Intro to Environmental science exam 2 study guide
Intro to Environmental science exam 2 study guide 11:375:101
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This 39 page Study Guide was uploaded by Rachel on Friday February 26, 2016. The Study Guide belongs to 11:375:101 at Rutgers University taught by Professor Phelps and Strom in Spring 2016. Since its upload, it has received 178 views. For similar materials see Intro to Environmental Science in Environmental Science at Rutgers University.
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Date Created: 02/26/16
▯ Chapter 9 ▯ ▯ Population ecology Population o Group of interbreeding individuals of the same species Population size governed by: o Births and deaths; immigration and emigration o Population change = (births + immigration) – (deaths + emigration) ▯ Population growth At a fixed percentage per year(j curve) ▯ Some factors that can limit population size There are always limits to population growth in nature Environmental resistance – factors that limit population growth Carrying capacity o Maximum population of a given species that a particular habitat can sustain indefinitely Limiting factor principle o Too much or too little of any physical or chemical factor can limit or prevent growth of a population, even if all other factors are at or near the optimal range of tolerance o Precipitation, nutrients, sunlight ▯ ***screen shot of slide 6 ▯ When a population exceeds its carrying capacity it can crash A population exceeds the area’s carrying capacity Reproductive time lag may lead to overshoot o Subsequent population crash Damage may reduce area’s carrying capacity ▯ ***screen shot of slide 8 ▯ Human population growth The continuing rapid growth of the human population and its impacts on natural capital raise questions about how long the human population can keep growing ▯ ****list population numbers from slide 10 Human population growth shows certain trends rate of population growth has slowed in recent decades human population growth is unevenly distributed geographically people are moving from rural to urban areas ▯ ***screen shot of annual growth rate diagram slide 12 ▯ ***screen shot of slide 13 ▯ Human Population growth impacts natural capital As the human population grows, so does the global total human ecological footprint Cultural carrying capacity o Total number of people who could live in reasonable freedom and comfort indefinitely without decreasing the ability of the earth to sustain future generations ▯ ***list from slide 15 ▯ What factors influence the size of the human population Population size increases through births and immigration, and decreases through deaths and emigration The average number of children born to women in a population(total fertility rate) is a key factor that determines population size ▯ The human population can grow, decline, or remain fairly stable Population change=(births+immigration)-(deaths+emigration) Fertility rate o Number of children born to a woman during her lifetime Replacement-level fertility rate o Average number of children a couple must have to replace themselves o Approx.. 2.1 in developed areas ▯ The worlds population is still growing Total fertility rate(TFR) o Average number of children born to women in population o Between 1955 and 2012, the global TFR dropped from 5 to 2.4 o However, to eventually halt population growh, the global TFR will have to drop to 2.1 ▯ Several factors affect birth rates and fertility rates Children as part of labor force Cost of raising and educating children Availability of private and public pension Urbanization Educational and employment opportunities for women Average age of women at marriage Availability of legal abortions Availability of reliable birth control methods Religious beliefs, traditions, cultural norms ▯ Several factors affect death rates Life expectancy Infant mortality rate o Number of live births that die in first year High infant mortality rate indicates o Insufficient food, poor nutrition, high incidence of infectious disease ▯ ***screen shot of slide 22 ▯ Migrations Affects an Areas population size Migration o The movement of people into and out of specific geographic areas Causes: o Economic improvement, religious and political freedom, o Environmental refugees ▯ Age structure The