Water Pollution. Distribution of Water Reservoirs

Transcription

1 Water Pollution Distribution of Water Reservoirs Ice Caps and Glaciers 1.725% Oceans 97% Atmosphere 0.01% Soil Moisture % Rivers, Lakes, and Inland Seas 0.141% Ground Water % 1

2 World Water Supply % salt water in the oceans % ice caps and glaciers % groundwater % surface water % soil moisture % atmospheric moisture Water Cycle Atm. - Ocean - Land Evap. - PPT - Runoff 2

3 Water Pollution Two major classifications Point Source Non-point Source Point Sources Single large source Can localize it to one spot Industrial Plants - Sewage pipes 3

4 Point Source - Example LUST - Leaky Underground Storage Tanks 22% of the 1.2 million UST are LUST Non-point Sources Diffuse source or many smaller point sources Automobiles Fertilizer on fields 4

5 Point and Nonpoint Sources NONPOINT SOURCES Rural homes Urban streets Cropland Animal feedlot Suburban development POINT SOURCES Factory Wastewater treatment plant Water Pollution: Many Forms Disease: In developing nations, 80% of diseases are water-related. Synthetic Organic Compounds Inorganic Compounds & Mineral Substances such as Acids, etc. Radioactive substances Oxygen-demanding wastes Plant Nutrients Sediments Thermal Discharges 5

6 Examples of Polluted Waters 6

7 A very personal look at water What happens to your water before you drink it? What happens to your water after you dispose of it? Approximately 99% of Swedes are served by wastewater treatment plants, 86.5% of Germans, 74% of Americans, and 57% of Canadians. What constitutes quality drinking water? Free of pollutants Tastes good Want Sodium Bicarbonate and Calcium Sulfate in same concentrations as found in saliva 10 o C As little chlorination as possible Calcium & magnesium account for most water hardness, death rates (cardiovascular disease) higher in soft water areas than in hard water areas Copper needed to absorb & metabolism iron, but >1mg/liter makes water unpalatable Does taste correlate with presence of toxic compounds? 7

8 Forms of Pollution Details Inorganic acids, salts, toxic metals One gram of lead in 20,000 liters of water makes it unfit for drinking. Lead is often found in the pipes of older homes What is the safe drinking water limit for arsenic? For lead? How much does UA water supply have? Forms of Pollution Details Organic: sewage, pesticides, plastics, etc. One drop of oil can render up to 25 liters of water unfit for drinking One gram of 2,4 D can contaminate 10 million liters of drinking water! One gram of PCBs can make 1 billion liters of water unsuitable for freshwater aquatic life! 8

9 Water ppm Phytoplankton ppm Herring gull 124 ppm Herring gull eggs 124 ppm Zooplankton ppm Lake trout 4.83 ppm Rainbow smelt 1.04 ppm Acid Precipitation: When Air Pollution Becomes Water Pollution 9

10 Pollution of Streams Discharge of untreated municipal sewage (nitrates and phosphates) Pollution of Lakes - Eutrophication Nitrogen compounds produced by cars and factories Discharge of detergents ( phosphates) Natural runoff (nitrates and phosphates Discharge of treated municipal sewage (primary and secondary treatment: nitrates and phosphates) Lake ecosystem nutrient overload and breakdown of chemical cycling Manure runoff From feedlots (nitrates and Phosphates, ammonia) Runoff from streets, lawns, and construction lots (nitrates and phosphates) Dissolving of nitrogen oxides (from internal combustion engines and furnaces) Runoff and erosion (from from cultivation, mining, construction, and poor land use) 10

11 Acid Rain Effects Aquatic Systems When the ph drops below 6.0 species start to die off. When one species dies, others that depend on it may as well Acid Neutralization How does this work? Cation Exchange on clay minerals Role of chemical weathering... 11

12 How does acid kill the fish? One way is mobilizing metals When all base cations are striped from soils Acid now reacts with metals e.g. aluminum Normally aluminum is immobile below ph 5 - mobile aluminum Fish breath in the water Aluminum comes out of solution Clogs gills - suffocate More Examples: Oxygen and Water Biochemical Oxygen Demand What does this mean? Anything in the water that bacteria can break down. Bacteria will use up oxygen in the water Other aerobic organisms will die 12

13 Oxygen and Water What else can affect the amount of O 2 in the water? Temperature Speed of water flow Roughness of surface over which water flows Stories about particular pollutant forms: Oil Both Point and Nonpoint Sources Largest source of oil pollution is pipeline leaks and runoff 61% ocean oil pollution river & urban runoff 30% intentional discharges from tankers 5% accidental spills from tankers 13

