Water chemistry


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Water chemistry

  1. 1. Analysis of Water Chemistry Urban Stream Restoration Project By: AG-Pentian
  2. 2. Outline <ul><li>Water Chemistry Background </li></ul><ul><li>Chemistry in Urban Streams </li></ul><ul><li>Methods </li></ul><ul><li>2003 Results </li></ul><ul><li>Comparison to 2002 </li></ul><ul><li>Conclusions </li></ul>
  3. 3. Outline <ul><li>Water Chemistry Background </li></ul><ul><li>Chemistry in Urban Streams </li></ul><ul><li>Methods </li></ul><ul><li>2003 Results </li></ul><ul><li>Comparison to 2002 </li></ul><ul><li>Conclusions </li></ul>
  4. 4. Temperature <ul><li>Most aquatic organisms are cold-blooded and have an ideal temperature range, specific to the organism: </li></ul><ul><li>Diatoms 15-25 degrees C </li></ul><ul><li>Green algae 25-35 degrees C </li></ul><ul><li>Blue greens 30-40 degrees C </li></ul><ul><li>Salmonids – cold water fish </li></ul>
  5. 5. Temperature, continued <ul><li>Affects development of invertebrates, metabolism of organisms </li></ul><ul><li>Affects dissolved oxygen (warm water holds less oxygen) </li></ul><ul><li>Warm water makes some substances more toxic (cyanide, phenol, xylene, zinc) and, if combined with low DO, they become even more toxic </li></ul>
  6. 6. Dissolved Oxygen <ul><li>Oxygen that is dissolved in water </li></ul><ul><li>DO increases with cooler water and mixing of water through riffles, storms, wind </li></ul><ul><li>Nutrient loading can lead to algal blooms which result in decreased DO </li></ul><ul><li>4-5 ppm DO is the minimum that will support large, diverse fish populations. Ideal DO is 9 ppm. Below 3 ppm, all fish die. </li></ul>
  7. 7. Dissolved Oxygen, continued <ul><li>Dissolved oxygen can also be expressed as % saturation </li></ul><ul><li>80-124% = excellent </li></ul><ul><li>60-79% = ok </li></ul><ul><li>< 60% = poor </li></ul>
  8. 8. Conductivity <ul><li>Measures the ability of water to carry an electric current </li></ul><ul><li>Measures the ions such as Na+, Cl- in the water </li></ul><ul><li>Differences in conductivity are usually due to the concentration of charged ions in solution (and ionic composition, temp.) </li></ul><ul><li>Reported as microsiemens per cm </li></ul>
  9. 9. pH <ul><li>pH measures the degree of acidity or alkalinity of the water (each number is a 10-fold difference) </li></ul><ul><li>0-6 = acid; 7 = neutral; 8-14 = base </li></ul><ul><li>Ideal for fish = 6.5 –8.2 </li></ul><ul><li>Ideal for algae = 7.5 – 8.4 </li></ul><ul><li>Acid waters make toxic chemicals (Al, Pb, Hg) more toxic than normal, and alter trophic structure (few plants, algae) </li></ul>
  10. 10. Turbidity <ul><li>Measures the cloudiness of the water </li></ul><ul><li>Turbidity caused by plankton, chemicals, silt, etc. </li></ul><ul><li>Most common causes of excess turbidity are plankton and soil erosion (due to logging, mining, farming, construction) </li></ul>
  11. 11. Turbidity, continued <ul><li>Excess Turbidity can be a problem: </li></ul><ul><li>Light can’t penetrate through the water – photosynthesis may be reduced or even stop – algae can die </li></ul><ul><li>Turbidity can clog gills of fish and shellfish –can be fatal </li></ul><ul><li>Fish cannot see to find food, but can hide better from predators </li></ul>
  12. 12. Phosphorus (Reactive) <ul><li>Is necessary for plant and animal growth </li></ul><ul><li>Natural source = phosphate-containing rocks </li></ul><ul><li>Anthropogenic source = fertilizer and pesticide runoff from farming </li></ul><ul><li>Can stimulate algal growth/bloom </li></ul>
  13. 13. Nitrates <ul><li>Formed by the process of nitrification (addition of O 2 to NH 3 by bacteria) </li></ul><ul><li>Used by plants and algae </li></ul><ul><li>Is mildly toxic, fatal at high doses </li></ul><ul><li>Large amounts (leaking sewer pipes, fertilizer runoff, etc.) can lead to algal blooms, which can alter community structure, trophic interactions and DO regimes) </li></ul><ul><li>Below 90 mg/L seems to have no effect on warm water fish, but cold water fish are sensitive </li></ul>
  14. 14. Alkalinity <ul><li>A measure of the substances in water that can neutralize acid and resist changes in pH </li></ul><ul><li>Natural source = rocks </li></ul><ul><li>Ideal water for fish and aquatic organisms has a total alkalinity of 100-120 mg/L </li></ul><ul><li>Groundwater has higher alkalinity than surface water </li></ul>
