Natural water chemistry
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Natural Water Chemistry Water Quality Parameters Temperature - Dissolved Oxygen (DO) - pH Alkalinity - Hardness Nitrates and Phosphates - Turbidity Conductivity - Temperature Affects: Water density Gas solubility Chemical reaction rates Organism growth rates

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Natural Water Chemistry

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Natural water chemistry l.jpg
Natural Water Chemistry


Water quality parameters l.jpg
Water Quality Parameters

  • Temperature - Dissolved Oxygen (DO) - pH

  • Alkalinity - Hardness

  • Nitrates and Phosphates - Turbidity

  • Conductivity

  • -


Temperature l.jpg
Temperature

Affects:

Water density

Gas solubility

Chemical reaction rates

Organism growth rates

Conductivity

pH

Dissolved Oxygen


Temperature naturally varies because of l.jpg
Temperature – naturally variesbecause of…

… Changes in seasonal/diurnal air temperature

… Thermal stratification in lakes

… Size and temperature of inflows

… Residence time (lakes)


Temperature artificially varies because of l.jpg
Temperature – artificially variesbecause of…

… Heated industrial effluent

… Runoff from asphalt/pavement

… Deforestation


Q 10 rule l.jpg
Q10 rule

cold-blooded aquatic organisms

Predicts that growth rate will double if temperature increases by 10˚C (18˚F) within their "preferred" range.


Dissolved oxygen do l.jpg
Dissolved Oxygen (DO)

DO is the measurement of oxygen dissolved in water and available for fish and other aquatic life.

Indicates health of an aquatic system.

Can range from 0-18 ppm.

Most natural water systems require 5-6 ppm to support a diverse population.

Varies with time of day, weather, temperature.


Dissolved oxygen do9 l.jpg

Increase in organic waste

Increase in algae/plant vegetation

Decrease in DO available to organisms

Leads to changes in ecosystem as

organisms needing lots of DO are

replaced by organisms needing little.

Dissolved Oxygen (DO)



Slide11 l.jpg

Sill

Saltwater from entry

point.

Freshwater from stream

and river runoff.

Highly stratified

Slow-circulating

Long residence time


Slide12 l.jpg

Hood Canal

Jan

Apr

Jun

Sept

Dec

Modified from Hood Canal Dissolved Oxygen Project, Collias, UW, PRISM 2005

http://www.hoodcanal.washington.edu/observations/historicalcomparison.jsp


Potential causes l.jpg
Potential causes

  • Natural

  • increased sunlight or other climate factors

  • increased nutrient availability

  • Changes in ocean properties

  • Changes in river input (e.g.: drought)

  • Changes in weather conditions

  • Artificial

  • human loading of nutrients or organic material

  • Changes in river input (eg: diversion)


Ph p otential of h ydrogen l.jpg
pH - p(otential of) H(ydrogen)

pH = -log [ H +]

Determines the solubility of nutrients (PO4-3, NO3-, C)

and heavy metals (Fe, Cu, etc)

Determines availability of these chemicals for use by aquatic life.

In natural water systems, determined largely by geology and soils.


Ph of natural waters l.jpg

Sea water

due to humic acid

Limestone, marble, CO3 rich

Pure rain, snow

pH of natural waters

Modified from www.waterwatch.org

http://www.vic.waterwatch.org.au/fortheteacher/manual/sect4f.htm


Factors that affect ph l.jpg
Factors that affect pH

  • Algal blooms

  • Bacterial activity

  • Water turbulence

  • Chemicals flowing into the water body

  • Sewage overflows

  • Pollution


How ph affects aquatic life l.jpg
How pH affects aquatic life

Decreasing pH

(e.g.: via acid rain)

Liberation of Al, metals

Toxic conditions

Chronic stress

Smaller, weaker fish


Alkalinity l.jpg
Alkalinity

Alkalinity refers to the capability of water to neutralize acid.

Buffering capacity – resistance to pH changes.

Common natural buffer: CO3

(carbonates – like limestone).

Protects aquatic life.

Commonly linked to water hardness.

In natural systems:

50 – 150 mg/L as CaCO3.

Limestone outcrop


Hardness l.jpg
Hardness

Reflects dissolved carbonate minerals.

Mostly of concern for drinking water standards.

Metals precipitate out of solution.

Create scale/hard water deposits

High alkalinity  Hard water

From USGS

http://water.usgs.gov/owq/news.html


Slide21 l.jpg

Nitrates

and

Phosphates

Nitrate (NO3-)

naturally-occurring form of nitrogen found in soil.

