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Risk, Toxicology and Human Health AP Environmental Science Chapter 8.

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1 Risk, Toxicology and Human Health AP Environmental Science Chapter 8

2 Human Health Health is a state of complete physical, mental, social and spiritual well-being and not merely the absence of disease or infirmity (disability)Health is a state of complete physical, mental, social and spiritual well-being and not merely the absence of disease or infirmity (disability)or The ability to lead a socially and economically productive lifeThe ability to lead a socially and economically productive life

3 Holistic Concept of Health This concept recognizes the strength of social, economic, personal freedom and environmental influences on healthThis concept recognizes the strength of social, economic, personal freedom and environmental influences on health DeterminantsDeterminants –Heredity –Health and family welfare services –Environment –Life-style –Socio-economic conditions

4 Disease Disease results from the complex interaction between man, an agent and the environmentDisease results from the complex interaction between man, an agent and the environment Ecological point of view – “maladjustment of the human organism to the environment”Ecological point of view – “maladjustment of the human organism to the environment”

5 Epidemilogical Triad Any Environment Vector (how infected: water, pollution, insect, contact) Vector (how infected: water, pollution, insect, contact) Pathogen: (Virus/bacteria) (Organism) Agent Host

6 Key Concepts Types of HazardsTypes of Hazards Exposure AssessmentExposure Assessment Risk estimation, management, and reductionRisk estimation, management, and reduction

7 Types of Hazards Biological HazardsBiological Hazards – –These are living organisms or their products that are harmful to humans

8 Biological Hazards Water-borne diseasesWater-borne diseases –Transmitted in drinking water Disease organisms shed into water in fecesDisease organisms shed into water in feces Can produce illness in those who consume untreated, contaminated waterCan produce illness in those who consume untreated, contaminated water

9 Biological Hazards Water-borne diseasesWater-borne diseases –municipal water treatment facilities are usually able to purify water removing these agents by filtrationremoving these agents by filtration killing them by disinfectionkilling them by disinfection

10 Biological Hazards Water-borne diseasesWater-borne diseases –Examples Polio virusPolio virus Hepatitis A virusHepatitis A virus SalmonellaSalmonella ShigellaShigella CholeraCholera Amoebic dysenteryAmoebic dysentery GiardiaGiardia CryptosporidiumCryptosporidium

11 E. coli outbreak in Walkerton In May 2000 the small community of Walkerton, Ontario was laid waste by a toxic strain of E. coli:0157.In May 2000 the small community of Walkerton, Ontario was laid waste by a toxic strain of E. coli:0157. –The contamination came from the public water supply. –Six people died in the first week including a two year old daughter of a local medical doctor. –Four new cases surfaced in late July, all very young children. –Over a thousand innocent people were infected. bss.sfsu.edu/ehines/geog600/ Freshwater%20and%20ocean%20Pollution.ppt

12 Waterborne Bacteria Escherichia coli Vibrio sp. Barbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio Disease symptoms usually are explosive emissions from either end of the digestive tractDisease symptoms usually are explosive emissions from either end of the digestive tract

13 Waterborne Protozoans Giardia sp.* *P. Darben Barbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio Disease symptoms are usually explosive emissions from either end of the digestive tractDisease symptoms are usually explosive emissions from either end of the digestive tract

14 Waterborne Human Viruses Hepatitis A virusHepatitis E virus Norwalk virus*Rotavirus* *F. Williams Barbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio

15 Indicator Tests Total coliform [Endo agar] Fecal coliform [m-FC agar] Fecal streptococci [M-enterococcus] Prescott et al., Microbiology Barbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio

16 Case Study on Eradicating Dracunculiasis Water and Sanitation – Critical Elements in Development - Mike Lee Hayward Water and Sanitation – Critical Elements in Development - Mike Lee Hayward

17 Guinea Worm Disease People have suffered from Guinea Worms for centuries – the “fiery serpent” was mentioned in the biblePeople have suffered from Guinea Worms for centuries – the “fiery serpent” was mentioned in the bible People are infected by drinking water that contain the larvae in a tiny freshwater crustacean called CyclopsPeople are infected by drinking water that contain the larvae in a tiny freshwater crustacean called Cyclops A year later, larvae mature into 3 feet worms that emerge through skin blistersA year later, larvae mature into 3 feet worms that emerge through skin blisters This is such a painful process that men and women can’t work, children can’t attend schoolThis is such a painful process that men and women can’t work, children can’t attend school Water and Sanitation – Critical Elements in Development - Mike Lee Hayward

