biol270chap_15_17 - Chapter 15 Environmental Hazards and...

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Unformatted text preview: Chapter 15 Environmental Hazards and Human Health Environmental Hazards and Human Environmental Hazards and Human Health Links between human health and the environment Pathways of risk Risk assessment Some Definitions Some Definitions Environment: combination of physical, chemical, and biological factors Hazard: anything that can cause injury, death, disease, damage to personal/public property, or deterioration or destruction of environmental components Risk: probability of suffering a loss as a result of exposure to a hazard Two types of risk Two types of risk Objective risk: The probability of suffering a injury or loss as a result of an event Perceived risk: Human risk perception: A subjective judgment about risk and the probability and severity of an outcome Heuristic models: the likelihood of an event is based on how quickly it comes to mind Human wildlife interactions and Human wildlife interactions and human risk perception Heuristic models: the likelihood of an event is based on how quickly it comes to mind Human wildlife interactions Human wildlife interactions Based on human risk perception Heuristic models Cognitive theories Affective theories Cultural theories Injury/death Objective Risk Interaction outcome Outreach Non/neutral Non/neutral Human Risk Perception Injury/death Injury/death Objective Risk Interaction outcome Outreach Non/neutral Non/neutral Human Risk Perception Injury/death Injury/death Social limits of outreach Objective Risk Interaction outcome Non/neutral Non/neutral Human Risk Perception Injury/death Injury/death Interaction outcome Increase Public outreach and education Social limits of outreach Objective Risk Reduce encounter probability Non/neutral Non/neutral Human Risk Perception Injury/death Avian Flu Avian Flu Smoking related deaths Smoking related deaths Morbidity: incidence of disease in a population Mortality: incidence of death in a population Epidemiology: study of presence, distribution, and control of disease in a population. The Picture of Health: Some The Picture of Health: Some Terms Causes of Human Mortality Causes of Human Mortality Environmental Hazards Environmental Hazards Cultural Biological Physical Chemical Cultural Hazards Cultural Hazards Consequence of choice Risky behavior To what cultural hazards do college students commonly subject themselves? Deaths from Various Cultural Deaths from Various Cultural Hazards in the United States Biological Hazards Biological Hazards Pathogenic bacteria Fungi Viruses Protozoans Worms Global Map of Tuberculosis, 2001 Global Map of Tuberculosis, 2001 Infectious Diseases Infectious Diseases More prevalent in but not exclusive to developing countries Contamination of food and water Ideal climates for transmission of vector­ borne diseases like malaria Lack of resources for sanitation Lack of education Physical Hazards Physical Hazards Natural disasters, e.g., tornadoes, floods, hurricanes, and wildfires Avoidance of risk important in prevention, e.g., building homes in flood plains, and living on the coast. Climate change: consequences of elevated green house gases Tsunami Damage Tsunami Damage Hurricane Damage Hurricane Damage Earthquake Damage Earthquake Damage Tornado Damage Tornado Damage Chemical Hazards Chemical Hazards Result of industrialization Exposure through ingestion, inhalation, absorption through skin May be direct use or accidental Many chemicals are toxic at low levels Chemical Hazards Chemical Hazards 74 chemicals are known to be carcinogenic (Table 15­2) Environmental carcinogens initiate mutations in DNA; several mutations lead to a malignancy A Paper Mill A Paper Mill Tannery Tannery Oil Refinery Oil Refinery A Plastics Factory A Plastics Factory Pathways of Risk Pathways of Risk The risks of being poor Risk and infectious diseases Toxic risk pathways Disaster risk The Risk of Being Poor The Risk of Being Poor One major pathway for hazards is poverty. No money for health insurance. Higher probability of exposure to environmental hazards. Environmental Health Environmental Health Factors contributing to the environmental health of a nation include: Education Nutrition Commitment from government More equitable distribution of wealth Risk and Infectious Diseases Risk and Infectious Diseases One major pathway of risk is contamination of food and water Inadequate hygiene Inferior sewage treatment Toxic Risk Pathways