WORK PLANS_CASE 1 - Laserfiche WebLink

Home Browse Search

AIR, WATER & HAZARDOUS WASTE LABORATORY CERTIFIED by CALIFORNIA DEPT of HEALTH SEpt':CES SAMPLING AND ANALYTICAL CONSIDERATIONS .J Fuels are highly complex mixtures of hydrocarbons which often contain more than a hundred identifiable components. Gcsolines are characterized by their lower boiling range and by their aliphatic and aromatic hydrocarbon distributions. These, together with the presence or absence of lead and ethylene dibromide and/or ethylene dichloride serve to distinguish between leaded and unleaded gasoline. CENTRAL COAST ANALYTICAL SERVICES, INC. , has modern instrumentation which can separate and simultaneously identify the type of fuel, the amount present, and the BTX-' Further, ethylbenzene, ethylene dibromide and ethylene dichloride, which are added to leoded gasoline, ore also separated and quontotively identified. CENTRAL COAST ANALYTICAL SERVICES, INC. , provides septum sealed viols free of charge to clients interested in collecting their own groundwater samples for fuel fingerprint analysis. These viols contain an ASTM-opproved preservative which adjusts the pH to 2 in order to block biodegradation which con otherwise be a very serious factor. Soils are best sampled using metallic Shelby tubes or brass rings and then covering the ends of the tubes with Teflon sheeting prior to emplocing a snugly-fitting plastic cop. The whole core is frozen or refrigeroted in the field. Once in the laboratory, subsomples may be removed and analyzed by a variation of the purge-and-trop gas chromatographic technique. Although it is unlikely that significant loss takes place if the samples are frozen, the holding time for volatile compounds in soil is 14 days from time of sampling until the time the sample is analyzed. 4.. Water samples are collected by completely filling the viols, sealing, checking for bubbles and refilling and reseoling if bubbles ore present, then placing the filled viols into plastic guard bottles which contain activated charcoal. The guard bottles which contain the charcoal ore refrigerated (NOT FROZEN) in the field. Analysis is performed using EPA Method 524.2 and compared to standards containing appropriate fuels and volatile Priority Pollutants. When free product is available, some of that should be sampled and submitted in a septum-seoled vial which is then placed in a guard bottle. The laboratory should be instructed to use the free product for the standard used to quantitate the fuel in the samples. During the initial stages of an investigation, it is recommended that samples be token at several depths to groundwater. If it is unclear whether or not groundwater has been contaminated, we recommend drilling be stopped if strong petroleum odors ore encountered. In the later stages of on investigation, drilling may be continued in such cases PROVIDED that precautions are taken to ensure that contamination will not follow the path of the drill as it posses through the contaminated zone. Oversompling followed by selected sample analysis is recommended. This strategy allows the laboratory to zero in on meaningful samples while avoiding costly resompling. CENTRAL COAST ANALYTICAL SERVICES, INC. employs both flame Ionization (FID) gas chromatography and selected ion GC/MS to obtain fuel fingerprints. We prefer the latter since it gives information about the distribution of aliphatic and aromatic hydrocorbons which is not available by Page 5 w CENTRAL COAST A•,.LYTICAL SEP�'iCES Scn Luis O: sco, Coliforr'o (eLZ5) 5A3_2.—3