WATER POLLUTION

Adapted from K.Sturges @ MBHS

Freshwater pollution

◦ Water for human consumption and other organisms needs to be:

◦ Disease-free

◦ Nontoxic

◦ Half of the world’s major rivers are seriously depleted and polluted

◦ They poison surrounding ecosystems

◦ Threatening the health and livelihood of people

◦ The invisible pollution of groundwater has been called a “covert crisis”

Point and nonpoint sources of pollution

◦ Pollution = the release of matter or energy that causes undesirable impacts on the health and well-being of humans or other organisms

◦ Point sources = discrete locations of water pollution

◦ Factories, sewer pipes

◦ Addressed by the U.S. Clean Water Act

◦ Nonpoint sources = pollution arises from multiple inputs over larger areas (farms, city streets, neighborhoods)

◦ The major source of U.S. water pollution

Point Source Pollution

◦ Water pollution that can be traced to

a specific spot (such as a factory or

sewage treatment plant) because it is

discharged into the environment

through pipes, sewers or ditches.

◦ Aka you can physically point to it’s

source.

Non-Point Source Pollution

◦ Pollutants that enter

bodies of water over

large areas rather than

being concentrated at

a single point of entry.

Ex. Agricultural fertilizer

runoff and sediments

from construction.

Freshwater pollution sources

Indicators of water quality

◦ Scientists measure properties of water to characterize its quality

◦ Biological indicators: presence of fecal coliform bacteria,

disease-causing organisms, algae, etc.

◦ Chemical indicators: nutrient concentrations, pH, taste, odor, hardness, dissolved oxygen

◦ Physical indicators: color, temperature, turbidity

Think back to our Eco-Columns!

Indicators

◦ DO- dissolved oxygen- The amount of oxygen gas dissolved in a

given volume of water at a particular temperature and pressure.

◦ Nitrates- causes eutrophication- contaminates shallow groundwater and usually comes from fertilizers.

◦ Phosphate- causes eutrophication Plant nutrients that cause

algae blooms. It comes from detergents, human wastes and

fertilizers.

Indicators

◦ Hardness- Calcium and magnesium dissolved in the water. A little is good but very low (biggest problem) or too high is a problem. Affects fish eggs, poor bone development.

◦ pH- Too high/too low can be bad; fish like 6.5-9.5; acid mine drainage can kill fish.

◦ Turbidity - Cloudiness/muddiness; blocks the light; coats fish gills.

Water Pollution from Agriculture

◦ Agriculture is leading source of water pollution in US

◦ Animal wastes and plants residues have high BOD

◦ Chemical pesticides can leach into groundwater

◦ Almost all streams and rivers are polluted with agricultural

pesticides

◦ 72% of water pollution in rivers is from agriculture

© 2012 John Wiley & Sons, Inc. All rights reserved.

Municipal Water Pollution

© 2012 John Wiley & Sons, Inc. All rights reserved.

Major Water Pollutants and Their SourcesType/Effects Examples Major Sources

Infectious agents

Cause diseases

Bacteria, viruses, parasites Human and animal wastes

Oxygen- demanding

wastes

Deplete dissolved O2

needed by aquatic species

Biodegradable animal

wastes and plant debris

Sewage, animal feedlots,

food processing facilities

Plant nutrients

Cause excessive growth of

algae and other species

Nitrates and phosphates Sewage, animal waste,

inorganic fertilizers

Organic Chemicals

Add toxins to aquatic

systems

Oil, gasoline, plastics,

pesticides, cleaning

solvents

Industry, farms, households

Inorganic chemicals

Add toxins to aquatic

systems

Acids, salts, metal

compounds

Industry, households,

surface runoff

Sediments

Disrupt photosynthesis,

food webs, other processes

Soil, silt Land erosion

Thermal

Make some species

vulnerable to disease

Heat Electric power and

industrial plants

Pathogens and waterborne diseases

◦ Enter water supplies through inadequately treated human

waste and animal waste from feedlots

◦ Fecal coliform bacteria indicate fecal contamination

◦ 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

◦ Conditions are improving

◦ 86% of people now have safe water

• Infectious organisms that cause diseases

– Originate in the wastes of infected individuals

• Common bacterial or viral diseases:

– Typhoid, cholera, bacterial dysentery and infectious hepatitis

Disease-causing Agents

◦ Monitored by testing for presence of E. coli in the water via a fecal

coliform test

◦ Indicates the presence of pathogenic organisms

© 2012 John Wiley & Sons, Inc. All rights reserved.