number of males and females in young, middle, and older age groups determine how fast a population grows or declines ▯ A populations age structure helps make projections Age categories o Prereproductive ages (0-14) o Reproductive ages (15-44) o Postreproductive ages (45 and older) ▯ ****scrren shot of slide 26 What factors lead to slower population growth human population growth slows when poverty is reduced, the status of women is elevated, and family planning is encouraged ▯ Demographic transition As countries become industrialized: first death rates decline, then birth rates decline ▯ 4 stages preindustrial, transitional, industrial, postindustrial ▯ ***screen shot slide 29 ▯ Empowering women slows population growth Factors that decrease TFR: o Education, paying jobs, ability to control fertility Women o Do most of domestic work and child care o Provide unpaid health care o 2/3 of all work for 10% of worlds income o discriminated against legally and culturally ▯ Family planning in less developed countries Responsible for 55% drop in TFR’s Financial benefits: money spent on family planning saves far more in health, education costs 3 big ideas The human population is increasing rapidly and may soon bump up against environmental limits Increasing use of resources per person o Expanding the overall human ecological footprint and putting a strain on the earth’s resources We can slow population growth by reducing poverty through economic development, elevating the status of women, and encourage family planning ▯ ▯ CHAPTER 10 ▯ ▯ Weather Temperature, precipitation, wind speed, cloud cover ▯ Climate Area’s general pattern of atmospheric conditions over decades and longer ▯ Climate zone Tropical, polar, temperate ▯ Key factors that determine global climate patterns Incoming solar energy, greenhouse effect, uneven heating and convection, the earth’s rotation ▯ Greenhouse gases H2O, CO2, CH4, N2O ▯ Natural greenhouse effect Gases keep earth habitable ▯ Human-enhanced global warming ▯ Air circulation in lower atmosphere due to Uneven heating of the earth’s surface by sun, rotation of the earth on its axis, properties of air, water and land ▯ ***slide 9 and 10 ▯ Ocean currents Prevailing winds, earth’s rotation, redistribution of heat from the sun, surface currents and deep currents ▯ Climate affects the nature and locations of Biomes Differences in average annual precipitation and temperature lead to the formation of tropical, temperate and cold deserts, grasslands, and forests, and larely determine their locations ▯ Climate helps determine where organisms can live Major Biomes o Large land regions with certain types of climate and dominante plant life Not uniform, mosaic of patches o Change with latitude and elevation ▯ ****slide 15, 16, and 17 ▯ 3 types of deserts tropical desert, temperate desert, cold desert o desert annual precipitation low and often scattered through the year often fragile ecosystems ▯ ***slides 19,20,21 ▯ Grasslands occur in: Interior continents too moist for deserts and too dry for forests ▯ 3 types: tropical, temperate, and cold(arctic tundra) ▯ **slides 23,24,25 ▯ temperate grasslands are most often converted for agriculture ▯ Forests: lands dominated by trees Tropical, temperate, cold(northern coniferous and boreal) ▯ ***slides 28,29,20 ▯ Tropical rain forests Hot and high moisture Stratification of specialized plant and animal niches Rapid cycling of scarce soil nutrients ▯ ***Slide 32 ▯ Temperate deciduous forests Cooler temperature and less moisture Broad-leaf deciduous tree Slow rate of decomposition ▯ Evergreen Coniferous forests: boreal and taigas Cold winters Few species of cone-bearing trees Slow decomposition ▯ Mountains: steep high elevation lands Majority of the worlds forests Islands of biodiversity Habitats for endemic species Help regulate the earth’s climate Major storehouses of water(role in hydrologic cycle) ▯ Human activities have affected the world’s terrestrial ecosystems Human activities are disrupting ecosystem and economic services provided by many of earth’s deserts, grasslands, forests and mountains ▯ Humans have disrupted much of the earth’s land About 60% of the worlds major terrestrial ecosystems are being degraded The human ecological footprint is spreading across the globe ▯ ***slide 39,40 ▯ 3 big ideas