Pollution- TEST FOUR
POLLUTION INTRO Waste Management Wastes are anything we dont want anymore Typical waste management includes o Air and water pollution o Solid and liquid waste o Hazardous waste o Recycling and composting The Problem Everything we do produces waste
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Archeology is all about waste o Remains of food o Remnants of pottery and tools Our wastes become different because our tools are different What do we do with waste? o Throw it away o Where is away? By away, we mean away from me o Everything actually goes somewhere o away is not a problem for a small population It is for a large population Where can we put the shit o NIMBY- Not In My Back Yard o NOTE- Not Over There Either o NIMEY- Not In My Election Year o BANANA- Build Absolutely Nothing Anywhere Near Anybody
Pollution Discussing waste management also means discussing waste mismanagment o If waste is anything we dont want anymore, then pollution is something somewhere we dont want it. o Ex. Lead in soil vs in a battery Ozone in lower vs upper atmosphere Ethanol in a stream vs in a keg Pollution: Point vs. Non Point sources
Point o Discrete location Smokestack, waste pipes Non Point o No single Location Agricultural runoff, vehicle exhausts Controlling pollution Much easier to prevent than to fix At the intersection of science and society o Human behaviors are difficult to change o How clean is clean, really? Pollution Regulations Obviously, a complete lack of regulations is unacceptable o Unmanaged dumping o Untreated sewage o Uncontrolled burning How much is enough? o How clean is clean? o What do we clean up and what do we leave alone? There is a turning point where cost outweighs the benefits of cleaning up the environment Case #1- Contrary Creek Loiusa County, VA: Mineral District o Shallow pod-shaped bodies of pyrite and pyrrhotite line creek o Weather to produce sulfuric acid Creek earned its name because nothing would live in it o Some acid due to mining, but some is natural Case #2- Zinc in Wisconsin Mined for 150 years o Water contains 2.5 ppm dissolved Zn. o PHS drinking water standard is 5 ppm 19 1970s EPA lowers mine water standard to .5 PPM Mines close, but Zn level doesnt change
AIR POLLUTION Waste in the air
o Two principal types Particulates and Gasses o Two Principal Origins Primary and Secondary Particulates and Gasses Particulates are fine, respirable solids o Suspended in the air Toxic gasses o A direct threat to health Reactive gasses o Participate in chemical reactions Primary vs. Secondary Emitted directly vs. created by reactions Case study #1- Ducktown, TN Georgia vs. Tennessee Copper Company o Supreme court limited sulfur emissions to 20 tons/ day in the summer Case study #2- London, December 1952 Unusual Weather and heating with coal created acid fog Positive feedback loop o Stagnant air clouds nucleate on particles Lowers temperature More coal burns Pollutants and sources Gasses o Transportation o Electricity o Industrial Particulates o Construction o Natural o Agricultural Effect- Acid Rain Rainfall is naturally acidic Sulfur from coal fired power plants
Nitrogen o Vehicle emissions o Other combustion Why the recent change? o Stack heights Less pollution nearby, spreads to wider areas Acid Rain Remediation o Stopping it before it starts Redesign combustion to minimize nitrogen oxides Sulfur scrubbers on power plants
o Cleanup is virtually impossible o Only suggestion have been to treat effects Adding limestone to acidified lakes Effects- Smog Photochemical reactions o NOx o VOC Topographic effects o Mountains can block airflow Weather effects o Temperature inversion traps air o Result- Hazy, unclean air Effects- Ozone Pollutant when in lower atmosphere o Important in upper atmopshere Ozone is O3 o Forms when UV radiation splits O2 molecules Free O atoms bond to other O2 molecules o Process decreases the amount of UV radiation below Equilibrium occurs between formation and destruction Ozone Killers: Chloroflourocarbons (CFC) UV radiation splits off Cl Free CL reacts with Oxygen Result?- Less ozone More UV radiation Where do CFCs Come from
Developed for refrigeration and air conditioning Acts as the working fluid to carry heat o Safer than prior fluids (ammonia) o Non-reactive in lower atmosphere o Chlorine +, Ozone o This can create an Ozone Hole Air Pollution reduction There are no strategies for removing existing pollutants from the air o Prevention is the only way Clean Air Act (1970) o Significant Carbon Monoxide reduction Also reduced Sulfur dioxide Nitric Oxides GEOLOGY AND CLIMATE Climate change Hazards Potentially the greatest hazard of all o Sea level changes o Catastrophic weather o Desertification Basics There is no single Earth Climate So what is meant by the climate o The mean of Earth surface conditions o Local variations get averaged out Short term variations also get averaged out
Climate
The climate has changed radically over geologic time o Ice ages are an example Long term climate variation controlled by a variety of factors o Energy balance is the key Most energy is re-radiated into space Some is trapped by absorptive gasses o Transparent to light, but absorb heat o This is the greenhouse effect
