Halogenated <br />Bromochloromethane <br />Bromodichloromethane <br />July 2015 30