differences in climate o based on long-term differences in average temperature and precipitation o largely determine the types and locations of the earth’s desserts, grasslands and forests the earth’s terrestrial systems provide important ecological and economic services human activities are degrading and disrupting many of the ecological and economic services provided by the earth’s terrestrial ecosystems ▯ ▯ CHAPTER 11 ▯ Land Management Costa Rica- global conservation leader o Suffered widespread deforestation o Still harbors great biodiversity Microclimates provide variety of habitats More than 25% of its land is nature reserves and national parks o Government pays landowners to restore forests ▯ Forests vary in their age, makeup, and origins Old-growth primary forest(about 36%) o Uncut not disturbed for several hundred years o Reservoirs of biodiversity Second- growth forest o Secondary ecological succession Tree plantation(tree farm, commercial forest) ▯ ***slide 6 ▯ Forest ecosystems provide ecosystem services far greater in value than the value of raw materials obtained from forests(nutrient cycling higherst)(recreation least) Store atmospheric carbon Provide habitats Influence local and regional climate Provide raw materials Provide health benefits o Medicines derived from plant species ▯ Major threats to ecosystems Chief threats to ecosystems o Unsustainable cutting and burning of forests o Fire, diseases and insects o Projected climate change ▯ Ways to harvest trees Selective cutting o Intermediate-age or mature trees are cut singly or in small groups Clear-cutting o All trees in an area are removed Strip cutting o Clear-cutting in strips ▯ ***SLIDES 12,13,14,15 ▯ Fire,insects and climate change can threaten forest ecosystems Surface fires o Usually burn leaf litter and undergrowth o Provide many ecological benefits Crown fires o Extremely hot-burns whole trees o Kill wildlife o Increase soil erosion ▯ Introduction of foreign diseases and insects Accidental or deliberate ▯ Global warming Rising temperatures Trees more susceptible to diseases and pests Drier forests-more fires ▯ Almost half the worlds forests have been cut down Deforestation o Temporary or permanent removal of large expanses of forest for agriculture, settlement or other uses Tropical forests o Especially in Latin America, Indonesia, and Africa Boreal Forests o Especially in Alaska, Canada, Scandinavia and Russia ▯ Deforestation Water pollution and soil degradation from erosion Acceleration of flooding Local extinction of specialist species Habitat loss for native and migrating species Release of CO2 and loss of CO2 absorption ▯ Tropical Forests are disappearing rapidly Majority of loss since 1950 o Mostly in Africa, Southeast Asia, South America o Clearing trees can accelerate climate change Drier climate o Risk of larger and more frequent forest fires Ecological tipping point o Forest cannot grow back ▯ Causes of Tropical deforestation are varied and complex Varied causes o Population growth o Poverty and subsistence farmers o Ranching o Lumber o Plantation farms-palm oil Begins with rebuilding of roads Many forests burned ▯ We can sustain forests by: Emphasizing the economic value of their ecosystem services Removing governemt subsidies that hasten their destruction Protecting old-growth forests Harvesting trees no faster than they are replenished Planting trees ▯ ***slide 25 ▯ We can improve the management of forest fires Prescribed fires o Remove flammable material Allow fires on public lands to burn Protect structures in fire-prone areas o Thin trees and vegetation within 60m of a structure Thin forests in fire-prone areas ▯ We can reduce the demand for harvested trees Improve the efficiency of wood use o 60% of US wood is wasted make tree-free paper o kenaf o hemp ▯ Parks and Natural reserves Sustaining biodiversity will require: o More effective protection of existing parks and nature reserves o The protection of much more of the earth’s remaining undisturbed land area ▯ National parks face many environmental threats Worldwide-6600 national parks Parks in developing countries o 1% protected against illegal: animan poaching, logging and minng ▯ Case study: stresses on US public parks There are 58 major national parks in US Biggest problem may be popularity Other problems include: nonnative species, poaching, commercial development ▯ National reserves occupy only a small part of earths land Currently less than 13% is protected Conservationists goal-protect 20% ▯ Protecting Wilderness is an important way to preserve biodiversity Wilderness o Land officially designated as having no serious disturbance from human activities o Wilderness Act of 1964 5% of US land is protected as wilderness ▯ 3 big ideas the economic values of the important ecological services provided by the world’s ecosystems are far greater than the value of the raw materials obtained from those systems We can manage forests and nature reserves more effectively by: o Protecting more land o Preventing overuse and degradation of these areas and the renewable resources they contain o ▯ CHAPTER 12 ▯ Marine Ecosystems Saltwater aquatic life zones cover almost three-fourths of the earth’s surface, with oceans dominating the planet Key factors determining biodiversity in aquatic systems o Temperature, dissolved oxygen content, availability of food, and access to light and nutrients necessary for photosynthesis ▯ Marine Modes of life Plankton – drifting o Phytoplankton Primary producers for most aquatic food webs o Ultraplankton Tiny photosynthetic bacteria o Zooplankton Secondary consumers Single-celled to large invertebrates like jellyfish o Nekton Strong swimmers – fish, turtles, whales o Benthos Bottom dwellers – oysters, sea stars, clams, lobsters, crabs o Decomposers Mostly bacteria ▯ Determining factors of biodiversity ▯ Key factors in the distribution of organisms Temperature Dissolved oxygen content Availability of food Availability of light and nutrients needed for photosynthesis ▯ Turbidity Degree of cloudiness in water Inhibits photosynthesis ▯ 3 major life zones: Coastal zone o Warm, nutrient rich, shallow; shore to edge of continental shelf; usually high NPP from ample sunlight and nutrients Open Sea Ocean Bottom ▯ ***slide 7 ▯ Oceans provide Vital ecosystem and economic services Saltwater ecosytems o Provide major ecosystem and economic services o Are irreplaceable reservoirs of biodiversity o Estimated 12 trillion dollars/ year in goods/services ▯ **slide 9 ▯ Estuaries Where rivers meet the sea ▯ Coastal wetlands Coastal land covered with water all or part of the year ▯ Seawater mixes with freshwater ▯ Very productive ecosystems with high nutrient levels(estuaries and coastal wetlands) ▯ Examples: river mouths, inlets, bays, sounds, salt marshes, sea grass beds, mangrove forests ▯ ***slide 12,13,14 ▯ Coral Reefs have biodiversity Marine equivalent of tropical rain forests Reefs are being destroyed and damaged worldwide Ocean acidification o Oceans absorb CO 2 o CO 2eacts with ocean water to form a weak acid that decreases levels of carbonate ions (CO ) nee3ed to form coral ▯ The open sea and ocean floor host variety of species Three vertical zones of the open sea o Euphotic zone Phytoplankton Nutrient levels low Dissolved oxygen levels high Upwelling brings nutrients from below o Bathyal zone Dimly lit Zooplankton and smaller fishes o Abyssal zone Dark and cold High levels of nutrients Little dissolved oxygen Deposit feeders Filter feeders NPP low in the open sea o Except in upwelling areas ▯ ***Slide 17 ▯ Human activities Threaten aquatic biodiversity Disrupt ecosystem and economic services provided by salt water systems ▯ The Chesapeake Bay- and Estuary in trouble Largest estuary in the US o Polluted since 1960 Large population increase Point and nonpoint sources raised pollution Phosphate and nitrate levels too high Excess sediments from runoff and decreased vegetation Oysters(keystone species) greatly reduced 1983: Chesapeake bay problem o integrated coastal management with local, state and federal govt’s, as well as citizens groups 2008 update: o 25 years and $6 billion o program failed to meet goals ▯ ***slide 21 ▯ Major threats to aquatic biodiversity and ecosystem services Aquatic species and the ecosystem and economic services they provide are threatened by: o Habitat loss, pollution, climate change, and overexploitation o All made worse by the growth of the human population and resource use ▯ ***slide 24,25,27 Habitat Loss Major threats to coastal marine systems include: o Coastal development o Habitat destruction by commercial fishing o Pollution