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The relatively large number of "credible" agents (chemical, radiological, and microbial contaminants) poses a special challenge for utilities,emergency responders, health agencies, and government regulatory agencies that may berequired to respond to a bioterrorism threat (i.e., how to quickly analyze for a wide variety ofcontaminants). Unfortunately, with the amount of time required to ship samples to reference laboratoriesand conduct standard analyses on water containing unknown agents, it is anticipated thatsignificant public health responses and utility operational responses would be required prior tothe receipt of definitive analytical results. Rapid screening techniques that could yield even"presumptive" results in a short amount of time, could provide important additional informationto decision makers managing the response to threatened or suspected incidents. Thesetechniques could include rapid immunoassays, rapid polymerase chain reaction screening, andacute toxicity tests that could be conducted either in the field at the suspected sites ofcontamination, or in a nearby utility, public health, commercial or regulatory agency laboratory.Obviously, rapid screening techniques do not provide the same accuracy, precision, orability to definitively identify a contaminant, as do standard laboratory procedures. However, they offer theadvantage of rapid, presumptive results in an emergency situation. It is necessary to carefullyevaluate these rapid analytical techniques to determine their capabilities and limitations, as wellas their accuracy and precision. The purpose of the current study is to help determine thesecharacteristics for two of the commercially available acute toxicity screening devices, Microtoxand Eclox. The Microtox system is a broad-spectrum acute toxicity bioassay that can be used in thelaboratory or the field. Microtox is the lab version and Delatox is the portable field version.Microtox (and Delatox) are based on a bacterial bioluminescence test described in method 8050of Standard Methods (1998). The assay is a metabolic inhibition test that utilizes a suspension ofluminescent bacteria as a test organism. The test provides a rapid means for detecting thepresence of toxic substances. The Eclox system is a simple-to-use water assay that was developed as a field testingkit for the British military. The original application was to enable soldiers to perform rapid testson raw water to determine treatability in the field and subsequently on treated water to determinesafety for consumption. However, the simplicity and speed of testing also make the kit attractivefor emergency use by water utilities concerned with the threat of intentional contamination.The Eclox screen is a rapid chemiluminescence test for the presence of toxic substances.The test utilizes a plant enzyme which when mixed with other reagents produces light. Certainpollutants when present in water interfere with the chemical reaction and reduce the amount ofluminescence. The extent of inhibition of chemiluminescence is assumed to be proportional tothe concentration of the contaminant. An effective rapid screening method would have the following characteristics:multiple toxins detectable;can test for contaminants of concern;appropriate detection levels (e.g., lower than public heath concerns);test is quantitative;test is reproducible;false positive and negative results are minimal;minimal time required to perform test;minimal analytical skill required to perform test; and,minimal cost for test equipment and supplies. The paper lists the sets of analyses that were performed to evaluate the effectiveness of the two screening methods. Includes 3 references, tables, figures.

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Edition: Vol. - No. Published: 11/02/2003 Number of Pages: 19File Size: 1 file , 420 KB