Clean and plentiful water is the cornerstone of prosperous communities and every society. Yet as we enter the 21st century, swelling demand and changing climate patterns are draining rivers and aquifers and pollution is threatening the quality of what remains. As of the present time dirty water is the world's biggest health risk, and continues to threaten both quality of life and public health. Water pollution or contamination of water with chemicals or other foreign substances that are detrimental to human, plant, or animal health is continuously putting every organisms now at risk. These pollutants include fertilizers and pesticides from agricultural runoff that are used in farming; sewage and food processing waste from the factories and establishments; lead, mercury, and other heavy metals; chemical wastes from industrial discharges; and chemical contamination from hazardous waste sites. Worldwide, nearly 2 billion people drink contaminated water that could be harmful to their health. Water pollution is commonly caused by many other factors within its vicinity like eutrophication, thermal pollution, siltation, red tide phenomenon, and ocean pollution.
Eutrophication is the accumulation of nutrients in aquatic ecosystems. It
alters the dynamics of a number of plant, animal and bacterial
populations; thus, bringing about changes in community structure.
It is a form of water pollution and like all other forms of pollution is the
result of human activities influencing ecological cycles.
An increase in chemical nutrients — compounds containing nitrogen or
phosphorus in an ecosystem, and may occur on land or in water.
However, the term is often used to mean the resultant increase in the
ecosystem's primary productivity (excessive plant growth and decay),
and further effects including lack of oxygen and severe reductions in
water quality, fish, and other animal populations.
STEPS OF EUTROPHICATION
Fertilizer flows into water
4. Plants in lower levels of water
to die, causing….
5. Decay using up O2 and increasing
2. Increased plant growth on the surface of
3. Decreased light in lower levels of water,
6. Death of fish and other animals.
The rise in eutrophic and
hypoxic events has been
attributed to the rapid
increase in intensive
industrial activities, and
population growth which
together have increased
nitrogen and phosphorus
flows in the environment.
The Millennium Ecosystem
Assessment (MA) found
that human activities have
resulted in the near
doubling of nitrogen and
tripling of phosphorus flows
to the environment when
compared to natural
Sources of Eutrophication
Discharge of untreated
(nitrates and phosphates)
produced by cars
Inorganic fertilizer runoff
(nitrates and phosphates)
Discharge of treated
(primary and secondary
nitrates and phosphates)
(from internal combustion
engines and furnaces)
Runoff from streets,
lawns, and construction
lots (nitrates and
and breakdown of
Runoff and erosion
and poor land use)
Overview of Cultural Eutrophication
Start with clear
water stream or
blue water lake.
The pathways of
these two nutrient
Increased biomass of phytoplankton
Toxic or inedible phytoplankton species
Increases in blooms of gelatinous zooplankton
Increased biomass of benthic and epiphytic algae
Changes in macrophyte species composition
Decreases in water transparency (increased turbidity)
Colour, smell, and water treatment problems
Dissolved oxygen depletion
Increased incidences of fish kills
Loss of desirable fish species
Reductions in harvestable fish and shellfish
Decreases in perceived aesthetic value of the water