Presentation on theme: "General Types of Water Pollution"— Presentation transcript:
1General Types of Water Pollution Water Quality NotesGeneral Types of Water Pollution
2Core Case Study: Using Nature to Purify Sewage Ecological wastewater purification by a living machine.Uses the sun and a series of tanks containing plants, snails, zooplankton, crayfish, and fish (that can be eaten or sold for bait).Figure 21-1
3Sediment Pollution Definition Excessive amounts of suspended soil particles that eventually settle out and accumulate on the bottom of a body of water.
4CausesErosion of agricultural lands, forest soils exposed by logging, degraded stream banks, overgrazed rangelands, strip mines, and construction.
5Environmental Effects Reduces light penetration, covering aquatic organisms, bringing insoluble toxic pollutants into the water, and filling in waterways.
6Health EffectsSediments adversely affect water quality by carrying toxic chemicals.The sediment particles provide surface area to which some insoluble, toxic compounds adhere; when the sediments enter the water, so do toxic chemicals.Disease-causing agents can also be transported into water via sediments.
8Sewage PollutionRaw or partially treated sewage is a common water pollutant.Sewage pollution results from the disposal of household and industrial wastes into rivers, lakes, and seas. Most communities apply some treatment to raw sewage prior to discharge from point sources, but even treated sewage can be high in nutrients.Sewage is a source of pathogens (disease-causing agents). During floods, human waste may mix with drinking water and increase the risk of water-borne diseases such as cholera.Raw sewage collecting, UKFlood waters can carry sewage, Bangladesh
9CausesRelease of waste water from drains or sewers (toilets, washing machines, and showers) and include human wastes, soaps and detergents.
10Environmental Effects Enrichment – the fertilization of a body of water, caused by the presence of high levels of plants and algal nutrients like nitrogen and phosphorus
11Sewage carries disease-causing agents. Health EffectsOxygen – dissolved oxygen is needed by organisms, like fish, but when sewage enters an aquatic ecosystem, the micro-organisms bloom, leaving less oxygen for the fish, etc., and then they dieSewage carries disease-causing agents.
12Disease-Causing Agents DefinitionInfectious organisms that cause disease.
13Environmental Effects CausesComes from the wastes of infected individuals.Environmental EffectsMunicipal wastewater contains bacteria, viruses, protozoa, parasitic worms, and other infectious agents that cause human or animal diseases.
14Health EffectsTyphoid, cholera, bacterial dysentery, polio and infectious hepatitis are some of the more common bacteria or viruses that are transmitted through contaminated food and water.
16Major Water Pollutants and Their Effects Water quality and dissolved oxygen (DO) content in parts per million (ppm) at 20°C.Only a few fish species can survive in water less than 4ppm at 20°C.Figure 21-3
17Inorganic Plant and Algal Nutrients Chemicals such as nitrogen and phosphorus that stimulate the growth of plants and algae. Read “The Dead Zone” Raven, page 517.
18CausesNitrates and phosphates come from sources such as human and animal wastes, plant residues, atmospheric deposition and residential land.
19Environmental Effects Inorganic plant and algal nutrients encourage excessive growth of algal and aquatic plants. This causes problems, including enrichment and bad odor.
20Organic Compounds Causes Chemicals that contain carbon atoms. Most of the thousands of organic compounds found in water are synthetic chemicals that are produced by human activities; these included pesticides, solvents, industrial chemicals and plastics, and seepage from landfills.
21Environmental Effects Health EffectsHundreds of synthetic organic compounds are toxic and some of these have been shown to cause cancer or birth defects.Environmental EffectsPollutes streams and groundwater.
23CausesChemicals are contaminants that contain elements other than carbon. Examples include acids, salts, and heavy metals. Many inorganic chemicals find their way into both surface water and groundwater from sources such as industries, mines, irrigation runoff, oil drilling and urban runoff from storm sewers.
24Environmental Effects Some of these inorganic pollutants are toxic to aquatic organisms.
