HA8 On-line Water Toxicity Monitoring
A105 & A106
8:00 AM - 12:00 PM, Thursday
() Application of an Automated Biomonitoring System for Source Water Protection.
Shedd, Tommy1, Widder, Mark1, van der Schalie, William1, Richardson, William2, Mikol, Yves2, 1 US Army Center for Environmental Health Research, Fort Detrick, MD, USA2 New York City Department of Environmental Protection, New York, NY, USA
ABSTRACT- An automated biomonitor was developed by the US Army Center for Environmental Health Research to rapidly identify developing toxic conditions caused by a wide range of chemicals in water supplies. The biomonitor continuously tracks ventilatory, gill purge, and body movements of bluegills (Lepomis macrochirus) as well as water parameters (pH, dissolved oxygen, temperature, and conductivity). If abnormal fish behavior or sudden changes in water quality are identified, a water sample is automatically taken and appropriate individuals notified via an autodialer. Data can be evaluated remotely and follow up action taken. The biomonitor has been field tested on source waters at Fort Detrick and New York City for over two years. System reliability has been high (on-line time >94%). Occasional biomonitor alarms unrelated to toxic water conditions can be minimized by limiting fish exposure time in the biomonitor to less than four weeks and by avoiding rapid temperature changes and temperatures below 8 deg. C. An expert system that models fish behavior is replacing current software and should reduce alarms due to benign changes in water quality parameters such as temperature or dissolved oxygen. Although alarms caused by toxic water conditions are rare events, rapid biomonitor response to accidental contamination was documented during the field trials. In one instance, the biomonitor responded to oil in the water from a small, otherwise undetected leak of diesel fuel, which was then remediated. In a second event, biomonitor alarms at the Fort Detrick water treatment plant led to an investigation of an acute toxicity event in the source water. Toxicity was associated with a solvent commonly used in paints and printing ink. A second set of fish continuously exposed to dechlorinated product water at the Fort Detrick site did not alarm during the event, showing an elimination of toxicity through the treatment process. Further, the solvent found in the source water was not detected analytically in the treated water. Relatively low maintenance and purchase costs make it possible to consider using these biomonitors as part of an overall early warning network for source water and water distribution systems.
Key words: real-time, biomonitor, bluegill, toxicity