  15. 15. Hardness <ul><li>The amount of Calcium and Magnesium in the water (the two minerals mostly responsible) </li></ul><ul><li>Natural source = rocks </li></ul><ul><li>Limestone = hard water, granite = not hard water </li></ul>
  16. 16. Hardness, continued <ul><li>Soft water can be a problem: in soft water, heavy metals are more poisonous, some chemicals are more toxic, drinking soft water over long periods can increase chance of heart attack </li></ul><ul><li>0 – 60 = soft water </li></ul><ul><li>61-120 = moderately hard water </li></ul><ul><li>121-180 = hard water </li></ul><ul><li>181+ = very hard water </li></ul><ul><li>Hardness and alkalinity are related </li></ul>
  17. 17. Outline <ul><li>Water Chemistry Background </li></ul><ul><li>Chemistry in Urban Streams </li></ul><ul><li>Methods </li></ul><ul><li>2003 Results </li></ul><ul><li>Comparison to 2002 </li></ul><ul><li>Conclusions </li></ul>
  18. 18. Physical Effects of Urbanization Related to Water Chemistry <ul><li>Riparian Vegetation Removal </li></ul><ul><li>Decreased Groundwater Recharge </li></ul><ul><li>Heat Island Effect </li></ul><ul><li>Increased Surface Runoff / Impervious Surfaces </li></ul><ul><li>Leaky Storm-water / Sewage Pipes </li></ul><ul><li>Point Source Pollution </li></ul>
  19. 19. Trends in Water Chemistry <ul><li>Temperature increases </li></ul><ul><li>Nitrate increases </li></ul><ul><li>Phosphorus increases </li></ul><ul><li>Conductivity increases (Increased ion concentration) </li></ul><ul><li>O 2 demand increases </li></ul>
  20. 20. Outline <ul><li>Water Chemistry Background </li></ul><ul><li>Chemistry in Urban Streams </li></ul><ul><li>Methods </li></ul><ul><li>2003 Results </li></ul><ul><li>Comparison to 2002 </li></ul><ul><li>Conclusions </li></ul>
  21. 21. Field Measurements <ul><li>Dissolved Oxygen </li></ul><ul><li>Temperature </li></ul><ul><li>Conductivity </li></ul><ul><li>pH </li></ul>
  22. 22. Water Collection For Laboratory Analysis <ul><li>Grab Samples </li></ul><ul><li>Three replicates (from multiple samples) </li></ul><ul><li>Measured within 24 hours (few exceptions) </li></ul>Picture Source: http://www.ci.gresham.or.us/ departments/des/stormwater/water_quality.htm
  23. 23. Laboratory Analysis <ul><li>Nitrate </li></ul><ul><li>Reactive </li></ul><ul><li>Phosphorus </li></ul><ul><li>Alkalinity </li></ul><ul><li>Hardness </li></ul><ul><li>Turbidity </li></ul>
  24. 24. Outline <ul><li>Chemistry in Urban Streams </li></ul><ul><li>Water Chemistry Measurements and Theory </li></ul><ul><li>Methods </li></ul><ul><li>2003 Results </li></ul><ul><li>Comparison to 2002 </li></ul><ul><li>Conclusions </li></ul>
  25. 25. Field Measurements 2003 SAL PB
  26. 26. Turbidity <ul><li>All values for 2003 <5 jtu </li></ul><ul><li>For 2002, all but one sampling date <5 jtu </li></ul><ul><li>The one date for 2002 >5 was during a storm event </li></ul>
  27. 27. Reactive Phosphorus 2003 PB SAL
  28. 28. Nitrate 2003 PB SAL
  29. 29. Alkalinity 2003 PB SAL
  30. 30. Hardness 2003 PB SAL
  31. 31. Outline <ul><li>Chemistry in Urban Streams </li></ul><ul><li>Water Chemistry Measurements and Theory </li></ul><ul><li>Methods </li></ul><ul><li>2003 Results </li></ul><ul><li>Comparison to 2002 </li></ul><ul><li>Conclusions </li></ul>
  32. 32. Field Measurement PB 2002 2003
  33. 33. Field Measurement For SAL 2002 2003
  34. 34. Paint Branch 2002 2003
  35. 35. Stewart April Lane 2002 2003
  36. 36. Outline <ul><li>Chemistry in Urban Streams </li></ul><ul><li>Water Chemistry Measurements and Theory </li></ul><ul><li>Methods </li></ul><ul><li>2003 Results </li></ul><ul><li>Comparison to 2002 </li></ul><ul><li>Conclusions </li></ul>
  37. 37. <ul><li>Between Site Differences </li></ul><ul><li>Land use – increased runoff cause increased input of particular constituents </li></ul><ul><li>Natural site variation – Substrate type </li></ul><ul><li>Between Years </li></ul><ul><li>Increased snow caused more runoff increased use of road-salt </li></ul><ul><li>Drought (temperature, DO) </li></ul>
  38. 38. <ul><li>“ . . . Rivers and the inhabitants of the watery element were made for wise men to contemplate, and fools to pass by without consideration, . . . for you may note, that the waters are Nature’s storehouse, in which she locks up her wonders.” </li></ul><ul><li>Izaak Walton </li></ul><ul><li>(from Ward, 1992) </li></ul>
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