envsci 5

Unit 4: 

Unit 4 Unit 5 – Water Pollution (STE 7th ed. Chapter 9)

Slide2: 

“It is not until the well runs dry that we know the worth of water” Benjamin Franklin

Quote: 

Quote “The noblest of the elements is water” -Pindar, 476 B.C.

Where are we going?: 

Where are we going? 1. Water: Importance and availability, shortages 2. Water Management / Conservation 3. Water Pollution, Water Quality Today 4. Pollution Control and Legislation

1. Water Resources: 

1. Water Resources Water Facts H2O Essential for life Moderates Climate Used in agriculture, industry, transportation Removes and dilutes pollution One of our most vital resources

Unique Properties: 

Water shrinks on melting (ice floats on water) Unusually high melting point Unusually high boiling point Unusually high surface tension Unusually high viscosity Unusually high heat of vaporization Unusually high specific heat capacity And more… Unique Properties

Major Compartments: 

Major Compartments - 2.4 % of all water on Earth is freshwater - Most is ‘locked’ away (frozen)

Residence Times: 

Residence Times

Hydrologic Cycle: 

Hydrologic Cycle watershed: region from which water drains into a water body Hydrologic Cycle precipitation: movement from atmosphere to surface as rain, sleet, hail, & snow runoff: movement along surface infiltration: movement from surface to groundwater evapotranspiration: (evaporation + transpiration): movement from surface to atmosphere

Purification: 

Purification

Groundwater: 

Groundwater water infiltrates to water table aquifer: porous, water–saturated layers of soil or rock through which groundwater flows unconfined aquifers: zone of infiltration above (unsaturated) & water table below (saturated) confined aquifers: bounded above & below by less permeable rock groundwater moves from recharge area through aquifer & out to discharge area (well, spring, lake, geyser, stream, or ocean)

Rivers, Lakes, Wetlands: 

Rivers, Lakes, Wetlands Lakes Contain 100x water than rivers and streams Baikal in Siberia, Gt. Lakes, Gt. Rift lakes of Africa Rivers Nile, Amazon, Orinoco, Congo, Yangtze, Mississippi

Lakes: 

Lakes The 15 largest lakes in the world (insert is outline of Great Britain) all drawn to same scale. The numbers indicate the rank in area, while the figures in brackets denote surface area in square kilometers (after Ruttner, 1963; in Burgess and Morris, 1987; updated to 1996 by ESIG/NCAR). Largest by volume, 20% Earth’s freshwater

Wetlands: 

Wetlands Wetlands Bogs, swamps, meadows, marshes Vegetation stabilize soil holds back runoff Allows time for perculation

Question: 

Question What changes might occur in the hydrologic cycle if our climate were to warm or cool significantly? - Changes in the availability of water resources Increased precipitation in areas, drought in others Possible feedbacks to the global climate system

Water Availability and Uses: 

Water Availability and Uses Water is a renewable resource Renewel takes time Western States have insufficient to meet demand

Distribution is Uneven:Water Area per Capita: 

Distribution is Uneven: Water Area per Capita 0.5% population 20 % water 20 % 7 % water

Uses of Water: 

Uses of Water World 70% irrigation (agriculture) 20 % Industry 10% residences World Resources 1998-99

Slide19: 

http://www.bdix.net/sdnbd_org/world_env_day/2003/water_year/consumption.html

Some Requirements: 

Some Requirements 2000 gallons / kg beef 100,000 gallons / car 3,000 gallons / kg Al 1 gallon = 3.8 L 50 times more water to produce a calorie from beef as it does from potatoes

Freshwater Shortages: 

Freshwater Shortages Many parts of the world are experiencing: Rivers running dry Lakes and seas shrinking Falling water tables from overpumped aquifers

Freshwater Shortages: 

Freshwater Shortages Clean drinking water Sanitation Prevents disease Essential for health Polluted water greatest environmental threat U.N estimates 1.5 billion lack access to safe drinking water 5 million deaths each year By 2025 2/3 world population living in water stressed areas Climate and population increase

Uneven distribution of water: 

Uneven distribution of water Subject to contamination Using water at a rate faster than it can be supplied (>100 due to use of sea water)

Aral Sea: 

Aral Sea Once world's 4th largest freshwater lake Shrinking & getting saltier since 1960 River water diverted for crops Increased pollutants pesticides, fertilizers, Weapons etc http://veimages.gsfc.nasa.gov//11040/a002117.mpg

Consequences and Restoration: 

Consequences and Restoration South Aral Sea - Beyond repair Desertification Vast salt plain Dust storms 20 of 24 native fish extinct North (little) Aral Sea – Salvagable Eastern half may evaporate before west As the agricultural land becomes contaminated by the salt, the farmers try to combat it by flushing the soil with huge volumes of water. What water makes its way back to the Sea is increasingly saline and polluted by pesticides and fertilizer.

