APES Thursday, April 23 rd, 2015  Reminders:  AP Testers: Princeton Review Assignment (not due till after AP Test)  APES Exam is Monday, May 4 8:00 am; LEOCT is Friday, May 8 th  Extra Credit: Due Friday, May 8 th  Learnerator : Extra Credit Test Grade  Cumulative Study Guide: Extra Credit Lab Grade (all or nothing)  Today’s Schedule:  Health Unit Notes

Human Health Chapter 19: Risk, Toxicology, and Human Health

Human Health  Risk  Risk: probability of suffering harm from a hazard that can cause injury, disease, death, economic loss, or damage  Risk assessment: process of using stats to estimate how much harm a particular hazard can cause to human health or environment  Risk management: deciding how to reduce risk to certain level and at what cost

Human Health  Risk

Human Health  Risk Analysis 1. Identify & Compare risks 2. Evaluate whether risk is acceptable and find affordable ways to reduce risk 3. Communicating risk to public

Human Health  Types of Hazards:  Biological hazards: pathogens, pollen, venomous animals  Pathogen: organism that causes disease: bacteria, viruses, parasites, protozoa, & fungi  Chemical hazards: in air, water, food, man-made products  Cultural hazards: unsafe working conditions, driving, crime  Natural hazards: fire, storms, etc.  Lifestyle choices: smoking, unsafe sex, drinking/drugs, etc.

Human Health  Greatest Health Risks: in the US  1. Poverty: malnutrition, disease (normally nonfatal)  Shortens lifespan by 7-10 yrs  2. Gender  Being male shortens lifespan by 7.5 yrs  3. Lifestyle Choices:  Smoking: lost 6-10 yrs  Overweight: 6 yrs  Driving: 7 months  Alcohol: 5 months

Human Health  Greatest Health Risks: Globally

Human Health  Biological Hazards  Infectious disease: caused when pathogen invades body & multiplies (either directly or through vector)  Ex: flu, malaria, measles  Can be Transmissible  Non-transmissible disease: not caused by organism & not spread  Ex: heart disease, some cancers, diabetes, etc.

Human Health  Biological Hazards  Infectious diseases spread through air, water, food, bodily fluids (blood, mucus)  Since 1950, infectious diseases have declined due to:  Better healthcare & sanitation  Antibiotics & vaccines  Still have problems, esp. in developing countries:  Epidemics: large-scale outbreak of infectious disease in an area or country  Pandemic: global epidemic

Human Health  Biological Hazards

Human Health  Biological Hazards: Current Issues  Tuberculosis (TB) – bacterial infection in lungs  1 in 3 have bacteria  Kills 1.8 mil per year  Problem: Genetic resistance! Multi-drug resistant TB getting more common

Human Health  Biological Hazards: Current Issues  Biggest viral killer… 1. Flu/Influenza virus 2. AIDS: Acquired immune deficiency syndrome, caused by human immunodeficiency virus (HIV)  HIV destroys immune systems & makes people vulnerable to infections  Identified in 1981; now >33 mil people have it – most in Africa  Infects 2.5 mil per year; kills 2 mil per year  With antiviral costing >$25,000 per year, can expect to live another 24 years

Human Health  Biological Hazards: Current Issues  3. Hepatitis B virus (HBV): damages liver; transmitted through sex, needles  Emergent Diseases: newly discovered  West Nile Virus  Avian Flu

Human Health  Biological Hazards: Current Issues  Malaria  Caused by protozoan parasite (Plasmodium), spread through Anopheles mosquitoes  Destroys RBCs, causing fever, pain, vomiting, & death  Problem: mosquitoes resistance to insecticide & Plasmodium resistance to antimalarial drugs  Solutions:  Genetically-engineered mosquitoes  Mosquito nets

Human Health  Biological Hazards  Antibiotic resistance  Genetic resistance occurs through natural selection  Causes:  Over-prescribed/ over-used  Use in livestock production  Anti-bacterial soap/hand sanitizer could be creating “stronger” bacteria  Methicillin-resistant staphylococcus aureus (MRSA)