of coastal wetlands and estuaries ▯ Population growth and pollution reduce biodiversity 80% of all humans living along coasts Nitrates and phosphates, mainly from fertilizers, enter water o Leads to eutrophication Toxic pollutants from industrial and urban areas Plastics o Ocean garbage ▯ Climate change is a growing threat Sea levels will rise and aquatic biodiversity is threatened o Coral reefs o Swamp some low-lying islands o Drown many highly productive coastal wetlands o Warmer ocean water stresses phytoplankton ▯ Overfishing and extinction Fishery – concentration of a particular wild aquatic species suitable for commercial harvesting in a specific area Fishing key factor in the depletion of up to 80% of the population of some wild fish species in only 10-15 years Trawlers o Destroy ocean bottom habitat Purse-seine fishing o Can kill dolphins Long-lining o Kills large numbers of sea turtles, dolphins, and seabirds Drift net fishing o Large bycatch ▯ ***slide 32.36 Overfishing leads to commercial extinction commercially valuable fish become scarce some marine mammals are also threatened due to overfishing ▯ ***slide 34 ▯ Why protect sharks? Sharks are keystone species o If they become extinct, their ecosystems will suffer ▯ For every shark that injures a person, people kill about 1.2 million sharks 32% of open-ocean shark species are threatened with extinction ▯ Biological extinction Overfishing, water pollution, wetlands destruction, excessive removal of water from lakes and rivers 34% of marine species are threatened ▯ We can help to sustain marine biodiversity by: Using laws and economic incentives to protect species Setting aside marine reserves to protect ecosystems and ecosystem services ▯ ***slide 39 ▯ Offshore fishing Exclusive economic zones for countries o 200 nautical miles o High seas governed by treaties that are hard to enforce ▯ Marine protected areas (MPAs) Protected from human activities ▯ Marine reserves Closed to: o Commercial fishing o Dredging o Mining and waste disposal Core zone o No human activity allowed Less harmful activities allowed o Example: recreational boating and shipping ▯ Fully protected marine reserves work fast Fish populations double Fish size grows Reproduction triples Species diversity increase by almost one-fourth ▯ Cover less than 1% of world’s oceans Marine scientists want 30-50% ▯ 3 big ideas: The earth’s aquatic systems provide important ecosystem and economic services Human activities threaten biodiversity and disrupt ecological and economic services provided by aquatic systems We can sustain aquatic biodiversity o Establish protected sanctuaries, manage coastal development, reduce water pollution, and prevent overfishing ▯ ▯ CHAPTER 12/13 Water resources ▯ Case Study Colorado river 2,300 km (1400 miles) 7 U.S. states + Mexico 14 dams and reservoirs Water mostly from Rocky Mountain snowmelt Supplies water/electricity for ~30 million people Los Angeles (2), Phoenix (6), San Diego (8), Las Vegas (30), Tucson (33) Irrigation of crops ▯ Issues: Very little water reaching Gulf of California The southwest recently has severe droughts ▯ Will we have enough water Using available freshwater unsustainably o wasting it o underpricing it o polluting it (next class) Domestic use in USA ≈ 100 gal/person/day ▯ Surface Water Lakes, rivers, streams Surface runoff Watershed (drainage) basin ▯ Groundwater Water beneath Earth’s surface – did not o evaporate o flow into rivers o get taken up by organisms Plays key roles in o hydrologic cycle o in meeting human needs 20% of all freshwater o but not all readily available Groundwater contained in aquifers ▯ Using increasing amounts of worlds reliable runoff Reliable runoff o 2/3 of surface runoff – lost by seasonal floods o Rely on remaining 1/3 Worldwide average uses o Agriculture: 70% (increased by green revolution) o Industrial use: 20% o Domestic: 10% ▯ Uses: Consumptive uses (water not returned) o most agricultural use, some industrial and domestic uses Non-consumptive uses o hydroelectric, some industrial and residential uses Virtual water o Water used to produce food and other products ▯ Freshwater Shortages will grow Main factors that cause scarcity: o Dry climates o Drought o Too many people using water o Wasteful use of water U.N. 2010 study o By 2025, 3 billion people will