Slide26: 

Dam installed between N and S.

2. Water Management: 

2. Water Management Cities are outbidding farmers for water supplies from rivers and aquifers Countries are importing grain as a way to reduce their water use More crops are being used to produce biofuels Our water options are: Get more water from aquifers and rivers, desalinate ocean water, waste less water

Groundwater: 

Groundwater Renewable resource (unless over used) Available year round Exists everywhere No evaporation loss Cheap to extract Use Half of all Americans 95 % rural population May get depleted Subsidence Reduced stream flow Easily polluted Salt water intrusion Costly if contaminated

Groundwater: 

Groundwater Areas of greatest aquifer depletion from groundwater overdraft in the continental U.S.

Ogallawa Aquifer: 

Ogallawa Aquifer World’s largest aquifer 90% withdrawn for irrigation; supplies 30% of irrigation water supports $32 billion agriculture most areas water withdrawn much faster than recharge Once held more water than all other sources on Earth

Dams, Canals and Reservoirs: 

Dams, Canals and Reservoirs Fundamental basis of civilizations 90 % built in last 100 yrs Hydroelectricity People benefit, ecosystems suffer

Slide33: 

Provides water for year-round irrigation of cropland Flooded land destroys forests or cropland and displaces people Large losses of water through evaporation Provides water for drinking Downstream cropland and estuaries are deprived of nutrient-rich silt Reservoir is useful for recreation and fishing Risk of failure and devastating downstream flooding Can produce cheap electricity (hydropower) Downstream flooding is reduced Migration and spawning of some fish are disrupted

Case Study: The Colorado BasinAn Overtapped Resource: 

Case Study: The Colorado Basin An Overtapped Resource The Colorado River has so many dams and withdrawals that it often does not reach the ocean. 14 major dams and reservoirs, and canals. Water is mostly used in desert area of the U.S. Provides electricity from hydroelectric plants for 30 million people (1/10th of the U.S. population).

Case Study: The Colorado BasinAn Overtapped Resource: 

Case Study: The Colorado Basin An Overtapped Resource Lake Powell, is the second largest reservoir in the U.S. It hosts one of the hydroelectric plants located on the Colorado River

Case Study: The Colorado BasinAn Overtapped Resource: 

Case Study: The Colorado Basin An Overtapped Resource Hoover Dam Colorado river would periodically overflow Built for flood control Water for LA Lake Mead – largest man-made reservoir in US

CA Water Project : 

CA Water Project The Problem most rainfall in northern California most population growth & agriculture in southern California The Solution water transferred via dams, pumps, & aqueducts The Controversy southern California wants more water for growth much of water wasted by inefficient irrigation north needs water for fisheries & flushing pollutants out of San Francisco Bay

Consequences of LA Aqueduct: 

Consequences of LA Aqueduct San Fernando Valley Irrigated Owens Lake Desertified Largest source of PM pollution in US Mitigated using flooding + vegetation http://geochange.er.usgs.gov/sw/impacts/geology/owens/

Other Methods: 

Other Methods Desalinization: expensive and produces large amounts of salty wastewater Distillation: heating saltwater until it evaporates Reverse osmosis: uses high pressure to force saltwater through a membrane filter Cloud seeding Towing icebergs?

Water Conservation: 

Water Conservation We waste about two-thirds of the water we use, but we could cut this waste to 15%. 65-70% of the water people use throughout the world is lost through evaporation, leaks, and other losses Water is underpriced through government subsidies The lack of government subsidies for improving the efficiency of water use contributes to water waste

Water Conservation: 

Water Conservation Wetland conservation Clear steady flow, vegetation reduces flow Reduces erosion Irrigation efficiency drip irrigation, central–pivot, computer monitoring Recycling use of gray water Repair leaky pipes Water conservation Low flush toilets, faucets, & shower heads Xeriscaping

Slide43: 

Center pivot Drip irrigation Gravity flow (efficiency 60% and 80% with surge valves) Above- or below-ground pipes or tubes deliver water to individual plant roots. Water usually comes from an aqueduct system or a nearby river. (efficiency 90–95%) (efficiency 80%–95%) Water usually pumped from underground and sprayed from mobile boom with sprinklers.

Raising the Price of WaterA Key to Water Conservation: 

Raising the Price of Water A Key to Water Conservation We can reduce water use and waste by raising the price of water When Boulder, Colorado introduced water meters, water use per person dropped by 40%. A 10% increase in water prices cuts domestic water use by 3-7%

Question: 

Question Do you think that pollution is worse now than it was in the past?

