Presentation on theme: "Risk Toxicology, and Human Health"— Presentation transcript:
1Risk Toxicology, and Human Health Chapter 11Risk Toxicology, and Human Health
2APES 1/24/11 Stamp on NB for 12 Notes on Chapter 11 Work on Population ? And FRQTomorrow Test Prep!Final on Wed..Scantron bring a number 2 pencil!Think of an activity you do:What are the risks?Are there other activities you do that are less risky?
3Chance of DYING 1 in a 100,000 chance 1 in a 10,000 chance
4RISKS AND HAZARDSRisk is a measure of the likelihood that you will suffer harm from a hazard.We can suffer from:Biological hazards: from more than 1,400 pathogens.Chemical hazards: in air, water, soil, and food.Physical hazards: such as fire, earthquake, volcanic eruption…Cultural hazards: such as smoking, poor diet, unsafe sex, drugs, unsafe working conditions, and poverty.
5Environmental health hazards can be divided into four types. 14_01a.jpgFigure 14-01aTitle:Environmental health hazards can be divided into four types.Caption:The sun's ultraviolet radiation is an example of a physical hazard (a). Excessive exposure increases the risk of skin cancer.Notes:Keywords:sunlight, electromagnetic radiation, health, diseases
6Environmental health hazards can be divided into four types. 14_01b.jpgFigure 14-01bTitle:Environmental health hazards can be divided into four types.Caption:Chemical hazards (b) include both artificial and natural chemicals. Much of our exposure comes from household chemical products, such as pesticides that some people apply to their lawns.Notes:Keywords:environmental health, toxicology, toxicants, pesticides
7Asbestos was widely used in insulation and other products. 14_04.JPGFigure 14-04Title:Asbestos was widely used in insulation and other products.Caption:A cause of lung cancer and asbestosis, the substance has now been removed from many buildings in which it was used. Its removal poses risks as well, however, and removal workers must wear protective clothing and respirators.Notes:Keywords:environmental health, toxicology, toxicants
8Figure 14-06 Title: DDT. Caption: 14_06.JPGFigure 14-06Title:DDT.Caption:Before the 1960s, the environmental and health effects of potent pesticides such as DDT were not widely studied or publicly known. Public areas such as parks, neighborhoods, and beaches were regularly sprayed for insect control without safeguards against excessive human exposure. Here children on a Long Island, New York, beach are fogged with DDT from a pesticide spray machine being tested in 1945.Notes:Keywords:environmental health, toxicology, toxicants, pesticides, foods, agriculture, farms, farming
9Environmental health hazards can be divided into four types. 14_01c.jpgFigure 14-01cTitle:Environmental health hazards can be divided into four types.Caption:Biological hazards (c) include other organisms that transmit disease. Some mosquitoes are vectors for certain pathogenic microbes, including those that cause malaria.Notes:Keywords:health, infectious diseases
10Environmental health hazards can be divided into four types. 14_01d.JPGFigure 14-01dTitle:Environmental health hazards can be divided into four types.Caption:Cultural or lifestyle hazards (d) include the decisions we make about how to behave, as well as the constraints forced on us by socioeconomic factors. Smoking is a lifestyle choice that raises one's risk of lung cancer and other diseases considerably.Notes:Keywords:health, diseases
11Becoming Better at Risk Analysis We can carefully evaluate or tune out of the barrage of bad news covered in the media, compare risks, and concentrate on reducing personal risks over which we have some control.Figure 18-3
13TOXICOLOGY: ASSESSING CHEMICAL HAZARDS Factors determining the harm caused by exposure to a chemical include:The amount of exposure (dose).The frequency of exposure.The person who is exposed.The effectiveness of the body’s detoxification systems.One’s genetic makeup.
14TOXICOLOGY: ASSESSING CHEMICAL HAZARDS Typical variations in sensitivity to a toxic chemical within a population, mostly because of genetic variation.Figure 18-10
15BIOACCUMULATIONBioaccumulation is the lifetime accumulation of a toxic substance in an individual organism’s body. Some toxic substances such as mercury or DTT (pesticide) do not easily leave the body once they have been absorbed and therefore accumulate over time.
16BiomagnificationBiomagnification, also known as bioamplification, or biological magnification is the increase in concentration of a toxic substance, such as the pesticide DDT or the heavy metal Mercury, as it moves upward through a food chain.