25Health EffectsLead and mercury are poisonous. Mercury exposure to developing fetuses in pregnant women has been linked to a variety of conditions such as mental retardations, cerebral palsy, and developing delays, causes kidney disorders and several damage the nervous and cardiovascular systems.Low levels of mercury in the brain cause neurological problems such as headache, depression, and quarrelsome behavior.
26Heavy Metals: Mercury & Lead Mercury is released by burning coal and mining gold and then transported through the air by currents and wind. The mercury can enter water through the water cycle of falling as dry particles or directly.The mercury dumped in Minamata Bay by a factory entered humans through their diet of fish by bioaccumulation caused Minamata disease. Mercury can also be ingested in food or water contaminated by soil or mine waste containing mercury. People showed mental impairments, birth defects, and death caused by the chronic effects of exposure to mercury.Lead is introduced through mining and refining processes but is also in paint, water pipes, lead glazes or ceramics. Humans are affected when they ingest food or water from ceramic tableware produced with lead containing glazes or plumbing.Mercury and lead are toxic heavy metalsMininata disease – effects of being exposed to mercury: birth defects, nervous system/brain damage, learning disabilities, mental retardation or paralysis.How else can metals enter the body? Inhaling dust or vapors.
27Radioactive Substances Contains atoms of unstable isotopes that spontaneously emit radiation
28CausesRadioactive substances get into water from several sources like the mining and processing of radioactive minerals such as uranium and thorium.The nuclear weapons industry use the largest amounts.Medical and scientific research facilities also use them.
29Environmental Effects Health EffectsMutations, birth defects, mental retardation, genetic disease, leukemia, cancer (breast, bone, thyroid, skin, lung), burns, cataracts, male sterility.Environmental EffectsPollutes air, water and soil.
30Thermal Pollution Causes When heated water produced during certain industrial processes is released into waterways.
31Thermal PollutionThermal pollution is the unnatural heating of water which changes the ambient temperature.Heated water is produces during industrial processes, specifically power production, and the released water is cooled in local waterways.In warmer waters the decomposition of waste occurs faster, depleting the water of oxygen; this affects the aquatics organisms ability to metabolize and obtain food.Three Mile Island next to a local waterwayThermal pollution changes the amount of D.O.
32Upstream of a thermal power station Thermal PollutionThermal pollution of waterways is a common consequence of thermal power generation and water cooled industrial processes.Upstream, water is withdrawn, used for cooling, and then released downstream as a (heated) thermal plume.Restrictions are placed on the percentage of water removed for cooling and the temperature of the release water. However, the increased thermal load reduces oxygen levels and may compromise sensitive species.Richard AllanBrendan HicksWater from a thermal power station is released over steps to increase cooling rate.Upstream of a thermal power station
33Environmental Effects Decomposition of wastes occurs faster, depleting the water of oxygen; this affects aquatic life.Health EffectsTypically affects animals, not humans.
34WATER POLLUTION: SOURCES, TYPES, AND EFFECTS Water pollution is any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired uses.Point source: specific location (drain pipes, ditches, sewer lines).Nonpoint source: cannot be traced to a single site of discharge (atmospheric deposition, agricultural / industrial / residential runoff)
35Point Source Pollution Water pollution that can be traced to a specific spot (such as a factory or sewage treatment plant) because it is discharged into the environment through pipes, sewers or ditches.
36Non-Point Source Pollution Pollutants that enter bodies of water over large areas rather than being concentrated at a single point of entry. Ex. Agricultural fertilizer runoff and sediments from construction.
37Sources of Pollution Agriculture Fertilizers, animal wastes, etc. Municipal WasteSewage, fertilizers, dumping into drainage ditches, etc.Industrial WasteChemicals left over from manufacturing, waste products, etc.
38Nutrient Enrichment Oligotrophic: nutrient-poor water Eutrophic: nutrient-rich waterWhat kind of plants would dominate inoligotrophic and eutrophic conditions?
