Introduction to Water pollution

Indroduction Water pollution occurs when harmful substances are released into the water in large quantities which cause damage to people, wildlife, or habitat or indirectly into water bodies without proper treatment to remove harmful compounds  Water pollution is a major problem in the global context It has been suggested that it is the leading worldwide cause of deaths and diseases, and that it accounts for the deaths of more than 14,000 people daily  WATER POLLUTION  Ideal water supply – Quality – Quantity  Water quality parameter – Physical  Suspended solid (SS), color, taste, smell, temp – Chemical  Dissolved substances, alkalinity, hardness, fluoride, heavy metal, organic compound, nutrient (nitrogen & phosphorus), pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD) – Biology  Bacteria, virus, protozoa, helminthes WATER POLLUTION Will cause – Soil contamination – Air contamination – Food chain contamination – Esthetic  Lack of clean water supply for – Domestic demand – Industry use – Agriculture use  WATER POLLUTION  Will also cause – Breeding of diseases vector – Spreading of water borne diseases – Food poisoning – Skin problem WATER POLLUTION 80% of diseases in developing countries are due to water supply contamination  – million child died every year due to water supply contamination  More than million died after severe diarrhea  Pollution Defined  Any chemical , biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired uses Types and Sources of Water Pollution Infectious Agents  Oxygen-Demanding  Inorganic Chemicals  Organic Chemicals  Plant Nutrients  Sediment  Radioactive  Thermal …  Water Pollution Two major classifications  Point Source  Non-point Source Sources of Pollution Point Sources -Discharge from a specific location (pipe, ditch or sewer) -Easier to identify and regulate Ex: Factories, Sewage Treatment Plants, Mines, Thermal Outlets and Oil Tankers OCEAN POLLUTION  The abyssal/benthic zones of open oceans, if they are not overloaded, can disperse and break down large quantities of degradable pollutants OCEAN POLLUTION  But pollution of coastal waters near heavily populated areas is a serious problem – About 40% of the world’s population lives within 160 miles of the coast – The EPA has classified of estuaries as threatened or impaired Coastal Water Pollution OCEAN POLLUTION  Harmful algal blooms (HAB) are caused by explosive growth of harmful algae from sewage and agricultural runoff HABs Harmful Algae Blooms “Red tide” OCEAN OIL POLLUTION  Most ocean oil pollution comes from human activities on land – Studies have shown it takes about years for many forms of marine life to recover from large amounts of crude oil (oil directly from ground) – Recovery from exposure to refined oil (fuel oil, gasoline, etc…) can take 10-20 years for marine life to recover OCEAN OIL POLLUTION  Tanker accidents and blowouts at offshore drilling rigs can be extremely devastating to marine life (especially diving birds, left) OCEAN OIL POLLUTION  Exxon Valdez oil spill: – March 24, 1989 – Prince William Sound, Alaska – Single-wall oil tanker runs aground – 10.8 million gallons of crude oil spilled – Captain was drunk – One of the worst single environmental disasters in US history Exxon Valdez In 1994, a jury awarded plaintiffs $287 million in compensatory damages and $5 billion in punitive damages Exxon appealed and the Ninth Circuit court reduced the punitive damages to $2.5 billion Exxon then appealed the punitive damages to the Supreme Court which capped the damages to $507.5 million in June, 2008 On August 27, 2008, Exxon Mobil agreed to pay 75% of the $507.5 million damages ruling to settle the 1989 Exxon Valdez oil spill off Alaska In June 2009, a federal ruling ordered Exxon to pay an additional $480 million in interest on their delayed punitive damage awards Exxon Valdez Exxon Valdez Aral Sea Disaster Large-scale water transfers in dry central Asia  Salinity  Wetland destruction and wildlife  Fish extinctions and fishing  Wind-blown salt  Water pollution  Climatic changes  Restoration efforts  Shrinking Aral Sea Solutions Coastal Water Pollution PREVENTION Reduce input of toxic pollutants CLEANUP Improve oil-spill cleanup capabilities 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 Sprinkle nanoparticles over an oil or sewage spill to dissolve the oil or sewage without creating harmful by-products (still under development) Protect sensitive areas from development, oil drilling, and oil shipping Require at least secondary treatment of coastal sewage Regulate coastal development Recycle used oil Use wetlands, solar-aquatic, or other methods to treat sewage Require double hulls for oil tankers Fig 21-14, p 509 [...]... Examples of Polluted Waters Water Quality Indicators We will now take a look at the water quality indicators TOTAL DISSOLVED SOLIDS (TDS) TDS is the measure of the material dissolved in water This measure is related to hardness, salinity and conductivity Hard water has more TDS than soft water Salinity Salinity refers to the salt concentration in water, mostly sodium chloride Salinity is historically measured... liter Salinity Saltwater can cause problems when it replaces fresh groundwater near the coastal areas TOTAL SUSPENDED SOLIDS (TSS) TSS is the measure of the sediment suspended in the water TSS is related to turbidity Water with high TSS usually has high Total Dissolved Solids (TDS) as well Sediment Erosion causes loose soil to enter the waterways Suspended sediment blocks sunlight to plants and reduces... electrical current Pure water is a poor conductor CONDUCTIVITY The addition of dissolved solids, especially salts, increases the conductivity of water Electrical current is measured using a conductivity meter Thermal Pollution Thermal pollution is the rise or fall in the temperature of a natural body of water caused by human influence  A common cause of thermal pollution is the use of water as a coolant... Magnesium  Hard water has high concentrations of these elements Soft water has low concentrations  Hardness Water hardness often originates from limestone  Hardness is used as an indicator of alkalinity but hardness is not a measure of alkalinity – magnesium or calcium sulfate increases hardness but has no affect on alkalinit  CONDUCTIVITY Conductivity measures the water s ability to conduct an electrical... it to one spot – Industrial Plants - Sewage pipes Point Source - Example LUST - Leaky Underground Storage Tanks  22% of the 1.2 million UST are LUST  Non-Point Sources -Cannot be traced to a specific discharge -Difficult to identify and control Ex: Golf Courses, Agriculture, … Non-point Sources Diffuse source or many smaller point sources  Automobiles  Fertilizer on fields Sources of Water Pollution. .. sediment blocks sunlight to plants and reduces dissolved oxygen As sediments settle, they can smother bottom (benthic) organisms TURBIDITY Turbidity refers to water clarity Sediments suspended in the water increase turbidity Secchi disk A secchi disk is one type of instrument used to measure turbidity Total Solids Types – suspended – settleable  Sources – runoff – uneaten food – feces   Safe levels... pollution is the use of water as a coolant by power plants and industrial manufacturers  Elevated water temperatures decreases oxygen levels (which can kill fish) and affects ecosystem composition  Thermal pollution can also be caused by the release of very cold water from the base of reservoirs into warmer rivers  TEMPERATURE Temperature is measured in Fahrenheit and Celsius degrees Temperature... accurate Most aquatic organisms live within a temperature range of +0º C (+32º F) to +32º C (+90º F ) Temperature Rapid temperature change and temperature extremes can stress aquatic organisms Temperature affects the oxygen-carrying capacity of water 14 Dissolved Oxygen (ppm) 12 10 8 6 4 Winter Summer As the water warms, the amount of dissolved oxygen decreases Temperature  Effects... warms, the amount of dissolved oxygen decreases Temperature  Effects – metabolic rate doubles for every 18oF increase – Influences spawning – Influences growth  Fish Categories – – – warmwater coolwater coldwater