18 The Guinea Worm grows down the leg and its sex organs appear at the ankle or on the foot usually, bursting when it senses water, releasing ova. Water and Sanitation – Critical Elements in Development - Mike Lee Hayward

19 No vaccine for Guinea worm is available.No vaccine for Guinea worm is available. People do not seem to build up any resistance and the disease can be reinfected over and over.People do not seem to build up any resistance and the disease can be reinfected over and over. No research is being conducted for any vaccine or cure.No research is being conducted for any vaccine or cure. Worms are removed slowly each day by winding around a stick.Worms are removed slowly each day by winding around a stick. Water and Sanitation – Critical Elements in Development - Mike Lee Hayward

20 Biological Hazards Food–borne diseasesFood–borne diseases –To protect against food-borne disease local health departmentslocal health departments –inspect »food service establishments (restaurants) »retail food outlets (supermarkets) »processing plants –verify that food »stored »handled properly

21 Biological Hazards Food-borne diseasesFood-borne diseases –Examples Salmonella, serotype enteritidisSalmonella, serotype enteritidis –Eggs or undercooked chicken –Reptiles Escherichia coli 0157:H7Escherichia coli 0157:H7 –Spinach –Undercooked meat »Jack in the Box

22 Biological Hazards Vector-borne diseasesVector-borne diseases –Transmitted by insects, other arthropods and other animals including humans –Improper environmental management can cause vector- borne disease outbreaks

23 Biological Hazards Vector-borne diseasesVector-borne diseases –Examples MosquitoesMosquitoes –Malaria –St. Louis encephalitis –La Crosse encephalitis –West Nile Virus FleasFleas –Bubonic plague – Murine typhus

24 3. Mosquito injects Plasmodium sporozoites into human host 2. Plasmodium develops in mosquito 1. Female mosquito bites infected human, ingesting blood that contains Plasmodium gametocytes 4. Parasite invades blood cells, causing malaria and making infected person a new reservoir Anopheles mosquito (vector) in aquatic breeding area eggs larva pupa adult

25 Fig , p. 409 Areas in which malaria has disappeared, been eradicated, or never existed Areas with limited risk Areas where malaria Transmission occurs

26 Biological Hazards Vector-borne diseasesVector-borne diseases –Examples HumansHumans –SARS –Tuberculosis –HIV –Gonorrhea –Syphilis –Chlamydia –Etc.

27 Deaths per 100,000 people < Tuberculosis epidemic, kills about 2 million people a year.

28 Biological Hazards Vector-borne diseasesVector-borne diseases –Greatest viral health threat to human life are virulent flu strain 1918 Swine Flu1918 Swine Flu –Killed 20 – 30 million Today flu killsToday flu kills –1 million per year worldwide –20,000 in the U.S.

29 Spread of Diseases Increases international travelIncreases international travel Migration to urban areasMigration to urban areas Migration to uninhabited areas and deforestationMigration to uninhabited areas and deforestation Hunger and malnutritionHunger and malnutrition Increased rice cultivationIncreased rice cultivation Global warmingGlobal warming Hurricanes and high windsHurricanes and high winds Accidental introduction of insect vectorsAccidental introduction of insect vectors FloodingFlooding

30 Reducing Spread of Diseases Increase research on tropical diseases and vaccinesIncrease research on tropical diseases and vaccines Reduce poverty and malnutritionReduce poverty and malnutrition Improve drinking waterImprove drinking water Reduce unnecessary use of antibioticsReduce unnecessary use of antibiotics Educate people on taking antibioticsEducate people on taking antibiotics Reduce antibiotic use in livestockReduce antibiotic use in livestock Careful hand washing by medical staffCareful hand washing by medical staff Slow global warmingSlow global warming Increase preventative health careIncrease preventative health care

31 Types of Hazards Biological HazardsBiological Hazards Chemical HazardsChemical Hazards –Harmful chemicals in the air, water, soil, and food –Most human have small amounts of about 500 synthetic chemicals

