Water Pollution

Chapter 16

Some terms Geochemical Cycles:

Movement of matter from one reservoir to another Carbon Cycle, Rock Cycle, Calcium Cycle etc

Residence Time = Capacity/Rate of influx Higher solubility = higher residence time Higher residence time=more problematic

Source Point Source Pollution: Pollution released

from a readily identifiable source e.g., a steel mill, a sewer outlet, a septic tank

Non Point Source Pollution: Source of pollution diffuse, e.g., road salt, fertilizer from fields, automobile exhaust Largest source of water quality problem 40% of US water bodies not fit for fishing or

swimming Almost all the beaches in US are polluted

Leading Source of Water Quality ImpairmentRank River Lakes Estuaries

1 Agriculture Agriculture Urban Runoff

2 Municipal Point Sources

Municipal Point Sources

Municipal Point Sources

3 Stream/Habitat Changes

Urban Runoff Agriculture

•Agriculture is the leading contributor•Nutrient and sediments are the chief pollutant

Industrial Pollutants10 million new chemicals till date: not

enough time to test safety of eachOf 66,000 new drugs, pesticides and

other industrial chemicals, no safety data exists on 70% of them

MTBE (methyl tetraburate ethyl): Added to gasoline for cleaner burning Very soluble in water

Inorganic Pollutants: Metals Metal: Often highly toxic, particularly the heavy metals

(Hg, Cd, Pb, Pu, Zn…) Accumulate in bodies of animals and the

concentration increases up a food chain Minamata Tragedy in Japan:

Fish at the top of food chain had 50 ppm Hg By 1960 43 people died, 116 affected

Hatter’s Shake Cadmium poisoning in Japan: itai-itai Lead: another potent source of poisoning Required substitution and regular monitoring

Other Inorganic CompoundsChlorine: harmful to aquatic life Industrial Acids: Now controlledAsbestos: Virulently carcinogenic

Organic Pollutants Organics (carbon-bearing compounds) Widespread use of herbicides and pesticides

Toxic, cumulative, carcinogenic DDT(Dichloro diphenyl trichloroethane): repeated use results in

resistant strains Accumulative, toxic to fish, causes thinning of egg shells in birds; banned

in 1972

Oil Spills and leaks: 10 million gallons in US waters every year

Plastics: PCB (Polychlorinated biphenyls) Caused birth defects and other ailments Banned in US since 1977 900 million pounds already been produced

Problem of ControlUS industry produced 900 million tons

of hazardous waste in 1984Cost of cleaning increases exponentiallyEven after cleaning stockpile of waste

is produced which require careful handling

Thermal PollutionFrom automobiles and heating systems

in citiesFrom electric generating plants and

cooling towersWarm water contains less oxygenMay be harmful to some organisms

(and beneficial to others)

Organic matter

Dead leaves, algae, human and animal waste, animal feed lots, food processing plants

Typically domestic, municipal, industrial and even storm run-offs, all come together in the sewer system and has potential to contaminate surface water

Aerobic decay: (in presence of Oxygen) and Anerobic Decay: (in absence of Oxygen, produces H2S and CH4 ) causes oxygen depletion

Biochemical Oxygen DemandBOD (Biochemical Oxygen Demand):

Amount of Oxygen required to breakdown organic matters aerobically. More organic matter in water, more BOD

Oxygen Sag Curve is produced when reoxygenation lags behind oxygen consumption: more serious for lakes

Eutrophication Breakdown of excess organic matter (or

fertilizer runoff from farm lands or phosphates from detergents) also produces nitrates and phosphates which encourage growth of algae leading to algal bloom.

Dead algae sinks to bottom and further increases organic load and increase BOD

% of eutrophic lakes in the farm belt: Iowa: 100%, Ohio:84%, major problem in the

Florida Bay and in parts of Everglades…

Agricultural Pollution Fertilizers

Nitrates, phosphates and potash Sediment Pollution

3 billion tons / year in US Reduces light, blankets bottom-habitats, fills up reservoirs,

damages power plants Herbicides and Pesticides

500 million lbs/yr Secondary breakdown products can be more toxic Alternative strategies:

Use only when needed Use bacteria, sterilization or insect traps to control pests

Reversing the Damage Dredging

Dig out the contaminated soil and put in landfills Cost upto $10/m3

Physical Isolation: Cover with plastic or clay Chemical treatment to fix nutrients

Decontamination EPA filtered toxic organic herbicide laden water

through activated charcoal and decontaminated Clarksburg Pond in NJ in 1974

Aeration: Bubbling or churning air or oxygen through oxygen starved water

Groundwater PollutionOut of sight, often go undetected by

house ownersGenerally slow spread of pollutants but

rapid in karst terrains (like Central and South Florida)

Pesticides, nitrates: mostly in agricultural belts, golf courses, public parks etc

Best if contained in source

Reversing the Damage: Groundwater Stop or reduce the flow of pollutants and then let nature take

over In situ decontamination: site and pollutant specific

Heavy metals: immobilization Chemicals added through injection wells Oxygen pumped for biological decontamination Water table skimmed for petroleum products

Post extraction decontamination Addition of alkalies to adjust pH: ppt of heavy metals Microbial treatment to breakdown organics Air stripping: aeration followed by separation of organic rich gas phase Activated charcoal as filters

Love canal: Origin In 1942, Hooker Chemicals and Plastics Corporation (now

Occidental Chemical) purchased the site of the Love Canal. Between 1942 and 1953 Hooker Chemical disposed of about

22,000 tons of mixed chemical wastes into the Love Canal. Shortly after Hooker ceased use of the site, the land was sold to

the Niagara Falls School Board for a price of $1.00. In 1955, the 99th Street Elementary School was constructed on

the Love Canal property and opened its doors to students. Subsequent development of the area would see hundreds of

families take up residence in the suburban, blue-collar neighborhood of the Love Canal.

Infrared aerial photo of Love Canal showing 99th Street Elementary School and two rings of home bordering the landfill

Original Love Canal site. Niagara River at the bottom of the picture

Love Canal: Problem surfaces Unusually heavy rain and snowfalls in 1975 and 1976 provided

high ground-water levels in the Love Canal area. Portions of the Hooker landfill subsided, 55-gallon drums

surfaced, ponds and other surface water area became contaminated, basements began to ooze an oily residue, and noxious chemical odors permeated the area. Physical evidence of chemical corrosion of sump pumps and infiltration of basement cinder-block walls was apparent.

Subsequent studies by the Agency for Toxic Substances and Disease Registry would reveal a laundry list of 418 chemical records for air, water, and soil samples in and around the Love Canal area.

In April of 1978 the New York Department of Health Commissioner, Robert Whalen, declared the Love Canal area a threat to human health and ordered the fencing of the area near the actual old landfill site.

In August, the Health Commissioner declared a health emergency at the Love Canal, closed the 99th Street School, and recommended temporary evacuation of pregnant women and young children from the first two rings of houses around the site.

Within a week, Governor Hugh Carey announced the intended purchase of all "Ring 1" houses (later expanded to 238 houses in Rings 1 and 2).

President Jimmy Carter simultaneously announced the allocation of federal funds and ordered the Federal Disaster Assistance Agency to assist the City of Niagara Falls to remedy the Love Canal site.

Love Canal: Disaster

Today, it remains a ghost town. The main dump site is fenced in (with a school and many homes bulldozed over and buried in the ground with the waste). Over the rest of the area of crumbling, dilapidated homes hangs a gaunt, eerie silence, reminding visitors of the specter that hazardous waste poses in our modern society.

Love Canal: Aftermath