14 Stories about particular pollutant forms: Detergents The nitrates in fertilizers promote excessive growth of algae and larger aquatic plants, causing offensive algae blooms and driving out sport fish. Phosphates are often thought to culprit, nitrogen is the limiting factor in most aquatic systems. Stories about particular pollutant forms: Sediments THE largest form of water pollution Erosion is source we ve sped up rate of erosion, e.g. during urban construction can lose up to 43 tons of topsoil/acre/year Natural rates of erosion: leads to aquatic succession 14

15 Succession in Aquatic Habitats Lake Oligotrophic Low in nutrients Sediments & Nutrients Accumulate Eutrophic High in nutrients Can sometimes see Methane gas bubbling up From sediments process of decomposition Stories about particular pollutant forms: thermal pollution 26% of all water in U.S. is affected by this Up to a point of adding heated water, you can get thermal enrichment Adding more heat, you get thermal pollution 15

16 We can also have cold water pollution In many areas fish and Other river organisms are Adapted to relatively warm water. Building a dam results in very cold water released Downstream killing organisms and changing species A special case: Groundwater What forms of pollution can affect groundwater? All of them except thermal pollution! Renewal time of groundwater is important Rivers: days Soil Moisture: 280 days Groundwater: 300 years 16

17 Groundwater doesn t stay in one place Leaking tank Water table Groundwater flow Free gasoline Gasoline dissolves in leakage plume groundwater (liquid phase) (dissolved phase) Migrating vapor phase Contaminant plume moves with the groundwater Water well 17

18 Groundwater Pollution: Causes Coal strip mine runoff De-icing road salt Pumping well Waste lagoon Accidental spills Pesticides Gasoline station Water pumping well Landfill Buried gasoline and solvent tank Cesspool septic tank Sewer Discharge Confined aquifer Hazardous waste injection well Leakage from faulty casing Groundwater flow Fig Oil Well Drilling & Groundwater 18

19 Oil Drilling Protocols Well must be cased from surface to below freshwater zone Casing must also be for 150 feet above pay zone Logging apparatus must be retrieved Oil Drilling Protocols Drilling fluids must be disposed of properly e.g. no Midnight Haulers Any spills must be reported and cleaned immediately Area will be subject to remediation efforts 19

20 Industry Nitrogen oxides from autos and smokestacks, toxic chemicals, and heavy metals in effluents flow into bays and estuaries. Cities Toxic metals and oil from streets and parking lots pollute waters; Closed beach Urban sprawl Bacteria and viruses from sewers and septic tanks contaminate shellfish beds Oxygen-depleted zone Closed shellfish beds Construction sites Sediments are washed into waterways, choking fish and plants, clouding waters, and blocking sunlight. Farms Runoff of pesticides, manure, and fertilizers adds toxins and excess nitrogen and phosphorus. Red tides Excess nitrogen causes explosive growth of toxicmicroscopic algae, poisoning fish and marine mammals. Toxic sediments Chemicals and toxic metals contaminate shellfish beds, kill spawning fish, and accumulate in the tissues of bottom feeders. Oxygen-depleted zone Sedimentation and algae overgrowth reduce sunlight, kill beneficial sea grasses, use up oxygen, and degrade habitat. Healthy zone Clear, oxygen-rich waters promote growth of plankton and sea grasses, and support fish. Fig , p. 505 Identifying Sources of Pollutants to the Chesapeake Bay We are going to do the same analysis that scientists did in 1998 to determine what some of the major sources of pollutants were to the Chesapeake Bay 20

21 21

22 Reducing Water Pollution through Sewage Treatment Primary and Secondary sewage treatment. Figure Technological Approach: Using Wetlands to Treat Sewage ( Sewage Wetland type plants Wetland type plants Treated water First concrete pool 45 centimeter layer of limestone gravel coated with decomposing bacteria Second concrete pool ( 22

23 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. 23

24 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. Drinking Water Quality Bottled water Safe Drinking Water Act Maximum contaminant levels 24

25 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. Using Laws to Protect Drinking Water The U.N. estimates that 5.6 million Americans drink water that does not meet EPA standards. 1 in 5 Americans drinks water from a treatment plant that violated one or more safety standard. 25

26 What Can You Do? Water Pollution Fertilize garden and yard plants with manure or compost instead of commercial inorganic fertilizer. Minimize your use of pesticides. Do not apply fertilizer or pesticides near a body of water. Grow or buy organic foods. Do not drink bottled water unless tests show that your tap water is contaminated. Merely refill and reuse plastic bottles with tap water. Compost your food wastes. Do not use water fresheners in toilets. Do not flush unwanted medicines down the toilet. Do not pour pesticides, paints, solvents, oil, antifreeze, or other products containing harmful chemicals down the drain or onto the ground. Water is life s matter and matrix, mother and medium. There is no life without water. Albert Szent-Gyorgyi (Hungarian Nobel Prize Winning Physiologist) 26