40Eutrophication Definition Relation to Pollution The enrichment of a lake or pond by inorganic plant and algal nutrients such as phosphorus.Relation to PollutionBecause this gets into our water supply from runoff, etc., and is something that is not normally in the water, it is considered pollution.
41EutrophicationAs nutrients are added from pollution, an oligotrophic condition rapidly becomes eutrophic.OligotrophicEutrophic
42Natural Vs. Cultural Eutrophication Natural eutrophicationaquatic successionoccurs over several hundreds of yearsCultural eutrophicationdriven by human activitiesoccurs rapidly
43Cultural Eutrophication Eutrophication: the natural nutrient enrichment of a shallow lake, estuary or slow moving stream, mostly from runoff of plant nutrients from the surrounding land.Cultural eutrophication: human activities accelerate the input of plant nutrients (mostly nitrate- and phosphate-containing effluents) to a lake.85% of large lakes near major population centers in the U.S. have some degree of cultural eutrophication.
44Cause/EffectFertilizers, erosion, sewage, etc. get into water and the effect is high photosynthetic productivity.Thus, the water is cloudy and usually resembles pea soup because of the algae and cyanobacteria that are supported by the nutrients.
45Combating Eutrophication Attack the symptomsChemical treatmentAerationHarvesting aquatic weedsDrawing water down
46Combating Eutrophication Getting at root causeControlling point sourcesControlling nonpoint sources
47Controlling Point Sources Ban phosphate detergentsSewage-treatment improvements
49POLLUTION OF FRESHWATER STREAMS Flowing streams can recover from a moderate level of degradable water pollutants if they are not overloaded and their flows are not reduced.In a flowing stream, the breakdown of degradable wastes by bacteria depletes DO and creates and oxygen sag curve.This reduces or eliminates populations of organisms with high oxygen requirements.
50Organic WastesDissolved oxygen (DO) in the water is depleted during decomposition of organic wastes.Water quality test.Biochemical oxygen demand (BOD): measure of the amount of organic material.
51Water Pollution Problems in Streams Dilution and decay of degradable, oxygen-demanding wastes and heat in a stream.
52Eutrophic (high nutrient) water frequently have a high BOD Biochemical oxygen demand is a measure of the polluting capacity of effluent where decomposition results in oxygen depletion. Organic matter decays as bacterial activity increases.BOD is measured as the weight (mg) of oxygen used by one liter of sample effluent stored in darkness at 20oC for five days.Runoff of animal waste can increase nutrient levels and bacterial content in a lake or stream usually this can be measured by the content of fecal coliform bacteria.When the BOD is high and dissolved oxygen becomes depleted, decomposition becomes anaerobic.Anaerobic microorganisms produce compounds with unpleasant odors, leading to a further deterioration in water quality.Eutrophic (high nutrient) water frequently have a high BODHypoxia (no oxygen) in the Mississippi River Delta has led to lower fishing yields.
53POLLUTION OF FRESHWATER STREAMS Most developed countries have sharply reduced point-source pollution but toxic chemicals and pollution from nonpoint sources are still a problem.Stream pollution from discharges of untreated sewage and industrial wastes is a major problem in developing countries.
54Global 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 21-5
55Case 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.
56Case 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.Figure 21-6
57POLLUTION OF FRESHWATER LAKES Dilution of pollutants in lakes is less effective than in most streams because most lake water is not mixed well and has little flow.Lakes and reservoirs are often stratified and undergo little mixing.Low flow makes them susceptible to runoff.Various human activities can overload lakes with plant nutrients, which decrease DO and kill some aquatic species.
58Importance of the Ocean Environment Marine EcologyImportance of the Ocean Environment
59Area Saltwater covers about 71% of the earth’s surface Life: There are 250,000 known species of marine plants and animals, many are food for other organisms, like us.
60TemperatureSolar heat is distributed by ocean currents & as ocean water evaporates.The oceans are major players in the earth’s climate & are a gigantic reservoir for carbon dioxide; therefore they help regulate the temp. of the troposphere.
