Groundwater Pollution

1
Groundwater Pollution

• Week 1 0304 Introduction to Groundwater

2

• Water in three states liquid, solid (ice), and
  water vapor in the air. Clouds are water
  droplets, condensed from vapor-saturated air.

3

• Water changes from one state to another. So water
  can be solid, liquid or gas.
• Water also moves.
• We call this the Water Cycle.

4

• http//ga.water.usgs.gov/edu/watercyclekoreanhi.ht
  ml

5

• http//ga.water.usgs.gov/edu/watercycleprint.html

6

• cycle ??
• circulation move around something like a circle.

7
1.72, Groundwater Hydrology Lecture Packet 1
Prof. Charles Harvey http//ocw.mit.edu/NR/rdonly
res/Civil-and-Environmental-Engineering/1-72Fall-2
005/4F444E12-8746-459D-A6BD-1F42F7498903/0/1_72_le
cture_1.pdf
8
1.72, Groundwater Hydrology Lecture Packet 1
Prof. Charles Harvey http//ocw.mit.edu/NR/rdonly
res/Civil-and-Environmental-Engineering/1-72Fall-2
005/4F444E12-8746-459D-A6BD-1F42F7498903/0/1_72_le
cture_1.pdf
9
1.72, Groundwater Hydrology Lecture Packet 1
Prof. Charles Harvey http//ocw.mit.edu/NR/rdonly
res/Civil-and-Environmental-Engineering/1-72Fall-2
005/4F444E12-8746-459D-A6BD-1F42F7498903/0/1_72_le
cture_1.pdf
10
1.72, Groundwater Hydrology Lecture Packet 1
Prof. Charles Harvey http//ocw.mit.edu/NR/rdonly
res/Civil-and-Environmental-Engineering/1-72Fall-2
005/4F444E12-8746-459D-A6BD-1F42F7498903/0/1_72_le
cture_1.pdf
11

• A lot of water is used for agriculture
• 56 is used by animals and plants
• 20 is lost when the water is moved
• 24 flows back into the stream or ground
• A lot of water is used for making electricity
• 87 of all industrial water use

1.72, Groundwater Hydrology Lecture Packet 1
Prof. Charles Harvey http//ocw.mit.edu/NR/rdonly
res/Civil-and-Environmental-Engineering/1-72Fall-2
005/4F444E12-8746-459D-A6BD-1F42F7498903/0/1_72_le
cture_1.pdf
12

• Water can dissolve many things.
•  
• Water consists of two atoms of hydrogen and one
  of oxygen, which give it a chemical formula of
  H2O.

13

• Water can dissolve at least small amounts of
  almost all substances that it contacts.
• Ground water usually contains the largest amounts
  of dissolved solids.

14

• The composition and concentration of substances
  dissolved in unpolluted ground water depend on
  the chemical composition of precipitation, on the
  biologic and chemical reactions occurring on the
  land surface and in the soil zone, and on the
  mineral composition of the aquifers and confining
  beds through which the water moves.

15
(No Transcript)
16
(No Transcript)
17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21

• The concentrations of substances dissolved in
  water are in units of weight per volume.
• In the International System (SI), the most
  commonly used units are milligrams per liter.

22

• A milligram equals 1/1,000 (0.001) of a gram,
• and a liter equals 1/1,000 of a cubic meter, so
• 1 mg/L equals 1 gram m-3.

23

• Because the concentration of most substances
  dissolved in water is relatively small, the
  weight per weight unit commonly used is parts per
  million (ppm).

24
Natural inorganic constituents commonly dissolved
in water that are most likely to affect use of
the water.
25
(No Transcript)
26
      Condensation       Evaporation
      Evapotranspiration       Freshwater storage
      Ground-water discharge       Ground-water storage
      Infiltration       Precipitation
      Snowmelt runoff to streams       Spring
      Streamflow       Sublimation
      Surface runoff       Water storage in the atmosphere
      Water storage in ice and snow       Water storage in oceans
      Desublimation       Plant uptake

27
Pollution of Groundwater

•  Pollution of ground water is any loss of quality
  of the water because of what people do.

28

• Most pollution of ground water comes from the
  disposal of wastes on the land surface, in
  shallow holes including septic tanks, or through
  deep wells and mines the use of fertilizers and
  other agricultural chemicals leaks in sewers,
  storage tanks, and pipelines and animal feedlots
  (excreta).