lack access to clean water Freshwater Resources in USA Enough renewable freshwater, but o unevenly distributed o polluted What are effects of o Drought o Floods o Pollution ▯ Ways to Increase Freshwater Supplies Withdrawing groundwater Building dams and reservoirs (capturing more runoff) Transporting surface water Converting saltwater to freshwater Water conservation ▯ Withdrawing groundwater Provides drinking water for ½ world Most aquifers are renewable o unless water is contaminated or removed Withdrawn faster than replenished in some areas (not sustainable) o water tables falling o primarily from crop irrigation ▯ Overpumping: Harmful Effects Limits future food production (not sustainable) Effect on surface water o dry streams, ponds, loss of wetlands Land subsidence o Mexico City o Permanent loss of aquifer Groundwater overdrafts near coastal regions o Contamination of groundwater with saltwater in NJ: South River, Cape May ▯ Overpumping the Ogallala Ogallala aquifer – largest known aquifer o Irrigates Great Plains (breadbasket) o Very slow recharge o Water table dropping Water pumped 10-40 times faster than recharge o Government subsidies to continue farming deplete the aquifer further o Biodiversity threatened in some areas ▯ ***SLIDE 26 ▯ Deep aquifers might be tapped May contain enough water to provide for billions of people for centuries Major concerns o Nonrenewable o Little is known about geological and ecological impacts of pumping deep aquifers o Some flow beneath more than one country o Costs of tapping are unknown, could be high ▯ Dams and reservoirs Provide benefits but create problems Main goal of a dam and reservoir system o Capture and store runoff Expands usable surface water resources o Release runoff as needed to: Control flooding Generate electricity Supply irrigation water Recreation (reservoirs) ▯ Other negative effects Dams can damage estuaries o only small amounts of Colorado River water reach Gulf of California o threatens species in river and estuary Current river withdrawals o not sustainable ▯ Water Transfers Can greatly increase water supply in some areas o China, South-North Water Diversion Project 6 trillion gallons of water Can also disrupt ecosystems Water loss through evaporation, leakage ▯ Mono Lake, CA Water diversions Lake receded Tufa formations ▯ Aral Sea Dry central Asia Large-scale water transfers led to: o Wetland destruction o Desertification o Greatly increased salinity o Fish extinctions, decline of fishing o Wind-blown salt Depositing on glaciers in the Himalayas o Altered local climate Hot dry summers; cold winters Desalination Convert salt (ocean) water to freshwater o Distillation – evaporate water, recondense leaves salts behind o Reverse osmosis filtration – use high pressure, through membrane High cost (energy intensive) Waste brine must be disposed of >15,000 plants in 125 countries o Cape May, NJ (for groundwater) ▯ Water Conservation Water that is saved is available for other uses ▯ How can we use freshwater more sustainably Cut water waste Raise water prices Protect aquifers,forests and other ecosystems that store and release freshwater ▯ Reducing Freshwater Losses 50-70% of water is wasted Cost of water to users is low Subsidies mask true cost Raising prices hurts lower-income farmers and city dwellers o Solution: establish lifeline rates ▯ Irrigation inefficiency Agriculture is 87% of worlds consumptive use of water(lost in leaks and evaporation) ▯ Irrigation methods Gravity flow o Efficiency 60% and 8-% with surge valves o Water usually comes from aqueduct or a nearby river Drip irrigation o Efficiency 90-95% o Above- or below- ground pipes or tubes deliver water to individual plant roots Center pivot o Efficiency 80% with low pressure sprinkler and 90-95% with LEPA sprinkler o Water usually pumped from underground and sprayed from mobile boom with sprinklers ▯ Reducing freshwater use in industry and homes Recycle water in industry Fix leaks in plumbing systems Use water-thrifty landscaping: xeriscaping Use gray water; re-use wastewater Use meters, raise water prices Use water saving appliances, low flow toilets, showerheads ▯ Flooding Human activities make floods worse o Levees can break or be overtopped o Paving and development increase runoff o Removal of water-absorbing vegetation o Draining