5.1 Direct-push water sampling is an economical method for obtaining discrete groundwater samples without the expense of permanent monitoring well installation (1-6).4 This guide can be used to profile potential groundwater contamination with depth by performing repetitive sampling events. Direct-push water sampling is often used in expedited site characterization (Practice D6235). Soils to be sampled must be permeable to allow filling of the sampler in a relatively short time. The zone to be sampled can be isolated by matching well screen length to obtain discrete samples of thin aquifers. Use of these sampling techniques will result in more detailed characterization of sites containing multiple aquifers. By inserting a protected sampling screen in direct contact with soil and with watertight risers, initial well development (Guide D5521) and purging of wells (Guide D6452) may not be required for the first sampling event. Discrete water sampling, combined with knowledge of location and thickness of target aquifers, may better define conditions in thin multiple aquifers than monitoring wells with screened intervals that can intersect and allow for intercommunication of multiple aquifers (4,6,7,9,13). Direct-push sampling performed without knowledge of the location and thickness of target aquifers can result in sampling of the wrong aquifer or penetration through confining beds.
5.2 For sites that allow surface push of the sampling device, discrete water sampling is often performed in conjunction with the cone penetration test (Test Method D6067) (4-9), which is often used for stratigraphic mapping of aquifers, and to delineate high-permeability zones. In such cases, direct-push water samplin......
在2011年和2012年的ICCP會議上,制定了開展實驗室間精度研究的計劃,2012-2013年期間,進行了實驗室間工作,并通過ASTM審核程序審查了其統計結果,在2014年形成了ASTM D7708標準。本次研究的一套6塊巖石樣本(表1)是美國地質調查局(USGS)與ICCP協商后,從已經編制并鑒定的25塊候選巖石中挑選出來的(其他表征方法見表2)。...
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