Pathogens cause human health problems

◦ 1 billion are still without safe water

◦ 2.6 billion have inadequate sewer or sanitary facilities

- Mostly rural Asians and Africans

◦ Health impacts kill 5 million people per year

◦ Solutions:

- Disinfect drinking water

- Treat sewage

- Public education to encourage personal hygiene

- Government enforcement of regulations protecting food

Nutrient pollution

• Nutrient pollution from fertilizers, farms, sewage, lawns, golf

courses leads to eutrophication

◦ 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 treating wastewater

◦ Reducing fertilizer application

◦ Using phosphate-free detergents

◦ Planting vegetation to increase nutrient uptake

Water Pollution Problems in Streams

◦ Dilution and decay of degradable, oxygen-demanding wastes and heat in a stream.

Figure 21-4

Inorganic Plant and Algal Nutrient-The Dead Zone

© 2012 John Wiley & Sons, Inc. All rights reserved.

Eutrophication is a natural process, but…

◦ Human activities dramatically increase the rate at which it occurs

Organic Compounds

◦ Chemicals that contain carbon atoms

◦ Natural examples: sugars, amino acids, and oils

◦ Human-made examples: pesticides, solvents, industrial chemicals,

and plastics

© 2012 John Wiley & Sons, Inc. All rights reserved.

Inorganic Chemicals

◦ Contaminants that contain elements

other than carbon

◦ Do not degrade easily

◦ Lead

◦ Found in old paint, industrial pollutants,

leaded gasoline

◦ Mercury

◦ Mercury bioaccumulates in the muscles

of top predators of the open ocean

◦ Comes from burning coal

◦ Neurotoxin

© 2012 John Wiley & Sons, Inc. All rights reserved.

Toxic chemicals

◦ Pesticides, petroleum products, synthetic chemicals

◦Arsenic, lead, mercury, acid rain, acid drainage from

mines

◦ Effects include poisoned animals and plants, altered

aquatic ecosystems, and decreased human health

◦ Solutions:

- Issue and enforce more stringent regulations of industry

- Modify industrial processes

- Modify our purchasing decisions

Case Study: Arsenic in Groundwater - a Natural Threat

◦ Toxic Arsenic (As) can naturally occur at high levels in soil

and rocks.

◦Drilling into aquifers can release As into drinking water

supplies.

◦According to WHO, more than 112 million people are

drinking water with As levels 5-100 times the 10 ppb

standard.

◦Mostly in Bangladesh, China, and West Bengal, India.

Sediment pollution (ie. Turbidity)

◦ Sediment in rivers can impair aquatic ecosystems

◦ Excessive amounts of suspended soil particles

◦ Originates from erosion of agricultural lands, forest soils exposed by

logging, degraded stream banks, overgrazed rangelands, strip mines,

and construction

◦ Problems

◦ Limits light penetration

◦ Covers aquatic animals and plants

◦ Brings insoluble toxins into waterways

◦ It dramatically changes aquatic habitats

◦ Fish may not survive

◦ Solutions:

◦ Better management of farms and forests

◦ Avoid large-scale disturbance of vegetation

© 2012 John Wiley & Sons, Inc. All rights reserved.

Thermal pollution

◦ Water that is too warm causes problems

◦ Warmer water holds less oxygen

◦ Dissolved oxygen decreases as temperature increases

◦ Industrial cooling heats water

◦ Removing streamside cover raises water temperature

◦ Water that is too cold also causes problems

◦ Water at the bottom of reservoirs behind dams is colder

◦ When water is released, downstream water temperatures drop

suddenly, killing aquatic organisms

Thermal Pollution

◦ Warm water increases decomposition which decreases DO

© 2012 John Wiley & Sons, Inc. All rights reserved.

