Chapter 19 Water Pollution - Shirleytempledolls
Chapter 19 Water Pollution
Learning Nature’s Ways to Purify sewage
Arcata California – took land that was once a dump and converted it into a marsh – where the water acts as an inexpensive waste water treatment plant. Sewage first into settling ponds – then to marsh where bacteria and aquatic plants filter out other things – hope to send it to a salmon hatchery and make $
19-1 Types and Sources of Water Pollution ( learn table 19-1)
Definition – Any chemical, biological or physical change in water quality that has a harmful effect or makes water unfit for desired uses.
Classes of Pollutants
Disease causing agents
pathogens (bacteria, viruses, protozoans, and parasitic worms ) diseases table 20-1
causes 80% of deaths in developing countries
good indicator is number of coliform bacteria
drinking water should be 0 colonies to 100ml
swimming should be 200 colonies/100ml
humans excrete 2 billion each day
Oxygen demanding wastes
organic wastes that bacteria feed on - need large amounts of oxygen
measured by BOD – biological oxygen demand – where we measure the amount of dissolved oxygen needed by aerobic decomposers to break down organic material over a 5 day period in a certain volume of water at a certain temp (20o C)
Water Soluble Inorganic Chemicals
acids, salts, mercury, lead etc.
Selenium – comes from irrigation run off and has caused the death of most fish and birds in Calif – Keterson wildlife refuge – authorities refused to recognize and demoted several until printed in Sports Illustrated.
Inorganic Plant Nutrients
nitrates and phosphates
cause excessive growth of algae thus toxins and when they die use up Oxygen from other organisms
lowers oxygen carrying capacity of blood – killing unborn and infants
Organic Chemicals
oil, gas plastics, pesticides, cleaning solvents, detergents
nervous system damage, reproductive disorders, cancers
Sediment or Organic matter
soil from erosion
reduces photosynthesis and fouls gills, clouds water, irritates gills of fish, carry pesticides,
Radioactive materials – (nuclear)
iodine, radon, uranium, cesium
genetic mutations, birth defects, cancers, miscarriages,
Heat
absorbed by water used to cool industrial power plants
Genetic pollution
caused by non native species
Detection of pollution
Chemical Analysis
Indicator species
Computer models
Sources of Water Pollution
Point sources
ditches, pipes of sewers – very specific
Nonpoint sources
souces that cannot be traced
usually runoff from large areas of land or airshed
33%-64% of water pollution from non point
difficult to control
19-2 + 3 Pollution of Streams and Lakes
Pollution problems of streams
Normally streams recover rapidly from pollution because they are moving and use dilution and bacterial decay
Don’t work well if dammed up or overloaded
Oxygen Sag curves – show have well a stream handles pollution
Progress made in reducing stream pollution
require cities to pull drinking water downstream instead of upstream would help tremendously
Water cleanup laws enacted in 1970’s have increased number of waste water treatment plants – and decreased the pollution of disease causing and oxygen demand organisms
Case study – Cuyahoga River in Ohio – once caught fire in 1959 and 1969 due to pollution. Today river used by boaters and anglers.
Great Britain has also cleaned up the Thames river
Bad News
Large fish kills and contamination still occurs – by industry, sewage treatment plants and by non-point runoff of pesticides from cropland.
Ex. Sandoz chemical plant in Switzerland caught fire and dumped chemicals into the Rhine river – killed life from Switzerland – Netherlands
Becoming more of a problem in developing countries
Pollution in Lakes
Stratification can intensify pollution problems
Because water is not moving and going somewhere dilution does not help much – in fact can be concentrated.
