WATER & SOIL POLLUTION

Chapter 21

YOUR responsibilities for Ch 21 Read chapter opening (487-488) Enviro-brief

Harmful algal blooms (pg 492)Something Fishy Near Sewage Treatment Plants (pg

505) Case in Point

Water pollution in the Great Lakes (pg 507-508) Water pollution in other countries (pg 509- 511) Soil Pollution (pg 511-512) Meet the Challenge (pg 506)

Water pollution Water Pollution:

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

There are 8 categories1. Sewage2. Disease causing agents3. Sediment pollution4. Inorganic plant and algal nutrients5. Organic compounds6. Inorganic chemicals7. Radioactive substances8. Thermal pollution

1. Sewage Sewage is the release of waste water from drains

or sewers and includes human waste, soaps and detergents.Problems… What do you think???

○ Disease causing agents present○ Enrichment: Fertilization of a body of water by presence of

high level of nutrients such as nitrogen & phosphorous

Sewage can be decomposed into CO2, water and materials by microorganismsProcess of cellular respiration (oxygen is required)

Sewage cont… Oxygen has a limited ability to dissolve in water

and when sewage is present, the microorganisms that break it down use up most of it

BIOCHEMICAL OXYGEN DEMAND (BOD) The amount of oxygen needed by micoorganisms to

decompose the waste into CO2, water, and minerals

Expressed as milligrams of dissolved

O2 per liter of water (mg O2/L)

Large amounts of sewage high BOD Robs the water of dissolved O2

Anerobic miroorganisms produce unpleasant odor..

bottom line…. High BOD =Poor water quality

2. Disease- Causing Agents Infectious organisms that cause disease. They

come from the wastes of infected individuals.Bacteria Viruses Protozoa Parasitic Worms

Diseases:

Typhoid Cholera Dysentery Polio Hepatitis

Our water systems are VULNERABLE!!!Milwaukee 1993

- Cryptosporidium contaminated the water supply

- 370,000 people developed diarrhea

- Several people diedOntario, Canada 2000

- Escherichia coli

- Several killed, thousands sick

Monitoring Water sources are constantly monitored for contamination

○ E. coli is used as it is an indication of the amount of sewage presentFecal Coliform Test

- Safe water should have no more that one coliform bacteria per 100 mL

- Most strains of coliform bacteria do not cause disease, but coliform test is a reliable indication of the presence of pathogens or disease causing agents in the water

3. Sediment Pollution

Excessive amounts of suspended soil

particles that settle out and accumulate on the bottom of a

body of water, due to decrease in water

velocity.

Causes:

Excess erosion

BRAINSTORM!

(what can cause that?)Problems:

Reduces light penetration, bring pollutants into the water, reservoir filling, channel changing (shipping)

Solution: Control the soil erosion

4. Inorganic Plant & Algal Nutrients Chemicals such as Nitrogen & Phosphorus that

stimulate the growth of plants and algae. Necessary in small amounts, but overload is dangerous

Sources: Human & animal wastes, plant residues, atmospheric deposition, fertilizer runoff from agricultural and residential areas

Problem: Excessive growth of algae and aquatic plants disrupting the natural balance between producers and consumers. Also causes enrichment, bad odors, and high BOD from excessive numbers of algae dying and decomposition.

○ Dead Zone in the Gulf of MexicoArea the size of NJ is “dead” from the

seafloor up due to excess animal waste

moving downstream in spring & fall

HYPOXIA- oxygen free environment

5. Organic Compounds Chemicals that contain carbon atoms (mostly synthetic)

Study: USGS found that 80% of waterways tested had at least one nonnative organic compound present, and 1/3 of all streams tested had 10 or more……things like antibiotics, caffeine, birth control pills, oil residues, BPA, etc…

What are they? pesticides, solvents, plastics,

industrial chemicals Where do they come from?

Seeping landfills, leaching, runoff, dumping How do we control organic compounds?

Stewardship of our water sources, use of alternative organic compounds, and tertiary water treatment.

