Field Sampling Technique

Cresser and A.C. Edwards, Acidification of Freshwaters , Cambridge University Press, Cambridge, 1987. 

Edwards, J. Creasey, and M.S. Cresser, in Hydrochemical Balances of Freshwater Ecosystems , IAHS Publication No. 150, Oxford, 187, 1984. 

Sampling suspended materials in rivers and lakes is particularly problematic. Not only does the suspended load tend to vary in space and time, but also it is necessary to take care not to introduce systematic error when taking the sample. For example, sampling devices which suck or pump water from depth along pipes can result in substantial loss of suspended materials by sedimentation. It is better therefore to have a sample bottle which may be both opened and then closed at the appropriate depth. 

This section is not intended to give a comprehensive account of environmental sampling problems, but rather to emphasize the importance of giving the necessary thought to sampling technique. Because many environmental samples are biologically active even when handed into the analytical laboratory, they must be stored and handled accordingly, especially if speciation studies are to be performed rather than total element analysis. 

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J. A. Cruze and D. O. Hitzman. Microbial field sampling techniques for MEOR (microbial enhanced oil recovery) processes. US DOE Fossil-energy RepNIPER-351 CONF-870858, September 1987. 

Cox, A.G. and McLeod, C.W. (1992) Field sampling technique for speciation of inorganic chromium in rivers. Mikrochim. Acta, 109, 161-164. 

Issues related to variations in measured THg associated with actual crude oil samples acquired using field sampling techniques from actual pipelines and from tankers during discharge to refinery tanks were examined. The items of concern were organized by task with each task designed to answer specific questions. Tasks were added and analytical procedures changed as data were acquired in the course of the experimental work. 

Only the field sampling techniques specified for the measurement program are used. 

Several manual and continuous analytical techniques are used to measure SO2 in the atmosphere. The manual techniques involve two-stage sample collection and measurement. Samples are collected by bubbling a known volume of gas through a liquid collection medium. Collection efficiency is dependent on the gas-liquid contact time, bubble size, SO2 concentration, and SO2 solubility in the collection medium. The liquid medium contains chemicals which stabilize SO2 in solution by either complexation or oxidation to a more stable form. Field samples must be handled carefully to prevent losses from exposure to high temperatures. Samples are analyzed at a central laboratory by an appropriate method. 

For an existing process plant, the designer has the opportunity to take measurements of the fume or plume flow rates in the field. There are two basic approaches which can be adopted. For the first approach, the fume source can be totally enclosed, and a temporary duct and fan system installed to capture the contaminant. For this approach, standard techniques can be used to measure gas flow rates, gas compositions, gas temperatures, and fume loadings. From the collected fume samples, the physical and chemical characteristics can be established using standard techniques. For most applications, this approach is not practical and not very cost effec tive. For the second approach, one of three field measurement techniques, described next, can be used to evaluate plume flow rates and source heat fl uxes. 

Voordouw G, JK Voordouw, RR Karkhoff-Schweiser, PM Eedorak, DWS Westlake (1991) Reverse sample genome probing, a new technique for identification of bacteria in environmental samples by DNA hybridization, and its application to the identification of sulfate-reducing bacteria in oil field samples. Appl Environ Microbiol 57 3070-3078. 

As the plastic liners are removed from the probe, they are capped on both ends, the appropriate labels affixed, and promptly placed in a freezer (an in-field sectioning technique used for further partitioning of the 0-15-cm core is described later in this section). By convention, red plastic caps are placed on top of the core (i.e., the end that was closest to the soil surface) and black caps are placed on the bottom. Use of the two-color capping system is important when the cores are sectioned at a later time. This approach is referred to as zero-contamination sampling and is the industry standard in field soil dissipation. 

From 8 to 30 pounds [or 120 leaves, if foliage (4)] of the field sample are used penetration samples are dissected or otherwise suitably treated so as to afford several pounds of the desired anatomical portion of the field sample. [The size of the field sample and its method of collection vary tremendously for different materials—e.g., olives vs. alfalfa hay. These two parameters are under statistical investigation, but the paucity of reliable and sufficiently extensive data precludes formal publication of field sampling and processing techniques for materials other than leaves 4). A manual of processing procedure (5) has been mimeographed for guidance of personnel, based upon empirical observations as data are accumulated, it will be revised and expanded periodically. ]... 

Although is has been in use for over 50 years and has become one of the most widely used routine analysis techniques, GC research remains vibrant and challenging. There are two key areas in which dramatic advancements are being made sampling and sample introduction methods and multi-dimensional separations. A summary of sampling techniques in use with GC is shown in Table 14.9, including the basic principle of the technique and some key applications. These techniques have become critical in extending the use of GC into the diverse fields described in the Applications section. 

By far the most widespread use of NMR in an on-line production environment is the utilization of downhole exploration tools by petroleum service companies such as Schlumberger, Halliburton, and Baker Hughes. Articles on these unilateral NMR systems are found in the patent databases, " academic literature, and on-line resources provided by the exploration companies. The references provided here are just a few examples in a very prolific field. The technique is applied in high-temperature and pressure situations and currently is used down to a depth of about 10 km (6 miles) to produce a picture of water/oil content in the adjacent rock formations as well as to derive permeability, diffusivity, and hydrocarbon chemistry information. Mobile unilateral NMR systems such as the NMR-MOUSE are also being developed in order to take benchtop NMR systems into the field to perform analysis of geological core samples at the drill site. NMR analyzers are also being developed to determine the bitumen content and properties in tar sand production and processing. " " ... 

The traditional subsurface rock characterization technique includes collection of field samples and subsequent analysis in the laboratory for both mineralog-ical and chemical data. A borehole or penetrometer sampler initially collects... 

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