Forms by microbial decomposition of fertilizers, plants, manures or other organic residues

Plants uptake nitrates (Spinach a good source).

Phosphate (PO4-3) naturally occurs in rocks and minerals.

Plants uptake weathered-out

elements and compounds.

Animals ingest plants.

Water soluble.

Redfield Ratio: 106:16:1


Nitrates l.jpg
Nitrates

  • Artificial sources:

  • Livestock

  • manure/urine

  • Failing septic

  • systems

  • Synthetic fertilizers

  • Can lead to:

  • eutrophication of natural water systems (overproduction of vegetation)

  • Blue baby syndromne

The U.S. EPA has set a maximum contaminant level for NO3- in drinking water of 10 parts per million (ppm)


Phosphates l.jpg
Phosphates

  • Artificial sources:

  • Sewage

  • Laundry, cleaning fluids

  • Synthetic fertilizers

  • Can also lead to eutrophication of natural water systems (overproduction of vegetation)

Blue green algae


1990 and 1999 comparison of nitrates in great lakes l.jpg
1990 and 1999 comparison of Nitrates in Great Lakes

From US EPA

http://www.epa.gov/glnpo/monitoring/limnology/SprNOx.html


Hypoxia in the gulf of mexico l.jpg
Hypoxia in the Gulf of Mexico

Gulf of

Mexico

Mississippi River drainage basin – 41% of US landmass.


Hypoxia in the gulf of mexico27 l.jpg
Hypoxia in the Gulf of Mexico

Hypoxic

waters

Image from Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC, January 2003


Hypoxia in the gulf of mexico28 l.jpg
Hypoxia in the Gulf of Mexico

From NCAT (Nat’l Center for Appropriate Technology)

http://www.ncat.org/nutrients/hypoxia/hypoxia.html


Slide29 l.jpg

Global distribution of oxygen-depleted coastal zones.

Annual = yearly events (summer or autumnal stratification)

Episodic = occurring at irregular intervals > one year

Periodic = occurring at regular intervals < one year

Persistent = all-year-round hypoxia

Sources: Boesch 2002, Caddy 2000, Diaz and others (in press), Green and Short 2003, Rabalais 2002


Slide30 l.jpg

Source: Patrick Heffer, Short Term Prospects for World Agriculture and Fertilizer Demand 2002/03 - 2003/04 (Paris: International Fertilizer Industry Association (IFA), December 2003); IFA Secretariat and IFA Fertilizer Demand Working Group, Fertilizer Consumption Report (Brussels: December 2001); historical data from Worldwatch Institute, Signposts 2002, CD-ROM, compiled from IFA and the U.N. Food and Agriculture Organization, Fertilizer Yearbook (Rome: various years).


Solutions l.jpg
Solutions?? Agriculture and Fertilizer Demand 2002/03 - 2003/04 (Paris: International Fertilizer Industry Association (IFA), December 2003); IFA Secretariat and IFA Fertilizer Demand Working Group, Fertilizer Consumption Report (Brussels: December 2001); historical data from Worldwatch Institute, Signposts 2002, CD-ROM, compiled from IFA and the U.N. Food and Agriculture Organization, Fertilizer Yearbook (Rome: various years).

Wetland restoration

Reduce fertilizers

Reduce soil erosion

Reduce emissions – WWTP/industry


Turbidity l.jpg
Turbidity Agriculture and Fertilizer Demand 2002/03 - 2003/04 (Paris: International Fertilizer Industry Association (IFA), December 2003); IFA Secretariat and IFA Fertilizer Demand Working Group, Fertilizer Consumption Report (Brussels: December 2001); historical data from Worldwatch Institute, Signposts 2002, CD-ROM, compiled from IFA and the U.N. Food and Agriculture Organization, Fertilizer Yearbook (Rome: various years).

Measures how

“murky” the water is

Estimates:

Mineral fraction

Organics

Inorganics

Soluble organic compounds

Plankton

Microscopic organisms

MODIS Image from NASA

http://rapidfire.sci.gsfc.nasa.gov/


Slide33 l.jpg

Turbid Agriculture and Fertilizer Demand 2002/03 - 2003/04 (Paris: International Fertilizer Industry Association (IFA), December 2003); IFA Secretariat and IFA Fertilizer Demand Working Group, Fertilizer Consumption Report (Brussels: December 2001); historical data from Worldwatch Institute, Signposts 2002, CD-ROM, compiled from IFA and the U.N. Food and Agriculture Organization, Fertilizer Yearbook (Rome: various years).

