2022-01-18_HYDROLOGY - M1983194 - Laserfiche WebLink

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at the current time. They provide a sample that represents the characteristics of the liquid being sampled at a particular point in space and time. Discrete samples are used where: • The flow of liquid may not be continuous (e.g., batch discharges or intermittent flows) • The characteristics of the liquid are known to be fairly constant • The samples are to be used for parameters with characteristics that are likely to change significantly with time (e.g., dissolved gases, bacterial decay, hydrolysis reactions, oxidation/reduction reactions) • The recharge rate is slow or where the wellbore volume to be purged would be excessive • The compositing process would significantly affect the concentration of an analyte. Interpretation of results depends upon knowledge of groundwater flow direction and formation transmissivity, lithology sampled, and a properly collected, preserved, and uncontaminated sample. See Table 5 through Table 10 for advantages and disadvantages of different sampling devices. A description of the depth of monitoring wells and a depth to the sample interval is necessary before proper sampling strategies can be chosen. B.6.4. Material Considerations The quality of the analytical data can be greatly affected by interactions between the sample and the sampling device. These interactions include chemical attack, microbial colonization, sorption, and leaching effects. To ensure the integrity of the sample and maximize the analytical quality,the sampling device shall be constructed of a nonreactive material. The materials listed below are generally used in construction of sampling devices and sampling containers. B.6.4.1. Rigid materials: • Nylon • Stainless steel • Polyvinyl chloride (PVC) • Teflon B.6.4.2. Flexible materials: • Nylon • Polypropylene • Linear polyethylene • Flexible PVC • Viton • Conventional polyethylene • Tygon • Teflon • Silicone/neoprene Daub &Associates, Inc. Page B-13 Natural Soda LLC 2022 SAP