Presence of Biofilm and Changes in the Quality of Water Stored in the Laboratory

Abstract

Purified waters for use in laboratory procedures, or those used to obtain them, are possibly subject to biofilm formation and quality changes. The objective of this test was to evaluate some variables related to water quality over storage time, for purified water (AP) and air conditioning condensation water (AC). Two barrels were filled with 10 L of water, one with AP and the other with AC. For a period of 10 days, electrical conductivity (EC), total dissolved solids (TSD), pH and levels of Nitrite, Nitrate, Ammonia Nitrogen (N-ammonium) and Phosphate were determined. The results show that EC, pH and Nitrate and Ammonium-N levels increased over the storage time, both for AP and AC, which is indicative of microbial activity in the stored water. The presence of Phosphate was not observed in the water samples analyzed and Nitrite did not change between the beginning and end of the storage period. It can be concluded that there was a loss of quality of the water stored during the observation period, which suggests the need to adopt conservation methods.