The solubility of atomic number 8 in irrigate is low and so any performer that affects concentration of fade away atomic number 8 has a major extend to on aquatic life because water pollutants reduce the cadence of dissolved type O in the water. The extent to which these pollutants reduce oxygen is measured using a Biochemical Oxygen look at (B.O.D.) test.
Biochemical Oxygen Demand
Biochemical Oxygen Demand is defined as the amount of dissolved oxygen consumed by biological action when a sample of water is unplowed in the dark at 20°C for volt geezerhood.
The more polluted the water, the more oxygen utilize up by micro-organisms. The rate at which micro-organisms use oxygen depends on temperature. A standard temperature is needed for valid comparisons between samples of water, so 20°C is used. The samples must be kept in the dark to stay fresh photosynthesis from replacing the oxygen used by the micro-organisms. The samples are kept in the dark for five twenty-four hour periods because a standard length of time is needed for comparison. quin days entirelyows the micro-organisms to adjust to their environment. Any longer would cause all the oxygen to be used up and measurements of the amount of dissolved oxygen would be impossible.
B.O.D. Test
When collecting samples for the B.O.
D test, the bottle must be filled under the surface of the water to prevent oxygen from the air entering the bottle, and should be filled to the brim to prevent air from being trapped under the lid. If the water is very(prenominal) polluted it must first be diluted because differently all the oxygen would be used up beforehand the five day period was over. Distilled water should be used for dilution and it should be well oxygenated as this ensures that there will be enough oxygen at the end of the five day period to carry out the test properly. The experimental solution might need to be multiplied by the dilution factor. This leads to a large B.O.D. value even though only to the highest degree 9 ppm of oxygen can dissolve in water at...If you want to get a full essay, order it on our website: Ordercustompaper.com
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