Water Pollution
Human activities that affect
water quality
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Agriculture
Industry and energy production
Mining
Water-system infrastructure
Uncontrolled disposal of human wastes
Population growth, urbanization,
development
• Climate change
Source: UNEP, 2010. Clearing the water.
Water Pollution Sources
• Point sources(點汙染源):
pollution comes from single, fixed, often large
identifiable sources such as factory and
wastewater treatment plant.
• Nonpoint sources(非點源):
Non-point source pollution is the result of
precipitation runoff from many diffuse sources
including fertilizers, nutrients, and pesticides
from agriculture; and oil, grease, and toxics from
urban settlements. These diffuse pollutants from
multiple sources are not easily regulated.
Source: http://www.oceanservice.noaa.gov/education/kits/pollution/welcome.html
Agricultural runoff accounts for a significant amount of nonpoint source
pollution. When large tracts of land are plowed, the exposed soil can erode
during rainstorms. This runoff, which ends up in the nearest water body,
often contains agricultural fertilizers and pesticides.
Source: http://www.oceanservice.noaa.gov/education/kits/pollution/welcome.html
Water Pollution Types
• Pathogens(致病菌)
• Oxygen demanding waste (耗氧的有機物): human waste,
storm sewers, runoff from agriculture, grazing and
logging, many others
• Chemical:
– Inorganic: heavy metals, acids, road salts,…
– Organic: petroleum, pesticides, detergents, …
– Toxic Substance : herbicides, pesticides and
industrial compounds.
• Sediments(沉滓): logging, road building, erosion
• Nutrients(養分):
– N, P from fertilizers, detergents
– leads to eutrophication(優養化)
• Elevated temperatures
Pathogens Carried by Sewage
• Disease-causing agents
– Typhoid
– Cholera
– Salmonellosis
– Diarrhea
–…
• Safety measures
– Purification of public water supply
– Sanitary collection/treatment of sewage
– Sanitary practices when processing food
Organic Wastes
• Dissolved oxygen (DO) in the water is depleted during
decomposition of organic wastes.
• As micro-organisms decompose (through respiration)
organic matter, they use up all the available oxygen.
• Biological Oxygen Demand (BOD): Amount of oxygen
required to decay a certain amount of organic matter.
• BOD represent the amount of organic material that can
be decomposed by micro-organism.
• If too much organic matter is added, the available
oxygen supplies will be used up.
Stream polluted by organic matters
• http://www.sciencescene.com/Environmen
tal%20Science/06WaterResources/MEDIA
%20Audio%20-%20Flash%20%20Video/river_pollution.swf
Erosion and agricultural sediment
Source: http://en.wikipedia.org/wiki/File:Sinuous_dunes_mcr1.JPG
Effect of Sediments on Stream Ecology
• Loss of hiding/resting places for small fish
• Attached aquatic organisms scoured from the rocks
and sand
• Poor light penetration
• Loss of soil due to erosion removes useful farmland,
adds to sediment loads, and can help transport
anthropogenic fertilizers into the river system, which
leads to eutrophication
Eutrophication
Too much of a good thing ?
Source: http://05lovesgeography.blogspot.com/2011/02/eutrophication.html
The Impacts of Nutrient Enrichment
• Oligotrophic: nutrient-poor water
• Eutrophic: nutrient-rich water
• As nutrients are added from pollution, an
oligotrophic condition rapidly becomes
eutrophic.
Oligotrophic lake(貧養湖)
• An oligotrophic lake is a lake with low primary
productivity, the result of low nutrient content.
These lakes have low algal production, and
consequently, often have very clear waters, with
high drinking-water quality. The bottom waters of
such lakes typically have ample oxygen; thus,
such lakes often support many fish species.
Eutrophic Lake(優養湖)
• An eutrophic body of water, commonly a lake,
pond, or estury, has high primary productivity
due to excessive nutrients and is subject to algal
blooms resulting in poor water quality. The
bottom waters of such bodies are commonly
deficient in oxygen. Eutrophic waters commonly
lack fish species like trout, which require cold,
well-oxygenated water. This oxygen deficiency is
most apparent in shallow lakes.
Natural and Cultural Eutrophication
• Natural eutrophication(自然優養化)
– aquatic succession
– occurs over several hundreds of years
• Cultural eutrophication(人為優養化)
– driven by human activities
– occurs rapidly
Fish kills can result from hypoxia, or very low levels of oxygen in the water.
Hypoxia occurs when excessive algae block out sunlight, killing off underwater
plants, which decay and deplete the oxygen in the water.
Source: http://www.oceanservice.noaa.gov/education/kits/pollution/welcome.html
Harmful algal blooms (HABs) occur under eutrophic conditions. Although these
organisms are not harmful in small quantities and exist naturally, they grow at rapid
rates when eutrophication occurs. When fish and shellfish feed on HABs, they
ingest toxins that the algae produce. If people eat this seafood, they can become
Source: http://www.oceanservice.noaa.gov/education/kits/pollution/welcome.html
sick.
