Analysis of Water Chemistry

1
Analysis of Water Chemistry

• Urban Stream Restoration Project

By Bob Smith Shelly Alicia
2
Outline

• Water Chemistry Background
• Chemistry in Urban Streams
• Methods
• 2003 Results
• Comparison to 2002
• Conclusions

3
Outline

• Water Chemistry Background
• Chemistry in Urban Streams
• Methods
• 2003 Results
• Comparison to 2002
• Conclusions

4
Temperature

• Most aquatic organisms are cold-blooded and have
  an ideal temperature range, specific to the
  organism
• Diatoms 15-25 degrees C
• Green algae 25-35 degrees C
• Blue greens 30-40 degrees C
• Salmonids cold water fish

5
Temperature, continued

• Affects development of invertebrates, metabolism
  of organisms
• Affects dissolved oxygen (warm water holds less
  oxygen)
• Warm water makes some substances more toxic
  (cyanide, phenol, xylene, zinc) and, if combined
  with low DO, they become even more toxic

6
Dissolved Oxygen

• Oxygen that is dissolved in water
• DO increases with cooler water and mixing of
  water through riffles, storms, wind
• Nutrient loading can lead to algal blooms which
  result in decreased DO
• 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.

7
Dissolved Oxygen, continued

• Dissolved oxygen can also be expressed as
  saturation
• 80-124 excellent
• 60-79 ok
• lt 60 poor

8
Conductivity

• Measures the ability of water to carry an
  electric current
• Measures the ions such as Na, Cl- in the water
• Differences in conductivity are usually due to
  the concentration of charged ions in solution
  (and ionic composition, temp.)
• Reported as microsiemens per cm

9
pH

• pH measures the degree of acidity or alkalinity
  of the water (each number is a 10-fold
  difference)
• 0-6 acid 7 neutral 8-14 base
• Ideal for fish 6.5 8.2
• Ideal for algae 7.5 8.4
• Acid waters make toxic chemicals (Al, Pb, Hg)
  more toxic than normal, and alter trophic
  structure (few plants, algae)

10
Turbidity

• Measures the cloudiness of the water
• Turbidity caused by plankton, chemicals, silt,
  etc.
• Most common causes of excess turbidity are
  plankton and soil erosion (due to logging,
  mining, farming, construction)

11
Turbidity, continued

• Excess Turbidity can be a problem
• Light cant penetrate through the water
  photosynthesis may be reduced or even stop
  algae can die
• Turbidity can clog gills of fish and shellfish
  can be fatal
• Fish cannot see to find food, but can hide better
  from predators

12
Phosphorus (Reactive)

• Is necessary for plant and animal growth
• Natural source phosphate-containing rocks
• Anthropogenic source fertilizer and pesticide
  runoff from farming
• Can stimulate algal growth/bloom

13
Nitrates

• Formed by the process of nitrification (addition
  of O2 to NH3 by bacteria)
• Used by plants and algae
• Is mildly toxic, fatal at high doses
• Large amounts (leaking sewer pipes, fertilizer
  runoff, etc.) can lead to algal blooms, which can
  alter community structure, trophic interactions
  and DO regimes)
• Below 90 mg/L seems to have no effect on warm
  water fish, but cold water fish are sensitive

14
Alkalinity

• A measure of the substances in water that can
  neutralize acid and resist changes in pH
• Natural source rocks
• Ideal water for fish and aquatic organisms has a
  total alkalinity of 100-120 mg/L
• Groundwater has higher alkalinity than surface
  water

15
Hardness

• The amount of Calcium and Magnesium in the water
  (the two minerals mostly responsible)
• Natural source rocks
• Limestone hard water, granite not hard water

16
Hardness, continued

• 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
• 0 60 soft water
• 61-120 moderately hard water
• 121-180 hard water
• 181 very hard water
• Hardness and alkalinity are related

17
Outline

• Water Chemistry Background
• Chemistry in Urban Streams
• Methods
• 2003 Results
• Comparison to 2002
• Conclusions

18
Physical Effects of Urbanization Related to Water
Chemistry

• Riparian Vegetation Removal
• Decreased Groundwater Recharge
• Heat Island Effect
• Increased Surface Runoff / Impervious Surfaces
• Leaky Storm-water / Sewage Pipes
• Point Source Pollution

19
Trends in Water Chemistry

• Temperature increases
• Nitrate increases
• Phosphorus increases
• Conductivity increases (Increased ion
  concentration)
• O2 demand increases

20
Outline

• Water Chemistry Background
• Chemistry in Urban Streams
• Methods
• 2003 Results
• Comparison to 2002
• Conclusions

21
Field Measurements

• Dissolved Oxygen
• Temperature
• Conductivity
• pH

22
Water Collection For Laboratory Analysis

• Grab Samples
• Three replicates (from multiple samples)
• Measured within 24 hours (few exceptions)

Picture Source http//www.ci.gresham.or.us/
departments/des/stormwater/water_quality.htm
23
Laboratory Analysis

• Nitrate
• Reactive
• Phosphorus
• Alkalinity
• Hardness
• Turbidity

24
Outline

• Chemistry in Urban Streams
• Water Chemistry Measurements and Theory
• Methods
• 2003 Results
• Comparison to 2002
• Conclusions

25
Field Measurements 2003
26
Turbidity

• All values for 2003 lt5 jtu
• For 2002, all but one sampling date lt5 jtu
• The one date for 2002 gt5 was during a storm event

27
Reactive Phosphorus 2003
28
Nitrate 2003
29
Alkalinity 2003
30
Hardness 2003
31
Outline

• Chemistry in Urban Streams
• Water Chemistry Measurements and Theory
• Methods
• 2003 Results
• Comparison to 2002
• Conclusions

32
Field Measurement PB
33
Field Measurement For SAL
34
Paint Branch
35
Stewart April Lane
36
Outline

• Chemistry in Urban Streams
• Water Chemistry Measurements and Theory
• Methods
• 2003 Results
• Comparison to 2002
• Conclusions

37

• Between Site Differences
• Land use increased runoff cause increased input
  of particular constituents
• Natural site variation Substrate type
• Between Years
• Increased snow caused more runoff increased use
  of road-salt
• Drought (temperature, DO)

38

• . . . 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 Natures
  storehouse, in which she locks up her wonders.
• Izaak Walton
• (from Ward, 1992)