Causes of highly

waters

  • In open waters, phytoplankton

  • Closer to shore, particulates Resuspended bottom sediments (wind)

  • Organic detritus from stream and/or wastewater discharges.

  • Dredging operations

  • Channelization

  • Increased flow rates

  • Floods

  • Too many bottom-feeding fish (such as carp)

  • Hippos


Slide34 l.jpg

Turbid Agriculture and Fertilizer Demand 2002/03 - 2003/04 (Paris: International Fertilizer Industry Association (IFA), December 2003); IFA Secretariat and IFA Fertilizer Demand Working Group, Fertilizer Consumption Report (Brussels: December 2001); historical data from Worldwatch Institute, Signposts 2002, CD-ROM, compiled from IFA and the U.N. Food and Agriculture Organization, Fertilizer Yearbook (Rome: various years).

Effects of highly

waters

  • Modify light penetration

  • Increase sedimentation rate

  • Smother benthic habitats

  • Settling clay particles can suffocate

  • newly hatched larvae

  • Fine particulate material also can

  • damage sensitive gill structures

  • Decrease organism resistance to disease

  • Prevent proper egg and larval development

  • Macrophyte growth may be decreased

  • Reduced photosynthesis can lead to lower daytime release of oxygen


Slide35 l.jpg

From waterontheweb.org Agriculture and Fertilizer Demand 2002/03 - 2003/04 (Paris: International Fertilizer Industry Association (IFA), December 2003); IFA Secretariat and IFA Fertilizer Demand Working Group, Fertilizer Consumption Report (Brussels: December 2001); historical data from Worldwatch Institute, Signposts 2002, CD-ROM, compiled from IFA and the U.N. Food and Agriculture Organization, Fertilizer Yearbook (Rome: various years).

http://waterontheweb.org/under/waterquality/turbidity.html


Conductivity l.jpg

Na+ Agriculture and Fertilizer Demand 2002/03 - 2003/04 (Paris: International Fertilizer Industry Association (IFA), December 2003); IFA Secretariat and IFA Fertilizer Demand Working Group, Fertilizer Consumption Report (Brussels: December 2001); historical data from Worldwatch Institute, Signposts 2002, CD-ROM, compiled from IFA and the U.N. Food and Agriculture Organization, Fertilizer Yearbook (Rome: various years).

Na+

Na+

Na+

Na+

Na+

Na+

Na+

Na+

Na+

Na+

Na+

Na+

Na+

Na+

Na+

Na+

Na+

Na+

Na+

Na+

Conductivity

Ability of a substance to conduct an electrical current.

In water, conductivity determined by types and quantities of dissolved

solids. (Commonly called Total Dissolved Solids = TDS)

Current carried by ions (negatively or

positively charged particles).

Eg: NaCl(aq) = Na + + Cl –

Cl-

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Na+

Na+

Cl-

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Cl-

Cl-

Cl-

Cl-

Cl-

Na+

Na+

Cl-

Cl-

Cl-

Cl-

Na+

Cl-

Na+

Na+

Na+

Cl-


Conductivity37 l.jpg
Conductivity Agriculture and Fertilizer Demand 2002/03 - 2003/04 (Paris: International Fertilizer Industry Association (IFA), December 2003); IFA Secretariat and IFA Fertilizer Demand Working Group, Fertilizer Consumption Report (Brussels: December 2001); historical data from Worldwatch Institute, Signposts 2002, CD-ROM, compiled from IFA and the U.N. Food and Agriculture Organization, Fertilizer Yearbook (Rome: various years).

Conductivity of natural waters depends upon:

Ion characteristics (mobility, valence, concentration)

Water temperature

Geology

Size of watershed

Evaporation

Some artificial factors that can affect conductivity:

Wastewater

Urban runoff (especially road salt)

Agricultural runoff


Slide38 l.jpg

Electrical Conductivity Agriculture and Fertilizer Demand 2002/03 - 2003/04 (Paris: International Fertilizer Industry Association (IFA), December 2003); IFA Secretariat and IFA Fertilizer Demand Working Group, Fertilizer Consumption Report (Brussels: December 2001); historical data from Worldwatch Institute, Signposts 2002, CD-ROM, compiled from IFA and the U.N. Food and Agriculture Organization, Fertilizer Yearbook (Rome: various years).

and

TDS

From wateronthweb.org

http://www.waterontheweb.org/under/waterquality/conductivity.html

Salt present in 1L water


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