WATER & SOIL POLLUTION

Chapter 21

YOUR responsibilities for Ch 21

Read chapter opening (487-488)Enviro-breif

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 microorganisms Process 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 organism that cause disease. They come from the wastes of infected individuals.

Bacteria Viruses Protozoa Parasitic Worms

Diseases: Typhoid Cholera Dysentery Polio

Hepatitis

How are our water systems vulnerable to such disease causing agents?

Milwaukee 1993• Cryptosporidium contaminated the water supply• 370,000 people developed diarrhea• Several people died

Ontario, Canada 2000• Escherichia coli• Several killed, thousands sick

Monitoring Water sources are constantly monitored for contamination

E. choli is used as it is an indication of the amount of sewage present Fecal Coliform Test

• Water is filtered and the filter is put in a petri dish and incubated.• 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 PollutionSEDIMENT POLLUTION: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: Erosion of agricultural

lands, forest soils exposed by logging,

degraded stream banks, overgrazed rangelands,

strip mines, construction

Problems: Reduces light

penetration, bring pollutants into the

water, reservoir filling, channel changing

(shipping)

Solution: Control of 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 Mexico Area the size of NJ is “dead” from the seafloor up due to excess animal waste moving downstream in spring & fallHYPOXIA- oxygen free environment

5. Organic Compounds

Chemicals that contain carbon atoms (mostly synthetic)Study: Researchers from USGS collected samples from 139 waterways- Water was tested for 95 organic compounds (antibiotics, caffeine, birth control pills etc.)- Found: low levels of 82 chemicals found & 80% of streams had one organic compound1/3 of all the streams tested had 10 or more organic compounds present

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

Propane

6. Inorganic Chemicals

Contaminants 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: Lead poisoning, 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 remain in the environment for a long time and are highly toxic to organisms

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 retardation, cerebral palsy, developmental delays in children. Kidney disorders, damage to the nervous and cardiovascular systems, headaches, depression

7. Radioactive Substances

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

nuclear plants, industries, medical & scientific facilities.

Indian Point Ground Water Contaminant Flows

(nuclear facility in NY)

8. Thermal Pollution

Heated water produced during certain industrial processes is released into waterways Produces 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

Turkey Point Nuclear Power plant Thermal Pollution

Oligotrophic LakeOligotrophic Lake Eutrophic lakeEutrophic lake

Slow flowing streams with minimal nutrients

Clear waterSupports small

populations (pike, sturgeon, whitefish cold )

Enrichment of water nutrients causing algal blooms

High BODFish populations

(catfish, carp use less O2)

How do NUTRIENTS affect water systems?

Types of Pollution

Point 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

Sources of Water Pollution

1. 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 particlesB. Screening & gravitational settling

1. Solid material that settles out is known as primary sludge

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

2. Secondary TreatmentA. Uses microorganisms to decompose the

suspended organic material1. Trickling filters: wastewater trickles through rock beds

containing bacterial which degrade the organic material2. 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 treatmentB. Variety of biological, chemical & physical processesC. Removes phosphorus & nitrogenD. 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 bottom Grease and oils form a scummy layer where bacteria

decomposes it Waste 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

Do you see how there could be a contamination problem here?

Septic Systems

The septic tank works much like primary treatment in municipal sewage treatment- sewage from the house is piped to the septic tank, where particles settle to the bottom

Wastewater containing suspended organic and inorganic material flows

into the drain field and gradually seeps into the

soil

POLLUTION CONTROL THROUGH LEGISLATION

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

- intended to reduce the release of pollutants into navigable rivers.

Governments control point source pollution by1. Imposing penalties on polluters2. Taxing polluters to pay for the cleanup

SAFE DRINKING WATER ACT

Prior to 1974, the states set their own standards for safe drinking water

SAFE DRINKING ACT Set uniform federal standards Required EPA to determine the maximum contaminant

level (MCL) which is the 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 those pose a health risk.

CLEAN WATER ACT

Controls the quality of rivers, lakes, aquifers, estuaries and coastal water in the United States.

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 up and monitor national emission limitations maximum permissible amount of water pollutants that can be

discharged from sewage treatment plants, factories and other point sources.

Clean Water Act continued….

Results Overall 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.

Non Point 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) 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.