17Effects of Chemicals on the Immune, Nervous, and Endocrine Systems Long-term exposure to some chemicals at low doses may disrupt the body’s:Immune system: specialized cells and tissues that protect the body against disease and harmful substances.Nervous system: brain, spinal cord, and peripheral nerves.Endocrine system: complex network of glands that release minute amounts of hormones into the bloodstream.
18CHEMICAL HAZARDSA hazardous chemical can harm humans or other animals because it:Is flammableIs explosiveAn irritantInterferes with oxygen uptakeInduce allergic reactions.
19CHEMICAL HAZARDSA toxic chemical can cause temporary or permanent harm or death.Mutagens are chemicals or forms of radiation that cause or increase the frequency of mutations in DNA.Teratogens are chemicals that cause harm or birth defects to a fetus or embryo.Carcinogens are chemicals or types of radiation that can cause or promote cancer.
20Effects of Chemicals on the Immune, Nervous, and Endocrine Systems Molecules of certain synthetic chemicals have shapes similar to those of natural hormones and can adversely affect the endocrine system.Figure 18-9
21The drug thalidomide turned out to be a potent teratogen. 14_07.JPGFigure 14-07Title:The drug thalidomide turned out to be a potent teratogen.Caption:It was banned in the 1960s, but not before causing thousands of birth defects in babies born to mothers who took the product to relieve nausea during pregnancy. Butch Lumpkin was an exceptional "thalidomide baby" who learned to overcome his short arms and deformed fingers, becoming a professional tennis instructor in Georgia.Notes:Keywords:environmental health, toxicology, toxicants, teratogens
22TOXICOLOGY: ASSESSING CHEMICAL HAZARDS Estimating human exposure to chemicals and their effects is very difficult because of the many and often poorly understood variables involved.Figure 18-11
23TOXICOLOGY: ASSESSING CHEMICAL HAZARDS Children are more susceptible to the effects of toxic substances because:Children breathe more air, drink more water, and eat more food per unit of body weight than adults.They are exposed to toxins when they put their fingers or other objects in their mouths.Children usually have less well-developed immune systems and detoxification processes than adults.
24TOXICOLOGY: ASSESSING CHEMICAL HAZARDS Under existing laws, most chemicals are considered innocent until proven guilty, and estimating their toxicity is difficult, uncertain, and expensive.Federal and state governments do not regulate about 99.5% of the commercially used chemicals in the U.S.
25Protecting Children from Toxic Chemicals The U.S. Environmental Protection Agency proposed that regulators should assume children have 10 times the exposure risk of adults to cancer-causing chemicals.Some health scientists contend that regulators should assume a risk 100 times that of adults.
26TOXICOLOGY: ASSESSING CHEMICAL HAZARDS Some scientists and health officials say that preliminary but not conclusive evidence that a chemical causes significant harm should spur preventive action (precautionary principle).Manufacturers contend that wide-spread application of the precautionary principle would make it too expensive to introduce new chemicals and technologies.
28environmental health, epidemiology, health, diseases 14_02a.jpgFigure 14-02aTitle:Death and disease.Caption:Infectious diseases are the second-leading cause of death worldwide, accounting for over one-quarter of all deaths per year (a). Data are for 2004, from World Health Organization.Notes:Keywords:environmental health, epidemiology, health, diseases
29environmental health, epidemiology, health, diseases 14_02b.jpgFigure 14-02bTitle:Death and disease.Caption:Six types of diseases—respiratory infections, AIDS, diarrhea, tuberculosis (TB), malaria, and childhood diseases such as measles—account for 80% of all deaths from infectious disease (b). Data are for 2004, from World Health Organization.Notes:Keywords:environmental health, epidemiology, health, diseases
30BIOLOGICAL HAZARDS: DISEASE IN DEVELOPED AND DEVELOPING COUNTRIES Diseases not caused by living organisms cannot spread from one person to another (nontransmissible disease), while those caused by living organisms such as bacteria and viruses can spread from person to person (transmissible or infectious)
31Transmissible Disease Pathway for infectious disease in humans.Figure 18-4
32Transmissible Disease WHO estimates that each year the world’s seven deadliest infections kill 13.6 million people – most of them the poor in developing countries.Figure 18-5
33Case Study: Growing Germ Resistance to Antibiotics Rabidly producing infectious bacteria are becoming genetically resistant to widely used antibiotics due to:Genetic resistance: Spread of bacteria around the globe by humans, overuse of pesticides which produce pesticide resistant insects that carry bacteria.Overuse of antibiotics: A 2000 study found that half of the antibiotics used to treat humans were prescribed unnecessarily.