61Zones of the Marine Environment Two major zones that break up into smaller zones – coastal and the open sea
62Intertidal or Beach Zone Broken up into five areas
63Lower ShorefaceThe deepest part of the beach; farther into the water, before the breaker bar that forms waves
64Upper ShorefaceShallow zone where the waves begin to form
65ForebeachContains the swash zone – place where the waves crash.
67Fore-Island DunesSand dunes; doesn't flood often, except during hurricanes, etc. Constantly changing due to the wind
68Where fresh water and salt water meet EstuaryWhere fresh water and salt water meetAn estuary is a coastal body of water, partly surrounded by land, with access to the open ocean and a large supply of fresh water from a river
70SalinitySalinity fluctuates with tidal cycles, the time of year, & precipitation. The organisms that live here must be able to tolerate these conditions
71Fertility of Estuaries Estuaries are the most fertile ecosystems in the worldGreater productivity than either the adjacent ocean or the fresh water upriver
72Reasons for High Fertility Nutrients are transported from the land into rivers that flow into the estuaryTidal action circulates nutrients and helps remove wastesA high level of light due to shallow waterMany plants provide an extensive photosynthetic carpet
73DifficultiesSandy beach – Life must deal with a shifting environment that threatens to engulf them & no protection against wave action. Most animals bury into the sand. They move with the tides, so they’re always underwater & don’t dry out.
74Difficulties (Continued) Rocky shore – high wave action at high tide; drying out & temperature changes during low. Animals have a way of sealing in moisture like a shell & find a way to cling to the rocks so they don’t get washed away with waves.
75The Open OceanPelagicThe open ocean environment; divided into neritic (open ocean from the shoreline to a depth of 200m) and oceanic provinces (depths > 200m).
76Euphotic ZoneLots of light. From meters. Photosynthesis takes place here.
77Bathyal ZoneThe dimly lit part of ocean. From meters.
78Benthic Characteristics (ocean floor) The ocean floor consists of sediments (mostly sand and mud)Many marine animals, like worms and clams, burrowBacteria are common & can go down 500 meters below ocean floor. The Benthic environment extends from the shore to the deep.
79Sea Grass BedsFlowering plants that have adapted to complete submersion in salty water.
80Location of sea grass Examples Eel, turtle, and manatee grass. Found in shallow water to depths of 10 meters where they can photosynthesize. Sea grasses are found in quiet, temperate, tropical, and subtropical waters; not in polar waters.ExamplesEel, turtle, and manatee grass.
81Ecological Importance Reduce surface erosion, provide food, & provide habitats for many marine organisms.Animals that eat sea grass are manatees, green turtles, parrotfish, sturgeon fish, and sea urchins.
82Abyssal ZoneCompletely dark. Extends to a depth of 4000 to 6000 meters (2.5 to 3.7 miles). Water here is very cold & has little dissolved oxygen.
83KelpThe largest of the brown algae, many reach lengths of 60 meters (200 feet). Common in cooler water & are found along rocky coasts. Provide habitat for many animals like tubeworms, sponges, clams, fish, & mammals. Some animals eat the kelp.
84Coral Reefs Characteristics Built from layers of calcium carbonate, coral reefs are found in warm, shallow sea water. The living portions must grow in shallow waters where light hits. They are the most diverse of all marine ecosystems.
85ExamplesMany coral reefs are made of red coralline algae that photosynthesize.Others have zooxanthellae (symbiotic algae) that live and photosynthesize in their tissues.Not all corals have zooxanthellae, but only those with it build reefs.Coral animals also capture food at night with stinging tentacles that paralyze zooplankton and small animals that drift nearby.
86Coral Reef WatersThe waters where coral reefs are found are often poor in nutrients. Yet, other factors are favorable such as temperature, sunlight year round, and zooxanthellae.
87GrowthCoral reefs grow slowly; as one dies, another organism grows on it.
88Types of Coral Reefs Fringing Reef The most common type of coral reef. It is directly attached to the shore of a volcanic island or continent.
