Water Use, Overuse, and Natural Contamination

China

India

Iran

Israel

Jordan

Mexico

Morocco

Pakistan

Saudi Arabia

South Korea

Spain

Syria

Tunisia

United States

Yemen

Withdrawals exceed recharge creating deficits in the aquifer

Over-exploitation of renewableand non-renewable aquifers

Water Mining

Lack of contemporary recharge

 

GROUNDWATER . (Mm3/yr)  

COUNTRY Total use % Non-renewable

Saudi Arabia 21,000 84%

Bahrain 258 35%

Egypt 4,850 18%

Jordan 486 35%

Libya 4,280 70%

Yemen 2,200 32%

Saudi Arabia and Libya, use 77% of the estimated total world extraction of non-renewable groundwater for urban supply and irrigated agriculture.

The Middle East

Falls in the water table between 1982 and 2000 range from 3 to 6 feet per year

Within 15 years Quetta will run out of water if the current consumption rate continues

Pakistan

Water table falling by 8.5 feet per year

Iran: Water Refugees

over pumping by an average of 5 billion tons (3.7 Ma-f)of water per year

Equivalent to 1/3 Iran’s annual grain harvest

Mashad

Villages Abandoned

71 percent drop in wheat harvest from a high of 4.1 million tons in 1992 to 1.2 million tons in 2005,

Saudi farmers are now pumping water from wellsthat are 4,000 feet deep

Paleowater35,000 years old

Qa-Disi Aquifer

water extraction exceeds the annual recharge by a factor of five,

Yemen

pumped dry by 2010

Options:

relocate the capitalpipelines

Water table dropping 6 meters (18 ft) per year

Other Large Deficits

IndiaChinaPakistan

½ the world’stotal use of groundwaterfor agriculture

Pumping: 325 million acre feet

Recharge: 205 million acre feet

Deficit: 120 million acre feet

1 acre-foot = 325,851 gallons

Area = 1 acre1 foot

Deep wells must reach more than half a mile to tap fresh water

Level of the deep aquifer is dropping nearly 3 meters (10 feet) per year

Deficit feeds 100 million people

Shallow , unconfinedaquifer depleted

water table falling by 20 feet per year

Deficit feeds 200 million

21 million wells

Failure of 246 surface irrigation projects

$600 electric pumps (1% of GDP)

Deficit of 80 million acre-feet

India

95 %

5 acres of land

Pumps 3200 gallons/hr

Irrigates alfalfa for 64 hours

24 times per year

Yield: 6.5 gallons milk/day

4.9 million gallons => 2400 gallons milk (2000 gallons water/ gallon milk)

4.9 million gallons water/yr

United States

United States

1/3 of irrigation water comes from groundwater

The 3 largest aquifers are in arid/semi-arid regions

Ogallala Aquifer MidwestCentral Valley Aquifer CaliforniaSouthwest Aquifer System Arizona, Utah, Nevada

Central Valley Aquifer (California)

Pumping 15% more water than is replaced

Southwest Aquifer (Utah, Nevada, Arizona)

Pumping 50% more water than is replaced

Deficit of 30 million acre-feet

Water storage capacity has declined by 50%

High Plains Aquifer (Ogallala)¼ gone in areas of Texas, Oklahoma, Kansas

Water table declines up to 100 feet in some areas

Phoenix Arizona Growing 2 acres/hr

Among the highest water users

tripled in population over the last 40 years

Tucson

Canal 335 miles long

44 billion gallons/yr

7% lost to evaporation

Central Arizona Project

Use, Overuse, Quality

USTsLandfillsSeptic systemsUrban RunoffAgricultureIndustryRainfall

ContaminantSources

Natural Groundwater Contaminants

Tapping water as deep as 1,000 meters

water table falling by 20 feet per year

21 million wells

India

Deeper Wells and Fluoride

Naturally occurring element in Granitewhich dissolves into the groundwater

Water near the surface is generally unaffected

Lowering water tables = deeper wells

Deep groundwater contains high fluoride levels

fluoride in water can be a cumulative poison

Intentional Fluoridation of Water in the U.S.

Fluoridation became an official policy of the U.S. Public Health Service in 1951.