34Case Study: The Growing Global Threat from Tuberculosis The highly infectious tuberculosis (TB) kills 1.7 million people per year and could kill 25 million people 2020.Recent increases in TB are due to:Lack of TB screening and control programs especially in developing countries due to expenses.Genetic resistance to the most effective antibiotics.
35Viral Disease · The viral life cycle · must have a host cell Treating Viral Disease· vaccines· why are vaccines not always effective ?
37Examples of Viral Disease Influenza (flu)World Influenza Pandemic ( )·1. global epidemic (pandemic) killed 20million people, in the U.S. alone·2. airborne and direct contact·3. no vaccine·4.particularly virulent strain
38Human Immunodeficiency Virus (HIV) 1. virus responsible for AIDS (acquired immunodeficiency syndrome)2. sexually transmitted disease, also blood borne… infected needles in IV drug users3. attacks the immune system and allows for secondary infectionsmost people do not die from AIDS, but from the resulting secondary infections (pneumonia or TB)4. no vaccine available5. some antiviral drugs show effectiveness and prolong the lives of those who are HIV positive· Internet article on HIV.. what’s working to halt the spread ?
39Viral DiseasesFlu, HIV, and hepatitis B viruses infect and kill many more people each year then highly publicized West Nile and SARS viruses.The influenza virus is the biggest killer virus worldwide.Pigs, chickens, ducks, and geese are the major reservoirs of flu. As they move from one species to another, they can mutate and exchange genetic material with other viruses.
40Viral DiseasesHIV is the second biggest killer virus worldwide. Five major priorities to slow the spread of the disease are:Quickly reduce the number of new infections to prevent further spread.Concentrate on groups in a society that are likely to spread the disease.Provide free HIV testing and pressure people to get tested.Implement educational programs.Provide free or low-cost drugs to slow disease progress.
42The Global HIV/AIDS Epidemic The virus itself is not deadly, but it cripples the immune system, leaving the body susceptible to infections such as Kaposi’s sarcoma (above).Figure 18-1
43The Global HIV/AIDS Epidemic AIDS has reduced the life expectancy of sub-Saharan Africa from 62 to 47 years – 40 years in the seven countries most severely affected by AIDS.Projected age structure of Botswana's population in 2020.Figure 18-2
44How Would You Vote?Should developed and developing nations mount an urgent global campaign to reduce the spread of HIV and to help countries afflicted by the disease?a. No. A global AIDS campaign could divert attention and resources from efforts to combat other serious threats.b. Yes. The disease is decimating the populations and destroying the economies of many developing countries.
45Avian Bird Flu Spread among birds · Most cases of avian influenza infection in humans have resulted from contact with infected poultry (e.g., domesticated chicken, ducks, and turkeys) or surfaces contaminated with secretion/excretions from infected birds.· You cannot contract bird flu by eating poultry· The strain that has spread to humans (H5N1) has a mortality rate of 50%· There have been a few cases of human to human transmission, but these are rare and unsustained· Some antiviral drugs have shown some effectiveness· Vaccines could be produced but stockpiles and ability to ramp up production in a pandemic are inadequate
46Bacterial DiseaseTreating Bacterial Infections· Antibiotics· Why do antibiotics lose their effectiveness ?