Biological magnification also a problem
Cultural Eutrophication – run off from surrounding lands increase plant nutrients and cause eutrophication plants take over and block out the light – then die and fall to the bottom as they are rotting they take up the oxygen asphyxiating other organisms
Prevention
advanced waste treatment
ban or limit phosphates in detergents
soil conservation and land use control
Cures
dredge bottom sediments to remove nutrients
remove excess weeds
pump air through the lakes
Case Study – Great Lakes
Contain 95% of surface freshwater in USA
Even though it is big – very susceptible to pollution – because only 1% of the water leaves thru the St. Lawerence
By 1960 suffering cultural eutrophication and genetic pollution – worst was Lake Erie because shallow
Since 1972 clean up has occurred and Great Lakes have less levels of phosphates, decreased levels of coliform bacteria, DDT
In 1991 US feels that the great lakes is an environmental Hot spot ( one of 27 and should be cleaned up), No $ provided
In spite of industry opposition Environmentalist urge ban
use of Cl in pulp and paper industries
all new incenerators in the area
discharge into the lakes 70 toxic chemicals
Concern – levels still rising
Toxic chemicals carried by air currents from TX and CA.
PCB built up in food chains
Zebra Mussel
In 1986 brought to Detroit by ship emptying bilge – no predator
Out compete native species, clog irrigation pipes, grow on ships, foul beaches – have spread to most of US
Damage has cost $10 billion
Good news for number of aquatic plants – because consumes algae, making water clearer, so plants increase photosynthesis
Quagga Mussel
In 1991 came from Russia
May be worse than Zebra mussel because can tolerate wider range of conditions. EX . colonize Chesapeake & FL
Case Study : Protecting Lake Baikal
Largest Freshwater lake located in Siberia – most biologically rich lake – watershed comes from taiga
Environmental battle started in 1960 to prevent paper plants – concern of waste water and deforestation – So allow the tree – pulp operation and then send pulp elsewhere for further treatment.
Now foreign interest in timber and lake reserves.
Hope to be a model of sustainable development of watersheds.
Heat Pollution – thermal pollution
Power plants use energy from coal or nuclear to heat water to turn turbines for electricity
Cheapest way is to pull water from surface and return it.
bad – many fish die being pulled on to screens over intake pipes
Thermal temp change – decreased Oxygen
Disrupt spawning and young fish
Thermal Shock from fluctuating temp
Some call it Thermal Enrichment
increase commercial fishing season
reduces winter ice cover
an extend growing season if used as irrigation water in frost prone areas
can grow oysters and other warm water organisms in aquaculture areas
Heat nearby buildings and greenhouses ( however because of pollution of power plants usually not near housing)
Ways to reduce or control thermal water pollution
use and waste less energy
limit the amount of heated water returned
return the heated water away from shore zone
transfer heat from water to atmosphere – through cooling towers
discharge heated water into shallow ponds or canals and then reuse it
19-5 – Ocean Pollution
How much can they tolerate
Oceans are the ultimate sink
Dilute, disperse and degrade large amounts of sewage, oil, industrial waste
Marine life much more resilient than any other group
It may be safer to put hazardous waste in deep oceans
Pollutants affect on coast
Coast has most of the global population
Most polluted coast off developing countries ex. Bangladesh, Thailand, etc.
But also 85% of the sewage goes to Mediterranean Sea
US – 35% of sewage goes to oceans – black mayonnaise covers the bottoms of some bays – mixture of feces, industrial waste and oil. Especially in California
Also agricultural runoff cause algal blooms and oxygen depletion
Case Study: The Chesapeake Bay
largest estuary in United States – in trouble because of human pop.
Very shallow – receives waste from 9 major rivers and 141 smaller streams and creeks
Since 1983 – a cooperative program – CHESAPEAKE BAY PROGRAM – has taken many governmental , industries, environmental, and recreational groups and $700 million impressive cleanup has occurred
Major problem now is non native invasive.
What pollutants are dumped into the ocean
Dredge spoils – materials scraped from bottom of harbors, channels and dumped in 110 sites off the Atlantic – often laden with toxic materials.
Sewage Sludge – dumped from waste water treatment plants – not allowed in US since 1992 – however Mexico still does and currents carry the waste to Calif. Beaches
In 50 countries - merchant fleets no longer dump sewage into oceans. This wastes kill millions of sea life
London Dumping Convention of 1972 – 100 countries agreed not to dump high level radiation into the ocean. However Soviet Union has be dumping low level radiation into the artic sea.