90Fringing Reef Bora Bora NASA JPL Satellite: Space Shuttle Sensor: SIR-C/X-SAR
91Atoll A circular reef that surrounds a central lagoon of quiet water. An atoll forms on top of the cone of a submerged volcanic island.More than 300 atolls are found in the Pacific and Indian Oceans.
93View of Midway Atoll from Space Shuttle View of Midway Atoll from Space Shuttle
94Atolls in The Maldives Landsat 7 Atolls in The Maldives Landsat 7
95Barrier ReefA lagoon of open water separates the land from the barrier reef.The largest barrier reef is the Great Barrier Reef off the coast of Australia.The second largest is off the coast of Belize.
98Ecological Importance of Coral ReefsProvides a HabitatProvides a habitat for a wide variety of marine organisms.
99Coastline ProtectionProtects coasts from shoreline erosion.
100Benefits for HumansProvides humans with seafood, pharmaceuticals, and recreational/tourism dollars
101Coral Reef RisksOf the 109 countries with large reefs, 90 are damaging them, and 27% of the coral reefs are at high risk, especially off the coast of Southeastern Asia.In the western Atlantic, 30-50% of all coral species are either rare or endangered.
102Coral Reef Risks Con’tSilt washing from downstream has smothered the reefsHigh salinity from fresh water diversion, over-fishing, boat groundings, fishing with dynamite or cyanide, hurricane damage, disease, coral bleaching, land reclamation, tourism, and the mining of coral for building materials.
104Protection of300 coral reefs in 65 countries are protected as reserves or parks, and another 600 have been recommended for protection.The good news is coral reefs can often recover from damage.
105Differences of Opinion Oceans dilute, disperse, and degrade large amounts of raw sewage, sewage sludge, oil, and some types of industrial waste, especially in deep-water areas.Marine life has proved to be more resilient than some scientists expected, some suggest it is safer to dump sludge & other hazardous wastes into the deep ocean than to bury them on land or burn them.
106Differences of Opinion Other scientists disagree, pointing out that we know less about the deep ocean than we do about space. They say that dumping waste in the ocean would delay urgently needed pollution prevention and promote further degradation of this vital part of the earth’s life-support system.
107Oil Spills When a tanker accident happens, it gets lots of publicity. But, more oil is released by normal operation of offshore wells, washing tankers & from pipeline or storage tank leaks.One estimate says that oil companies spill, leak, or waste per year an amount of oil equal to that shipped by 1000 huge Exxon Valdez tankers.
108Floating OilOil coats the feathers of birds (especially diving birds) and the fur of marine animals, destroying the animals’ natural insulation and buoyancyMany drown or die of exposure from loss of body heat.
109Other InformationOil is broken down by bacteria over time; slower in cold waters.Heavy oil components can smother bottom-dwelling organisms such as crabs, oysters, mussels, and clams, or make them unfit to eat.Oil spills have killed coral reefs. A recent study showed that diesel oil becomes more toxic to marine life with the passage of time.
110Mechanical MethodsFloating booms contain the oil spill or keep it from reaching sensitive areasSkimmer boats are used to vacuum up some of the oil into collection bargesAbsorbent pads or large feather-filled pillows are used to soak up oil on beaches or in waters that are too shallow for skimmer boats
111Chemical MethodsCoagulating agents cause floating oil to clump together for easier pickup or sink to the bottom, where it usually does less harm.Dispersing agents break up oil slicks. However, these can also damage some types of organisms.Fire can also burn off floating oil, but crude oil is hard to ignite.