Organisms affected

Temperature affects

reproductive cycles,

digestion rates, and

respiration rates

Warm water holds less DO

than cold water

Groundwater pollution is a difficult problem

◦ Groundwater is increasingly contaminated

◦ But is hidden from view and difficult to monitor

◦ “Out of sight, out of mind”

◦ Groundwater pollution is hard to address

◦ It retains contaminants for decades and longer

◦ It takes longer for contaminants to break down because of

lower sunlight, microbes, and dissolved oxygen

Sources of groundwater pollution

◦ Some toxic chemicals occur naturally

◦ Aluminum, fluoride, sulfates

◦ Pollution from human causes wastes

leach through soils

◦ Pathogens enter through improperly

designed wells

◦ Leaking underground storage and

septic tanks

So far, the EPA has

cleaned up 388,000

leaking tanks

Agriculture and industry pollute groundwater

◦ Agricultural pollution comes from several sources

◦ Pesticides are in most of the shallow aquifers tested

◦ Nitrates from fertilizers have caused cancer, miscarriages, and

“blue-baby” syndrome

◦ Pathogens like Escherichia coli (E. coli)

◦ Manufacturing industries and military sites have been heavy

polluters

◦ By-products seep into water from miles around

◦ Radioactive wastes will contaminate water for 750,000 years

Fig. 21-9, p. 504

Solutions

Groundwater Pollution

CleanupPrevention

Find substitutes for toxic chemicals

Install monitoring wells near landfills and underground tanks

Require leak detectors on underground tanks

Ban hazardous waste disposal in landfills and injection wells

Store harmful liquids in aboveground tanks with leak detection and collection systems

Pump to surface, clean, and return to aquifer (very expensive)

Pump nanoparticles of inorganic compounds to remove pollutants (may be the cheapest, easiest, and most effective method but is still being developed)

Keep toxic chemicals out of the environment Inject

microorganisms to clean up contamination (less expensive but still costly)

POLLUTION OF FRESHWATER STREAMS

◦Most developed countries have sharply reduced point-source

pollution but toxic chemicals and pollution from nonpoint sources

are still a problem.

◦ Stream pollution from discharges of untreated sewage and industrial

wastes is a major problem in developing countries.

Global Outlook: Stream Pollution in Developing Countries

◦Water in many of central

China's rivers are greenish

black from uncontrolled

pollution by thousands of

factories.

Figure 21-5

Case Study: India’s Ganges River: Religion, Poverty, and Health

◦ Religious beliefs, cultural traditions, poverty, and a large population

interact to cause severe pollution of the Ganges River in India.

◦Very little of the sewage is treated.

◦Hindu believe in cremating the dead to free the soul and

throwing the ashes in the holy Ganges.

◦ Some are too poor to afford the wood to fully cremate.

◦ Decomposing bodies promote disease and depletes DO.

Case Study: India’s Ganges River: Religion, Poverty, and Health

◦ Daily, more than 1 million Hindus in

India bathe, drink from, or carry out

religious ceremonies in the highly

polluted Ganges River.

Figure 21-6

OCEAN POLLUTION

◦ Oceans, if they are not overloaded, can disperse and break

down large quantities of degradable pollutants.

◦ Pollution of coastal waters near heavily populated areas is a

serious problem.

◦ About 40% of the world’s population lives near on or near the

coast.

◦ The EPA has classified 4 of 5 estuaries as threatened or

impaired.

Fig. 21-10, p. 505

Healthy zoneClear, oxygen-richwaters promote growthof plankton and sea grasses,and support fish.

Oxygen-depleted zoneSedimentation and algaeovergrowth reduce sunlight,kill beneficial sea grasses, useup oxygen, and degrade habitat.

Red tidesExcess nitrogen causesexplosive growth of toxicmicroscopic algae,poisoning fish andmarine mammals.

FarmsRunoff of pesticides, manure, and fertilizers adds toxins and excess nitrogen and phosphorus.

Toxic sedimentsChemicals and toxic metals contaminate shellfish beds, kill spawning fish, andaccumulate in the tissues of bottom feeders.

Construction sitesSediments are washed intowaterways, choking fish and plants, clouding waters, and blocking sunlight.

Urban sprawlBacteria and viruses fromsewers and septic tanks contaminate shellfish beds

Oxygen-depletedzone

Closedbeach

CitiesToxic metals and oil from streets and parking lots pollute waters;

IndustryNitrogen oxidesfrom autos andsmokestacks,toxic chemicals,and heavy metals in effluents flow into bays and estuaries.

Closedshellfish beds

OCEAN POLLUTION

◦Harmful algal blooms (HAB) are caused by explosive growth of

harmful algae from sewage and agricultural runoff.

Figure 21-11

Oxygen Depletion in the Northern Gulf of Mexico

◦A large zone of oxygen-

depleted water forms for

half of the year in the

Gulf of Mexico as a result of HAB.

