The water pollution problem

Chapter 21.1 notes

History of pollution

• We know that before the sanitary landfillwas invented, people dumped theirtrash anywhere they wanted

– Some ended up in the streets– Some ended up in the water

History of pollution

• Recall that landfills were invented inresponse to disease outbreaks thatwere resulting from all the trash

– Typhoid– Cholera– Dysentery

History of pollution

• Many parts of theworld still dump trashin the ocean

• In addition to this, wehave other waterpollution issues

Sewage

• Sewage is water that contains organicwastes from humans and industry

– Comes from toilets, sinks, dishwashers,washing machines, factories etc.

– Sewage is treated in the U.S.– Many developing countries do not treat

sewage

Sewage

• From the toilet / sink / etc., wastes travelthrough a network of pipes called the sewersystem

– These pipes connect to a place where the watercan be cleaned

• Sewage-treatment plants are facilities thatprocess raw sewage before the sewage isreturned to surface water

Sewage

• Once at the sewage-treatment plant, thewater goes through a series of processes

1. Water is filtered to remove debris

2. Bacteria are used to digest organiccontaminants, called sludge

3. Chlorine is added to sanitize and deodorizethe water

Sewage

• If the water-treatment plant is overloaded,some untreated sewage may be releasedinto surface waters

– Overload may result from heavy storms ormechanical malfunctions at the plant

– This can cause water contamination.

• Happened in Des Moines, Iowa in 1993

Sewage

• Untreated water from Tijuana Mexico hascaused beach closures in San Diego, CA

– The pollution traveled with the current andcrossed the border

Pathogens

• Many disease-causing organisms comefrom untreated water

• Pathogens include parasites, bacteria, andviruses that cause disease in living things

– i.e. Schistosomiasis• Is a worm that enters human body through the skin• Attacks liver, bladder and intestines

Pathogens

• Pfiesteria

– Is a dinoflagellate (type ofanimal-like algae)

– Population boom of thesealgae causes the water tolook red

• Called red tide

Pathogens

• The algae is toxic to fish,humans, and other organisms

– Fish kill = Fish are killed inmass due to toxin that isreleased, causing lesions andparalyzing the fish

– In humans, symptoms mayinclude memory loss, burningsensations, vomiting, rashes,etc.

Fish killTypes of water pollution

• 1st largest source = agriculture runoff• 2nd largest source = sewage

• In both of these sources, the most commonpollutants are:

– Pathogens– Nutrients– Sediments– Toxic Chemicals

Chemical Pollutants

Chapter 21.2 notes

Chemicals

• Toxic chemicals are elements andcompounds that are directly harmful to livingthings

– Inorganic = do not contain carbon

– Organic = contain carbon; usually come fromliving things

Inorganic Chemicals

• Include:– Acids– Salts– Heavy metals = metallic element with high mass

number• Cadmium• Mercury• Lead• Chromium• Nickel

– Plant nutrients (NPK = nitrogen, phosphorous,potassium)

Inorganic Chemicals

• Acids & Heavy metals

– Enter groundwater and surface water due toseepage, runoff, and direct discharge

• Mines• Hog lagoons• Landfill leaching• Sewage pipes

– Point Source = any pipe or other source wherepollution directly gets released into the environment

Inorganic Chemicals

• Acids & Heavy metals

– Many heavy metals come from industrialprocesses

• Metal treatment• Plastic production• Paint production

– Ingesting these chemicals can cause healthproblems such as brain, liver and kidneydamage, coma, and death

Inorganic Chemicals• In Minamata, Japan, a

mysterious case of mercurypoisoning took place in the1950s

– Birds fell out of trees and flew intobuildings

– Cats foamed at the mouth and ranin circles until they died

– Humans had headaches,dizziness, blurred vision, andnumbness in the hands and feet

Inorganic Chemicals

• Cause was plastics factory that wasdumping mercury into the Minamata Bay

• Seafood was the main diet of these people

– 8,000 people suffered paralysis or brain damage;hundreds died

Organic Chemicals

• Many organic chemicals come from living things– Food waste– Excrement

• Others can be synthetic– Gasoline– Oil– Plastic– Pesticides– Fertilizers– Solvents– Wood preservatives

Organic Chemicals

• Wastes may come from petroleum refineries,chemical factories, and food processing plants

• May also come from farmland runoff that has largeamounts of insecticides, herbicides, and fertilizers

• Also can come from:– Oil spills (recall the Exxon Valdez spill we discussed)– Gas-powered boats– Dumping

Eutrophication• Too much fertilizer can cause major environmental

issues

– Recall that fertilizer contains high quantities of NPK(nitrogen, phosphorous, and potassium)

• Eutrophication is the process of changing lakes andponds due to excess plant nutrients

– This is what we are trying to simulate in our buckets outside!

