Environmental Sampling Techniques - Fundamentals of Environmental Sampling and Analysis - page 96

to thewater table inWell 1, 2, and 3 are in the order of 10.0m, 10.2m, and 10.1m, respectively.
Draw the well diagram and determine the flow direction and the hydraulic gradient.
20. A well has a water column depth of 10 ft and diameter of 6 in. (a) What is the well
volume in gallons? (b) How much water need to be purged before samples can be
collected?
21. Describe the special considerations in taking water samples from: (a) flowing waters
(rivers and streams), (b) static waters (lakes and ponds), and (c) estuaries.
22. Describe why purging is important prior to groundwater sampling? What are the
common approaches in groundwater purging?
23. Explain why cross contamination is especially important in groundwater sampling as
compared with, for example, surface water sampling.
24. Explain which one of the following has the least potential for cross contamination:
(a) PVC, (b) FRE, (c) Teflon, and (d) stainless steel?
25. Which surface sampling approach is appropriate in a tiled floor suspected of PCB
contamination: (a) wiping sampling, (b) chip sampling, or (c) dust sampling?