Light is downshifted into heat Heat radiates out slowly Greenhouse gasses Required for life on Earth o Without them, average earth Temperature would be -19 C o With them, average earth Temperature is 14 C Include o Water o Carbon dioxide o Methane Water as a Greenhouse gas Volumetrically, the most abundant absorptive gas in the atmosphere o However, not a factor in climate change Water is in dynamic equilibrium with the atmosphere o Evaporation=precipitation o No net increase in atmospheric water Carbon as a greenhouse gas Carbon-based gasses are only a trace of the atmosphere The Carbon Cycle o Carbon moves around the earth Stored in reservoirs Moves are called fluxes o Small fluxes to/from the lithosphere Until the Industrial revolution Anthropogenic flux CO2 and Temperature o We know that carbon dioxide traps heat Hence the term greenhouse o Can we determine temperatures from before thermometers were invented Water with light oxygen evaporates more easily Low temperature= high Heavy to Light oxygen ratio found in old rocks High Temperature= low heavy to light oxygen ratio found in old rocks
o When we plot CO2 increase and Temperature increase They match, with a lag Agreements: o CO2 causes a greenhouse effect o CO2 levels have increased over the last 100 years o Too much CO2 will raise global temperature Arguments? o How much of the CO2 increase is anthropogenic? o How much CO2 is needed to raise temperatures? o How high temperatures must get before they are damaging?
Computer Modeling A way to test the experiment ahead of time o Divide earths surface and atmosphere into 300 x 300 x 300 mile cells o Calculate incoming/outgoing radiation o Balance heat transfer between cells o Results: Depending upon the model, temperatures increasing 1.5 C to 4.5 C Model Validation Feed the model data with a known result o Does the calculated result match the known one Provides confidence that assumptions built into model are reasonable o Or indicates what changes need to be made Results: o Models predict global temperature of 2-5 C o Models run using last 100 years of data predict an increase of greater than 2
o Models run backwards say there was an ice age 100 years ago Climate Proxies We cant go back in time to measure the climate o Computer models need refinement Climate changes affect other Earth Systems o Biosphere, hydrosphere, cryosphere o Second-order effects
What should we do? Stop all extra CO2 production o Safest o Difficult economically and politically Ignore it o What if it doesnt go away? The middle ground o A compromise, but doable o Improve efficiencies and develop new sources The problem? o Unknown lag times from current CO2 levels WATER POLLUTION Situation similar to that of water supply o Different sources have different problems Groundwater and surface water pollution discussed separately o Problems may be distinct or related The Major Difference?- Persistence Eliminate the source of surface water pollution o And the problem is solved o Pollutants have all flowed away Eliminate the source of groundwater pollution o The problem still remains o Pollutants are still there o Groundwater flows much more slowly Groundwater Pollution Some pollution sources similar to surface water sources o Industrial chemicals/landfill leachate o Agricultural chemicals Some pollution sources differ greatly from surface waters o Sewage o Saltwater Chemical Pollution Forms a trail underground from the source o A plume of contaminant Problems/solutions differ depending on contaminant
o Miscible or immiscible with water o More or less dence than water Septic tanks Rural areas without sewage lines or treatment facilities Waste pipes lead to settling tank o Liquids flow to drain field Drain (leach) fields vary in size o Dependent on soil quality Each building requires sufficient acreage o Limits housing density Remediating groundwater How? o It moves slowly o Its underground o Its very expensive to remedy In many cases, only the most sever problems get addressed o A common fix is to stop using your wells Extraction wells o Pump out water and treat it o May use underground barriers o May rely on volume Injection well o Pump in more water to block contaminated water o Or pump in microorganisms to treat water (bioremediation) Treatment Beds o Intercept flow with reactive matters o All takes place underground Surface Water Pollution Pollutants tend to be more varied o Pathogenic, sediment, and thermal pollution Major Difference is the effect on the biosphere o Not much lives in the groundwater Stream Health = O2 levels A widely used measure of the health of a stream is the levels of dissolved oxygen o Referred to as dO2 or dO