3. Water Pollution: 

3. Water Pollution Physical, biological, or chemical change in water quality that adversely affects living organisms or makes water unsuitable for desired uses

Sources: 

Sources point sources – discrete and identifiable e.g., factories, sewage treatment plants, mines, oil wells, oil tankers nonpoint sources – diffuse and hard to identify e.g., acid deposition, substances picked up in runoff, seepage into groundwater nonpoint sources: Agriculture: largest source of water pollution in the U.S. (64% of pollutants into streams & 57% of pollutants entering lakes) Industry: Atmospheric deposition sometimes from many thousands of km away Mining

Point and Non-point Sources: 

Point and Non-point Sources Smol, 2002

Pollutants: 

Pollutants Health Problems Infectious agents Inorganic chemicals Organic chemicals Radioactivity Ecosystem Disruption Sediment Plant nutrients Oxygen demanding wastes Thermal pollution

Biological Pollution: 

Biological Pollution Infectious Agents from human waste Typhoid, cholera, dysentry, enteritis, polio, hepatitis Insect borne diseases Malaria, yellow fever Fecal Coliform ‘coliform bacteria’ basis for water quality testing E. Coli, Salmonella, Listeria Bacteria (microbe) of colon or intestines

O2 Demanding Wastes: 

O2 Demanding Wastes All animal life in natural waters is dependent on the presence of dissolved O2 (DO) Amount of DO indicates water quality O2 consumed by sewage and organic materials Water in streams and rivers is constantly replenished with oxygen. Stagnant water and deep lakes can have depleted oxygen

Thermal Pollution: 

Thermal Pollution As temperature of water rises, gases are removed Do concentration decreases

Pollutant ClassificationsVary Country to Country: 

Pollutant Classifications Vary Country to Country Inorganic Organic Radioactive Metals Metalloids Non-metals Toxic Non-Toxic Transition Metals Heavy Metals Chemical type: Make connections

Pollutant ClassificationsVary Country to Country: 

Pollutant Classifications Vary Country to Country Inorganic Organic Radioactive Metals Metalloids Non-metals Toxic Non-Toxic Transition Metals Heavy Metals Chemical type

Inorganic Pollutants: 

Inorganic Pollutants Heavy metals Lead, cadmium, mercury Soluble salts Arsenic, selenium, nitrate, sulfate, perchlorate Acids and bases Acid deposition e.g. mercury from incinerators and coal burning plants; acid-mine drainage Generally warned to not exceed one meal of fish per week

Organics: 

Organics Uses Pesticides, plastics, pharmaceuticals, pigments etc. Sources Household waste, pesticide runoff, bacteria, VOC’s Bioaccumulate very rapidly in fat e.g. PCB’s, DDT

Biological Magnification: 

Biological Magnification concentrations increase at increasing levels in the food chain POP’s PCBs (polychlorinated biphenyls) DDT Metals Mercury Cadmium Arsenic

Question: 

Question What is the difference between bioaccumulation and biomagnification?

Pollution of Streams & Rivers: 

Pollution of Streams & Rivers flowing water can recover rapidly by dilution & decay ‘Oxygen Sag Curve’

Reducing Point-Source Pollution: 

Reducing Point-Source Pollution water pollution laws of 1970s greatly increased number & quality of wastewater treatment plants in U.S. also improvements in Canada, Japan, & most western European countries; large fish kills & contamination of drinking water still occur, especially in developing countries lakes, reservoirs & ponds more vulnerable to contamination than streams because of less mixing & aeration.

Pollution of Lakes: 

Pollution of Lakes Eutrophic = well-nourished Increase in nutrients and biological productivity Elevated Nitrogen and Phosphorus Algal blooms, aquatic plants Increase of bacterial populations Cloudy, turbid, bad tasting and smelly water Accelerates natural ‘aging’ of water bodies 95% US surface fresh water

Case Study: Lake Onondaga: 

Case Study: Lake Onondaga Contaminated with raw sewage, salt (sodium and calcium chloride) from soda ash industry 1946 mercuric waste discharged from production of chlorine via mercury cell process http://www.onlakepartners.org

Case Study: Lake Onondaga: 

Case Study: Lake Onondaga Placed on Superfund list in 1995 Most contaminated lake in US Nutrients – phosphate, nitrate, ammonia, bacteria, turbidity, salinity, mercury, excess sedimentation Metals do not degrade, est. 165,000 lbs of Hg Much of which becomes methylated and bioconcentrated

Newspaper Coverage: 

Newspaper Coverage ‘One of the worst chemical spills ever…’ Anonymous

Historical ExampleRhine River, 11-01-86: 