32 Hazardous Chemicals Methods to determine threatMethods to determine threat –Case Studies MD with actual patient recordMD with actual patient record

33 Case Studies In-depth, longitudinal examination of a single instance or event 18 year- old, 5-8, 145 pound healthy male 18 year- old, 5-8, 145 pound healthy male –Circumstances Collapsed on 2/4/07 at 4:30 PM while in the kitchenCollapsed on 2/4/07 at 4:30 PM while in the kitchen Ambulance rushed him to VHH where he died of cardiac arrest a little after 5 PMAmbulance rushed him to VHH where he died of cardiac arrest a little after 5 PM Toxicology results – negativeToxicology results – negative Brain AneurysmBrain Aneurysm –History Broken neck at age 7Broken neck at age 7 Hit by car June of 2005Hit by car June of 2005

34 Pesticide Effects odes/frogs-the-thin-green-line/video- agricultures-effect-on-frogs/4848/http://www.pbs.org/wnet/nature/epis odes/frogs-the-thin-green-line/video- agricultures-effect-on-frogs/4848/http://www.pbs.org/wnet/nature/epis odes/frogs-the-thin-green-line/video- agricultures-effect-on-frogs/4848/http://www.pbs.org/wnet/nature/epis odes/frogs-the-thin-green-line/video- agricultures-effect-on-frogs/4848/ The effect of atrazine on amphibians and eventually humans.The effect of atrazine on amphibians and eventually humans.

35 Hazardous Chemicals Methods to determine threatMethods to determine threat –Case Studies MD with actual patient recordMD with actual patient record –Epidemiology Health officials investigating case studiesHealth officials investigating case studies

36 Epidemiology Study of the distribution and causes of disease in populationsStudy of the distribution and causes of disease in populations –how many people or animals have a disease –the outcome of the disease (recovery, death, disability, etc.) –the factors that influence the distribution and outcome of the disease

37 Epidemiology of Rabies In 2001, 49 states, the District of Columbia, and Puerto Rico reported 7,437 cases of rabies in animals and no cases in humans to CDCIn 2001, 49 states, the District of Columbia, and Puerto Rico reported 7,437 cases of rabies in animals and no cases in humans to CDC The total number of reported cases increased by 0.92% from those reported in 2000 (7,369 cases)The total number of reported cases increased by 0.92% from those reported in 2000 (7,369 cases)

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39 Epidemiology of Rabies Wild animals accounted for 93% of reported cases of rabies in 2001Wild animals accounted for 93% of reported cases of rabies in 2001 Outbreaks of rabies infections in terrestrial mammals like raccoons, skunks, foxes, and coyotes are found in broad geographic regions across the United StatesOutbreaks of rabies infections in terrestrial mammals like raccoons, skunks, foxes, and coyotes are found in broad geographic regions across the United States

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45 Epidemiology of Rabies Geographic boundaries of currently recognized reservoirs for rabies in terrestrial mammals

46 Epidemiology of Rabies Domestic species accounted for 6.8% of all rabid animals reported in the United States in 2001Domestic species accounted for 6.8% of all rabid animals reported in the United States in 2001 The number of reported rabid domestic animals decreased 2.4% from the 509 cases reported in 2000 to 497 in 2001The number of reported rabid domestic animals decreased 2.4% from the 509 cases reported in 2000 to 497 in 2001

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48 Epidemiology of Rabies Successful vaccination programs that began in the 1940s caused a decline in dog rabies in this countrySuccessful vaccination programs that began in the 1940s caused a decline in dog rabies in this country But, as the number of cases of rabies in dogs decreased, rabies in wild animals increasedBut, as the number of cases of rabies in dogs decreased, rabies in wild animals increased

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50 Epidemiology of Rabies Human rabies Declined from 100 or more each year to an average of 1 or 2 each yearDeclined from 100 or more each year to an average of 1 or 2 each year ProgramsPrograms –Animal control and vaccination programs begun in the 1940's have practically eliminated domestic dogs as reservoirs of rabies in the United States –Effective human rabies vaccines and immunolglobins have been developed