Effects of oil on Ocean Ecosystems
Oil from crude petroleum and refined petroleum sometimes enter the ocean through accidents or on purpose
Accidents like Valdez get a lot of attention but actually US oil companies leak /spill/waste as much as 17 Valdez in the Mediterranean alone.
Kills larval forms – but evaporates quickly in warm seas
Some form tar like globs that float on surface and coat fur and feathers
Other oil sinks to the bottom and kills benthic organisms
Most sea life recovers after 3 years – takes longer in cold temp,
Considered low risk ecological problem
How can oil spills be Cleaned up
Mechanical means
Floating booms to contain the oil
Skimmer boats that vacuum up the oil
Absorbent bags or feather pillows to soak up oil
Chemical Means
coagulating methods
dispersing agents
Fire
Natural means – action of wind and waves emulsifies the oil and bacteria break it down.
These methods only breakdown part of the oil and some do as much harm – reason why P2 (pollution prevention) – is so important.
Case Study: The Exon Valdez
In Alaska – 1989 - a tanker hit submerged rocks and spilled oil – caused a spill the length of NJ – SC
Environmentalist wanted oil to come by pipeline instead of tanker because of dangers
Alyeska (company of oil exporters from alaska) did not want the pipeline it was too expensive – also was not prepared for the disaster – too little too late.
Cleanup actually did more harm than good – the areas cleaned killed more than areas not cleaned
At fault – alcoholic captiain – drunk – fatigued crew
Clean up cost $8.5 billion would have been prevented by $22.5 million double hull – now required on all tankers
P2 important because only 15% of spilled oil can be recovered
Solutions – Protecting Coastal Waters
Key – reduce the flow of pollution from land to streams to oceans
Prevention
separate sewage and storm run off in coastal urban areas
discourage ocean dumping of sluge and toxics
protect ecologically fragile and valuable areas from development, oil drilling and shipping
Double hulls for all oil tankers by 2002
Recycle used oil
Cleanup
improve oil cleanup
require at least secondary treatment of coastal sewage
19-6 Solutions – Surface Water Pollution
Non point sources
leading source in agriculture
use none or moderate slow release fertilizers on steep sloping land
Plant buffer zones of trees - Sometimes called SMZ – stream management zone
Apply pesticides only when needed
Reforest critical watersheds
Point Sources – Legal approach
Federal Water Pollution Control Act (1972) renamed CLEAN WATER ACT (1977) – make all US surface waters safe for fishing and swimming by 1983 – some progress – didn’t make the goal. Areas tested have increased from 36%(1972) - 62% in 1992.
$85 billion by government and $500 billion by industry spent – mainly on end pipe controls
Environmentalist want act strengthened by
control non point sources of pollution
phase out certain toxic discharges
provide and integrated water and air shed
permit states to take over some parts
expand private citizens ability to bring lawsuits against polluters
Some oppose want act weaken because
too restrictive and costly
want to be compensated for land/water they cannot make a profit from – takings rights
more local discretion of which water test to do
US house proposed weakening act in 1995 but bill did not pass the Senate
Point Sources – Technological Sources
Septic Tanks – in 25% of all US homes mostly rural or suburban homes with suitable soils.
tank that catches solids and allow bacteria to work on them – settle to the bottom
Water drains from top of the tank and goes to drain field – a system of perforated pipes on be of gravel
Must not be placed too close together, or in too wet of soil and should be pumped out every 3 – 5 years to prevent the settling tank from overflow
Urban areas use Sewage treatment plants
primary treatment – mechanical process that screens out debris – uses screens and polymers to remove suspended solids
Secondary treatment – biological process
-Aerobic bacteria are bubbled in and remove 90% of oxygen demanding waste
Then goes to a sedimentation tank where most of the suspended solids and bacteria (bugs) sink and are removed -–this is what is called sludge
Sludge is usually incinerated and dumped into oceans, landfills or applied to land as fertilizers.
Water is usually chlorinated too – some concern because if mixes with hydrocarbons – have chlorinated hydrocarbons in drinking water – some estimate that 7 – 10% cancers could be due to chlorinated drinking water
No radioactive isotopes or pesticides removed in this stage
As a result of Clean Water Act most cities now have Secondary water treatment plants – not all – 34 East coast cities only do primary treatment – any one want to swim?
