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DEPLOYMENT OF A WATER QUALITY EARLY WARNING SYSTEM USING ON-LINE TOXICITY MONITORS
Citation:
ALLEN, JOEL J., D. M. SHAW, C. NIETCH, S. P. SHAW, AND L. H. SHAW. DEPLOYMENT OF A WATER QUALITY EARLY WARNING SYSTEM USING ON-LINE TOXICITY MONITORS. Presented at INTERNATIONAL SYMPOSIUM ON TOXICITY ASSESSMENT, TOYAMA, JAPAN, August 19 - 24, 2007.
Description:
Contaminants are of concern when they are found in concentrations that are toxic to plants and/or animals. On–line Toxicity Monitors (OTMs) integrate all factors resulting in stress including physical and chemical qualities. 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 EPA’s National Risk Management Research Laboratory use organisms ranging from single cells to whole organisms. 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.
OTMs 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, the low parts per million range for toluene and atrazine. 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 they are a toxicologically reasonable approach to monitoring water quality. OTMs are the only devices available to monitor toxicity for use in continuously screening water quality. In the watershed protection context, detection of changes in water quality can initiate further investigation into the cause(s) of the change. Use of OTMs in such an approach will be discussed. Results to date generated at the Experimental Stream Facility will be presented as well as preliminary nanoparticle research.