Transcript Water Pollution - Liberty Union High School District

Water Pollution
Chapter 14
Thursday, February 16th, 2017
Water Pollution
 Refers
to degradation of water quality.
Generally look at the intended use of the
water
 How far the water departs from the norm
 Its effects on public health
 Or its ecological impacts
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Water Pollution
 Water
 Heavy
pollutants includes
metals
 Sediment
 Certain radioactive isotopes
 Heat
 Fecal coliform bacteria
 Phosphorus
 Nitrogen
 Pathogenic bacteria and viruses
Water Pollution
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Primary water pollution problem is the lack
of clean, disease free drinking water.
(Sanitary water)
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Outbreaks of waterborne disease affects several
billion people worldwide
E.g. cholera, Crytosporidium
Quality of water determines its potential
uses.
 All segments of society may contribute to
water pollution.
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Pollution Sources
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Water pollution is the contamination of water by substances
produced by human activities and that negatively affect organisms
Point source pollution comes from a distinct location that can
easily be traced (factory, pipe)
Nonpoint source pollution cannot easily be traced to the source
(urban areas, farms). More difficult to control and more common
Nutrient pollution
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Nutrient pollution comes from fertilizers, farms, sewage, lawns,
golf courses, and leads to eutrophication
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Fertilizers add phosphorus to water, which boosts algal and aquatic
plant growth
Spreading algae cover the surface, decreasing sunlight
Bacteria eat dead algae, reducing dissolved oxygen
Fish and shellfish die
Solutions include:
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Treating wastewater
Reducing fertilizer application
Using phosphate-free detergents/fertilizers
Planting vegetation to increase nutrient uptake
Human Wastewater
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Human wastewater is water produced by human activities
(sewage, laundry water). High in nutrients. Leads to 3
concerns
1.
Oxygen demanding waste is organic matter that enters water and
feeds the growth of microbes that are decomposers.
 The more waste in the water, the more microbes. More
microbes, the more they demand oxygen
 Biological oxygen demand (BOD) is the amount of oxygen
microbes use when breaking down waste (measures odw)
 High BODs typically mean more wastewater. Eventually leads to
dead zones because not enough oxygen to support life
Continued…
2.
3.
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When organic matter is decomposed, nutrients are
released
 Eutrophication – nutrients added to water which
brings algae blooms. These die and bacteria increases
and uses up oxygen
 Cultural eutrophication is caused specifically by humans
Wastewater can carry parasites and bacteria that can
make humans ill. These are called pathogens
 Cholera, typhoid fever, flu, diarrhea
3.1 million deaths per year caused by unsafe drinking water
We only test for certain bacteria in our water since there are so
many different kinds
Eutrophication
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Oligotrophic lake (BOD is low)
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Lake w/ relatively low concentration of chemical
elements required by life
Clear water
Low abundance of life – animals are diverse (mosquitos,
fish, aquatic insects and bugs)
Eutrophic lake - (BOD is high)
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Lake w/ high concentration of chemical elements
Often w/ mats of algae and murky water
Abundance of life, but few animals – only algae, bacteria,
and some other higher plant species
Cultural Eutrophication
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Human processes that add nutrients to water
Solution fairly straightforward
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Ensure that high concentrations of nutrients do not
enter water
Accomplished by
 use of phosphate-free detergents
 controlling nitrogen runoff
 disposing or reusing treated wastewater
 advanced water treatment methods
Treatment of Wastewater
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Septic systems are sewage treatment systems found in rural
areas. Has two major components
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Sewage treatment plants are used for urban areas
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Septic tank takes wastewater in one end, and releases it out the other
Leach field are pipes where the septage (clear layer full of bacteria)
moves out. Septage slowly leaks out of pipes into the ground
Primary treatment lets solid stuff settle and become sludge. From
there it can be taken to landfill, farms, etc
Secondary treatment uses bacteria to break down remaining organic
matter. Also has a settling tank
Water gets released to nature, but contains high N and Ph levels
During times of heavy rain, treatment plants are overloaded and
release raw sewage into nearby bodies of water
A typical wastewater treatment facility
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Sludge = solid material
resulting from treatment
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Is decomposed microbially
Then landfilled, incinerated, or
used as fertilizer on cropland
Methane-rich gas created by
decomposition can be burned
to generate electricity
Heavy Metals and Acid Deposition
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Lead enters water through old lead pipes. Can damage brain,
kidneys, and nervous system (especially babies)
Arsenic occurs naturally in rocks, but is increased by humans
breaking up rocks. Leads to various cancers.
Mercury is natural and is also increased by human activities.
Most human related mercury comes from burning ff.
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Attacks central nervous system and fetuses. Often found in fish,
mostly top consumers (bioaccumulation)
Acid deposition comes from burning fossil fuels. Leads to death
of trees and aquatic ecosystems. Coals scrubbers and static help
Synthetic Organic compounds
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SOC are man-made organic compounds
Pesticides help control pests, but lead to other problems
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Don’t only kill pest they are designed to kill
Affect organisms down the food chain that eat these pests
Cancer, birth defects, bioaccumulation
Other common compounds found in water include military
compounds, pharmaceutical drugs, and industrial compounds
Oil Spills
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Toxic to many species, including algae which starts aquatic food
webs
Surface oil is sucked up, skimmed up, chemicals are applied that
break it up, bacteria is applied that eats it up, or coagulate it
No easy way to clean up underwater plumes
Not All Pollutants are Chemicals
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Solid waste production
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Sediment pollution comes from small particles carried in rivers
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Occurs from land erosion (mostly in agricultural areas)
Reduce sunlight, this reducing photosynthesis
Clog gills
Thermal pollution is when human activity causes water temp to
change (power plants)
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Plastic rings strangle animals
Medical waste hazardous to humans
Coal ash, which contains heave metals
Dissolved oxygen decreases as temperature increases
Noise pollution can affect animal communication (SONAR)
Pathogens and waterborne diseases
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Enter water supplies through inadequately treated human
waste and animal waste from feedlots
Fecal coliform bacteria indicate fecal contamination
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They are not pathogenic organisms
But the water may also hold other disease-causing pathogens
(e.g., giardiasis, typhoid, hepatitis A)
Bacterial pollution causes more human health problems than
any other type of water pollution
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Conditions are improving
86% of people now have safe water
Dissolved Oxygen (DO)
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DO (measured in PPM) is necessary for aquatic life
Most comes from atmosphere
Rapidly moving water has higher DO levels
Stagnant water with high levels of organic matter can contain
oxygen consuming bacteria that leads to eutrophication
As water temp increases, DO levels decrease, thus
eutrophication is worse in summer
Laws
 Clean water act (1972)
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Supports the protection and propagation of wildlife and
recreation in and on the water
Defined standards of acceptable limits of various
pollutants
Control how much discharge industries and put in water
Safe drinking water act (1974, 1986, 1996)
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Established max contaminant level for 77 different
elements or substances in surface and ground water
Problem:
In 2010, the South Anna River had a largemouth bass population
of 25,000 individuals over a 10–mile stretch. In early 2011, a
chemical spill occurred and the population of largemouth bass
decreased to only 5000 individuals over the same area. Calculate
the percent change in largemouth bass in the South Anna River.