112Reducing Water Pollution through Sewage Treatment Septic tanks and various levels of sewage treatment can reduce point-source water pollution.Figure 21-15
113Sewage TreatmentSewage includes all waste water that has been used by a household or industry.It does not include storm-water from road and property runoff, which is usually diverted directly into waterways.In some cities, sewage and storm-water systems may be partly combined, and sewage may overflow into storm- water during high rainfall.Trickling filters at a waste treatment plantSewage pipes discharging into a holding tank
114Aeration tank: activated sludge Processing SewageSewage usually undergoes several levels of treatment (purification):Pre-treatment removes any large objects, such as tree limbs, leaves, condoms, & tampons, with screens.Primary treatment uses mechanical processes, such as screening and settling, to remove suspended sand and silt. This forms the primary sludge.Secondary treatment uses microorganisms to decompose the suspended organic material in the waste water aeration tank. The bacteria-laden solids settle out as sewage sludge.Disinfection (usually by chlorination but ozone and UV light can also be used) kills any bacteria and other pathogens before the waste water is discharged.Final treatments using biological, chemical, and physical processes is required to remove nitrogen, phosphorus, heavy metals, and synthetic organic compounds.Sedimentation tankPrimary sewage treatment: a physical process that uses screens and a grit tank to remove large floating objects and allows settling.Secondary sewage treatment: a biological process in which aerobic bacteria remove as much as 90% of dissolved and biodegradable, oxygen demandingorganic wastes.Tertiary sewage treatment: a mixture of processes that includes chlorine disinfection.Aeration tank: activated sludge
115Reducing Water Pollution through Sewage Treatment Primary and Secondary sewage treatment.
116Reducing Water Pollution through Sewage Treatment Advanced or tertiary sewage treatment:Uses series of chemical and physical processes to remove specific pollutants left (especially nitrates and phosphates).Water is chlorinated to remove coloration and to kill disease-carrying bacteria and some viruses (disinfect).
117Reducing Water Pollution through Sewage Treatment Raw sewage reaching a municipal sewage treatment plant typically undergoes:Primary sewage treatment: a physical process that uses screens and a grit tank to remove large floating objects and allows settling.Secondary sewage treatment: a biological process in which aerobic bacteria remove as much as 90% of dissolved and biodegradable, oxygen demanding organic wastes.
119PrimaryRemoves suspended and floating particles, such as sand and silt, by mechanical processes such as screening and gravitational settling. The solid material that is settled out is called primary sludge.Bar screens, grit chambers, primary clarifiers, digesters and pre-aeration
120SecondaryUses microorganisms to decompose the suspended organic material in wastewater. Ex. trickling filters – where wastewater trickles through aerated rock beds that contain bacteria and other microorganisms, which degrade the organic material in the water.
121Secondary (Cont.)Or activated sludge process – wastewater is aerated and circulated through bacteria-rich particles; the bacteria degrade suspended organic material. After several hours, the particles and microorganisms are allowed to settle out, forming secondary sludge.Use aeration basins, settling tanks and sand filters
122TertiaryThis includes a variety of biological, chemical and physical processes used to remove phosphorus and nitrogen, the nutrients most commonly associated with enrichment. Tertiary treatment can also be used to purify wastewater so that it can be reused in communities where water is scarce.Use chlorine as a disinfection and then chlorine is removed by SO2 so it can be released into river.
123Reducing Water Pollution through Sewage Treatment Sewage sludge can be used as a soil conditioner but this can cause health problems if it contains infectious bacteria and toxic chemicals.Preventing toxic chemicals from reaching sewage treatment plants would eliminate such chemicals from the sludge and water discharged from such plants.
124Reducing Water Pollution through Sewage Treatment Natural and artificial wetlands and other ecological systems can be used to treat sewage.California created a 65 hectare wetland near Humboldt Bay that acts as a natural wastewater treatment plant for the town of 16,000 people.The project cost less than half of the estimated price of a conventional treatment plant.
125Water Quality United States Groundwater contamination still occurs, especially due to non-point source pollution, but laws like the Safe Drinking Water Act, Clean Water Act, and Water Quality Act have helped in the U.S.
126Global ProblemsAccording to the World Health Organization, an estimated 1.4 billion people still do not have access to adequate sanitation systems. Worldwide, at least 250 million cases of water-related illnesses occur each year, with 5 million or more of these resulting in death. Read Raven page
127Specific Water Quality Measures Dissolved OxygenThe amount of oxygen gas dissolved in a given volume of water at a particular temperature and pressure.
