2022-01-18_HYDROLOGY - M1983194 - Laserfiche WebLink

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B.13.5. Sample Preservation Guidelines Samples are preserved by a variety of means to stabilize specific parameters so that the samples can be shipped to a laboratory for analysis. Preservatives are intended to retard biological effects, retard hydrolysis, reduce sorption effects, and reduce volatility of constituents. Preservation methods are generally limited to pH control, chemical addition, refrigeration, and protection from light. The following guidelines shall be considered during sample preservation: • Preservation of samples uses a variety of strong acids and bases; care shall be taken in their storage and use. • Preserve samples prior to or as soon after collection as possible. • Take care not to cross-contaminate samples with preservatives. Sulfuric and nitric acids are used as preservatives. Follow all MSDS and HASP safety precautions when using these acids. • ACZ supplies sample bottle sets and ensures the proper preservative and quantity is included in the appropriate bottles. NS is responsible for verifying the correct bottles are received and they contain preservatives prior to sampling. B.13.6. Quality Assurance In the Water Sampling Field Data Sheet, record the following information about the sample collection, and preservation for QA documentation: • The bottle size, bottle type, and number of samples collected B.14. Special Sampling Considerations B.14.1. Volatile Organic Compounds(VOC)Analysis Groundwater samples for VOC analysis must be collected in 40 ml glass vials with Teflon® septa. The vial may be either preserved with concentrated hydrochloric acid or unpreserved. Preserved samples have a two-week holding time, whereas unpreserved samples have a seven- day holding time. The preserved vials are generally used to take advantage of the extended holding time. At Natural Soda, however, it is necessary to use unpreserved vials. The groundwater in the DS aquifer typically has a higher concentration of dissolved sodium bicarbonate and would cause an effervescent reaction between the hydrochloric acid (preservative) and the groundwater sample, producing large numbers of fine bubbles. This reaction would likely create a gaseous headspace in the vial and render the sample unacceptable. In this case, unpreserved vials should be used and arrangements must be confirmed with the laboratory to ensure that they can accept the unpreserved vials and meet the shorter sample holding times. Daub &Associates, Inc. Page B-31 Natural Soda LLC 2022 SAP