WATER POLLUTION

Water pollution  What is it? The contamination of water in lakes, rivers, oceans, aquifers and groundwater. Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds.

Categories of water pollution Point source refers to contaminants that enter the water from a single, easy-to-identify source like a pipe or a storm drain.

Categories of water pollution  Non-point source pollution is pollution that comes from a big area and not from a single, easy-to-identify source like an agricultural field or a shopping centre parking lot.

Point and Nonpoint Sources NONPOINT SOURCES Urban streets Suburban development Wastewater treatment plant Rural homes Cropland Factory Animal feedlot POINT SOURCES

Type of water pollution  Bacteria,Viruses,Protozoa, Parasitic worms  Oxygen demanding substances  Inorganic plant nutrients  Organic chemicals  Sediment or suspended matter  Thermal pollution  Genetic pollution

1. Bacteria & Co.  Often comes from fecal (poop) material – untreated or poorly treated sewage, farmers’ fields (animal poop) or septic tanks  Major cause of acute contamination of human drinking water – can immediately make people sick  Major issues: E. coli, giardia, cryptosporidium, Norovirus

1. Bacteria & Co. Health Impacts? – diarrhea, vomiting, etc. Preventing contamination?  Treated by water treatment plants – various chemicals  Filtering or boiling well water and water that you are not sure about

Access to clean water  Not everyone in the world has access to clean water – we are lucky here in Canada!  Solutions?

Type of water pollution  Bacteria,Viruses,Protozoa, Parasitic worms  Oxygen demanding substances  Inorganic plant nutrients  Organic chemicals  Sediment or suspended matter  Thermal pollution  Genetic pollution

Oxygen demanding substances  Usually organic compounds that are broken down by bacteria that need oxygen  Like what?  Green waste (leaves, grass cuttings, etc.), food waste, garbage

Oxygen demanding substances So what? When there are many organic compounds decomposing at the same time (and consuming oxygen), they can reduce the amount of oxygen available to suffocate organisms that need oxygen to live. Could kill plants and fish in the water!

What can happen? Fish kills….

Type of water pollution  Bacteria,Viruses,Protozoa, Parasitic worms  Oxygen demanding substances  Inorganic plant nutrients  Organic chemicals  Sediment or suspended matter  Thermal pollution  Genetic pollution

Inorganic plant nutrients  What is inorganic?  A chemical compound that does not have any carbon (C) in it.  Examples: nitrate (NO 3 -), phosphate (PO43-), sulfate

Inorganic plant nutrients  Where do they come from ?  Agricultural fields (fertilizer or manure), feedlots, septic tanks….

Inorganic plant nutrients  Where do nitrates, phosphates and sulfates end up?  In surface water (water we can see)  In ground water

Inorganic plant nutrients  What is the problem? 1. Eutrophication of water bodies – too many nutrients 2. Harmful health effects – blue baby syndrome and cancer

1. Eutrophication Eutrophication – also known as lots of nutrients, more than necessary, released into a water body Eutrophication comes from too much nitrogen, phosphorus and sulfate from fertilizers used in agriculture, septic tanks and industry.

Problems with eutrophication  Too many nutrients – more algae will grow  Algae use up all the oxygen in the water  Low oxygen in the water means there is none left for other organisms in the water

 That means that fish and insects could die  Too many algae on the surface of the water could block the sunlight – no light to water plants, they can die  Some algae can produce toxins – red tide  Toxins can move up the food chain

Eutrophication

Eutrophication cont’d….

2. Blue-baby syndrome - infants under 4 months of age who drink well water with nitrates - Nitrates turn into other chemicals in the body and make it difficult for the body to take up oxygen - Blue-baby syndrome can lead to fatigue, coma, convulsions, asphyxia and death

Rainbow smelt 1.04 ppm Zooplankton ppm Phytoplankton ppm Water ppm Herring gull 124 ppm Lake trout 4.83 ppm Herring gull eggs 124 ppm Biological Magnification

Pollution of Lakes  Eutrophication Discharge of untreated municipal sewage (nitrates and phosphates) Nitrogen compounds produced by cars and factories Discharge of treated municipal sewage (primary and secondary treatment: nitrates and phosphates) Discharge of detergents ( phosphates) Natural runoff (nitrates and phosphates Manure runoff From feedlots (nitrates and Phosphates, ammonia) Dissolving of nitrogen oxides (from internal combustion engines and furnaces) Runoff and erosion (from from cultivation, mining, construction, and poor land use) Runoff from streets, lawns, and construction lots (nitrates and phosphates) Lake ecosystem nutrient overload and breakdown of chemical cycling Fig.22.7, p. 499

Fig Aquifer Water well Migrating vapor phase Contaminant plume moves with the groundwater Free gasoline dissolves in groundwater (dissolved phase) Groundwater flow Water table Gasoline leakage plume (liquid phase) Leaking tank Bedrock

Groundwater Pollution: Causes Coal strip mine runoff Pumping well Waste lagoon Accidental spills Groundwater flow Confined aquifer Discharge Leakage from faulty casing Hazardous waste injection well Pesticides Gasoline station Buried gasoline and solvent tank Sewer Cesspool septic tank De-icing road salt Unconfined freshwater aquifer Confined freshwater aquifer Water pumping well Landfill Fig

Fig , p. 505 Healthy zone Clear, oxygen-rich waters promote growth of plankton and sea grasses, and support fish. Oxygen-depleted zone Sedimentation and algae overgrowth reduce sunlight, kill beneficial sea grasses, use up oxygen, and degrade habitat. Red tides Excess nitrogen causes explosive growth of toxicmicroscopic algae, poisoning fish and marine mammals. Farms Runoff of pesticides, manure, and fertilizers adds toxins and excess nitrogen and phosphorus. Toxic sediments Chemicals and toxic metals contaminate shellfish beds, kill spawning fish, and accumulate in the tissues of bottom feeders. Construction sites Sediments are washed into waterways, choking fish and plants, clouding waters, and blocking sunlight. Urban sprawl Bacteria and viruses from sewers and septic tanks contaminate shellfish beds Oxygen-depleted zone Closed beach Cities Toxic metals and oil from streets and parking lots pollute waters; Industry Nitrogen oxides from autos and smokestacks, toxic chemicals, and heavy metals in effluents flow into bays and estuaries. Closed shellfish beds

Global Outlook: Stream Pollution in Developing Countries  Water in many of central China's rivers are greenish black from uncontrolled pollution by thousands of factories. Figure 20-7

Case Study: India’s Ganges River: Religion, Poverty, and Health  Religious beliefs, cultural traditions, poverty, and a large population interact to cause severe pollution of the Ganges River in India.  Very little of the sewage is treated.  Hindu believe in cremating the dead to free the soul and throwing the ashes in the holy Ganges. Some are too poor to afford the wood to fully cremate. Decomposing bodies promote disease and depletes DO.

Case Study: India’s Ganges River: Religion, Poverty, and Health  Daily, more than 1 million Hindus in India bathe, drink from, or carry out religious ceremonies in the highly polluted Ganges River.

Is Bottled Water the Answer?  Some bottled water is not as pure as tap water and costs much more.  1.4 million metric tons of plastic bottles are thrown away.  Fossil fuels are used to make plastic bottles. The oil used to produce plastic bottles in the U.S. each year would fuel 100,000 cars.