51 Hazardous Chemicals Methods to determine threatMethods to determine threat –Case Studies MD with actual patient recordMD with actual patient record –Epidemiology Health officials investigating case studiesHealth officials investigating case studies –Laboratory Investigations Substances that are fatal to more than 50% of the test animals (LD50) at a given concentrationSubstances that are fatal to more than 50% of the test animals (LD50) at a given concentration

52 Laboratory Investigations Animal StudiesAnimal Studies –Populations of lab animals usually rodents –Measured doses under controlled conditions –Takes two to five years –Costs $200,000 to $2,000,000 per substance Newer methodsNewer methods

53 Laboratory Investigations Newer methodsNewer methods –Bacteria –Cell and tissue culture Appropriate tissueAppropriate tissue Stem cellsStem cells –Chicken egg membrane

54 Fig. 16.5, p Percentage of population killed by a given dose Dose (hypothetical units) LD 50

55 Why?

56 Fig. 16.3, p. 398 Very Sensitive Majority of population low Sensitivity Dose (hypothetical units) Number of individuals affected

57 Laboratory Investigations Validity ChallengedValidity Challenged –Human physiology is different –Different species react different to same toxins Mice die with aspirinMice die with aspirin –Species can be selected depending on physiological area Pigs circulatory very similar to humansPigs circulatory very similar to humans

58 Toxicity ToxicityLD 50 Lethal DoseExamples Super < 0.01less than 1 drop dioxin, botulism mushrooms Extreme <5less than 7 drops heroin, nicotine Very drops to 1 tsp. morphine, codeine Toxic tsp. DDT, H 2 SO 4, Caffeine Moderate 500-5K1 oz.-1 pt. aspirin, wood alcohol Slightly5K-15K 1 pt. ethyl alcohol, soaps Non-Toxic>15K>1qt. water, table sugar (LD50 measured in mg/kg of body weight)

59 Hazardous Chemicals Why so little is known of toxicityWhy so little is known of toxicity –Only 10% of at least 75,000 commercial chemicals have been screened – ~ 2% determined to be carcinogen, teratogen or mutagen – >1000 new synthetic chemicals added per year – >99.5% of US commercial chemicals are NOT regulated

60 Dose-Response Curves Nonlinear dose-response Linear dose-response Threshold level Effect Dose Nonlinear dose-response Linear dose-response No threshold Effect Threshold Dose Fig. 16.6, p. 401

61 Chemical Hazards Hazardous ChemicalsHazardous Chemicals MutagensMutagens –Chemicals (and ionizing radiation) that changes DNA or RNA in cells

62 Chemical Hazards Hazardous ChemicalsHazardous Chemicals MutagensMutagens –Teratogens Chemicals, radiation, or viruses that cause birth defects while the human embryo is gestating, especially in the first three monthsChemicals, radiation, or viruses that cause birth defects while the human embryo is gestating, especially in the first three months

63 Teratogens Examples:Examples: –Rubella –Mercury in water –Fetal alcohol syndrome –Crack babies –Methamphetamine

64 Ocean Pollution: Mercury and Minamata Disease Mercury has many industrial uses but is extremely toxicMercury has many industrial uses but is extremely toxic A chemical plant released large quantities of mercury into Minamata Bay, JapanA chemical plant released large quantities of mercury into Minamata Bay, Japan Residents who ate highly contaminated fish suffered neurological disease and birth disordersResidents who ate highly contaminated fish suffered neurological disease and birth disorders bss.sfsu.edu/ehines/geog600/ Freshwater%20and%20ocean%20Pollution.ppt

65 Chemical Hazards Hazardous ChemicalsHazardous Chemicals MutagensMutagens –Teratogens –Carcinogens

66 Carcinogens Causative agentsCausative agents –Chemicals – Tobacco smoke –Radiation – Pilots and cosmic radiation –Viruses – HPV and cervical cancer Texas Governor mandated vaccination of all School females with Merck’s HPV vaccineTexas Governor mandated vaccination of all School females with Merck’s HPV vaccine Promote growth of malignant tumorsPromote growth of malignant tumors

67 Carcinogens Latent PeriodLatent Period –Long time lapse between exposure SmokingSmoking EatingEating Lifestyle choices – laying in sunLifestyle choices – laying in sun –Symptoms Lung cancerLung cancer AIDSAIDS MelanomaMelanoma