o Too low: fish die, organic wast accumulates Oxygen demand is the requirement for dO o Chemical oxygen demand is COD o Biological oxygen demand is BOD Sag Curves Longitudinal plots of dO in streams o A demand increases, dO decreases or sags o Corresponds to pollutants Sewage Treatment Relatively modern invention o Older systems carried waste away o Fundamentally, sewage treatment is a form of composting Multiple stages involved o Primary- Trapping Solids o Secondary- Decomposition o Tertiary- involves purification Not always included Agricultural runoff The major non-point source of water pollution o Fertilizers o Pesticides/Herbicides o Animal wastes o Sediments Fertilizer and Animal Waste runoff Rich in nitrogen and phosphorous Promotes algal growth which consumes oxygen o The major causes of lowered dO Eutrophication o Pulses of nutrients from animal waste that stimulate algae growth o Happening in the gulf of Mexico due to nutrients carried by the Mississippi river Controlling Sedimentation Soil loss from cultivation also impacts surface waters o Clay particles suspended in water Reduces Light penetration, killing plants
Eliminates Habitats Lowers dO No-till agriculture or stilling ponds help to reduce effects Acid Mine Drainage Pyrite and pyrrhotite are keys o Not economical to mine o Common in tailings When Pyrite and Pyrrhotite weather you get H2SO4 o Lowered pH makes other metals soluble Limits plant growth SOLID WATE DISPOSAL Managing Solid waste How do we get rid of stuff Trash it o Dumps, landfills, incineration Use it again o In its current form Re-use o In a new form Recycle/compost Where do wastes consist of Paper products Chemical producs Food products Stone/clay/glass Lumber/wood Petroleum/coal What do Mineral extraction/ processing Animals we do about it US mainly landfills Other countries around the world o More Incineration o More recycling Solid waste disposal
Modern
Originally, just hauled away o Brought to a convenient, semi remote location Over time, sanitary landfills evolved o Gradually increasing regulations o Old dumps and early landfills still around Sanitary Landfills Driving concept: Waste isolation o Keeping the inside in and the outside out Construction o Impermeable seals below and above
Operation o Daily deposits buried with soil o Creates cellular structure o Leachate trash juice removed and treated Monitor groundwater Landfill Problems Waste isolation prevents decomposition o Waste will never disappear o Old buried newspapers are still legible No liquid in or out o Entering water creates new leachate o Excess leachate creates a bathtub effect Must be removed o Leaks are inevitable Requires permanent monitoring Landfills that serve urban areas are filling up o Trash gets exported to other states or countries Old sealed landfills are not entirely stable
o Surfaces subside as contents compact Operations are costly o Expense resisted in some (often rural) areas o Roadside dumping NYC Trash The larges urban center has the biggest problem o Fresh Kills landfill closed in 2001 Where does it go now
o Exported to other states (mainly PA) o Interstate trash transport is constitutionally protected Incineration Burning minimizes volume o Extensive past use Now used mainly for hazardous wastes Complete High Temperature destruction in principle o Difficult engineering in practice Can disperse heavy metals Recycling Using waste as a resource o Glass, metals, plastics, paper Not a new or radical idea o Industries have always recycled internally by reprocessing scraps Recycling by the public is fairly new o Product end user recycling has sharply increased over the last 30 years End User Recyling
o Pre 1960, many end user products were reusable Diapers, soft drink and milk bottles o 1960-1970 Products/packaging became disposable Mentality for convenience Recycling Types Predisposal o End user sorts waste Separate containers for each type of waste o Easier for waste processor Inconvenient for end users o Permits detail in processing Mistakes limit usability Post-disposal o Processor sorts waste Single bin for most all recyclables o Most common type for curbside
o Convenient for end users Limited sorting necessary Advantages of Recycling Landfill space is freed o Nearly 2/3s of municipal waste is actually recyclable Air pollution o Aluminum recycling reduces processing pollution by 95% Energy o Think of the energy equivalent of 1 aluminum can Recycling Limitations 100% recycling is impossibility o Some material is always lost or unusable Recycled materials can be inferior or only for lower quality usage o Paper can only be recycled a few times o Plastics usually decrease in grade after each recycling Extra labor required for processing can make it cost ineffective Composting Organic waste destruction o Much like a septic tank o Piles up waste like vegetable scraps and yard waste o Produces heat and fertilizer during decomposition Done on both small and large scale o DIY compost heap o Greenwaste centers in cities Hazardous waste disposal Toxic Hazards o Lead, Cadmium, Mercury o Pesticides, solvents, process chemicals o Require special precautions to isolate Require special precautions to isolate Love Canal Built in1892 to divert water from Lake Erie for hydroelectric power o Used for recreation until 1940s Purchased by Hooker Chemical o Used as a chemical dump o Filled, sealed by clay, fenced off.
