Water Quality and Pollution Water Pollution Water Pollution is any chemical, biological, or physical change in water quality that has a harmful effect on living organisms and makes water unsuitable for desired uses Air and water pollution are closely related because they mix together Pollution Sources 1. Point Source: Specific site of pollution dumping. Ex: Pipes from factories and houses. 2. Nonpoint sources: are not easily determined. No direct point of entry Ex: runoff from a field or road, acid rain Point Pollution Non-point Pollution 3. STORM RUNOFF - during heavy storms water mixes in the sewers and the sewage treatment plants can not handle the overload excess is released 4. Agricultural runoff Open fields are especially at risk because the excess water leaches down into the ground water carrying phosphates and nitrates. Farmers can reduce this by leaving a zone of undisturbed land at the end or near drains or streams. 5. Mining runoff: moves iron, copper, sulfuric acid (from coal) sulfur and zinc = acid mine drainage This is an add-in. Yes, I know its not in your packet. Find a space. 1. 2FeS 2 + 7O 2 + 2H 2 O 2FeSO 4 + 2H 2 SO 4 Iron Pyrite (Iron (II) Sulfide) reacts with water and oxygen to form Iron (II) Sulfate and Sulfuric acid 2. 2Fe /2 O 2 + 2H + 2Fe 3+ + H 2 O The Iron (II) ion dissociates and oxidizes to form Iron (III) 3. Fe H 2 O Fe(OH) 3 + 3H + Iron (III) ion reacts with water to form the insoluble Iron (III) Hydroxide which is a yellow orange color. Precipitates out of solution and kills fish by clogging their gills. Also makes the water more acidic. Water Pollutants 1) Disease causing organisms a) Bacteria - a) Bacteria - i) Cholera - Vibrio cholerae - highly spreadable. One fish packer in Equador died of Cholera and before they could contain the fish that he packed, it went to 8 countries. 300,000 cases and 3000 deaths came from that one person. i) Cholera - Vibrio cholerae - highly spreadable. One fish packer in Equador died of Cholera and before they could contain the fish that he packed, it went to 8 countries. 300,000 cases and 3000 deaths came from that one person. Vibrio cholerae Vibrio cholerae ii) E. coli - Bacteria associated with sewage causes horrible stomach problems for many days. ii) E. coli - Bacteria associated with sewage causes horrible stomach problems for many days. CholeraE. coli CholeraE. coli Good indicator for quality of drinking and swimming water is the number of coliform bacteria present in 100-mL sample WHO recommends 0 colonies for drinking EPA recommends max of 200 colonies for swimming Avg. person excretes 2 billion bacteria a day iii) Bacterial dysentery - diarrhea, vomiting, upset digestive tract for 4-5 days iii) Bacterial dysentery - diarrhea, vomiting, upset digestive tract for 4-5 days b) Protozoans - Amoebic dysentery - vomiting, diarrhea, and colon perforation causing death b) Protozoans - Amoebic dysentery - vomiting, diarrhea, and colon perforation causing death c) Giardiasis - a problem in high mountain springs. People think the water is safe and drink it only to have 3-4 days of diarrhea and vomiting. Dehydration is a problem as well as fatigue. Video VideoVideo d) Parasitic worms Video e) Viruses e) Viruses 2) Oxygen Demanding Wastes: organic wastes that can be decomposed by aerobic bacteria which depletes oxygen - sewage, animal manure and some industrial wastes. - decomposition uses available oxygen and releases excess phosphorous - cause high level algal growth which blocks the sunlight from other plants and they die more decomposition = less oxygen = fish death Level of oxygen required for the break down of material is called Biological oxygen demand (BOD): amount of dissolved oxygen needed by aerobic decomposers to break down over 5 day 20C (68F) Test Procedure 1. Take 2 samples of water 1. Take 2 samples of water 2. Record the DO (DISSOVLED OXYGEN) level (ppm) of one immediately using the method described in the dissolved oxygen test. 2. Record the DO (DISSOVLED OXYGEN) level (ppm) of one immediately using the method described in the dissolved oxygen test. 3. Place the second water sample in an incubator in complete darkness at 20 C for 5 days. 3. Place the second water sample in an incubator in complete darkness at 20 C for 5 days. 4. After 5 days, take another dissolved oxygen reading (ppm) using the dissolved oxygen test kit. 4. After 5 days, take another dissolved oxygen reading (ppm) using the dissolved oxygen test kit. 5. Subtract the Day 5 reading from the Day 1 reading to determine the BOD level. Record 5. Subtract the Day 5 reading from the Day 1 reading to determine the BOD level. Record BOD Level (ppm) Water Quality Interpretation 1-2 Very Good Little waste 3-5Fair Moderately Clean 6-9Poor Bacterial decomposition of Organic Matter present 10-99Polluted Higher amounts of waste 100 or greater Very Poor Very polluted - High BODs indicate that too much organic materials are in the water. - oxygen is used and the anerobic bacteria begin to produce chemicals that smell and have a unpleasant taste. - Food wastes are not as bad as detergent wastes. Soap and detergent have phosphates in them, which creates a problem 3) Water-Soluble Inorganic Materials: water-soluble nitrates and phosphates - excessive growth of algae and other aquatic plants that die and deplete the O 2 content (kills fish) - excessive growth of algae and other aquatic plants that die and deplete the O 2 content (kills fish) EX: acids Salts: phosphate (X 3 PO 4 ), nitrates (XNO 3 ) and sulfur (X 2 SO 4 ) Toxins/toxicants -- lead, arsenic salts Toxins/toxicants -- lead, arsenic salts Can lead to Eutrophication: Eutrophication EutrophicationEutrophication: natural enrichment of lakes Eutrophication