47Tuberculosis (the silent global epidemic) Kills 1.6 million and infects 8 million· Respiratory infection spreads airborne droplets containing thebacterium· 1 in 3 people globally infected with TB· About 10% will develop active TB infections and then spread thedisease to about others· Treatmento There are drugs that are effective but they must be taken for about 6-8 weekso Strains resistant to commonly used antibiotics have ariseno Screening a population is very effective in identifying infected individuals· AIDS make infected individuals less able to fight the disease· Population growth and urbanization makes spreading the diseasemore likely
53· Symptoms include fever, chills, anemia, enlarged spleen, abdominal pain, headaches, weakness, greater susceptibility to other disease. Liver and kidney damage insome cases· These symptoms come about when the organism reproduces in red blood cells and causes these cells to rupture· There are drugs that are effective at killing the parasites in infected humansResistant strains are developingDevelopment of a vaccine is a major research
54Malaria - efforts to eradicate Local efforts funded by Gates Foundation1. Controlling the vector (mosquito) will slow the spread of the disease2. Remove sources of standing water… habitat needed by the mosquito to reproduce3. Use DDT to kill mosquitoesResistant mosquito strains are emerging
55Case Study: Malaria – Death by Mosquito Economists estimate that spending $2-3 billion on malaria treatment may save more than 1 million lives per year.Figure 18-6
56Case Study: Malaria – Death by Mosquito Spraying insides of homes with low concentrations of the pesticide DDT greatly reduces the number of malaria cases.Under international treaty enacted in 2002, DDT is being phased out in developing countries.
57Solutions Infectious Diseases Increase research on tropical diseases and vaccinesReduce povertyDecrease malnutritionImprove drinking water qualityReduce unnecessary use of antibioticsEducate people to take all of an antibiotic prescriptionReduce antibiotic use to promote livestock growthFigure 18.8Solutions: ways to prevent or reduce the incidence of infectious diseases, especially in developing countries. QUESTION: Which three of these approaches do you think are the most important?Careful hand washing by all medical personnelImmunize children against major viral diseasesOral rehydration for diarrhea victimsGlobal campaign to reduce HIV/AIDSFig. 18-8, p. 424
58Ecological Medicine and Infectious Diseases Mostly because of human activities, infectious diseases are moving at increasing rates from one animal species to another (including humans).Ecological (or conservation) medicine is devoted to tracking down these connections between wildlife and humans to determine ways to slow and prevent disease spread.
59Case Study: A Black Day in Bhopal, India The world’s worst industrial accident occurred in 1984 at a pesticide plant in Bhopal, India.An explosion at Union Carbide pesticide plant in an underground storage tank released a large quantity of highly toxic methyl isocyanate (MIC) gas.15,000-22,000 people diedIndian officials claim that simple upgrades could have prevented the tragedy.
60How Would You Vote?Should we rely more on the precautionary principle as a way to reduce the risks from chemicals and technologies?a. No. Assuming that every chemical or technology is a serious health or environmental threat will lead to wasteful over-regulation, high costs and hinder the development of critically needed pesticides, plastics, and other commercial products.b. Yes. Preventing the commercialization of harmful chemicals and technologies is better than dealing with the high costs of medical treatments and environmental damage.
61RISK ANALYSISScientists have developed ways to evaluate and compare risks, decide how much risk is acceptable, and find affordable ways to reduce it.Figure 18-12
62RISK ANALYSISEstimating risks from using many technologies is difficult due to unpredictability of human behavior, chance, and sabotage.Reliability of a system is multiplicative:If a nuclear power plant is 95% reliable and human reliability is 75%, then the overall reliability is (0.95 X 0.75 = 0.71) 71%.
63RISK ANALYSISAnnual deaths in the U.S. from tobacco use and other causes in 2003.Figure 18-A
64RISK ANALYSISNumber of deaths per year in the world from various causes. Parentheses show deaths in terms of the number of fully loaded 400-passenger jumbo jets crashing every day of the year with no survivors.Figure 18-13
65Perceiving RiskMost individuals evaluate the relative risk they face based on:Degree of control.Fear of unknown.Whether we voluntarily take the risk.Whether risk is catastrophic.Unfair distribution of risk.Sometimes misleading information, denial, and irrational fears can cloud judgment.
66RISK ANALYSISComparisons of risks people face expressed in terms of shorter average life span.Figure 18-14
67The Global HIV/AIDS Epidemic According to the World Health Organization (WHO), in 2005 about 42 million people worldwide (1.1 million in the U.S.) were infected with HIV.There is no vaccine for HIV – if you get AIDS, you will eventually die from it.Drugs help some infected people live longer, but only a tiny fraction can afford them.
69environmental health, epidemiology, infectious diseases 14_03a.jpgFigure 14-03aTitle:West Nile virus.Caption:In the map (a), colors show the year that West Nile virus was first detected within each state. The disease spread westward across the country in less than 5 years. Data from Centers for Disease Control and Prevention.Notes:Keywords:environmental health, epidemiology, infectious diseases