By 1960 water fluoridation had become widely used in the U.S. reaching about 50 million people.

By 2006, 69.2% of the U.S. population on public water systems were receiving fluoridated water.

How does it work?

Tooth enamel is made of a mineral called hydroxyapatite

Ca5(PO4)3OH

Hydroxyapatite is subject to dissolution by acids (H+)

Fluoridation changes the chemical composition ofhydroxyapatite to a crystal less subject to acid dissolution

Bacteria in the mouth create acids (H+)

Ca5(PO4)3

Sodium fluorosilicate (Na2SiF6)

Sodium fluoride (NaF)

NaF Na+ + F-

OH

Ingestion of fluoridated water increases the F- concentration in saliva

F- replaces OH in hydroxyapatite making fluoroapatite

F-

Fluoroapatite is less soluble in acid than hydroxyapatite

Fluoride concentrationsIn U.S. tap water

0.6 – 1.1 mg/L

Lower values in warm climates

1.6 to 6.6 mg/day

Colorado Brown Stain

Dental Fluorosis

Intake:

Permissible fluoride limit in India is 1.2 mg/L

Fluoride levels between 5-25 mg/L have been found

Fluoride levels > 1.5 mg/L

9 mg/day to 12 mg/day

Fluorosis has risen from 1 million to 25 million and now to 60 million people in India.

Skeletal Fluorosis

Intake

Fluoride levels > 10 mg/L

Groundwater and Arsenic

Arsenic is Naturally Occurring

occurs primarily in association with sulfur-containing minerals

mean values of arsenic content in soils, the earth’s crust, and sediments are between 1.5, and 7.7 mg/kg

Mobilization of arsenic in the environment arises from anthropogenic activities related to mining and ore processing,

metallurgy, agriculture, wood preservation, and industry.

Natural waters, in general, contain low levels of total arsenic

Inorganic Forms of Arsenic

AsO4-3AsO3

-3

Arsenite Arsenate

Low Oxygen High Oxygen

Arsenite is more toxic than arsenate, interfering withenzyme activities which catalyze metabolic reactions

Arsenite compounds are also more mobile in the environmentdue to higher solubility compared to arsenate compounds

Both arsenate and arsenite are chronic accumulative toxins

“The World’s Largest Mass Poisoning”

Bangladesh and W. India

ranked among the world's 10 poorest countries

Accumulation ofthick mudsin the floodplainsand deltas

Floodplain and Delta of theGanges and Brahmaputra Rivers.

Floodplain: area paralleling a river that is periodically inundated

Deltas are formed from the deposition of sediment carried by the river as the flow leaves the mouth of the river

Himalayas

Ganges-Brahmaputra Delta

Prior to 1970s

One of the highest infant mortality rates in the worldPrincipally due to waterborne disease.

Ineffective water and sewage systemsPeriodic monsoons and floods

cholera, dysentery

water-borne pathogens

Deaths Due to Surface water contamination: 250,000/yr

Deaths Due to Surface water contamination: 250,000/yr

The Solution: Tap groundwater resources

• easy• inexpensive

First 1 million were sunk with aid fromWorld Governments

UNICEFWorld Bank

12 million hand-operated tube wellsdeliver water to over 80% of the rural village population

Infant mortality and diarrheal illness reduced by 50%

Wells in Floodplain and Delta Sediments

Water Bearing Muds

Natural erosion ofarsenic to water-bearing units.

Well depths between 20m and 100 m

Majority of wells > 50 ppb arsenic Some wells contain 500 - 1000 ppb

WHO/U.S limit: 10 ppbBangladesh limit: 50 ppb

Exposure Estimates

Above 50 ppb: 35 million

Above 10 ppb: 57 million

Early Symptoms:

Skin lesions and thickeningStrong skin pigmentation

2003 Studies

83 million people

Bihar: 40% wells contaminated

Red River Delta

11 million people

First wells sunk7 years ago

End Lecture 17

Next: Florida’s Aquifers

Sea Levels

Temporary reestablishment of carbonate deposition

Vulnerability

One gallon of gasoline cancontaminate 1 million gallonsof drinking water

1 ppm

MetalsNutrientsPesticidesPetroleum Solvents