evaluation of a water purification system for use in animal facilities

A commercially available water purification system was evaluated for its ability to minimize chemical and microbial contaminants. The reduction or removal of these impurities from the drinking water of experimental animals would reduce experimental variability. 3 strains of bacteria were collected from the processed water. An increase in the total number of bacteria was observed the longer the filters remained in use. Determinations of heavy metals in water samples before and after processing were made for lead, zinc, copper, nickel, manganese, iron, arsenic and mercury. Calcium and magnesium levels were also determined. The concentrations of these inorganic chemicals were reduced by the purification process except at 2 time points in which desorption of the chemical could have occurred. Bacterial colonization and desorption of these chemicals were controlled by installing new filter cartridges. Volatile halocarbon concentrations were determined for water samples before and after purification. All volatile halocarbons analyzed were less than 10 ppb before and after purification at all time points. Other organic chemicals were greatly reduced by the purification process. In a study of contaminants associated with installation of the unit, it was found that flushing the unit for 8 days reduced lead and methyl ethyl ketone concentrations to insignificant levels. The purification system was found to be effective in providing high quality drinking water as verified by a microbial and chemical testing program.