Cultural Eutrophication: process of human activities accelerating the input of nutrients: farming, golf courses Prevention of cultural eutrophication = advanced waste water treatment which bans/ limits the amount of phosphates in detergents, soil conservation, and land use control Cleanup methods = dredging bottom sediments, removing excess weeds, controlling plant growth with herbicides and algaecides, pumping air thorough lakes and reservoirs 4) Organic Chemicals: threatens human, animal and aquatic plant life EX: oil, gas, plastic, pesticides, detergents, ext. a) Synthetic organic chemicals plastics, detergents, oil, solvents and pesticides Most of it comes from runoff. Most of it comes from runoff. Oil is highly toxic because it destroys the organisms ability to swim, stay afloat and to feed. It is poisonous in small amounts. It coats the water with a fine film to not allow O 2 or CO 2 movement to the air. It coats corals and other underwater species with film so the air exchange is impossible. Oil Tanker spills and blowouts, offshore drilling rig accidents, Almost of the oil reaching the oceans is waste oil dumped, spilled, or leaked onto the land or into sewers by cities, individuals and industries The effects of oil on ocean depend on The type of oil (crude or refined) The type of oil (crude or refined) amount released amount released distance of release from shore distance of release from shore time of year time of year weather conditions weather conditions average water temperature average water temperature ocean currents ocean currents Oil Research shows that most (but not all) forms of marine life recover from exposure to large amounts of crude oil within 3 years: Recovery from exposure to refined oil take >10 yrs Research shows that most (but not all) forms of marine life recover from exposure to large amounts of crude oil within 3 years: Recovery from exposure to refined oil take >10 yrs Moderate oil spills can be cleaned up by mechanical, chemical, fire, and natural methods Moderate oil spills can be cleaned up by mechanical, chemical, fire, and natural methods Oil Mechanical methods include: Mechanical methods include: Floating booms to contain the oil spill or keep it from reaching sensitive areas Floating booms to contain the oil spill or keep it from reaching sensitive areas Skimmer boats to vacuum up some of the oil into collection barges Skimmer boats to vacuum up some of the oil into collection barges Absorbent pads or large feathered filled pillows to soak up oil on beaches or in waters to shallow for skimmer boats Absorbent pads or large feathered filled pillows to soak up oil on beaches or in waters to shallow for skimmer boats Oil Chemical methods include: Chemical methods include: Coagulating agents to cause floating oil to clump together for easier pick up or sink to the bottom where is usually does less harm Coagulating agents to cause floating oil to clump together for easier pick up or sink to the bottom where is usually does less harm Dispersing agents to break up oil slicks Dispersing agents to break up oil slicks Natural Methods: Natural Methods: Oil digesting bacteria spray on slick Oil digesting bacteria spray on slick 5) Sediments or Suspended Matter: particles of soil/solid that stay suspended in water and made the water cloudy, reduces photosynthesis and disrupts food webs and clogs harbors, reservoirs, channels and artificial lakes sediments - Sediments are not an immediate problem. take time to pollute take time to pollute block the sunlight. block the sunlight. May have small amounts of toxins in them that build up May have small amounts of toxins in them that build up clog fish gills clog fish gills cover and destroy the natural plants of a lake or reservoir. cover and destroy the natural plants of a lake or reservoir. remove nesting sites of fishes. remove nesting sites of fishes. 6) Water-Soluble Radioactive Isotopes: could lead to cancer 7) Thermal Pollution: rise in water temp because water used to cool power plants - occurs when water is removed from a source, heated to a high heat, driving off the oxygen and placing the water back into the source Ex: cooling electric generator and steam. Thermal Pollution Prevention: 1) large pond that is not attached to any other water - hot water is placed into one end and the cooled water is used from the other. - hot water is placed into one end and the cooled water is used from the other. 2) cooling towers water is sprayed in and cooled by evaporation 3) cooling tower in which the water is moved into the tower inside tubes and the heat is released, not the water 4) Discharging the heated water into shallow ponds or canals, and reusing it as cooling water Problems with Thermal Pollution: Affects fish spawns Thermal shock: the effect of sharp changes in water temperature (kills fish that cant adapt) Thermal enrichment: beneficial uses of heated water - Lengthens the commercial fishing season, reduces winter ice cover in cold areas, can extend the growing seasons, help heat nearby buildings and greenhouses 8) Genetic Pollution: deliberate or accidental addition of non-native species disrupts aquatic systems and crowd out natives: reduces biodiversity: principal way they are introduced = intake and ballast from ships Ex: Zebra mussels 9) GROUNDWATER POLLUTION - due to percolation of pollutants to the water table - Typical Pollutants: 1. Pesticides 2. Fertilizers: farming and septic tanks 3. Gasoline: leaking underground tanks MTBE methyl-tert butyl ether oxygenate enhance octane rating of gasoline 4. Toxins/toxicants: landfills 10) SALINIZATION - Increasing salt in the soils creates salt in the water. - Increasing salt in the soils creates salt in the water.