128Carbon DioxideEnters aquatic systems from the atmosphere and from respiration by animals.The concentration of CO2 varies at different depths because of light/photosynthesis.
129NitrateContaminates shallow groundwater (100 feet or less) and usually comes from fertilizers. It’s a concern in rural areas where 80-90% of the residents use shallow groundwater for drinking. This harms humans because it reduces the blood’s ability to transport oxygen.
130SulfateProblem because too much can kill fish. Gets in water from industrial processes and mining.
131IronCauses problems because it separates out of the water and forms particulates (sediment), it tastes bad if it gets in our water, and can coat fish’s gills. Groundwater problems in wells, from natural minerals in rocks.
132PhosphatePlant nutrients that cause algae blooms. It comes from detergents, human wastes and fertilizers.
133ColiformGeneral group of bacteria from animal wastes. It uses up available oxygen. Also causes e-coli disease.
134GiardiaOrganism (protozoa) that can cause diarrhea if you drink unchlorinated water. It is a natural organism that lives in the guts of animals.
135ChloridePart of salts, but too many can cause too much salt in the water. Too much is bad; a little is okay. It is naturally found in water, but can come from pollution.
136pHToo high/too low can be bad; fish like ; acid mine drainage can kill fish.
137HardnessCalcium and magnesium dissolved in the water. A little is good ( ppm for fish is good), but very low or high is a problem. Low is more of a problem. Affects fish eggs, poor bone development.
138TurbidityCloudiness/muddiness; blocks the light; coats fish gills.
139Hard WaterDefinitionCalcium and magnesium in the water. Can cause problems with cleaning clothes. Soap doesn’t bubble as much.
140Methods of Treating Ion Exchange Substitute sodium for calcium and magnesium. Water softeners usually do this.
141Reverse OsmosisMembrane system that allows water to go through but calcium and magnesium cannot.
142Major Users – United States & global Water UsageMajor Users – United States & globalAgricultural users are the biggest by volume, then industrial and municipal.
143POLLUTION OF GROUNDWATER Leaks from a number of sources have contaminated groundwater in parts of the world.According the the EPA, one or more organic chemicals contaminate about 45% of municipal groundwater supplies.By 2003, the EPA had completed the cleanup of 297,000 of 436,000 underground tanks leaking gasoline, diesel fuel, home heating oil, or toxic solvents.
144Case Study: Arsenic in Groundwater - a Natural Threat Toxic Arsenic (As) can naturally occur at high levels in soil and rocks.Drilling into aquifers can release As into drinking water supplies.According to WHO, more than 112 million people are drinking water with As levels times the 10 ppb standard.Mostly in Bangladesh, China, and West Bengal, India.
145Safe Drinking Water Act of 1974 Water LegislationSafe Drinking Water Act of 1974It required the EPA to determine the maximum contaminant level, the max permissible amount of any pollutant that might adversely affect human health.
146PREVENTING AND REDUCING SURFACE WATER POLLUTION Most developed countries use laws to set water pollution standards, but such laws rarely exist in developing countries.The U.S. Clean Water Act sets standards fro allowed levels of key water pollutants and requires polluters to get permits.EPA is experimenting with a discharge trading policy similar to that for air pollution control.
147Clean Water Act of 1972 Has two basic goals: To eliminate the discharge of pollutants in U.S. waterwaysTo attain water quality levels that make these waterways safe to fish and swim in.
148Water Quality Act of 1987 controlling toxic pollutant discharges control non-point sources of pollutionauthorized $18 billion for wastewater treatmentaddress problems such as coastal estuaries, the Great Lakes, and the Chesapeake Bay
149Using 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.Industry pressures to weaken the Safe Drinking Act:Eliminate national tests and public notification of violations.Allow rights to pollute if provider cannot afford to comply.
150Is 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.