Figure 21-A

Fig. 21-A, p. 507

Mississippi

River

Mississippi

River Basin

Gulf of Mexico

Ohio River

Mississippi River

Missouri River

TX

MSLA

Depleted oxygen

LOUISIANA

Gulf of Mexico

Case Study: The Chesapeake Bay –An Estuary in Trouble

◦ Pollutants from six states

contaminate the shallow

estuary, but cooperative efforts

have reduced some of the

pollution inputs.

Figure 21-12

OCEAN OIL POLLUTION

◦ Most ocean oil pollution comes from human activities on land.

◦ Studies have shown it takes about 3 years for many forms of marine life to

recover from large amounts of crude oil (oil directly from ground).

◦ Recovery from exposure to refined oil (fuel oil, gasoline, etc…) can take 10-20 years for marine life to recover.

OCEAN OIL POLLUTION◦ Tanker accidents and

blowouts at offshore drilling rigs

can be extremely devastating

to marine life (especially diving

birds, left).

◦ Ex. Exxon Valdez killed over 250

thousand animals

◦ The BP oil spill threatens more

than 600 animal species

Figure 21-13

Fig. 21-14, p. 509

Reduce input of toxic pollutants

Solutions

Coastal Water Pollution

Prevention Cleanup

Use wetlands, solar-aquatic, or other methods to treat sewage

Require at least secondary treatment of coastal sewage

Sprinkle nanoparticles over an oil or sewage spill to dissolve the oil or sewage without creating harmful by-products(still under development)

Improve oil-spill cleanup capabilities

Recycle used oil

Regulate coastal development

Protect sensitive areas from development, oil drilling, and oil shipping

Ban ocean dumping of sludge and hazardous dredged material

Ban dumping of wastes and sewage by maritime and cruise ships in coastal waters

Separate sewage and storm lines

Require double hulls for oil tankers

Great Pacific Garbage Patch

◦ Is a gyre of marine litter in the central

North Pacific Ocean and estimated to

be the twice the size of Texas

◦ An estimated 80% of the garbage

comes from land-based sources, and

20% from ships

◦ Some of these long-lasting plastics end up in the stomachs of marine birds and animals baby chicks

◦ Besides the particles' danger to wildlife, the floating debris can absorb organic pollutants from seawater, including DDT

◦ Aside from toxic effects, when ingested, some of these are mistaken by the endocrine system as estradiol, causing hormone disruption in the affected animal.

◦ These toxin-containing plastic pieces are also eaten by jellyfish, which are then eaten by larger fish. Many of these fish are then consumed by humans, resulting in their ingestion of toxic chemicals.

◦ Marine plastics also facilitate the spread of invasive species that attach to floating plastic in one region and drift long distances to colonize other ecosystems.

It is best to prevent pollution

◦ It is far better to prevent pollution than use “end-of-pipe”

treatment and cleanup

◦Other options are not as good:

◦ Removing just one herbicide from water in the U.S.

Midwest costs $400 million/year

◦ Pumping, treating, and re-injecting it takes too long

◦Consumers can purchase sustainably made products

◦ Become involved in local “riverwatch” projects

◦Urge government to pursue policies to fight pollution

Legislative efforts reduce pollution

◦ Water pollution was worse decades ago

◦ Citizen activism and government response resulted in

legislation during the 1960s and 1970s

◦ The situation is much better now

◦ The Federal Water Pollution Control Act (1972)

◦ Renamed the Clean Water Act in 1977

◦ It is illegal to discharge pollution without a permit

◦ Sets standards for industrial wastewater

◦ Funded sewage treatment plants

Enforcement of water quality is decreasing

◦ Underfunded and understaffed state and federal regulatory

agencies were pressured by industries and politicians

◦ Violations of the Clean Water Act have risen to over 100,000

documented violations/year

◦ 10% of Americans are unknowingly exposed to unsafe drinking

water

◦ The new EPA administrator has promised to improve

◦ Citizens pushed politicians to improve the Great Lakes

◦ The water quality of the lakes has dramatically improved

We treat our drinking water

◦ Technology and government regulation have improved

our pollution control

◦ Treated drinking water is widespread and successful in developed nations

◦ Before water reaches the user, it is chemically treated,

filtered, and disinfected

◦ The EPA sets standards for over 90 drinking water

contaminants

◦ Local governments and private water suppliers must

meet these standards