68 Chemical Hazards Hazardous ChemicalsHazardous Chemicals MutagensMutagens –Teratogens –Carcinogens Hormonally Active AgentsHormonally Active Agents

69 Hormonally Active Agents Estrogen-like chemicalsEstrogen-like chemicals –Alter development Early pubescenceEarly pubescence Low sperm countLow sperm count Runts in wildlifeRunts in wildlife –Examples of hormone mimics PCBPCB Organophosphates pesticidesOrganophosphates pesticides Industrial solventsIndustrial solvents

70 Hormone Receptor Cell Normal Hormone Process Normal Mimic Hormone Blocker Estrogen- like chemicalAntiandrogen chemical

71 Hormone Receptor Cell Normal Hormone Process Normal Mimic Hormone Blocker Estrogen- like chemicalAntiandrogen chemical

72 Hormone Receptor Cell Normal Hormone Process Normal Mimic Hormone Blocker Estrogen- like chemicalAntiandrogen chemical

73 Chemical Hazards Hazardous ChemicalsHazardous Chemicals MutagensMutagens –Teratogens –Carcinogens Hormonally Active AgentsHormonally Active Agents Precautionary PrinciplesPrecautionary Principles

74 Precautionary Principle Better safe than sorryBetter safe than sorry –Two scenarios Assume new chemicals guilty – Humans are not guinea pigsAssume new chemicals guilty – Humans are not guinea pigs Most Chemicals not toxic and too expensive to testMost Chemicals not toxic and too expensive to test

75 Precautionary Principle Better safe than sorryBetter safe than sorry –Two scenarios Assume new chemicals guilty – Humans are not guinea pigsAssume new chemicals guilty – Humans are not guinea pigs Most Chemicals not toxic and too expensive to testMost Chemicals not toxic and too expensive to test

76 Precautionary Principle BioaccumulationBioaccumulation –An increase in concentration of a chemicals in specific organs or tissues in organisms

77 Precautionary Principle BiomagnificationBiomagnification –Increase in concentration in organisms DDTDDT PCBPCB Slowly degradable, fat-soluble chemicalsSlowly degradable, fat-soluble chemicals –At successively higher trophic levels of food chains or in fatty tissue

78 DDT in fish-eating birds (ospreys) 25 ppm DDT in large fish (needle fish) 2 ppm DDT in small fish (minnows) 0.5 ppm DDT in zooplankton 0.04 ppm DDT in water ppm, Or 3 ppm

79 Types of Hazards Biological HazardsBiological Hazards Chemical HazardsChemical Hazards Physical HazardsPhysical Hazards – –Ionizing radiation, airborne particles, equipment design, fire, earthquake, volcanic eruptions, flood, tornadoes, and hurricanes

80 Physical Hazards Example: RadonExample: Radon –Source: Arises naturally from decomposition of uranium in the earthArises naturally from decomposition of uranium in the earth Occurs at dangerous levels in some buildings and homesOccurs at dangerous levels in some buildings and homes –Can cause lung cancer –Test kits available for under $20

81 Types of Hazards Biological HazardsBiological Hazards Chemical HazardsChemical Hazards Physical HazardsPhysical Hazards Cultural HazardsCultural Hazards –Sociological –Psychological

82 Cultural Hazards SociologicalSociological –result from living in a society where one experiences noise, lack of privacy and overcrowding Population growthPopulation growth –Beyond carrying capacity when environmental resources can support no further growth

83 Cultural Hazards PsychologicalPsychological –Environmental factors that produce psychological changes expressed as stress, depression, hysteria

84 Key Concepts Types of HazardsTypes of Hazards Exposure AssessmentExposure Assessment Methods of toxicologyMethods of toxicology Risk estimation, management, and reductionRisk estimation, management, and reduction

85 Exposure Assessment 4 important considerations 1. Route 2. Magnitude 3. Duration of exposure 4. Frequency

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87 Key Concepts Types of HazardsTypes of Hazards Exposure AssessmentExposure Assessment Risk estimation, management, and reductionRisk estimation, management, and reduction

88 Risk Analysis How can risks be estimated, managed and reduced?How can risks be estimated, managed and reduced?

89 Risk Analysis involves… Identifying hazardsIdentifying hazards Evaluate risksEvaluate risks Ranking risksRanking risks Determining options and deciding course of actionDetermining options and deciding course of action Informing policy makers and public about risksInforming policy makers and public about risks

