Chapter 19 Water Pollution

Transcription

1 Chapter 19 Water Pollution Miller Living in the Env. 13 th Edition APES - Chaper 19 1

2 Water Pollution Index Slide Water Pollution Defined Categories of Water Pollution Sag Curve Groundwater Pollution Ocean Pollution Waste Water Treatment Drinking Water Treatment Water Pollution Poster Children Images of water Pollution Eutrophication Other Facts APES - Chaper 19 2

3 Basics Water Pollution Any physical, biological, or chemical change in water quality that adversely affects living organisms or makes water unsuitable for desired uses Point Source single, identifiable source of pollutants Non-point Source scattered or diffuse sources includes atmospheric deposition APES - Chaper 19 3

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5 More Numbers Developed countries 95% of populations have clean water 90% populations have sewage treatment Less Developed Countries 2.5 to 3.0 billion people lack adequate sanitation 1.5 billion lack clean water 80% of illness related to water/sewage 2 million childhood deaths due to poor sanitation APES - Chaper 19 5

6 Categories of Water Pollutants Oxygen Demanding Wastes Inorganic Chemical Organic Chemicals Plant Nutrients Sediment Radioactive materials Heat (thermal pollution) APES - Chaper 19 6

7 Focus-Stream Pollution Impacts on streams Point and non-point pollutants Sediment, industrial, agricultural wastes most common Remediation Recovery rate and success usually dependent on oxygen content of water (BOD) Riparian and wetland areas critical to stream health through entrapment of pollutants Dilution is not always the solution to pollution APES - Chaper 19 7

8 Oxygen Demand BOD biological oxygen demand Measure of how much dissolved O 2 in water is consumed by aquatic and micro organisms over a 5 day period High BOD indicates poor stream health (need for additional oxygen to meet demands) DO dissolved oxygen due to plant contributions and turbulance Oxygen Sag decrease in DO downstream from a pollution source APES - Chaper 19 8

9 Oxygen Sag Curve Clean Zone Normal O2 Trout, perch, macro invert Decompositio n Zone Pollutant enters Trash fish Septic Zone Fish absent, sludge, worms, Recovery Zone Trash Fish, leeches, isopods Clean Zone Normal O2 Trout, perch, macro invert DO BOD Upstream Downstream APES - Chaper 19 9

10 Focus-Freshwater Lakes Impacts to Lakes Water often stratified, slow to exchange Contaminants remain trapped in sediments Small bodies have limited water volumes More vulnerable than streams to: Plant nutrients Oil Pesticides/herbicides Toxic metals/inorganic substances Biomagnification impact greater on freshwater fish species APES - Chaper 19 10

11 Great Lakes-some numbers 95% of U.S. fresh surface water 20% of World fresh surface water Impacted by population of 38+ million people, major industrial centers Very low/slow water exchange rates (1%) 1960 s Lake Erie declared dead Situation has improved, but still much work to return waters to healthy condition APES - Chaper 19 11

12 Groundwater Pollution Out of site, out of mind Serious contamination due to: Surface infiltration Landfill leaching Agricultural contaminants Lowered water tables and flow rates Difficulty in detecting toxins Difficulty in cleaning up toxins APES - Chaper 19 12

13 Groundwater Pollution Prevention much easier than cleanup! Monitoring programs Leak detection and remediation of underground storage tanks Restrictions on landfill wastes Restrictions on hazardous waste storage sites Use good livestock waste management techniques APES - Chaper 19 13

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15 Ocean Pollution No, it s not too big to pollute! Man has proven that!!!! Pollutants come from: On-shore refuse and toxin disposal Marine dumping and disposal Untreated waste disposal into marine bodies Major impact on coastal areas Estuaries, coastal swamps, shorelines APES - Chaper 19 15

16 Ocean Pollution Most polluted marine areas are: Area around India, SE Asia Pacific Gyre (Trash Island) Mediterranean Sea Large estuaries (Chesapeake Bay, others) Gulf Coast (agricultural runoff, oil production) APES - Chaper 19 16

