How to Monitor Pollution With Microbes

Monitoring pollution and toxicity with live organisms or cells is more effective than using standard chemical analyses.

Monitoring environmental pollution with microbes involves using organisms or cells from native or genetically modified test species. Pollutants monitored using these natural bio-sensors can be in air, soil, wastewater or industrial effluents. Highly sensitive toxicity bio-assays using bioluminescence inhibition are common, standardized and commercially available. They offer the most accurate results over a large range of different chemicals to be tested.

Things You'll Need

• Marine bacteria Vibrio Fischeri
• Mobile or semipermanent bio-assay laboratory
• Plate luminometer
• Safety gloves

Instructions

1. Create a natural bio-sensor using a marine bacteria such as Vibrio Fischeri (a naturally bioluminescent bacterium).

2. Using the luminometer, take a preliminary measurement of light emitted by the natural bio-sensor in a sample of water you know is not polluted. This serves as your control.

3. Station a small laboratory at the site or sites to be tested for pollution. Take a container suitable for collecting the water to be tested and safety equipment depending on the type of pollution expected. You also need your luminometer.

4. Add the bio-sensor organisms to the suspected polluted medium (river, waterway or effluent).

5. Collect a sample of the polluted medium containing the bio-sensor.

6. Measure the blue-green light emitted using a luminometer. According to Aboatox, it only takes between 5 and 30 minutes to perform this test accurately using a modern plate luminometer. If the bacteria sustain a reduced metabolic enzymatic activity due to pollutant contamination, they will produce proportionally less light. The wavelength you should be expecting is 490 nanometers (nm).

Tips & Warnings

• The exposure time of the bio-sensor to the polluted source should not exceed 96 hours, for best results.

• Commercially available kits can conduct environmental monitoring, such as Aboatox's BioTox luminometric toxicity test kit, a standardized test using the bacteria Vibrio fischeri, as mentioned. The kits can be stored and used in the same way as any other laboratory reagent.

• Some newly developed, specialist methods for environmental testing, such as heavy metal contamination, also use bacteria to sense particular metals (for instance, lead or mercury), so if you require a specific pollutant to be monitored, a kit containing these specialist bacteria may be more suitable. They all use luminometric end-point detection, as described earlier.

• Effluent and polluted water is dangerous. Handle with care. Wear protective gloves and goggles when working with or in close to potentially harmful substances. Extra safety precautions may be required if you are working at an industrial site.

References

• Aboatox: Environmental Monitoring: Luminometric Toxicity Tests
• Molecular Plant Biotechnology: Pollution Control: Environmental Bio-monitoring

Resources

• "Trends In Microbiology": The Applications of Microbes In Environmental Monitoring