Other Issues in Water Pollution. Urbanization. Genera

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Other Issues in Water Pollution

• Urbanization
• General Population Growth
• Increased Run-off and Pollution
• Non-point Pollution Sources (eg Agriculture)
• Pesticide Use (Module 5)
• Toxic Organic Chemicals
• Industrial Effluents
• Organic Loading
• Wood burning for Fuel (eg East African lakes -
  Lake Victoria)
• Deforestation
• Microbiological Contamination (Module 4)

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• Some Observations
• General Population Growth was for many years
  considered the single most important issue
  affecting actual and future water pollution.
• This has changed with changes in estimates of
  population growth rates. Since 1969 population
  has grown from 3.7 billion to 6 billion. But
  annual rates of population growth have slowed
  from 2.04 to 1.33 per cent, and should fall
  further. Annual additions peaked in 1985-1990 at
  86 million. They should fall gradually in the
  next 20 years and more rapidly thereafter.

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• This view now has changed to one that
  emphasizes Urbanization and population
  concentration in the larger cities often on sea
  coasts
• Eleven of the world's 15 largest cities lie
  along the coast or on estuaries.
• In the United States, around 53 of the
  population lives near the coast

New calculations show that 37-39 percent of the
world's population live within 100 kilometres of
the coast (Cohen et al., 1997). Since the coastal
100 kilometre strip represents 18.7 of the total
land area (27,491,108 km2 out of 146,874,796
km2), the average human population density in
coastal areas is about 80 persons per square
kilometre, twice the global average. Considering
that many coastlines are sparsely populated or
uninhabited (Antarctica, the far North, etc.),
the actual population pressure on the coast in
more habitable areas is very high http//earthwat
ch.unep.net/oceans/coastalthreats.html
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Because more urbanized watersheds tend to have
greater impervious areas as well as higher
quantities of urban and industrial pollution,
this map also shows greater pressure on
freshwater systems. This map shows that highly
urbanized watersheds are concentrated along the
east coast of the United States, Western Europe,
and Japan, with lesser concentrations in coastal
China, India, Central America, most of the United
States, Western Europe, and the Persian Gulf
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This map shows the level of human modification of
the coastal zone, by examining the population
within 100 kilometres from the coast. As human
population increases in coastal areas, so does
pressure on coastal ecosystems through habitat
conversion, increased pollution, and demand for
coastal resources. The degree of direct human
modification of coastal ecosystems can be
inferred by looking at the population density
within the coastal zone. Globally, the number of
people living within 100 km of the coast
increased from roughly 2 billion in 1990 to 2.2
billion in 199539 percent of the world's
population.
http//earthtrends.wri.org/maps_spatial/maps_detai
l.cfm?theme1
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Distribution of Renewable Water resources per
capita There is a rapid change from 1995 to
2025 in the availability of water resources .
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Data From USGS National Water Quality Assessment
and the Pesticide National Synthesis Project
The concentration of population in the US around
water bodies and the coastal regions is also
apparent
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• The effects of the population and intensive
  farming in the areas of the US is also clear when
  examining the
• deposition of nitrogen from the atmosphere (air
  pollution)
• non-point sources of nitrogen from animal
  manure
• application of nitrogen and phosphorus in
  fertilizers
• Population change and migration continues.
  Figures from the US show a marked migration from
  rural to urban areas (and a movement southwest
  and southeast)

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• These urban populations cause water pollution,
  but the rural populations (although decreasing)
  are required to increase food output for the
  increased population in urban areas.
• This has many ramifications one of these is
  increased groundwater pollution and aquifer
  contamination due to intensive farming
  applications being done over vulnerable aquifers.
  
• Surface waters can also become contaminated from
  these acivities

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Pesticides and their Distribution Note in the
following slides the distribution of different
kinds of pesticides Atrazine, Cyanazine and
Paraquat are herbicides Note the wide
distribution in the Mid-West of Atrazine and
Cyanazine commonly used on corn crops. Paraquat
is a total kill herbicide used for no-till
agriculture and is also widely used in the
Mid_west and California Chlorpyriphos is an
insecticide It is widely used in many
crop-growing and vegetable/fruit growing
areas 2,4-D is a selective herbicide It is
widely used in both the Mid-West and the western
wheat areas as well as California Ethion is an
insecticide It is used in vegetable and fruit
growing areas to control pests of those crops
(Florida, California, etc.)
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Deforestation
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Deforestation
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Other Issues in Water Pollution

• General Population Growth
• Urbanization
• Increased Run-off and Pollution
• Non-point Pollution Sources (eg Agriculture)
• Pesticide Use (Module 5)
• Toxic Organic Chemicals
• Industrial Effluents
• Organic Loading
• Wood burning for Fuel (eg East African lakes -
  Lake Victoria)
• Deforestation
• Microbiological Contamination (Module 4)