1953, local school board demands property o sold for $1- as a hazardous site 1960s, sold to Occidental Petroleum o School board sells excess land to developers o Memories of the dump were lost Mid 1970s o Waste begins to surface o Enters yards and homes o Tests reveal presence of the dump CERCLA
o Comprehensive Environmental Response Compensation Liability Act o Developed in 1980 Creates a list of hazardous sites Pays for cleanup when no one else can Paid by company fees until 1996 Radioactive waste Waste materials that emit ionizing radiation Amount of hazard depends on the amount of radiation above background Many concerns arise from a lack of understanding o NIMBY is a huge problem Radioactivity vs Radiation Radioactivity o Spontaneous random decay of unstable atomic nuclei o Measured in Becquerel 1 Becquerel=Amount of material that produces 1 nuclear disintegration per second o Radioactivity around us An average banana has about 15 Bq of K-40 1 Kilogram of average granite has about 1000 bq 1 adult has 7000 Bq 1 ionizing smoke detector has about 30000 Bq of Am 1 kilo of uranium metal has about 25 MBq Radiation o Any energy that is emmited
Ionizing Can knock electrons off atoms Alpha and beta particles X rays and gamma rays Non ionizing Much lower energy Visible light, Microwaves, infrared, ultraviolet o Ionizing radiation measured in Roentens o Level of energy absorbed from radiation is different This is what we really care about Measured in Sievert 1 Sv= 1 J/kg o Radiation exposure around us Dental X-ray= .005 mSv Flying 2500 miles = .01 mSv Living in the US for 1 year = 2.4 mSv 1 mammogram= 5 mSv Standing in Fukushima #2 turbine room for 1 hour = 1 Sv Everything is Radioactive There are small amounts of radioactivity everywhere o And there always has been Natural radioactivity comes from natural isotopes o Artificial radioactivity is caused by humans turning stable isotopes unstable Contributes to background exposure o What everyone absorbs simply by living 1.5- 3 mSv o Annual limit for public 1 mSv LD-50= 5 Sv Types and sources of Radioactive Waste Low o Contaminated supplies o Mine tailings
Intermediate o Material used to handle spent nuclear fuel High o Spend reactor fuel assemblies Radioactive waste disposal Low level waste requires a secure landfill o Not unlike other similarly hazardous wastes o One per state or group of states Intermediate and High level waste require special precautions o Stored onsite until safer to handle o Then moved to a permanent repository Spend Fuel Assemblies .1 percent of volume, 96 percent of the radioactivity o original uranium fuel o transuranic elements o fission products Assembly fresh out of reactor Yucca Mountain 1n 1987, Congress selects Yucca Mountain as a High level waste containment center o Preliminary geologic studies found promising o Overlaps Nevada test Site Detailed studies start in 1986 o Construction to begin in 1997 o Begin storing waste in 2003 Studies reveal potential problems o Controversies, lawsuits o Most recent expected start date: 2017
Moving the waste Concerns also raised about transportation to repository o Nuclear sites around the country o Must be shipped by road or rail What is currently being done Nothing o Waste is still being stored in temporary holding locations at nuclear plant sites around the country.
5/4/2011 3:04:00 PM
5/4/2011 3:04:00 PM