Toxic Risk Pathways Categories of impact of airborne pollutants Chronic: effect takes place over a period of years Acute: life­threatening reaction within a period of hours or days Carcinogenic: pollutants initiate cellular change leading to cancer Hazardous fumes from home products Well­insulated buildings Long exposure to indoor air Indoor Air Pollution: Developed Indoor Air Pollution: Developed Countries Risk Assessment Risk Assessment The process of evaluating the risks associated with a particular hazard before taking some action in which the particular hazard is present. Risk Management Risk Management Usually involves: Cost­benefit analysis: Decisions are based on the total expected costs relative to the total expected benefits. Benefits > costs = YES; costs > benefits = NO Risk­benefit analysis: Decisions are based ob objective risk relative to the benefits. *Individuals can be lost in averaging values, or high benefit outcome. Risk Assessment/Management Risk Assessment/Management Some suggest we use distributive justice rather than procedural justice to in making decisions about risk Ethical process of making certain that everyone receives proper consideration Should reduce environmental racism/injustice Risk Assessment/Management Risk Assessment/Management Not a perfect system Precautionary principle Lack of certainty should not be used as a reason for preventing environmental degradation/hazards Chapter 17 Water Pollution and Its Prevention Dead Zone in the Gulf of Mexico Dead Zone in the Gulf of Mexico Photosynthesis in aquatic systems Photosynthesis in aquatic systems Benthic plants Emergent vegetation Submerged aquatic vegetation (SAV’s) Phytoplankton Green filamentous and single cell Bluegreen single cell Diatoms single cell Oligotrophic: nutrient­poor water Clear water Low productivity The Impacts of Nutrient The Impacts of Nutrient Enrichment Eutrophic: nutrient­rich water Turbid/cloudy water High productivity Eutrophication In Shallow Lakes Eutrophication In Shallow Lakes and Ponds Oligotrophic As nutrients are added from pollution, an oligotrophic condition rapidly becomes eutrophic. Eutrophic Natural eutrophication Natural and Cultural Natural and Cultural Eutrophication Cultural eutrophication aquatic succession occurs over several hundreds of years driven by human activities occurs rapidly Water pollution Waste water management and treatment Eutrophication Public policy Water Pollution and Its Water Pollution and Its Prevention Pollution Pollution Pollution: “the presence of a substance in the environment that because of its chemical composition or quantity prevents the functioning of natural processes and produces undesirable environmental and health effects.” Categories of Pollution Categories of Pollution Pollution is almost always the by-product of something beneficial/useful Pollution Categories Pollution Categories Air Particulates Acid­forming compounds Photochemical smog CO2 CFC’s Pollution Categories Pollution Categories Water and land Nutrient oversupply Solid wastes Toxic chemicals Pesticides/herbicides Nuclear waste Water Pollution: Point and Water Pollution: Point and Nonpoint Sources Nonpoint source pollution: Pollution from diffuse sources (leading cause of water pollution in the US) Point source pollution: An identifiable localized source of pollution Pathogens: Disease­causing agents (Table 17.1) Organic Wastes: Can act as excessive nutrient loads and lead to eutrophication and dead zones Chemical: Water Pollution Types Water Pollution Types Inorganic chemicals Heavy metals, acids, road salts Organic chemicals Petroleum, pesticides, detergents Sediments: see below Nutrients: eutrophication (ecological effects e.g., trophic dynamics) and dead zones Eutrophication Increased turbidity Loss of hyporheic functions Refugia during disturbance Physical, chemical, and biological filtering. Effect of Sediments on Stream Effect of Sediments on Stream Ecology Wastewater Collection and Wastewater Collection and Treatment Systems Storm drains for collecting runoff from precipitation Sanitary sewers to receive all the wastewater from sinks, tubs, and toilets Development of Sewage Collection Development of Sewage Collection and Treatment Systems Through the 1970s sewage was discharged directly into waterways Clean Water Act of 1972 Septic Tank Treatment Aerobic digestion of solids in septic tank. Flow of liquids into drain field for evaporation, infiltration, or irrigation. ...
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