Water Quality

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Water Quality

• Chemical and Biological Indicators

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Why is water quality important?

• Human health drinking water
• Fisheries
• Water for industry and
• agriculture
• Aesthetic reasons
• Species habitat
• Water for recreation
• (swimming, fishing, boating)

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What types of tests do we use to measure water
quality?

• Dissolved oxygen
• Nitrogen (usually nitrate-nitrogen)
• pH
• Macroinvertebrates
• Phosphorus (usually phosphate-phosphorus)
• Alkalinity
• Conductivity
• Chloride
• Salinity
• Suspended solids
• Fecal coliform bacteria

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Dissolved Oxygen

• The presence of oxygen gas molecules (O2) in the
  water.
• Why is it important?
• The oxygen in H2O is not dissolved oxygen.

Whats coming out of the diffuser?
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Dissolved Oxygen

• How does oxygen get into the water?
• -diffusion from the surrounding air
• -during the process of photosynthesis

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DO levels are affected by

• Altitude
• Temperature
• Speed of water movement (dams as well as natural
  differences and tides)
• Addition of wastes
• Vegetation

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Hudson River near Newburgh, NY, summer
Hudson River near Warrensburg, NY, winter

• Which do you think has more DO the stream on the
  left or the stream on the right? Why? What else
  do you need to know?

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Different Organisms Require Different Amounts of
DO

• Trout and salmon require high amounts of
  dissolved oxygen, as do most fish larvae

• Carp and catfish can survive with much less.

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How do Humans Affect the Amount of DO in the
Water?

• Addition of oxygen-consuming organic wastes

www.al.nrcs.usda.gov
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Changing the Flow of the Water
Which dam is this?
The Croton Dam
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Activities That Raise the Water Temperature
Source http//www.ger.com/indpt.jpg
Riparian zone vegetation, power plant cooling
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pH

• The measure of the acidity of a solution
• Acids produce H (hydrogen ions)
• Bases produce OH- (hydroxide ions)

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Why is pH important?

• If the pH is too low, it could indicate pollution
  from acid rain
• Acid rain can kill insects and other organisms,
  and harms vegetation, often killing forests
  (especially in high altitude areas because of
  acidic fog)

Photo courtesy of C. Harris
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How is pH measured?
-pH is measured on a scale of 0 to 14. -A
solution with equal hydrogen and hydroxide ions
would have a pH of 7 -What would the pH of a
solution be that had more hydrogen than hydroxide
ions? -A decrease of one unit on the pH scale is
the result of a 10 fold increase in hydrogen
ions.
Drawing by J. Jenkins
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basic
neutral
acidic
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How Does pH Affect a River?

• It changes the availability of different
  nutrients and metals in the water, making it hard
  for some animals to survive
• Metals that leach from the soils when pH changes
  especially affect immature stages of aquatic
  insects and fish

Fish larvae exposed to biotoxins that cause
morphological abnormalities.
www.nwfsc.noaa.gov
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What Causes a pH Change?

• Atmospheric deposition (acid rain)
• Surrounding rocks and soils
• Wastewater discharges from business and industry
• Acid mine drainage

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Acid Rain in U.S.
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Nitrogen Pollution

• Do you contain nitrogen?

Does the air contain nitrogen? What about plants
and animals?
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Nitrogen so what?

• Plants and animals need nitrogen
• Butthere can be too much of a good thing!
• Too much nitrogen results in.

There is both cultural (human) and natural
eutrophication
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Nitrogen Pollution

• Too much nitrogen can cause
• Eutrophication

Increase in nutrients
Aquatic life suffers
Increase in plant growth
Dissolved oxygen declines as plants are decomposed
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Nitrogen in the Hudson

• Where does it come from?
• -human waste
• -acid deposition
• -fertilizer
• -agriculture fixation and feed
• Where does it go?

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• Nitrogen
• Why so
• much
• from
• the
• middle
• of the
• USA?

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1850s Iowa beige color is prairie
1990s Iowa beige color is prairie, gray is row
crops
Source  Compiled from Landsat Thematic Mapper
satellite imagery, Iowa Dept. of Natural
Resources.
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Humans and the Nitrogen Cycle
Last 100 years humans have more than doubled the
amount of fixed nitrogen that is pumped into the
atmosphere every year. Consequences acid rain,
ground level ozone, groundwater contamination,
surface water pollution, eutrophication
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Phosphorous

• Where does it come from?
• -not a gas
• -weathers from rock
• -reuse from already present phosphorous in
  detritus
• Why is it important?
• -less abundant and available than N
• -often the limiting nutrient in freshwater
  ecosystems

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Phosphorus Cycle

• Phosphates in rocks are mined
• Dissolves in water
• Plants take up inorganic phosphate
• We create phosphate-rich fertilizer
• Organisms use organic phosphates
• Decomposers convert organic waste back to
  inorganic P in the soil

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Phosphorous in the Hudson

• Main source detritus
• Used by plants during the growing season
• Some P is lost to the ocean and some becomes
  buried in sediment

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Macroinvertebrates

• Why do we sample invertebrates??
• Its a way to measure the health of an
  ecosystems aquatic life
• Scientists usually take several samples, looking
  at diversity and abundance, as well as species
  evenness

Dobsonfly larvae (helgrammite). Photo from Cary
Institute.
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Aquatic Ecosystem Biodiversity
www.hainaultforest.co.uk
www.fresc.usgs.gov
www.dkimages.com
www.eduwebs.org
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Species Diversity

• Diversity differs depending on time of year,
  habitat, ecosystem, sampling location, and water
  quality
• Macroinvertebrates are one way to assess water
  quality, but other measurements should be taken
  to ensure accuracy

Students from Tabernacle Christian Academy,
Poughkeepsie
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Alkalinity

• A measure of the capacity of water to neutralize
  (or buffer) acids
• Streams with high alkalinity would be able to
  resist a change in pH more than a stream with low
  alkalinity
• Alkalinity is reported as mg/L of CaCO3

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What are the Sources of Alkalinity?

• Compounds that create alkalinity include calcium
  carbonate, sodium bicarbonate, and calcium
  hydroxide.
• Limestone bedrock, like that in the Hudson River,
  produces water with relatively high alkalinity

Photo by H. Malcom
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Fecal coliform

• Fecal coliform bacteria refers to a group of
  micro-organisms that live in the digestive tracts
  of warm-blooded animals, such as humans
• Indicates sewage or manure

http//ucce.ucdavis.edu/files/filelibrary/5453/658
1.gif
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http//www.waterfilterreview.com/images/contaminan
ts/ h20_contaminants_200/fecal_coliform_200.jpg

• Health risk for humans due to disease causing
  bacteria/viruses (hepatitis A and typhoid fever)

http//www.water-research.net/images/ICE-TEA2.GIF
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Suspended Solids

• Suspended solids is a measure of how many
  particles are suspended in the water
• Caused by soil erosion, sewage discharge, algal
  growth, and movement of the water
• It is often measured along with turbidity, which
  is faster to measure
• Usually measured in mg/L

• Photo courtesy of C. Harris

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• Suspended particles can clog fish gills, smother
  eggs of fish and aquatic insects, and reduce
  growth rates.
• High suspended solids can decrease dissolved
  oxygen by blocking sunlight for plants and
  increasing the temperature of the water by
  absorbing light from the sun.

Photo C. Harris
http//www.kbac-hi.org/BMPs/images/tss2.gif
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