wetlands and building on them o Rising sea levels from global warming means more coastal flooding ▯ We can lessen threat of flooding by: o Protecting more wetlands and natural vegetation in watersheds o Not building in areas subject to frequent flooding Floodplains o Highly productive wetlands o Provide natural flood and erosion control o Maintain high water quality o Recharge groundwater o Fertile soils o Nearby rivers for use and recreation o Flatlands for urbanization and farming ▯ Reducing Flood damage Prevention o Preserve forests on watersheds o Preserve and o CHAPTER 16 Treatment sytems: potable water Sanitation ▯ Waterbourne Diseases: Routes of infection Ingestion – most important o drink o food preparation o fecal-oral route (water contaminated with feces) Contact o Washing, swimming, wading, splash o Schistosomiasis (flatworm; fecal contamination) Inhalation ▯ Schistosomiasis (Bilharziasis) Debilitating tropical disease - 200,000,000 people Caused by a flatworm (fluke) Standing water ▯ Cercarial Dermatitis(swimmers itch) ▯ Contact Washing, swimming, wading, splash Schistosomiasis o flatworm; fecal contamination Swimmer’s Itch o bird schistosomes Primary Amebic Meningoencephalitis o Naegleria/Acanthamoeba ▯ Waterbourne diesses: routes of infection Ingestion – most important o drink o food preparation o fecal-oral route (water contaminated with feces) Contact o Schistosomiasis o Swimmer’s itch o Primary Amebic Meningoencephalitis Inhalation o Legionnaires’ Disease (bacteria – “natural”) 1976 American Legion Convention, Philadelphia, 26 deaths Legionella death in Edison, NJ, motel September, 2008 - St Peters Hospital, New Brunswick ▯ Fecal Oral Route(sewage to river to other towns water) Historic (and Present) Concerns o Cholera o Typhoid Fever o Hepatitis A (virus) o Salmonellosis o Bacterial Dysentery (Shigellosis) o Amoebic Dysentery (Amoebiasis) ▯ Broad street pump London, 1854,Cholera outbreak,Dr. John Snow,First known epidemiol. Study,Red (added) dots – pumps,Black marks – cholera deaths Public Health measure - removed pump handle ▯ Snow’s second Study Two competing private water suppliers o Southwark and Vauxhall Company o Lambeth Company Water from Thames, untreated o SVC got water from in London (polluted) o LC got water from upstream of London (clean) Cholera death rate o per 1000 houses served o SVC: 31.5 o LC: 3.7 ▯ More recent outbreaks Campylobacter o 1978, Bennington, VT o 2000 sick out of 10,000 Giardia (amoeba) o cysts o hikers Cryptosporidium (sporozoan protozoa) o oocysts o Milwaukee, WI, 1993 – 400,000 sick, 100 deaths Sydney, Australia, 1999 – threatened Olympics o Giardia and Cryptosporidium ▯ Breaking the Chain Sick people excrete large numbers of pathogens. Poor sanitation allows pathogens into water. Inadequate water treatment does not remove all of the pathogens. Contaminated water makes many people sick. Sick people excrete large numbers … ▯ Safe Drinking Water Act Passed 1974 o major amendments, 1986 Public water systems o 15 service connections or 25 people/day o for ≥ 60 days/yr National Interim Primary Drinking Water Standards o 8 metals o 6 pesticides o nitrate, fluoride o radiological o microbiological Maximum Contaminant Levels (MCLs) and MCL Goals o health-based Secondary MCLs o aesthetic, economic ▯ MCLs Microorganisms Disinfectants Disinfection Byproducts Inorganic Chemicals Organic Chemicals Radionuclides ▯ Disinfection Chlorine most common o problem – chlorinated organics Ozone also becoming common o problems some chlorinated organics no residual Ultraviolet light (uv) o works for Cryptosporidium ▯ Home “Filters” Consists of o small filter o activated carbon adsorption Effectiveness? o pesticides/PCBs - good o trihalomethanes, solvents - some o lead - moderate o taste and odor - good chlorine chlorophenols o microbes - no ▯ Is Bottled Water a Good Option The U.S. has some of the world’s cleanest drinking water Bottled water can be useful but: o expensive o less regulated than tap water o can create environmental problems 67,000,000 plastic bottles discarded daily energy for manufacturing and transport release of toxic chemicals BPA and other chemicals in water? ▯ Cost About $1 for o Pint bottle o Gallon bottle o Approx. 200 gallons of tap water ▯ ▯ ▯ ▯ ▯ ▯ ▯
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