Uploaded byLeandro Michael Delos Santos Jr.
Dissolved oxygen
This document discusses dissolved oxygen (DO) levels in drinking water and their importance for aquatic life. It provides a table comparing drinking water quality standards in different countries that includes testing for microbiological, chemical, physical, and radiological parameters. The document discusses the sources and importance of DO, how aquatic organisms rely on it, and consequences of unusual DO levels. It also outlines several common methods for analyzing DO levels, including optical, electrochemical, colorimetric, and titrimetric methods.
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Dissolved oxygen
- 1. PRESENTED BY: LEANDROMICHAEL C. DE LOS SANTOS, JR.
- 2. Philippines (PNSDW 2007) Thailand Cambodia(MIME, MRD, PPWSA) Singapore (EPH) Microbiological Quality √ √ √ √ Total Coliform, Fecal Coliform and Heterotrophic Plate Count E. coli Chemical & Physical Quality √ √ √ √ Color, Hardness,Taste, Acidity, Alkalinity, Nitrate, pH, Phenols,Turbidity, pesticides, Flouride, etc. excluding DO excluding DO excluding DO excluding DO Radiological Quality √ √ √ √ Gross alpha activity, Gross beta, Radon toxic elements Radon 222 Comparative DrinkingWater Quality Standard
- 3. Comparative Acceptable D.OLevel in Freshwater & Marine
- 4. What is dissolvedoxygen? - refers to the level of free, non-compound oxygen present in water or other liquids. It is an important parameter in assessing water quality because of its influence on the organisms living within a body of water
- 5. Importance of dissolvedoxygen in aquatic life - dissolved oxygen is necessary to many aquatic animals as they use oxygen in respiration - microbes and fungi also require DO to decompose organic material at the bottom of a body of water
- 6. Where does DOcome from? Through air Plant byproduct
- 7. Aquatic organisms &their DO requirements
- 8. Consequences of unusualDO levels Fishkill orWinterkill Gas Bubble Disease
- 9. Uses of dissolvedoxygen analysis: • Determine the health or cleanliness of a lake or stream • Determine the amount and type of biomass a freshwater system can support • Determine the amount of decomposition occurring in the lake or stream
- 10.
- 11. Different Methods ofAnalysis OpticalSensor Method Optical DO Sensor
- 12. Different Methods ofAnalysis ElectrochemicalDO Sensor or Amperometric or Clark-type Sensors
- 13. Different Methods ofAnalysis ColorimetricMethod Indigo Carmine Rhodazine D
- 14. Different Methods ofAnalysis TitrimetricMethod WinklerTitration
- 15.
Editor's Notes
- #5 In limnology (the study of lakes), dissolved oxygen is an essential factor second only to water itself . A dissolved oxygen level that is too high or too low can harm aquatic life and affect water quality.
- #8 Comparative description of aquatic organisms and their DO requirements In summary, colder, deeper fresh waters have the capability to hold higher concentrations of dissolved oxygen, but due to microbial decomposition, lack of atmospheric contact for diffusion and the absence of photosynthesis, actual DO levels are often far below 100% saturation ¹⁰. Warm, shallow saltwater reaches 100% air saturation at a lower concentration, but can often achieve levels over 100% due to photosynthesis and aeration. Shallow waters also remain closer to 100% saturation due to atmospheric contact and constant diffusion ¹⁰.
- #9 Furthermore, low concentrations of DO, when combined with the presence of toxic substances may lead to stress responses in aquatic ecosystems because the toxicity of certain elements, such as zinc, lead and copper, is increased by low concentrations of dissolved oxygen (Enderlein et al., 1996).
- #13 In order to consistently polarize and de-polarize the electrodes for these short time periods, a pulsing polarographic DO sensor includes a third, silver reference electrode, separate from the silver anode 7. The electrochemical reaction (silver oxidation and oxygen reduction) remains the same. As rapid-pulse polarographic sensors reduce flow dependence when taking DO measurements, the water sample does not need to be stirred when using this sensor 7.