Chapter 21Chapter 21Water PollutionWater Pollution

Types of Water PollutionTypes of Water Pollution Water pollutionWater pollution

Any physical or chemical change in water that Any physical or chemical change in water that adversely affects the health of humans and adversely affects the health of humans and other organisms other organisms

1.1. SewageSewage

2.2. disease-causing agents disease-causing agents

3.3. sediment pollutionsediment pollution

4.4. inorganic plant and algal nutrientsinorganic plant and algal nutrients

5.5. organic compoundsorganic compounds

6.6. inorganic chemicals inorganic chemicals

7.7. radioactive substances radioactive substances

8.8. thermal pollution thermal pollution

1. Sewage1. Sewage

Causes 2 serious environmental Causes 2 serious environmental problems:problems:1. 1. EnrichmentEnrichment

Fertilization of water by high levels N and PFertilization of water by high levels N and P

2. 2. Increase in Biological Oxygen Increase in Biological Oxygen Demand (BOD)Demand (BOD) BOD-amount of oxygen needed by BOD-amount of oxygen needed by

microorganisms to decompose biological microorganisms to decompose biological wasteswastes

BOD Dissolved Oxygen (DO) BOD Dissolved Oxygen (DO)

SewageSewage

Sewage: EutrophicationSewage: Eutrophication OligotrophicOligotrophic

Unenriched, clear water that supports small Unenriched, clear water that supports small populations of aquatic organisms populations of aquatic organisms

Sewage: EutrophicationSewage: Eutrophication EutrophicEutrophic

Slow-flowing stream, lake or estuary enriched by Slow-flowing stream, lake or estuary enriched by inorganic plant and algal nutrients such as inorganic plant and algal nutrients such as phosphorus phosphorus

2. Disease-causing Agents2. Disease-causing Agents

Infectious Infectious organisms that organisms that cause diseasescause diseases from wastes of from wastes of

infected individuals infected individuals Examples:Examples:

Typhoid, cholera, Typhoid, cholera, bacterial dysentery, bacterial dysentery, polio, and infectious polio, and infectious hepatitishepatitis

India

3. Sediment Pollution3. Sediment Pollution Excessive amounts of suspended soil Excessive amounts of suspended soil

particles. From:particles. From: erosion of agriculturalerosion of agricultural

landslands logginglogging degraded stream banksdegraded stream banks overgrazingovergrazing miningmining constructionconstruction

4. Inorganic Plant and Algal 4. Inorganic Plant and Algal NutrientsNutrients N and P stimulate the growth of N and P stimulate the growth of

plants and algaeplants and algae Sources:Sources:

Human and animal wastes, plant Human and animal wastes, plant residues, atmospheric deposition, and residues, atmospheric deposition, and fertilizer runofffertilizer runoff

It Causes:It Causes: Enrichment, bad odors, and a high BOD Enrichment, bad odors, and a high BOD

Inorganic Plant and Algal Inorganic Plant and Algal Nutrients: The Dead ZoneNutrients: The Dead Zone

5. Organic Compounds5. Organic Compounds

Chemicals that contain carbon atomsChemicals that contain carbon atoms Natural examplesNatural examples: sugars, amino acids, : sugars, amino acids,

and oils and oils Human-made examplesHuman-made examples: pesticides, : pesticides,

solvents, industrial chemicals, and solvents, industrial chemicals, and plastics plastics

Dangerous!

Volatile Organic Compounds Volatile Organic Compounds in Groundwaterin Groundwater

6. Inorganic Chemicals6. Inorganic Chemicals

Contaminants that contain elements Contaminants that contain elements other than carbonother than carbon

Do not degrade easilyDo not degrade easily Examples:Examples:

LeadLead-- Mercury-Mercury-

7. Radioactive Substances7. Radioactive Substances

Unstable isotopes that emit radiation Unstable isotopes that emit radiation Sources:Sources:

MiningMining Processing radioactive materialsProcessing radioactive materials Nuclear power plantsNuclear power plants Natural sourcesNatural sources

Why is this bad?Why is this bad? Temperature Temperature

affects reproductive affects reproductive cycles, digestion cycles, digestion rates, and rates, and respiration rates respiration rates

Warm water holds Warm water holds less less DO DO than cold than cold waterwater

8. Thermal Pollution8. Thermal Pollution

Factories release heated water into Factories release heated water into waterways waterways

Two Types of Water Two Types of Water PollutionPollution1. Point Source Pollution1. Point Source Pollution

Water pollution that can be traced to a Water pollution that can be traced to a specific origin specific origin

2. Non-point Source Pollution2. Non-point Source Pollution Pollutants that enter bodies of water Pollutants that enter bodies of water

over large areas rather than being over large areas rather than being concentrated at a single point of entry concentrated at a single point of entry

Water Pollution from Water Pollution from AgricultureAgriculture AgricultureAgriculture is leading source of is leading source of

water pollution in USwater pollution in US Animal wastes and plants residues have Animal wastes and plants residues have

high BODhigh BOD Chemical pesticides Chemical pesticides

Almost all streams and rivers are Almost all streams and rivers are polluted with agricultural pesticidespolluted with agricultural pesticides

Important****Important****There is little regulation!!!!There is little regulation!!!!

Municipal Water PollutionMunicipal Water Pollution

Industrial Wastes in WaterIndustrial Wastes in Water

Different industries generate Different industries generate different pollutantsdifferent pollutants Food processing plants- high BODFood processing plants- high BOD Paper mills- High BOD and toxic Paper mills- High BOD and toxic

compoundscompounds

Green ChemistryGreen Chemistry

Groundwater PollutionGroundwater Pollution

Water Pollution in Other Water Pollution in Other CountriesCountries Lake Maracaibo, VenezuelaLake Maracaibo, Venezuela Po River, ItalyPo River, Italy Ganges River, IndiaGanges River, India

Purification of Drinking Purification of Drinking WaterWater In US most municipal water supplies In US most municipal water supplies

are treated are treated

Purification of Drinking Purification of Drinking WaterWater Treated water distributed to Treated water distributed to

customerscustomers

Purification of Drinking Purification of Drinking WaterWater Chlorine DilemmaChlorine Dilemma

Chlorine byproducts are linked to Chlorine byproducts are linked to numerous cancers, miscarriages and numerous cancers, miscarriages and birth defectsbirth defects

Peru Peru FluoridationFluoridation

Prevents tooth decayPrevents tooth decay Linked to cancer, kidney diseaseLinked to cancer, kidney disease

Municipal Sewage Municipal Sewage TreatmentTreatment Primary treatmentPrimary treatment

Removing suspended and floating Removing suspended and floating particles by mechanical processes particles by mechanical processes

Secondary treatmentSecondary treatment Treating wastewater biologically to Treating wastewater biologically to

decompose suspended organic material; decompose suspended organic material; reduces BOD reduces BOD

Municipal Sewage Municipal Sewage TreatmentTreatment

Laws Controlling Water Laws Controlling Water PollutionPollution Citizen Watchdogs to Monitor PollutionCitizen Watchdogs to Monitor Pollution Safe Drinking Water Act (1974)Safe Drinking Water Act (1974)

Set uniform federal standards for drinking Set uniform federal standards for drinking water including maximum contaminant levelwater including maximum contaminant level

Clean Water Act (1972)Clean Water Act (1972) EPA sets up and monitors National EPA sets up and monitors National

Emissions LimitationsEmissions Limitations Effectively improved water quality from Effectively improved water quality from

point sourcespoint sources