90 Risk Analysis  Risk The possibility of suffering harm from a hazard that can cause injury, disease, economic loss, or environmental damage. Risk is Expressed in terms of probability, a mathematical statement about How likely it is that some event or effect will occur. Risk=Exposure X Harm  Risk The possibility of suffering harm from a hazard that can cause injury, disease, economic loss, or environmental damage. Risk is Expressed in terms of probability, a mathematical statement about How likely it is that some event or effect will occur. Risk=Exposure X Harm Fig. 16.2, p. 297

91 Fig , p. 412 Risk probability Risk assessment Risk severity Is the risk acceptable? Acceptable if benefits outweigh costs Cost–benefitExpressed preferences Acceptable if people agree to accept the risks Natural standards Acceptable if risk is not greater than those created by natural hazard Revealed preferences Acceptable if risk is not greater than those currently tolerated

92 Risk Analysis Usefulness Organize and analyze available scientific informationOrganize and analyze available scientific information Identify significant hazardsIdentify significant hazards Focus on areas that warrant more researchFocus on areas that warrant more research

93 Risk Analysis Usefulness Help regulators decide how money for reducing risks should be allocated,Help regulators decide how money for reducing risks should be allocated, Stimulate people to make more informed decisions about health and environmental goals and priorities.Stimulate people to make more informed decisions about health and environmental goals and priorities.

94 Risk Perception If chance of death is 1 in 100,000 people are not likely to be worried or change behavior.If chance of death is 1 in 100,000 people are not likely to be worried or change behavior. Most of us do a poor job of assessing relative risks from hazards around us.Most of us do a poor job of assessing relative risks from hazards around us.

95 Risk Perception Most people deny the high-risk activities they voluntarily enjoyMost people deny the high-risk activities they voluntarily enjoy –Motorcycles (1 in 50) –Smoking (1 in 300 pack a day smokers, by 65) –Hang-gliding (1 in 2,500)

96 What do you think are the highest risk hazards in the U.S.?

97 Fig. 16.1, p. 396 DeathsCause of Death Tobacco use431,000 Alcohol use Accidents Pneumonia and Influenza Suicides Homicides Hard drug use AIDS 150,000 95,600 (42,000 auto) 84,400 30,500 19,000 15,000 14,000

98 Fig , p. 414 Hazard Shortens average life span in the United States by 7-10 years Poverty Born male Smoking Overweight (35%) Unmarried Overweight (15%) Spouse smoking Driving Air pollution Alcohol Drug abuse AIDS Drowning Pesticides Fire Natural radiation Medical X rays Oral contraceptives Toxic waste Flying Hurricanes, tornadoes Living lifetime near nuclear plant 7.5 years 6 years 5 years 2 years 1 year 7 months 5 months 4 months 3 months 1 month 8 days 5 days 4 days 1 day 10 hours

99 Yet some of these people are terrified of dying from… Commercial plane crashCommercial plane crash –1 in 4.6 million Train crashTrain crash –1 in 20 million SnakebiteSnakebite –1 in 36 million Shark attackShark attack –1 in 300 million

100 Each year 99.1% of the people on Earth do not die. Average life expectancy continues to increase.

101 Bibliography 1. 1.Humayun, Ayesha, “Introductory Lecture on Environment and Bent Flyvbjerg, “Five Misunderstandings About Case-Study Research,” Qualitative Inquiry, Volume 12, Number 2, April Centers for Disease Control: National Center for Infectious Disease, “Epidemiology of http://bss.sfsu.edu/ehines/geog600/Freshwater%20and%20ocean%20Pollution.ppthttp://bss.sfsu.edu/ehines/geog600/Freshwater%20and%20ocean%20Pollution.ppt 5. 5.Barbara E. Moore, Ph.D., Department of Biology, University of Texas at San Issues I final.ppt Issues I final.ppt 6.Water and Sanitation – Critical Elements in Development - Mike Lee Hayward Water and Sanitation – Critical Elements in Development - Mike Lee HaywardWater and Sanitation – Critical Elements in Development - Mike Lee Hayward


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