Share thisWith the growth of laboratory animal research, the need to control environmental variables is becoming increasingly critical. The quality of animal drinking water is one environmental variable that is receiving increased scrutiny.
During an Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC) site visit, inspectors generally try to assess the extent to which a facility has enacted a water quality assurance plan that is compatible with both the nature of the research being done and the health and microbiological status of the animals being maintained. Because there is no universally accepted water quality standard, each facility must determine the necessary water quality according to the requirements of their protocols. Ultimately, the facility staff will have to carry out the testing and documentation to demonstrate they are meeting their internal standard.
To accomplish this, many vivariums are investing in water purification and treatment systems to maintain consistent levels of water quality for their animal populations. This consistency is not only important to eliminate variables from the research, but also helps to ensure animal health, and can even improve efficiency in the vivarium. Once these systems are in place, however, the water must continually be monitored to ensure that the system is working. This article focuses on water testing and monitoring techniques that help ensure that purification systems are functioning properly and that animals are receiving consistent, high-quality drinking water.
Inorganic Contaminants
Inorganic contaminants commonly found in water consist primarily of salts and metals. These include calcium and magnesium (i.e., hardness), iron, heavy metals (e.g., cadmium, chromium, lead, copper), and sulfides, which are all quite common in water. This classification of contaminants has the property of increasing the electrical conductivity of the water. Therefore, you can continuously monitor the level of inorgan-ics in the water by measuring its conductivity. This is a very effective and accurate technique and is a standard feature of most reverse osmosis (RO) purification machines. It does not measure the levels of any one specific contaminant, but is a measure of the overall level of inorganics in the water. This is a very useful value for determining system trends, such as in increase or decrease in total inorganics over time, as well as determining the effectiveness of purification systems.
To determine the levels of specific inorganic contaminants, a laboratory test is required. There are hand-held test kits available for many of these contaminants that are simple to use, but have limited accuracy. For best results, a water sample should be sent to an outside laboratory for analysis. A general guideline would be to sample both the inlet water to the system and the outlet water that has undergone purification and treatment once per year by an outside laboratory. This time period can be adjusted to meet the facility’s needs. Sampling periods from quarterly to “as needed” are typical. Many test packages are available from laboratories that will test for the most common inorganics present. These packages offer a cost-effective way to obtain a comprehensive analysis. When combined with continual conductivity monitoring, this sampling schedule will yield a highly effective monitoring program for inorganic contaminants.