Fire at Sandoz Ltd. released pesticides, solvents and dyes Pulse release 10 days to travel to North Sea ½ million fish killed Disulfoton (pesticide) Capel et al, 1988 Historical Example Rhine River, 11-01-86

Groundwater Pollution: 

Groundwater Pollution Cannot dilute and disperse like lakes and rivers can Low DO concentrations and colder temperatures slow degradation of contaminants Extremely difficult to clean up contaminated groundwater; prevention more effective Main approach: pump groundwater to surface, purifying water, & returning to aquifer; costs high

Groundwater Pollution :Prevention: 

Groundwater Pollution :Prevention Reduce sources that feed into the aquifer; Monitor aquifers near landfills & underground storage tanks Require leak detection systems & liability insurance for existing & new underground tanks that store hazardous liquids Ban or more strictly regulate disposal of hazardous wastes in deep injection wells & landfills Store hazardous liquids aboveground with more safeguards

Ocean Pollution: 

Ocean Pollution Coastal areas most impacted – especially wetlands & estuaries, coral reefs, & mangrove swamps; Half of world's population lives within 100 km (60 miles) of oceans & 14 of 15 largest cities coastal U.S. about 35% of municipal sewage discharged virtually untreated in marine waters Ocean ultimate repository of waste Dumping of industrial waste directly into ocean off U.S. coasts stopped, but many countries still dump large quantities of toxic substances

Oil Spills: 

Oil Spills Crude & refined petroleum accidentally & deliberately released into environment; Most from normal operation of offshore wells, washing tankers, & leaks of pipeline & storage tanks; Tanker & offshore drilling rig accidents can release large amounts in short time;

Effects of Oil Spills: 

Effects of Oil Spills volatile organics immediately kill of many aquatic organisms (especially plankton & larvae) & contaminate fish; floating oil coats birds & marine mammal; destroys natural insulation & buoyancy, & causes deaths; heavy oil sinks to ocean bottom & washes into estuaries where it contaminates crabs, oysters, mussels, clams, etc. oil slicks on beaches harm intertidal life & cause economic losses to tourism & fishing industries.

Case Study: Exxon Valdez Oil Spill: 

Case Study: Exxon Valdez Oil Spill March 24, 1989, tanker in Prince William Sound, Alaska, worst oil spill in U.S. waters; coated 1,600 of shoreline, killed wildlife, & caused serious contamination; Exxon spent $2.2 billion on direct cleanup + $1 billion fines & damages; another $5 billion being appealed.

Water Quality Today: 

Water Quality Today legislation: Clean Water Act (1972, amended 1977) & Water Quality Act (1983) in U.S.; main goals: 1) to make U.S. surface waters safe for fishing & swimming by 1983; & 2) to restore chemical, physical & biological integrity of waters; progress made, but goals not met; technology: septic tanks, sewage treatment; most effective for point pollution sources.

4. Pollution Control and Legislation: 

4. Pollution Control and Legislation Most effective method is to not produce pollution Elimination of lead from gasoline Banning of DDT and PCB’s in 1970’s Recycling or reclaming materials

Nonpoint Sources and Land Management: 

Nonpoint Sources and Land Management Requires changing farming practices to reduce runoff from fertilizer, pesticides, & livestock, as well as to reduce soil erosion Soil conservation Wetland preservation (e.g. Olentangy River Wetland Research Park Project) Non–farm use of fertilizers & pesticides (golf course, lawns, & public lands) can be similarly controlled

Case Study: Chesapeake Bay: 

Case Study: Chesapeake Bay Largest estuary in U.S. Severely degraded by water pollution from 6 states Also deposition of air pollutants Land-use regulations to control runoff Ban on phosphate detergents Phosphorus discharge dropped 40% since 1980’s Nitrogen levels still high

Question: 

Question What are the sources of nitrogen to Chesapeake Bay?

Sewage Treatment: 

Sewage Treatment trap greases & large solids & discharge the remaining wastes over drainage field

Primary Treatment: 

Primary Treatment Involves screens & settling tanks to remove solids from sewage

Secondary Treatment: 

Secondary Treatment uses biological processes to break down biodegradable, oxygen–demanding wastes

Advanced Treatment: 

Advanced Treatment Uses one or more processes to remove specific pollutants

Demo: 

Demo Water Treatment Model

Water Legislation: 

Water Legislation Much of the world's drinking water contaminated & poses serious health threats Most drinking water purified by storage in reservoir (suspended matter settles), & treated by sand filters, activated charcoal, & addition of chlorine; U.S. Safe Drinking Water Act of 1974 requires EPA to establish national drinking water standards; Many using bottled water & home filters; bottled water is often more contaminated than tap water.