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Environmental Technology Listing
Title of Listing:
Microtox Acute Toxicity Test
Characterization Technologies
*Water, Waste, Soil, All Listings
Soil, Solid, Sediment, Water
VOCs, PCBs, Dioxins/Furans, PNAs, Heavy Metals
Web Site:
Technology Description:

The Microtox Acute Toxicity Test (Microtox) is a rapid bioassay based on bacterial bioluminescence. The luminescent microorganisms, Vibrio fischerii, emit light as a normal consequence of respiration. Chemicals or chemical mixtures which are toxic to the bacteria cause a reduction in light output proportional to the strength of the toxin. Including setup, a bioassay takes about an hour to perform. Many different sample types and phases can be tested with the Microtox, including freshwater, brackish, and saltwater aqueous samples, pure compounds, soils and sediments.

          The system is two-part, consisting of the microorganism and a temperature controlled luminometer which reads the bacterial light output. A computer is often linked to the system to provide processing and storage capabilities. The luminometer is quite rugged and weighs under 30 pounds. Several units have been used in mobile laboratories and in-field situations.

          The key to the Microtox system's replicability and uniformity is the "reagent," lyophilized microorganisms. Produced under strict controls at Microbics Corporation, the reagent is exceptionally consistent in its response to toxic materials. The reagent can also be stored for up to 18 months in a standard deep freezer before use. There are no stock cultures to maintain, no specially-lighted environmental chambers to construct. The reagent is "reconstituted" with pure water, and then used in the Microtox assay.

          Volumes are kept small in the Microtox test. Only 2.5mL of sample is necessary to run the assay, making collection, storage, and disposal of sample materials easy and inexpensive. The Microtox test is simple to operate even with minimal lab experience. It yields an EC50 endpoint which is comparable to LD50 values generated by traditional bioassays. Monitoring target include standard ecotoxicology monitoring targets, waste, and process streams.
Performance Status/

Performance Status:

          AZUR Environmental is a world leader in bioluminescence technology. The Microtox Acute Test is one of three technologies which have been developed at Microbics. The other two are the Microtox Chronic Toxicity Test, and the Mutatox test which measures genotoxicity and mutagenicity. The Microtox Acute Toxicity Test is a worldwide standard in environmental toxicology. Over 60 countries use the Microtox as a regulatory tool, including the United Kingdom, France, Germany, and Canada. The ASTM uses Microtox in standard D5660-95 for water and soil. Finally, the Water Environment Federation (WEF) has included Microtox as a method in Standard Methods for the Examination of Water and Wastewater, 19th Edition (just published) under section 8550.


          The Microtox Acute test has the same major limitation which afflicts all bioassay techniques. Total toxicity of a sample can be readily measured, but the nature of the contaminant must still be determined by chemical analysis. Bioassays cannot differentiate between toxicants.
Analytical Testing, Technologies, Characterization
Additional Topics/Tags/Keywords
Bioassay, VOCs, Test Kit

AZUR Environmental (formerly Microbics)
2322 Rutherford Road
Primary (619) 438-8282
Zip/Postal Code:
United States
Fax:(619) 438-2980
Branch Locations: