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Chapter 17 and 21 “All substances are poisons: there is none which is not a poison. The right dose differentiates a poison and a remedy." Paracelsus (1493-1541)

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Presentation on theme: "Chapter 17 and 21 “All substances are poisons: there is none which is not a poison. The right dose differentiates a poison and a remedy." Paracelsus (1493-1541)"— Presentation transcript:

1 Chapter 17 and 21 “All substances are poisons: there is none which is not a poison. The right dose differentiates a poison and a remedy." Paracelsus ( )

2 Risk: probability of suffering harm from a hazard that can cause injury, disease, death or economic loss or damage Risk assessment Risk management Biological, chemical, natural, cultural and lifestyle hazards

3 Biological Hazards Infectious disease (flu, malaria, TB) Transmissible disease (measles, HIV) Nontransmissible disease (cancer, asthma, diabetes, malnutrition) Major concerns include flu, AIDS (HIV), Hepatitis B, malaria and emergent diseases (west nile, Ebola) Eliminate through infectious disease prevention, education, vaccines, improving quality of life and decreasing malnutrition

4 Chemical Hazards Toxic chemical: can cause temporary or permanent harm or death to humans or animals Top 5 include: arsenic, lead, mercury, vinyl chloride (plastics) and PCBs Carcinogen: promotes cancer Arsenic, benzene, formaldehyde, gamma and UV radiation, PCBs, radon, tobacco smoke, vinyl chloride Mutagen: increases frequency of mutations Teratogen: cause harm or birth defects to fetus/embryo Alcohol, benzene, formaldehyde, lead, mercury, PCBs, phalates, thalidomide, vinyl chloride

5 Chemical Hazards Neurotoxins (disrupt nervous system—brain, spinal cord) PCBs, arsenic, lead, pesticides, methylmercury Endocrine disruptors (alter hormones and development) BPA, Aluminum, atrazine, DDT, PCBs, mercury, pthalates Immune system disruptors (limit immune response) Arsenic, methylmecury, dioxins

6 Evaluating Chemical Hazards Toxicity: measure of the harmfulness of the product Dose: amount ingested, inhaled, or absorbed Response: damage to health, may be acute or chronic Depends on age, genetic makeup, solubility of compound (water vs. oil) and persistence Dose-response Studies Tests on animals with measure doses of chemical Plot results of chemical tests to determine curve and lethal doses

7 LD 50 Lethal dose 50: Amount of chemical that kills 50% of a test population within 18 days. Varies depending on substance Determines if a new substance is more or less lethal than other chemicals used Usually tested on rats…then extrapolated to humans Gives values for acute toxicity Lower LD 50 = More toxic

8 The Dirty Dozen BPA Dioxins Pthalates PCBs Arsenic Benzene Formaldehyde Mercury Asbestos Lead Vinyl Chloride (PVC) Ethylene Glycol *Go to s.php and click on “Chemicals” at the top of the page. *Find your chemical on the list and answer the following questions… 1. Describe what the chemical is. What products/processes is it found in? 2. Where is the chemical located in the environment? How does it get there? How are humans exposed to it? 3. What are the health concerns?

9 Waste Management Solid waste: any unwanted or discarded material we produce that is not a liquid or a gas Industrial solid waste- produced by mines, farms and industry (40%) Municipal solid waste (MSW)- produced by homes and workplaces; ends up in landfills/incinerators (60%) Average 4.5 pounds per person per day! Hazardous toxic waste- threatens human health because it is poisonous, chemically reactive, corrosive or flammable

10 Waste Managing waste refers to controlling the environmental harm of waste, not decreasing its production Reducing waste is concerned with producing less waste and pollution (prevention) Recycling is reusing or repurposing materials instead of throwing them away

11 What do we throw away? Paper (31%) Food (13%) Yard waste (13%) Wood (7%) Rubber, Leather and Clothing (8%) Plastic (12%) Metal (8%) Glass (5%) Other (3%)

12 Recycling Importance… Decreases use of energy making products Decreases waste and pollution (amount into landfills) Increases jobs Saves $$$ Primary (closed-loop) recycling: materials recycled into new products of the same type (aluminum to aluminum) Secondary (open-loop) recycling: waste materials converted into different products (plastic to clothing)

13 Burning and Burying Waste Waste-to-Energy Incinerators (13%) Garbage and waste is burned, water is boiled and energy is created Produces high number of pollutants Sanitary Landfills (54%) Waste buried underground in layers, alternating with clay, plastic or foam; sides of landfill are lined to prevent leaching of chemicals; pipes to collect leaching liquid (prevent soil and water contamination) Methane (byproduct of decomposition) is collected and burned for fuel Concerns about chemicals leaking to groundwater (leachate)

14 Hazardous Waste Priority in reducing waste Most comes from industrial processes (textiles, computer manufacturing, dry cleaners, service stations) Difficult to dispose of…responsibility is on company or homeowner Can convert to non-hazardous substances Physical, chemical or biological methods Must be treated before disposal Stored forever Deep well disposal Surface impoundments Steel Drums

15 Legislation Resource Conservation and Recovery Act Manages hazardous waste, “cradle-to-grave” tracking CERCLA (Superfund Act) Identifies contaminated sites EPA manages National Priorities List Currently about 1200 sites Funding for clean-up is lacking Brownfield: abandoned industrial and commercial sites, contaminated with hazardous waste


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