DDT Acetone

6. Inorganic ChemicalsContaminants that contain elements other than carbon:

Acids, Salts, Heavy Metals

1. LeadSources: Paint, gas, incinerator ash dumped in ordinary landfills, air pollution from factories, pesticides & fertilizer residue on produce, food cans, serving plates & old pipes.

Medical Problems: hypertension, miscarriages, stillbirths, mental & physical impairments, hearing loss, ADD, lowered IQ, learning disabilities.

2. Mercury

Vaporizes at room temperature DANGEROUS! Once mercury settles into sediment, it is converted by bacteria to

methyl mercury compounds which are more toxic.

- Mercury accumulates in the muscles of tuna, swordfish, sharks

- Methyl mercury compounds are very persistent and highly toxic

Sources: Coal burning power plants (33%), municipal waste incinerators (18%), Medical waste incinerators (10%), smelting metals (lead, copper, zinc), industrial waste water, household trash (batteries, paints, plastics)Medical Problems: mental impairments,

cerebral palsy, developmental delays in children. Kidney disorders, nervous & cardiovascular system damage, headaches, depression

7. Radioactive Substances

Contain atoms of unstable isotopes that emit radiationSources: Mining & processing radioactive minerals,

nuclear plants, industries, medical & scientific facilities.

8. Thermal Pollution Heated water produced during certain industrial

processes is released into waterwaysProduces chemical & biological effects

○ Chemical: decomposition of waste occurs faster depleting water of oxygen. Less oxygen dissolves in warm water

○ Biological: less oxygen dissolved less animals or animal stress, reproductive, digestion rates & respiration rates are affected

http://www.crocodile-clips.com/absorb/AC4/sample/LR1105_mg.html

It’s HOT… & suddenly I feel EXHAUSTED!

Oligotrophic LakeOligotrophic Lake Eutrophic lakeEutrophic lake Slow flowing streams with

minimal nutrients Clear water Supports small

populations (pike, sturgeon, whitefish cold )

Enrichment of water nutrients causing algal blooms

High BOD Fish populations

(catfish, carp use less O2)

How do NUTRIENTS affect water systems?

Types of PollutionPoint Source:

Pollution is discharged into the environment through pipes, sewers or ditches from specific sites

Non-Point Source:Pollution caused by land pollutants that enter bodies of water over large areas rather than at a single point. Agricultural runoff, mining wastes, municipal wastes, construction sediments

Discussion

What challenges do

Point & Nonpoint Source Pollution

present for management?

Sources of Water Pollution1. Agriculture Discussed in chapter 13

2. Municipal:Contains salts, asbestos, chlorides, copper, cyanides, grease, lead, zinc, hydrocarbons, motor oil, organic wastes, phosphates, sulfuric acid

Combined Sewer System: Human and industrial wastes are mixed with urban runoff or snowmelts that overpower the treatment plant & raw sewage flows into waterways without being treated

3. Industrial - High BOD, toxic compounds, sludge - Some industries are cleaning water before they discharge it

Groundwater Pollution

Improving Water Quality

Purification of Drinking Water Water supplies include streams, rivers,

lakes, and reservoirs (dams)1. Water is treated with aluminum sulfate

causing suspended particles to come out2. Water is then filtered through sand3. Some cities pump water through activated

carbon granules to remove organic cmpds.4. Addition of chlorine to kill disease- causing

agents. Some cities use UV instead of Cl.

Should we use chlorine??5. Fluoridation – adding fluoride to municipal

water sources to prevent tooth decay.

Municipal Sewage Treatment

Waste water undergoes several treatments at a sewage treatment plant to prevent

environmental and public health problems. The treated water is then discharged into

rivers, lakes or the ocean.

