Water pollution

• William Ruckelshaus: 'Today everybody is downwind or downstream from somebody else.'
• Water pollution


  Any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or that makes water unsuitable for desired uses

  
• Major categories of water pollutants

  • Infectious agents
  • Oxygen-demanding wastes
  • Inorganic chemicals
  • Organic chemicals
  • Plant nutrients
  • Sediment
  • Radioactive materials
  • Heat (thermal pollution)

  
• Examples of water pollutants

  • Road salts
  • Oil spill from Exxon Valdez
  • Animal manure
  • Algal bloom (Lake Erie)
  • Sediment pollution
  • Nuclear power plant
• How to measure water quality

  • Bacterial count
  • Physico-chemical analysis
  • Dissolved oxygen (DO)
  • pH
  • Water turbidity
  • Chemical analyses (concentration of organic and inorganic chemicals)
  • Indicator organisms (biomonitoring)

  
• Point source pollution


  Direct discharge into the water from a specific place (e.g. a pipe), easy to identify, monitor and regulate

  
• Nonpoint source pollution


  Diffuse and scattered pollution associated with surface runoff, cannot be traced back to a single discharge point and difficult to control and regulate

  
• Major sources of water pollution

  • Agricultural activities
  • Industrial facilities
  • Mining
  • Municipal effluents

  
• Dilution and decay of degradable, oxygen-demanding wastes and heat in a stream

  1. Oxygen sag curve (blue)

  2. Curve of oxygen demand (red)

  3. Streams recover from oxygen-demanding wastes and heat if they are given enough time and are not overloaded
• Developed countries have sharply reduced point-source pollution, but accidental or deliberate releases of toxic chemicals by industries or mines and malfunctioning sewage treatment are still a problem, and nonpoint sources are a problem

  
• Developing countries have serious and growing water pollution problems, with over 2/3 of India's water resources and more than 70% of the lakes and rivers in China being polluted, due to cultural traditions, religious beliefs, poverty, little economic development, large population, and insufficient law enforcement
• Cultural eutrophication


  Enrichment of lakes in nutrients (e.g. nitrate and phosphate) can cause algal and cyanobacteria blooms

  
• 70% of U.S. lakes and 25% of the lakes in China suffer from cultural eutrophication
• Canada's Experimental Lakes Area (ELA)

  • Established near Kenora, ON, in 1967
  • Scientific study area aimed at determining causes of lake death
  • Long-term ecosystem research
  • Led to controls of phosphorus in Canada, the United States, and Europe
  • Re-balanced pH of lakes with addition of calcium carbonate
  • Government funding pulled in 2012, project taken over by international institute

  
• By the 1960s, many areas of the Great Lakes were suffering from severe cultural eutrophication, but since 1972, Canada and the United States have joined forces and spent more than $20 billion (U.S.) on a Great Lakes pollution control program, including sewage treatment plants, treatment of industrial wastes, and bans on use of phosphate-containing detergent

  
• Despite improvement in water quality, about 3/4 of the shoreline of the Great Lakes is not clean enough for swimming or for supplying drinking water
• Oceans can disperse and break down large quantities of degradable pollutants, if they are not overloaded
• The London Dumping Convention (1972) and its Protocol (1996) had 100 countries agree not to dump highly toxic pollutants and radioactive wastes, but there are difficulties in monitoring and enforcement, and dumping toxic wastes is still unregulated in many developing countries
• Deepwater Horizon blowout


  • Blowout of methane gas and oil that escaped from offshore well in Gulf of Mexico
  • Minimum 5 million barrels spilled (Exxon Valdez only 0.75 million max)
  • Oil widely distributed through the Gulf of Mexico, impacted marine animals, fishing and tourism
  • Most ocean oil pollution comes from human activities on the land (e.g. stormwater runoff of waste oil lost on roads)
• Solutions for preventing and cleaning up excessive pollution of coastal waters

  • Reduce input of toxic pollutants
  • Separate sewage and storm lines
  • Ban dumping of wastes and sewage by maritime and cruise ships in coastal waters
  • Ban ocean dumping of sludge and hazardous dredged material
  • Protect sensitive areas from development, oil drilling, and oil shipping
  • Regulate coastal development
  • Recycle used oil
  • Require double hulls for oil tankers
  • Improve oil-spill cleanup capabilities
  • Sprinkle nanoparticles over an oil or sewage spill to dissolve the oil or sewage without creating harmful by-products (still under development)
  • Require at least secondary treatment of coastal sewage
  • Use wetlands, solar-aquatic, or other methods to treat sewage
• Solutions for preventing and reducing surface water pollution

  • Reduce agricultural and industrial runoff (e.g. reduce soil erosion, plant vegetation buffer zones, use slow-release fertilizer)
  • Legal approach (e.g. legislation, discharge trading policy)
  • Technological approach (e.g. septic tanks, improved sewage treatments, use wetlands for biological filtration/purification of waste water)
• Roger Rosenblatt: 'It is a hard truth to swallow, but nature does not care if we live or die. We cannot survive without the oceans, for example, but they can do just fine without us.'
• Documentary title: Poisoned Waters, Show: FRONTLINE (episode 12), Broadcaster: Public Broadcasting Service (PBS), Release date: 2009, Duration: ~1h50 min, Link: https://www.pbs.org/wgbh/frontline/film/poisonedwaters/, Synopsis: More than two decades after the Clean Water Act was supposed to make America's waters clean enough for swimming and fishing again, two iconic waterways — the great coastal estuaries of Puget Sound and the Chesapeake Bay — are in perilous condition. With polluted runoff still flowing in from industry, agriculture and massive suburban development, scientists fear contamination to the food chain and drinking water for millions of people. A growing list of endangered species is also threatened in both estuaries. As a new president, Congress and the states set new agendas and spending priorities, FRONTLINE correspondent Hedrick Smith examines the rising hazards to human health and the ecosystem, and why its so hard to keep our waters clean.