This document discusses various issues related to water pollution. It begins by describing different industrial uses of water, such as for cooling, processing, and transport. It then discusses how industrial activities and mining can pollute surface and groundwater through runoff, spills, and aerial pollution. Next, it examines how pollution can disrupt aquatic ecosystems by overloading their self-cleaning capacity. It proceeds to define various water pollutants and parameters used to measure water quality, such as dissolved oxygen, organic content, nutrients, and heavy metals. Finally, it analyzes specific pollution problems including deoxygenation, acid mine drainage, eutrophication, and heavy metal contamination from sources like road runoff.

1. ENVIRONMENTAL
MANAGEMENT
Kwame Atta Ashun, PhD
Course code:
CE/EL/MC 365
GM/MN/RN 365
1

2. CHAPTER SEVEN (6)
WATER POLLUTION
ISSUES
2
EL/MC/CE 365
GM/MN/RN 365

3. WATER POLLUTION ISSUES
3
1. WATER USE IN INDUSTRY
Water is utilised in many stages of mining &
mineral processing & other industrial processes:
EL/MC/CE 365
 Cooling Water for equipment & machine parts
e.g., crusher bearings, pumps, compressors, electricity
generating plants, etc.

4. WATER POLLUTION ISSUES
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1. WATER USE IN INDUSTRY……….cont’d
EL/MC/CE 365
 Process Water
Used in:
• Wet screening, gravity separation (shaking tables, jigs),
flotation
• Washing water (fines from metal ores, clays from stone)
• Wet scrubbers for air pollution control

5. WATER POLLUTION ISSUES
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1. WATER USE IN INDUSTRY……….cont’d
EL/MC/CE 365
 Transport Water
Used in:
• slurry media transportation of ores between different
stages of processing

6. WATER POLLUTION ISSUES
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1. WATER USE IN INDUSTRY……….cont’d
EL/MC/CE 365
 Other water uses in industry
 dust control,
 vehicle washing,
 domestic,
 sanitary, etc

7. WATER POLLUTION ISSUES
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1. WATER USE IN INDUSTRY……….cont’d
EL/MC/CE 365
 Influence of other activities of mining &
construction:
 Pumped water from water influx due to rainfall or
groundwater interception.
 Run-off after rain or snow.
 Percolation of water into sumps, etc.
 Leaching of ore (e.g. sulphides) after the ground
is disturbed.

8. WATER POLLUTION ISSUES
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1. WATER USE IN INDUSTRY……….cont’d
EL/MC/CE 365
 Influence of other activities of mining &
construction…….cont’d:
 Groundwater interception during excavation,
 Spillage of substances to contaminate surface &
ground waters,
 Aerial pollution usually fall out to affect surface
water.

9. WATER POLLUTION ISSUES
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2. ACQUATIC ECOSYSTEM
EL/MC/CE 365
 A breakdown of ecosystem’s self-cleaning
capacity may be a result of any or both of the
following: @
i. Overloading a particular conversion
e.g. introducing excess organic matter
ii. Eliminating one or more stages
e.g. killing fish

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3. WATER POLLUTANTS
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A substance is a water pollutant depending on
the following:
i. The nature (type) of pollutant,
ii. The concentration of pollutant,
iii. The total load of pollutant discharged,
iv. The nature of the receiving water,
v. The capacity of the receiving water to absorb the
waste load.

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3. WATER POLLUTANTS
EL/MC/CE 365
Toxicity to Aquatic Life
Median Tolerance Limit (TLm):
The range of concentrations of a pollutant in which
the population of test organism (usually fish - trout or
goldfish) suffer 50% mortality within a specific time
(normally 96 hours).
o Represented as TLm 96 or 96-LC50

12. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
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To know the extent of water pollution in more
specific & practical terms, we must precisely
define the characteristics of the water (i.e.,
parameters)
Concentrations of parameters are usually
measured in mg/L or ppm.

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4. WATER QUALITY PARAMETERS
EL/MC/CE 365
The most frequently cited parameters are:
I. Dissolved Oxygen
II. Oxygen Demand
III. Organic Content
IV. Solids
V. Nutrients
VI. Metals
VII.Cyanides
VIII.Others

14. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
EL/MC/CE 365
I. Dissolved Oxygen
It is the amount of molecular oxygen dissolved in
water.
Also affects wastewater treatment processes that
utilise micro-organisms, corrosion chemistry &
other chemical reactions.
GM/MN/RN 365

15. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
EL/MC/CE 365
I. Dissolved Oxygen
The amount of DO decreases with increasing
water temperature.

