AWWA WQTC69278

The Philadelphia Water Department has been developing its toolbox for response to potential contamination, and has evaluated the use of the Eclox test kit to: establish a baseline for source water and finished water; detect specific contaminants; and, report reliable and reproducible results. Baseline toxicity studies were completed for Philadelphia's intakes and finished waters from three water treatment plants. De-ionized water samples spiked with various contaminants at different concentrations were also tested. Quality control samples included vendor-supplied de-ionized water as a reference standard, and laboratory prepared phenol solutions as a positive control standard. Matrix effects were also studied. Networking with some experts in this field revealed that results were consistent with their findings. The Eclox kit was used in an event of an industrial spill of cyanide that caused a fish kill in one of the tributaries to our source water. The fish kill occurred due to an accidental release of large quantities of potassium thiocyanate into a wastewater treatment plant that discharges to the tributary. The affected water samples were analyzed from different locations of the source water using Eclox. The average percentage inhibition for the affected samples was 95.2% and the unaffected water samples showed an average of 77.8%. The Eclox test was able to measure a difference in inhibition; however, the difference was marginal. Hence, the Eclox test alone could not serve as primary indicator of water quality contamination; however, it did prove to be useful for screening samples that might represent the water that has been contaminated. Includes table, figures.