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WATERSHED EARLY WARNING SYSTEMS
Citation:
ALLEN, JOEL J. WATERSHED EARLY WARNING SYSTEMS . Presented at NATO ECOTER Workshop, Budapest, HUNGARY, October 05, 2006.
Impact/Purpose:
To inform the public
Description:
Contaminants are of concern when they are found in concentrations that are toxic to plants and/or animals. On-line Toxicity Monitors (OTM) integrate all dissolved and bound chemicals found in water. This is important because of the limitations of chemical specific monitoring; you only find what you are looking for and only if the chemical is present in measurable concentrations. No chemical specific approach has this capability. Only an organism can integrate all factors that contribute to stress. Detection of chemicals in toxic concentrations provides the most reliable protection of water resources. This approach can best be described as the aquatic version of the “Canary in the Coal Mine.” Automated systems are now available to continuously monitor water sources providing data collection, analysis, and decision making on a temporal order of minutes from sample observation to decision algorithm completion. Current OTMs under investigation by WQMB use organisms ranging from single cells to whole organisms. Spectroscopic methods are used to measure fluorescence in the bacteria Vibrio fischeri and algae Chlorella vulgaris, CCD sensors are used to monitor swimming behavior in Daphnia magna, myoelectric action potentials are measured in the fish Lepomis macrochirus. Results indicate that exposures of short duration (<1-2 hours) elicit responses at concentrations similar to those of longer term (48-96 hour) acute assays, and sometimes approach chronic values. It is important to note that these systems are not the only OTMs available but were selected to cover a range of species and endpoints. Single contaminant toxicity assays performed at NRMRL's Test and Evaluation facility indicate these systems are quite sensitive relative to both concentration and time to response. Effective concentrations are generally in the parts per billion range for copper, cadmium, cyanide, and diazinon, and the low parts per million range for toluene and atrazine. Results indicate varied responses of the OTMs under investigation. They also detail the need for careful consideration of the potential contaminants and desired sensitivity ranges when selecting OTMs for deployment in EWSs. General conclusions can be drawn given the conditions under which each OTM was challenged. It is important to recognize that no one OTM is most sensitive for all contaminants. The range of sensitivities of the OTMs under investigation are generally protective of human health and were in the low ppb to low ppm range. Given the rapid response of these and other OTMs (within 1-2 hours of exposure), they are ideally suited for the task of continuous monitoring of water supplies to screen for changes in water quality due to chemical contamination. While there are still gaps in knowledge concerning OTMs, results here indicate them to be a toxicologically reasonable approach to monitoring water quality. OTMs are the only devices available to monitor toxicity for use in continuously screening water quality. Detection of changes in water quality can then initiate further investigation into the cause(s) of the change. Future research will investigate OTMs use in distribution systems, operational use in source water CWSs, and methods to quickly identify causes of observed toxicity. A pilot effort is currently being implemented in the Cincinnati, OH area. OTMs are being deployed on the Ohio, East Fork of the Little Miami, and Licking Rivers. Installation is scheduled to be completed by the end of 2006. Further research into OTM technology use to monitor distribution system water quality is planned to commence in 2007.