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4. WATER QUALITY PARAMETERS
EL/MC/CE 365
I. Dissolved Oxygen Measurement
In the laboratory:
o Chemicals (wet chemistry) – Winkler Method
o DO meter
On the field:
o DO meter
GM/MN/RN 365

17. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
EL/MC/CE 365
II. Oxygen Demand
It is a term for the amount of oxygen required to
oxidise a waste.
it is an indirect measure of the amount of
organic or carbon-containing impurities in water.

18. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
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II. Oxygen Demand Measurement
Most common ways to estimated or measure:
biochemical oxygen demand,
chemical oxygen demand,
theoretical oxygen demand.
GM/MN/RN 365

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4. WATER QUALITY PARAMETERS
EL/MC/CE 365
II. Oxygen Demand Measurement……..cont’d
Biochemical oxygen demand (BOD):
It is the amount of oxygen required to
oxidise any organic matter present in the
water biochemically.

20. 20
4. WATER QUALITY PARAMETERS EL/MC/CE 365
Biochemical oxygen demand (BOD):
waste stabilisation:
The process of oxidising wastes (specifically
organic matter) to CO2 & H2O
NB: The measurement of above is termed
Carbonaceous Biochemical Oxygen Demand
(CBOD)
II. Oxygen Demand Measurement……..cont’d

21. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
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Chemical Oxygen Demand:
The equivalent amount of oxygen required
to oxidise any organic matter in a water
sample by means of a strong chemical
oxidising agent.
II. Oxygen Demand Measurement……..cont’d

22. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
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Theoretical Oxygen Demand:
It is the amount of oxygen required to
oxidise a known compound completely to
CO2 & H2O.
II. Oxygen Demand Measurement……..cont’d

23. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
EL/MC/CE 365
III. Organic Content
The organic content of water is important because
of the oxygen it will consume & because some
organics are toxic.
It is the amount of o

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4. WATER QUALITY PARAMETERS
EL/MC/CE 365
III. Organic Content Measurement
 Total Organic Carbon
 Oil & Grease:

25. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
EL/MC/CE 365
III. Organic Content Measurement………..cont’d
 Total Organic Carbon:
The amount of organic carbon in a sample –
used in the estimation of the amount of organic
contaminant in water or waste water

26. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
EL/MC/CE 365
III. Organic Content Measurement
 Oil & Grease:
they form thin films over the surface of the
water, thus interfering with re-oxygenation of
the water

27. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
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IV.SOLIDS
 These are solid materials in wastewater
Dissolved component Suspended component
Either be i. Volatile (organic) or
ii. Fixed (Inorganic)

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4. WATER QUALITY PARAMETERS
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IV.SOLIDS
 Include:
Chlorides (Cl)
Nitrates (NO3)
Nitrites (NO2)
Phosphates (PO4)
OF
Sodium (Na)
Calcium (Ca)
Magnesium (Mg)
Iron (Fe)
Manganese (Mn)

29. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
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IV.SOLIDS
 Include:
Chlorides (Cl)
Nitrates (NO3)
Nitrites (NO2)
Phosphates (PO4)
OF
Sodium (Na)
Calcium (Ca)
Magnesium (Mg)
Iron (Fe)
Manganese (Mn)
Dissolved SOLIDS

30. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
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IV.SOLIDS - CLASSIFICATION
 Based on quantity of dissolved solids
 Fresh Water 100 mg/L salts as Cl
 Brackish Water 100 to 1,000 mg/L salts as Cl
 Salt Water 1,000 mg/L salts as Chlorides
Dissolved SOLIDS

31. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
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IV.SOLIDS - EFFECTS
 interfere with self-purification of water
by diminishing light penetration (by up
to 50%)
 get deposited as silt over food of organisms
in the water, & could kill fish when ingested
Suspended
SOLIDS

32. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
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V. Nutrients
Major Nutrients in water & wastewater
 Nitrogen
 Phosphorus

33. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
EL/MC/CE 365
V. Nutrients
 Usefulness
 required for growth of the micro-organisms
used in wastewater treatment processes

34. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
EL/MC/CE 365
VI.Metals
 Some toxic metals include:
 Cr, Hg, Zn, Pb & Cu

35. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
EL/MC/CE 365
VI.Metals
 Measured:
 Using Atomic Absorption Spectrometer (AAS)

36. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
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VI.Metals  Measured:
AAS Operation

37. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
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VII.Cyanides  Occurrence:
 Gold mill waste waters at concentrations of 0.01
- 0.03 mg/L.
 Lethal to many fish at very low concentrations,
as little as 0.04 mg/L CN for trout.
 smaller concentrations 0.009 mg/L can decrease
the ability of trout to swim .

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4. WATER QUALITY PARAMETERS
EL/MC/CE 365
VI.Cyanides

39. WATER POLLUTION ISSUES
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4. WATER QUALITY PARAMETERS
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VI.Cyanides
Exposure dose
(HCN) mg/m3
Exposure time
(min)
Effect
<60 20 - 60 can be tolerated without
immediate or late effects
120–150 30 - 60 dangerous to life and may
lead to death
150 30 likely to be fatal
200 10 likely to be fatal
300 immediately fatal
Table A: Effects of Human exposure to cyanides
(Source: WHO, 2004)

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4. WATER QUALITY PARAMETERS
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 Other Water Quality Parameters
 Colour
 Temperature
 Turbidity
 Hardness
 Alkalinity
 pH

41. SPECIFIC WATER POLLUTION PROBLEMS
41
EL/MC/CE 365
 Deoxygenation
 Acid Mine Drainage (AMD)
 Eutrophication
 Heavy metal pollution

42. I. Deoxygenation
42
 The removal of molecular oxygen (O2) from a
reaction mixture or solvent, or
 the removal of oxygen atoms from a molecule
EL/MC/CE 365
Specific water pollution problems

43. II. Acid Mine Drainage (AMD)
43
 the outflow of acidic water from:
o abandoned metal mines or coal mines
o areas where the earth has been disturbed
o rock weathering process (natural)
 AKA, Acid rock drainage (ARD)
 Results from sulphide minerals upon exposure to
water and oxygen, oxidizes to form sulfuric acid
EL/MC/CE 365
Specific water pollution problems

44. II. Acid Mine Drainage (AMD)
44
EL/MC/CE 365
Specific water pollution problems
Fig A1. Occurrence of AMD/ARD
GM/MN/RN 365

45. III. Eutrophication
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 a process whereby water bodies, such as, lakes,
estuaries, or slow-moving streams receive excess
nutrients that stimulate excessive plant growth
(algal bloom)
 Sources of nutrients into water bodies:
EL/MC/CE 365
Specific water pollution problems
o fertilizer application
o deposition of nitrogen from the atmosphere
o erosion of soil containing nutrients
o Sewage/wastewater treatment plant discharges

46. III. Eutrophication
46
EL/MC/CE 365
Specific water pollution problems
Fig A2. Occurrence of Algae bloom (Eutrophication)
GM/MN/RN 365

47. III. Eutrophication
47
EL/MC/CE 365
Specific water pollution problems
Fig A3. Nuisance aquatic plant

48. IV. Heavy metal pollution
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 SOURCES:
o areas of intensive industrial activity;
o roadways and automobiles
EL/MC/CE 365
Specific water pollution problems
 EXAMPLES: As, Pb, Cd, Ni, Hg, Cr, Co, Zn, Se
• Brakes – Cu
• Tyre wear – Zn
• Engine/motor oils – accumulate metals
 Run-offs carry them to water bodies after rainfall
GM/MN/RN 365

49. IV. Heavy metal pollution
49
EL/MC/CE 365
Specific water pollution problems
Common Heavy Metals Source
Pb leaded gasoline, tire wear, lubricating oil and grease,
bearing wear.
Zn tire wear, motor oil, grease, brake emissions, corrosion of
galvanized parts
Fe vehicle body rust, engine parts.
Cr air conditioning coolants, engine parts, brake emissions.
Ni diesel fuel and gasoline, lubricating oil, brake emissions
Cd tire wear, fuel burning, batteries
Cu bearing wear, engine parts, brake emissions
Table B: Common heavy metals in road run-off
GM/MN/RN 365

50. End
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EL/MC/CE 365
CHAPTER 6