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Redwood City <br /> Water Quality Monitoring Program Plan <br /> <br /> <br />© 2014 DKF Solutions Group, LLC Page 17 of 41 <br />7. BOD (biological oxygen demand) <br /> Discussion: Most natural waters contain small quantities of organic <br />compounds. Microorganisms living in oxygenated waters use <br />dissolved oxygen to oxidatively degrade the organic <br />compounds, releasing energy which is used for growth and <br />reproduction. Populations of these microorganisms tend to <br />increase in proportion to the amount of food available. This <br />microbial metabolism creates an oxygen demand <br />proportional to the amount of organic compounds useful as <br />food. Under some circumstances, microbial metabolism can <br />consume dissolved oxygen faster than atmospheric oxygen <br />can dissolve into the water or the autotrophic community <br />(algae, cyanobacteria and macrophytes) can produce. Fish <br />and aquatic insects may die when oxygen is depleted by <br />microbial metabolism. The BOD value is most commonly <br />expressed in milligrams of oxygen consumed per litre of <br />sample during 5 days of incubation at 20 °C and is often <br />used as an indicator of the degree of organic pollution of <br />water. <br /> Sample Container: Plastic or glass <br /> Sample Type: Grab <br /> Sample Volume Required: 250ml <br /> Hold Time: 48 hours <br /> Preservative: None (store at 0-6 degrees Celsius) <br /> Analytical Method: Method 510 B Standard Methods for the Examination of <br />Water or Wastewater, 21st Edition <br /> <br /> <br />8. SAMPLING EQUIPMENT AND CALIBRATION <br /> <br />A. Sampling Equipment Used At Redwood City <br />The following are the sampling equipment used by the City <br /> Sampling pole with fixed container <br /> Sampling pole with removable container <br /> Portable pH and temperature probe <br />o Hach HQ30d <br /> Portable dissolved oxygen meter <br />o Hach, Pocket Pro pH Tester <br /> Sampling pail and rope <br /> Stream velocity meter <br />o Flow Probe Velocity Meter or equivalent <br /> Grab-n-Go Sample Kit containing: <br />o Ice pack <br />o Waterproof pen <br />o Sample labels <br />o Camera <br />o Sample bottles <br />o Etc. <br /> <br /> <br /> <br />6.2.A. - Page 183