Combating Eutrophication
• Attack the symptoms
– Chemical treatment
– Aeration
– Harvesting aquatic weeds
– Drawing water down
• Getting at root cause
– Controlling point sources
– Controlling nonpoint sources
Thermal Pollution
• Elevated temperatures
• water is used for cooling purposes, then
heated water is returned to its original source
• any increase in temperature, even a few
degrees, may significantly alter some aquatic
ecosystems.
Groundwater Pollution
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Agricultural products
Underground storage tanks
Landfills
Septic tanks
Surface impoundments
海洋污染
•鄰近的都市與河川所排放
•船舶操作
•意外漏油及化學品外洩
•大氣沉降
•探勘與生產
Litter plays a significant role in damaging our marine environment. Discarded plastics,
metals and other types of trash not only degrade the aesthetic beauty of an area, they can
leach harmful chemicals into the environment. They can also contribute to disease
transmission.
Source: http://www.oceanservice.noaa.gov/education/kits/pollution/welcome.html
嚴重的海域漏油事件
• 阿拉斯加港灣漏油事件發生於1989年3月24日午夜，欲前往加州
長灘的埃克森油輪瓦迪茲號在阿拉斯加州威廉王子灣觸礁，導致泄漏
了一千一百萬加侖原油。這起事件被認為是當時最嚴重的環境污染事
件。
• 墨西哥灣漏油事件，又稱英國石油(BP)漏油事故，是2010年4月20
日發生的一起墨西哥灣外海油污外漏事件。起因是英國石油公司所屬
一個名為「深水地平線」（Deepwater Horizon）的外海鑽油平臺故
障並爆炸，導致了此次漏油事故。爆炸同時導致了11名工作人員死亡
及17人受傷。據估計每天平均有12,000到100,000桶原油漏到墨西哥
灣，導致至少2,500平方公里的海水被石油覆蓋著。專家們擔心此次
漏油會導致一場環境災難影響多種生物。此次漏油還影響了當地的漁
業和旅遊業。
• 阿瑪斯號貨輪油污事件，發生於2001年1月的公害事件，污染範
圍位於台灣墾丁國家公園境內的龍坑生態保護區。事件為保護區的生
態帶來浩劫。2003年，環保署向挪威法院提出賠償訴訟，這成為台灣
首宗跨國訴訟的油污事件。
Source: 維基百科
Oil and Chemical Spill
• Each year, there are thousands of oil and chemical spills
in coastal waters around the world. These spills range
from small ship collisions to fuel transfer mishaps to
massive spill events like the BP Deepwater Horizon oil
spill.
• The release of oil and chemicals into our coastal
waterways is a major problem. Spills can kill wildlife,
destroy habitat, and contaminate critical resources in the
food chain. Spills can also wreak havoc on the
economies of coastal communities by forcing the closure
of fisheries, driving away tourists, or temporarily shutting
down navigation routes. And these environmental and
economic damages can linger for decades.
Source: http://oceanservice.noaa.gov/hazards/spills/
oil and chemical spills
• When dealing with oil and chemical spills,
there are many questions that need
answered. What was spilled? Where is the
spill likely to travel in the water? How is
the local environment affected now—and
how might it be affected down the road?
What's the best way to clean up the spill?
How will balance be restored to the
environment after the damage has been
done?
Source: http://oceanservice.noaa.gov/hazards/spills/
Source: UNEP, 2010. Clearing the water.
Water quality solutions
• Pollution prevention
• Treatment
– Drinking water treatment
– Treatment for other uses
• Wastewater treatment
– Domestic wastewater treatment
– Industrial wastewater treatment
– Agricultural wastewater treatment
• Ecological restoration and ecohydrology
– Ecohydrology
– Groundwater
Source: UNEP, 2010. Clearing the water.
Pollution Prevention
• Preventing pollution at its source, in industry, agriculture,
and human settlements, is often the cheapest, easiest,
and most effective way to protect water quality.
• in industry, reformulating products that produce less
pollution and require less resources during their
manufacture and use;
• in agriculture, reducing the use of toxic materials for pest
control, nutrient application, and water usage;
• in human settlements, reducing the amount of hazardous
materials used and disposed and reducing wastewater
production;
• reducing water consumption.
Source: UNEP, 2010. Clearing the water.
Mechanisms to achieve solutions
• Education and awareness
• Monitoring/data collection
• Governance and regulation
– Policies, laws, and regulations
– Establishing water quality standards
– International water quality guidelines
– International governance and law
– Managing transboundary waters
– Financing water quality
Source: UNEP, 2010. Clearing the water.