Advanced Sewage Treatment
chemical and physical processes that remove specific pollutants.
Usually expensive to build and operate
Used in Finland, West Germany, Switzerland, Sweden
Other ways to purify water – as described at beginning of the chapter
19-5 Groundwater Pollution and prevention
Groundwater pollution – serious problem
Out of sight pollution
Low risk ecological problem – that can be high risk if ground water is drinking water.
Laws protecting ground water are weak or non-existant
Ground water can not cleanse itself because it is slow and not turbulent – pollution can not be diluted and dispersed
Takes hundreds to thousands of years to cleanse of degradable wasted because cold temp slow decomposition
Many wells – as many as 9% may be contaminated with nitrates – Good news- a small company in Germany has developed an enzyme that can convert nitrates to nitrogen gas
Many aquifers are polluted – all in NJ
FL – 92% of drinking water is ground water
Contamination comes mainly from leaking tanks and leaking land fills.
Cleaning ground water involves pumping to surface, cleaning it and pumping it back – very $$$$ - P2 very imp.
Solutions – protect ground water
monitor aquifers near landfills and underground tanks
require leak detection systems for new and old tanks
Require liability insurance for hazardous liquid tanks
Banning disposal of hazardous waste by deep injection wells and in landfills
Store hazardous liquids in above ground tanks with leak detection systems – and collect each leak
19-7 Drinking Water Quality
Is water safe to drink?
In most developed countries – yes – developing – no
1980 UN recommended – spending $300 billion to supply the world with clean drinking water and adequate sanitation by 1990. $1.5 billion /year was actually spent – not there yet –
Trying to find cheap ways to purify water ex.
Solar power UV lamp zaps water as it passes thru the tap – kills germs
Horseradish and peroxide rids water of phenols
Slime of blue green algae that remove chemical toxins.
How is drinking water purified
very similar to waste water treatment – settling – then run through sand filters and activated charcoal before it is disinfected.
How is Drinking Water Quality Protected
Safe Drinking Water At of 1974 – requires EPA to establish national drinking water standards – called maximum contaminant levels
Privately owned wells do not have to meet these standards – because of the cost to test – over $1000 per well
Have had problems in municipal water programs with cyptosporium ( caused 104 deaths in Milwaukee in 1993) and Giardia
Some want Safe Drinking Water Act weakened
eliminate national test of drinking water
eliminate the requirement of media notification
allow states to violate a standard if the state feels it is too costly
eliminate the requirement that systems remove cancer causing contaminants
Some want the Safe Drinking Act strengthened
Combine water systems – reduce administrative cost
Strengthen the public notification systems
Ball all lead in new plumbing ( now 10% qualifies as lead free)
Is Bottled Water the Answer?
No – many is dirtier than tap water
Only way to know is look for IBWA seal – cost companies $2,500/year to test for 200 chemical and biological contaminants
Home Water Purification Systems
Type Price Pros Cons
|Activated Carbon Filters |$35 – 2,500 |Removes chlorine, organic chem and radon – |Does not remove biological pathogens –|
| | | |can be breeding ground – if not |
| | | |changed or cleaned |
|Reverse Osmosis |$600 – 1,000 |Removes particulates by forcing water |Produces 4 gallons of waste for every |
| | |through semipermeable membranes |one gall produced – does not remove |
| | | |toxic chem and some pathogens |
|Distillation |$200 – 700 |Removes most everything except volatile |$ to operate, uses lots of energy, |
| | |chem and radon |produces flat tasting water |
|UV light |$300 |Kills pathogens |Does not remove other pollutants |
|Water Softeners |$1,000 |Remove dissolved minerals – |Does not remove pathogens and toxic |
| | | |substances |
best to use machines that use a variety of methods – EPA does not approve any machines – does register them
Solutions
Integrated approach to managing water resources through out each watershed and air shed.
Shift emphasis from water pollution clean up to pollution prevention
source reduction
reuse waste water instead of discharging
recycling pollutants
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