Human Health  Chemical Hazards  Toxic chemical: substance that when inhaled, ingested, or absorbed can cause temporary or permanent harm or death to humans and animals  Top 5 according to EPA: 1. Arsenic 2. Lead 3. Mercury 4. Vinyl chloride 5. Polychlorinated biphenyls (PCBs)

Human Health  Chemical Hazards  T hree major types of toxic chemicals: 1. Carcinogens: chemicals, radiation, or viruses that cause cancer  Ex: arsenic, benzene, formaldehyde, PCBs, UV radiation 2. Mutagens: chemicals or radiation that cause or increase frequency of mutations in DNA 3. Teratogens: chemicals that cause harm or birth defect to fetus  Ex: alcohol, PCBs, lead, mercury

Human Health  Chemical Hazards  Focus on Polychlorinated biphenyls (PCBs):  = class of 200 chlorine-containing organic compounds  Used as lubricants, insulators, paints, pesticides, etc.  Banned in 1977  Problem: long persistence and biomagnify (fat- soluble)  ~70% of all PCBs made in US still in environment

Human Health  Chemical Hazards  Neurotoxins: harm nervous system:  Ex: PCBs, arsenic, lead, some pesticides, methylmercury  Effects: learning disabilities, ADD, Parkinson’s, etc.  Hormonal Disrupters:  Some pesticides & synthetic chemicals have same molecular shape as hormones (called Hormonally Active Agents/ HAAs)  Ex: aluminum, Atrazine, DDT, PCBs, mercury, BPA  Gender benders: estrogen mimics & hormone blockers that affect sexual development & reproduction  Thyroid disrupters cause growth & weight problems

Human Health  Chemical Hazards  Hormonally-Active Agents:  BPA: bisphenol A  A estrogen mimic used in hard plastics (esp. food containers, bottles, etc.)  Leaches into food & drink, even when not heated  Effects: brain damage, early puberty, breast cancer, obesity, liver damage, impaired immune function, etc.  Phthalates:  In PVC bottles & solvents (perfume, lotions, shampoos, etc.)  Banned in EU and 14 other countries  Associated with birth defects, liver & kidney damage, immune problems etc.

Human Health  Toxicology  = study of harmful effects of chemicals on humans & other organisms  Toxicity: how harmful something is. Depends on:  Dose: amount exposed to  Frequency  Genetic make up of those exposed  Health of those exposed

Human Health  Toxicology  Toxicity: Other factors include:  Solubility (water or fat)  Water soluble: usually inorganic toxins; gets into water system  Fat soluble: usually organic toxins; accumulate in body (bioaccumulation)  Persistence  Biomagnification (build up through food chain)  Chemical interactions (antagonistic or synergistic)

Human Health  Toxicity  Response: the damage to health resulting from exposure to a toxin   Acute effects: immediate effect of exposure  Chronic effects: long-lasting effects from one or repeated exposures

Human Health  Determining Toxicity  Expose a population of lab animals to measured doses under controlled conditions  Create a dose-response curve: determine effects at various doses  Median Lethal Dose (LD 50 ): dose that can kill 50% of the animals in a test pop within certain time period

Human Health  Toxicity Measurement  Lower the LD 50 number = more toxic the chemical (Units: mg/kg)  Poison = any substance that has an LD 50 of 50 mg or less per kg of body weight

Human Health  2 Types of Dose-Response Curves:  Threshold dose-response curve: a threshold dose must be reached before any detectable harmful effects occur.

Human Health  2 Types of Dose-Response Curves:  Nonthreshold dose-response curve: any dosage of a toxic substance causes harm that increases with the dosage.  The smallest amount of the dosage has a harmful effect

Human Health Are trace levels harmful? We don’t know

Human Health  Prevention  In 2000, POPs Treaty: ban or phase out dirty dozen - 12 most persistent pollutants detrimental to life:  DDT & 8 other pesticides  PCBs  POPs treaty went into effect in 2004, not yet ratified by U.S.  In 2007, European Union enacted REACH (registration, evaluation, and authorization of chemicals)