【国外标准】 Standard Practice for Sampling Liquids Using Bailers

5.1 A bailer is a device for obtaining a sample from stratified or un-stratified waters and liquid wastes. The most common use of a bailer is for sampling ground water from single-screened wells (Fig. 1) and well clusters (see Guide D4448).5.2 This practice is applicable to sampling water and liquid wastes. The sampling procedure will depend on sampling plan and the data quality objectives (DQOs) (Practice D5792).5.3 Bailers may be used to sample waters and liquid wastes in underground and above ground tanks and surface impoundments. However, the design of the unit and associated piping should be well understood so that the bailer can access the desired compartment and depth. Any stratification of the liquid should be identified prior to sampling.NOTE 1: Viscous liquids and suspended solids may interfere with a bailer's designed operation.5.4 Bailers do not subject the sample to pressure extremes. Bailing does disturb the water column and may cause changes to the parameters to be measured (for example, turbidity, gases, etc.).5.5 The use of bailers in low flow wells for purging can result in increased agitation and turbidity in the sample and can introduce errors into the sample if the water surface level is drawn down below the top of the screen. In such cases, alternate methods of sampling such as Passive Sampling (Guide D7929) or Low Flow Sampling (Practice D6771) should be considered.1.1 This practice covers the procedure for sampling stratified or un-stratified waters and liquid waste using bailers.1.2 Three specific bailers are discussed in this practice. The bailers are the single and double check valve and differential pressure.1.3 This standard does not cover all of the bailing devices available to the user. The bailers chosen for this practice are typical of those commercially available.1.4 This practice should be used in conjunction with Guide D4687, Practice D5088, and Practice D5283.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.