17 Water Treatment Developed countries treat sewage to eliminate: Particulate and biological activity Rarely treat inorganic toxins like lead, mercury, steroids, pesticides, etc. U.S. Drinking water treated to achieve Clarity 0% bacterial contaminants Other contaminants per U.S. EPA standards APES - Chaper 19 17

18 Waste Water Treatment APES - Chaper 19 18

19 The following pictures are from the Statesville Waster Water Treatment Facility Individual pictures are referenced to the Oxygen Sag Curve Zones Coarse Screen trash separation APES - Chaper 19 19

20 Aeration (Decomposition Zone- High BOD met by mechanical aeration) APES - Chaper 19 20

21 Skimmer and Grit Removal (Recovery Zone bio solids removed, high bacterial count) APES - Chaper 19 21

22 APES - Chaper Dewatered Bio solids used as fertilizer

23 Final Discharged Water heading for Third Creek (Clean Zone) APES - Chaper 19 23

24 Waste Water Treatment APES - Chaper 19 24

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26 Laws to Know Safe Drinking Water Act of 1974 Established maximum levels for many toxins Clean Water Act Focus on water quality of U.S. lakes and streams Standards for body contact and water quality APES - Chaper 19 26

27 Water Pollution Poster Children Yellow River, China sediments, very low flow volumes, high level of organic, inorganic chemical contaminants Colorado River, U.S. low flow volumes, salt buildup, dams Lake Chad, Africa diversion of water for irrigation, salt buildup Aral Sea, Kazakhastan diversion of water for irrigation, salt buildup APES - Chaper 19 27

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30 Ganges River, India APES - Chaper 19 30

31 NPR Oil Rig and slick in Gulf of Mexico APES - Chaper 19 31

32 Changes and loss of the Aral Sea APES - Chaper 19 32

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34 Japanese Nuclear Power Plant APES - Chaper 19 34

35 Plant Nutrients Cultural Eutrophication Increased nutrient load in water systems due to human activity Nitrogen, phosphate, ammonium as runoff from agriculture, feed lots Over-fertilizes algae, water plants Increases reproduction rate of plants Plants then die and decay which uses dissolved oxygen (DO) Aquatic life dependent on O2 content of water dies of suffocation! APES - Chaper 19 35

36 Cultural Eutrophication cont. Examples Mediterranean Coast +85% of sewage from cities enters ocean untreated! Farm Runoff over fertilization or runoff of nutrients to waterways Mississippi River concentrated municipal and farm waste, higher water temperatures cause hypoxia in Gulf most summers. Area affected growing annually!. APES - Chaper 19 36

37 Some Extras The following slides simply list some types of water pollutants that you should know APES - Chaper 19 37

38 Oxygen Demanding Waste Any waste that increases the demand for oxygen to decompose or clear a body of water. Typically plant nutrients from animal, human waste or agricultural runoff. Numbers: DO of > 6ppm supports desirable aquatic life DO of < 2ppm supports worms, detritus feeders APES - Chaper 19 38

39 Inorganic Chemicals Acids, caustics, salts, metals Industrial and household wastes Lead, mercury, tin, cadmium Selenium, arsenic (often from natural sources) Many are neurotoxins that accumulate in tissue to reach toxic levels Chronic health impacts Salts in irrigation water of Colorado River, Asia, Middle East APES - Chaper 19 39

40 Organic Chemicals Organic Chemicals Pesticides, detergents, gasoline Industrial and household wastes which end up in landfills and may leak into water supplies Agricultural runoff 500,000 tons of pesticides used in U.S. annually! Golf courses largest users of herbicides and pesticides; followed by U.S. household use. Bioaccumulation APES - Chaper 19 40

41 Sediments Sedimentation Excessive sediment in water Leads to smothering, reduction of sunlight to plants, animals Caused by logging, farming, surface disturbance. Common after forest fires and hurricanes which cause surface disturbance. APES - Chaper 19 41

42 Other Pollutants Radioactive materials Typically the result of mine outflow or industrial waste; some natural occurrence in areas of high concentration Examples: Rocky Flats, Colorado; Uranium mining areas of Colorado, Utah; Fuel disposal (WIIP, Eastern Idaho) Heat or Thermal Pollution Outflow from industrial plants (power plant cooling water) APES - Chaper 19 42