29
(No Transcript)
30
(No Transcript)
31
(No Transcript)
32
(No Transcript)
33
(No Transcript)
34

• The size of any pollution problem depends on the
  size of the area affected and the amount of the
  pollutant involved, the solubility, toxicity, and
  density of the pollutant, the mineral composition
  and hydraulic characteristics of the soils and
  rocks through which the pollutant moves, and the
  effect or potential effect on ground-water use.

35

• Affected areas range in size from point sources,
  such as septic tanks, to large urban areas having
  leaky sewer systems and numerous municipal and
  industrial waste-disposal sites.

36

• Nearly all substances are soluble to some extent
  in water, and many chemical wastes are highly
  toxic even in minute (very small) concentrations.
  

37
(No Transcript)
38
Effects of Contamination

• Why do we care if there was only 1ppm
  (1/1,000,000) of a particular contaminant?
• It seems like too small of a number to matter.

39

• With groundwater contaminants, both chemical and
  biological, a very small concentration of
  contaminant could still lead to serious health
  effects.
• Different kinds of contaminants have different
  concentration limits at which they start to
  effect us or the environment.

40

• In dealing with groundwater contamination
  problems, it is necessary to find out both the
  specific type of contaminant and the
  concentration of the contaminant.

41

• The concentration of different contaminants in
  the groundwater.
• Mr. Blue reacts in the same way a healthy person
  would to these chemicals.
• A person who is not as healthy, such as an older
  person or a small child, might suffer the effects
  even more.
• http//techalive.mtu.edu/meec/module04/Contaminati
  onEffects.html

42

• Which chemical needs to exist in the least
  concentration in the groundwater in order to
  avoid hurting someone?

43
Density

• The density of a liquid substance - that is, the
  weight per unit volume of the substance relative
  to that of water - affects its underground
  movement.

44

• Densities range from those of petroleum products
  that are less dense than water other substances
  that are denser than water.

45

• Substances less dense than water stay at the top
  of the saturated zone if, like petroleum, they
  are immiscible, they will tend to spread in all
  directions as a thin film.

46

• Substances denser than water tend to move
  downward through the saturated zone to the first
  extensive confining bed.

47
Contaminant Movement

• Contaminants can enter the groundwater by seeping
  in from the surface or by flowing in from another
  part of the aquifer. Once in the aquifer they
  move with the groundwater flow.

48

• As contamination moves it disperses. This means
  that the concentration decreases as it moves
  farther away from the source of the pollution.
  For that reason there are different
  concentrations of contaminants at different
  points in the aquifer.

49

• The mineral composition and physical
  characteristics of soils and rocks through which
  pollutants move may affect the pollutants in
  several ways.

50

• If a pollutant enters the ground at a "point," it
  will be dispersed longitudinally and laterally in
  granular materials so that its concentration will
  be reduced in the direction of movement.

51

• The visual representation of these different
  concentrations is called a contamination plume.
  How the plume looks depends on the type of
  contamination source, the specific
  contaminant(s), where the aquifers are located,
  and different soils in that area.

52

• These animations show the two main categories of
  plumes based upon their source.
•  
• Here are two animations of the Dispersal of a
  Pollutant from a Point source
• http//techalive.mtu.edu/meec/module04/OneTimePlum
  e.html (Click Play)
• http//techalive.mtu.edu/meec/module04/ContinuousP
  lume.html (Click Play)

53
Organic Substances

• Organic substances and other biodegradable
  materials tend to be broken down both by
  oxidation and by bacterial action in the
  unsaturated zone.

54

• Certain earth materials, especially clays and
  organic matter, may also absorb trace metals and
  certain complex organic pollutants and reduce
  their concentration as they move through the
  underground environment.

55

• The hydraulic characteristics of the soils and
  rocks determine the path taken by and the rate of
  movement of pollutants.

56

• Substances dissolved in water move with the water
  except when they are tied up or delayed by
  adsorption.

57

• The movement of pollutants is most through the
  most permeable zones the farther their point of
  origin from a ground-water discharge area, the
  deeper they penetrate into the ground-water
  system and the larger the area ultimately
  affected.

58

• The movement of pollutants must be carefully
  considered in the selection of waste-disposal
  sites, animal feedlots, and sites for other
  operations that may cause ground-water pollution.

59

• Here is an animation to allow you to Pick the
  Best Site for a New Well
•  
• http//techalive.mtu.edu/meec/module06/WellSiting.
  htm