Process:1. Primary Treatment

A. Removes suspended & floating particles

B. Screening & gravitational settling1. Solid material that settles out is known as primary sludge

2. Does not eliminate the inorganic & organic compounds remaining in the wastewater.

2. Secondary Treatment

A. Uses microorganisms to decompose the suspended organic material

1. Trickling filters: wastewater trickles through rock beds containing bacterial which degrade the organic material

2. Activated sludge process: Wastewater is aerated and circulated through bacteria rich particles.

3. Particles and microorganisms are allowed to settle out forming Secondary Sludge

** Water is clear and free of organic wastes such as sewage**

Primary and Secondary Treatment

3. Tertiary TreatmentA. Considered an advanced water treatment

B. Variety of biological, chemical & physical processes

C. Removes phosphorus & nitrogen

D. Can be used to purify wastewater so that it can be reused in communities where water is scarce.

Question to think about-

What do we do with the primary and secondary

sludge?

1.Anaerobic digestion2.Fertilizer

3.Incineration4.Ocean dumping5.Sanitary landfill

Individual Septic Systems Many private residences use individual septic systems instead of municipal sewage treatment.Household sewage is piped into the septic tank Particles settle to the bottomGrease and oils form a scummy layer where bacteria

decomposes itWaste water containing suspended organic and

inorganic material flows into the drain field through a network of perforated pipes set in trenches of crushed stone○ Purified wastewater then percolates into

the groundwater or evaporates from the soil

Septic TANK

Septic SYSTEM

What’s the problem here?

Discuss various approaches to pollution management with respect to this diagram.

How can we manage the problem of Eutrophication with respect to this diagram?

Describe and Evaluate various strategies.

How can we manage the problem of Eutrophication with respect to this diagram?

• Altering the Human Activity Producing Pollution:– Alternative methods of enhancing crop growth– Alternative detergents– Others?

• Regulating and Reducing Pollutants at the Point of Emissions:– Sewage treatment processes– How does this help?

• Cleanup and Restoration:– Pumping mud from eutrophic lakes– Reintroducing plant and fish species

POLLUTION CONTROL THROUGH LEGISLATION

The United States has attempted to control water pollution through legislation since the passage of the Refuse Act of 1899.

(reduced pollution of rivers)

Governments control point source pollution by

1. Imposing penalties on polluters

2. Taxing polluters to pay for the cleanup

SAFE DRINKING WATER ACT (1974)

Set uniform federal standards before, states set their own standards

Required EPA to determine the maximum contaminant level (MCL) maximum permissible amount of any pollutant that

might adversely affect human health.

Amended in 1996- requires municipal water suppliers to tell consumers what contaminants are present in their city’s water and if they pose a health risk.

CLEAN WATER ACT (1972)Controls the quality of rivers, lakes, aquifers,

estuaries, and coastal water in the US.

Original name: Water Pollution Control Act of 1972 Two basic goals:

Eliminate discharge of pollutants in US waterways Attain water quality levels that make waterways safe to

fish and swim in.

EPA is required to set and monitor national limits for point sources (like industrial and sewage treatment facilities).

Clean Water Act continued….

ResultsOverall the CWA has been effective at improving the quality of

water from point sources.○ Point sources must obtain permits from the National pollutant

Discharge Elimination System to discharge untreated water.

Nonpoint Source Pollution is more difficult and expensive to control○ CWA expanded in 1987 to allow National Pollutant Discharge

System to include non point sources such as sediment from erosion from construction sites.

○ NO real effective policy to address non-point source pollution.

Laws that Protect Groundwater Resource, Conservation and Recovery Act

deals with the storage and disposal of hazardous wastes and helps prevent groundwater contamination.

Safe Drinking Water Act contains provisions to protect underground aquifers that are important sources of drinking water. Also regulates underground injection of wastes.

Several laws related to pesticides, strip mining and cleanup of abandoned hazardous waste sites (brownfields & superfund sites) also indirectly protect groundwater.

Effects of Salinized Soil on Plants

Normally, the water concentration inside

plant cells is lower than that in the soil resulting

in a net movement of water into the root cell.

When soil contains a high amount of salt, its

relative water concentration can be lower than the water concentration inside

cells. This causes water to move out of the roots into the soil, even when

the soil is wet.