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Ll n Section No: 6 Page: 1 of 16 Revision No: 2.0 Date: January 15, 1994 1IIM' i`; Sample collection ,and sample handling techniques are important aspects of the overall sample analysis process and have a major impact on the quality and validity of the results. Specific containers and preservatives are used to ensure that sample integrity is not lost through volatility or degration. In addition, contaminants that are likely to interfere or effect the quality of analytical data must be minimized oreliminated. If a client chooses to collect their own samples, experienced lab staff brief clients by telephone on the proper methods of sample collection. Detailed procedures to ensure sampling consistency and compliance with method requirements are available. The correct container types, bottle sizes, preservatives, container closures, and holding times for sampling are shown in Table 6-1. 6.1 FGL Sampling Protocols 6.1.1 General Precautions The result of any analytical determination can be no better than the sample on which it is performed. The objective is to obtain a sample that meets the requirements of the sampling program and manage it in such a way that it does not deteriorate or become contaminated before reaching the laboratory. This objective implies that the relative proportions or concentrations of all pertinent components will be the same in the samples as in the material being sampled, and that the sample will be processed in such a way that no significant changes in composition occur before the tests are made. A sample may be presented to the laboratory for specific determinations with the collector taking responsibility for its validity. Often the laboratory conducts or prescribes the sampling program which is determined in consultation with the user of the test results. Such consultation is essential to insure the selection of the appropriate sample and analytical methods that provide a true basis for answering the questions that prompted the sampling. Before filling, ri the sample bottle two or three times with the water being collected, unless the bottle contains a preservative. Depending on determinations to be performed, fill container f (most organics determinations) or leave space for aeration, mixing, etc. (microbiological analyses). For samples that will be shipped, preferably leave an air space of about one (1) percent of container capacity to allow for thermal expansion. Special precautions are necessary for samples containing organic compounds and trace metals. Because many constituents may be present at concentrations of micrograms per liter, they may be totally or partially lost if proper sampling and preservation procedures are not followed. Representative samples of some sources can be obtained only by making composites of samples collected over a period of time or at many different sampling points. The details of collection vary so much with local conditions that nos specific recommendations would be universally applicable. Sometimes it is more informative to analyze numerous separate samples instead of one composite so as not to obscure high and low results. Sample carefully to insure that analytical results represent the actual sample composition. Important factors affecting results are; the presence of suspended matter or turbidity; the method chosen for its removal, and; the physical and chemical changes brought about by storage or aeration.