Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Civil Engineering


The need to collect and analyze samples of water resources periodically has been realized for many years by people concerned. with the use and preservation of water resources. As water use increased, routine analysis of water quality also increased. In order to obtain representative results of analyses, care must be taken to obtain samples which are representative of the existing field conditions. Care must also be taken to have a sample which is representative of the field conditions at the time the sample is being analyzed. The time lapse between collection and analysis of water samples can become quite lengthy for the following reasons: time of transport to the testing laboratory, lack of convenience or manpower, number of samples to be tested, and laboratory testing capacity. During the time lapse between collection and analysis, the composition of the sample may change because of the chemical reactions that constantly occur in all substances. Freezing has been used as a method to preserve the chemical quality of the sample at the time of collection. Therefore, a simple, practical water sample preservation method such as freezing would be very beneficial to a water quality surveillance program. A practical freezing process for preservation would involve the following: collection of representative samples, preservation by simply freezing in a convenient food storage freezer or locker, storage in the frozen state until the time the samples are to be analyzed, thawing the samples at room temperature, and, finally, analyses of the samples. A rapid freezing technique such as the utilization of dry ice and acetone seems to be less practical and may be dangerous. If the more feasible freezing process (food storage freezer) preserved. the chemical integrity of water samples, the process could easily be implemented. within a water quality surveillance program. A literature review revealed that adequate statistical evaluations of some of the freezing preservation processes were not made, and as a result, conflicting opinions on the effects of preservation by freezing prevailed. This research was undertaken to determine whether the freezing or thawing of water samples would significantly change the chemical quality of the samples. The decision to evaluate the data statistically was made in order to support the conclusions of this research project.

Library of Congress Subject Headings

Water -- Analysis



Number of Pages



South Dakota State University