Eutrophication

• When there’s too much fertilizer, populationsof algae grow very fast

– Sometimes called Algal Blooms

– They produce lots of oxygen through photosynthesis

Eutrophication

• After all the algae eat up the fertilizer, theyrun out of food and starve to death

• All the dead algae sink to the bottom of thewater

Eutrophication

• Bacteria decompose the dead algal bodies.

– Decomposition consumes all the oxygen inthe water.

– The water becomes depleted of oxygen, sonothing can live there

• Sometimes called a dead lake

Eutrophication

• Scientists estimate that more than 65% of the lakesin the U.S. are affected by human-causedeutrophication

– One of the most significant cases is the Chesapeake Bay,which is the largest estuary in the U.S.

• Farms use too much fertilizer in order to produce more andbigger plants

• Eutrophication is causing a sharp drop in many fish andshellfish populations

Eutrophication

– Virginia’s DEQ (Dept. of Env. Quality) and DCR (Dept. ofConservation & Recreation) are working to minimize theseeffects on the Bay

Radioactivity&

Thermal PollutionChapter 21.3 notes

Radioactivity

• Recall that radioactive elements are used fora number of things…

– Nuclear power– Medicine (i.e. cancer treatment)– Nuclear weapons

• All of these uses generate radioactive waste

– Nuclear weapons detonations and power plantaccidents produce the most waste

Radioactivity

• Tiny amounts of radiation are released into theair and water near nuclear power plants

– These emissions are miniscule and not dangerous

• The wastes produced by these plants, though,are dangerous and difficult to dispose of

– Often temporarily disposed of in metal drums,which corrode

– Results in these wastes leaching intogroundwater

Radioactivity

• Radioactive waste in groundwater is bad– Can contaminate drinking water

– Can make fish and shellfish toxic

– Can cause cancer in humans

Thermal Pollution

• Thermal pollution occurs when there’s a largeincrease in water temperature due to humanactivity

– Usually caused by power plants andindustrial sites

– These plants and factories use water fromlakes and streams as part of their coolingsystems

– Basically, cool water goes in and hot watercomes out

• How does thermal effluent affectecosystems?

– Fish are partially ectothermic (coldblooded)

• Body temp. is regulated byenvironment

• Increased body temp. results inincreased metabolism

• Increased metabolism results inincreased respiration

• Increased respiration results in moreoxygen needed by the fish

Thermal Pollution

– Warm water decreases dissolved oxygenlevels

– Developing eggs and young fish areharmed / killed

ControllingWater Pollution

Chapter 21.4 notes

Water Pollution Laws

• There are numerous laws / acts / policies thatattempt to regulate water pollution

– Rivers and Harbors Act (1899)– Water Quality Act (1970)– Clean Water Act (1972)– Safe Drinking Water Act (1974)

• Your textbook lists 12 of these laws and what they areintended to accomplish

Water Pollution Laws

• What YOU need to know

– It is VERY difficult to enforce these laws, so theydon’t accomplish a whole lot

RAR

• These kinds of laws are called “Paper Tigers”because they don’t have any real “teeth”

Water Pollution Laws

• Reasons the laws are hard to enforce…

– Water moves, so it’s difficult to trace the pollutionback to a source

• Especially true of non-point source pollution

– The fines are not hefty enough• Many companies would prefer to pay $10,000 for polluting than

spend $10 million to buy fancy new equipment

– Many municipalities don’t enforce the laws becausethey don’t want the companies to relocate

• Remember: these industries fuel our economy

Water Pollution Laws

• We HAVE seen some improvements over theyears

– The Chesapeake Bay isnow less eutrophic

– The Cuyahoga River hasn’tcaught on fire in a while– (as it did in 1937)

– Phosphate pollution inLake Erie has beenreduced