Water Pollution

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Water Pollution

• Chapter 16

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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 timemore problematic

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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

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Leading Source of Water Quality Impairment

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

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Industrial Pollutants

• 10 million new chemicals till date not enough
  time to test safety of each
• Of 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

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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
• Hatters Shake
• Cadmium poisoning in Japan itai-itai
• Lead another potent source of poisoning
• Required substitution and regular monitoring

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Other Inorganic Compounds

• Chlorine harmful to aquatic life
• Industrial Acids Now controlled
• Asbestos Virulently carcinogenic

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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

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Problem of Control

• US industry produced 900 million tons of
  hazardous waste in 1984
• Cost of cleaning increases exponentially
• Even after cleaning stockpile of waste is
  produced which require careful handling

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Thermal Pollution

• From automobiles and heating systems in cities
• From electric generating plants and cooling
  towers
• Warm water contains less oxygen
• May be harmful to some organisms (and beneficial
  to others)

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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

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Biochemical Oxygen Demand

• BOD (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

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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, Ohio84, major problem in the
  Florida Bay and in parts of Everglades

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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

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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

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Groundwater Pollution

• Out of sight, often go undetected by house owners
• Generally 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

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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

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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.

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Original Love Canal site. Niagara River at the
bottom of the picture
Infrared aerial photo of Love Canal showing 99th
Street Elementary School and two rings of home
bordering the landfill
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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.

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Love Canal Disaster

• 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.

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Love Canal Aftermath

• 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.