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• APPENDIX B COLLECTION OF WATER UAQ LITY SAMPLES B. 1. GENERAL INFORMATION The objective of sampling is to collect a portion of material in a small enough volume to be transported conveniently and handled in a laboratory while still representing the whole material being sampled. This 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 handled in such a way that no significant changes in composition occur before the tests are made. A few general practices are required to meet the above goal. These include the following: I. Minimize disturbance of the sample during collection. Do not stir up sediment from the bottom of streams or springs. Do not aerate sample by creating turbulence. 2. Collect samples in bottles provided by the laboratory. 3. Rinse sampling apperatus in sample water prior to collecting samples. 4. Put sample bottles on i ce immediately after collection and refrigerate or keep on ice until delivered to laboratory. 5. Deliver samples to laboratory as soon after collection as • possible and no more than 48 hours after collection. 6. Sample bottles that have preservative put in by the laboratory . should not be filled to the top. An airspace to allow for expansion and to prevent loss of preservative during sampling should be left in bottle. 7. Unpreserved bottles should be filled completely to minimize oxidation of the sample. 8. Always measure temperature immediately on sample collection. 9. It is preferable to measure pH, conductivity, and dissolved gases immediately upon sample collection. However, the samples may be analysed up to two hours after collection if the samples are cooled in completely filled sample bottles. B. 2. BAILER SAMPLES In wells where there is no pump installed, the samples are often collected by using a bailer. The optimum procedure in sampling a well is to remove water until the temperature, pH, and/or conductivity become constant inorder to ensure that fluid from the formation and not stagnant casing water is removed. This usually requires that one to three casing volumes of fluid be removed. The procedure to follow when sampling with a bailer is as follows: 1. Obtain sample bottles from the laboratory. 2. Check that bailer is clean and free of dirt and grease. Also, before each day of sampling, rinse bailer in tap water. C~ B-1