Hormonally Active Agents (HAAs)
-pesticides/synthetic chem's that can act as hormone impostors
-can impair reproductive syst/sexual devel'ment or cause physical/behavioral disorders
-includes hormone mimics
-hormone blockers can disrupt system by preventing natural hormones from attachi
Bisphenol A (BPA)
-chemical building block in hardened plastics used in bottles and food storage containers
-is a hormone mimic
-BPA can stay in syst for up to 24 hrs after being ingested
-most Americans have trace levels over current threshold level, more in children/adol
Risk
-probability of suffering harm from a hazard that can cause injury, disease, death, econ loss, or damage
-expressed as mathematical statement about likelihood
Risk Assessment
-use statistical methods to estimate how much harm a particular hazard can cause to human health/enviro
-helps estimate probability of risk, compare it with probability of other risks, and establish priorities for avoiding/managing risks
Risk Management
-involves deciding whether/how to reduce particular risk to a certain level and at what cost
Pathogen
-organism that can cause disease in another organism
Biological Hazard
-from pathogens that can infect humans
Chemical Hazard
-from harmful chemicals in air, water, soil, food, and human-made products
Physical/Natural Hazard
-includes fire, quakes, volcanic eruptions, floods, and storms
Cultural Hazard
-includes unsafe working conditions, unsafe highways, criminal assault, and poverty
Lifestyle Choices
-includes smoking, food choices, alcohol consumption, sexual responsibility
Infectious Disease
-caused when pathogen invades the body and multiplies in cells and tissues
-includes flu, malaria, TB, measles
Bacterial Disease
-spreads as bacteria multiply
-i.e. TB
Viral Disease
-spreads as virus takes over cell's genetic mechanisms to copy selves
-i.e. flu, HIV
Transmissible Disease
-infectious disease that can be transmitted from one person to another
-i.e. flu, TB, measles
Nontransmissible Disease
-caused by something other than a living organism
-doesn't spread from person to person
-tends to develop slowly and have multiple causes
-as life expectancy increases, more people will suffer/die from these
-i.e. cardiovascular diseases, cancer, asthma,
Four Most Serious Infectious Diseases
-pneumonia/flu, HIV/AIDS, TB, diarrheal diseases
How Infectious Diseases Enter Body
-human to human contact
-human to fetus or baby
-pets, livestock, wild animals, insects, food, water, or air to humans
Epidemic
-large-scale outbreak of an infectious disease in an area or country
Pandemic
-global outbreak of an infectious disease
Increased Genetic Resistance to Antibiotics
-spread of bacteria around world from human travel and international trade
-overuse of pesticides that increase populations of pesticide-resistant insects and other carriers of bacterial diseases
-some drug-resistant bacteria can quickly transfer resistan
Tuberculosis (TB)
-extremely contagious bacterial infection of lungs
-many people don't appear to be sick while infected, and only 1/2 know they're infected
-one person can infect many if unaware of illness
-without treatment about 1/2 the people with active TB die from ba
Factors Accounting for Spread of TB
-too few screenings and control programs
-most strains have developed genetic resistance to the majority of effective antibiotics
-population growth, urbanization, and air travel have increased person-to-person contact
-people in poor countries often have
Flu
-biggest viral disease killer
-easily transmitted by body fluids and airborne emissions of infected person
Hepatitis B
-third largest viral killer
-damages liver
-transmitted through unsafe sex, sharing hypodermic needles, infected mothers passing onto child, or exposure to infected blood
Emergent Disease
-virus that's adapted and emerged as a new disease or pathogenic strain
West Nile Virus
-transmitted to humans through mosquito bites that were infected by feeding on birds with virus
-caused severe illnesses in many cases since emerging in US in 1992, i.e. viral encephalitis or viral meningitis (both deal with brain and spinal cord)
-chance
HIV/AIDS
-HIV isn't deadly, but AIDS cripples immune system and leaves the body vulnerable to infections
-transmitted by unsafe sex, sharing hypodermic needles, infected mothers passing onto child, or exposure to infected blood
-most people with HIV are living in
Treatment of HIV/AIDS
-combinations of expensive antiviral drugs can slow progress of AIDS and person could live up to 24 years after being infected, but very expensive
-cost is too high for less devel'd countries
-without treatment, takes 10-11 yrs for HIV to become AIDS
Malaria
-no vaccine for prevention
-caused by parasite spread by certain mosquitoes, contaminated blood transfusions, sharing hypodermic needles
-infects and destroys red blood cells
-causes intense fever, chills, drenching sweats, severe abdominal pain, vomiting
Prevention of Malaria
-working to develop new antimalarial drugs, vaccines, and biological controls for mosquitoes
-developing mosquitoes resistant to malaria parasite
-outbreeding malaria-carrying mosquitoes through genetic engineering
-killing mosquitoes through dehydration
Ecological Medicine
-new interdisciplinary field devoted to tracking down unwanted connections spreading diseases from animals to humans
-have identified human practices encouraging this spread of disease, i.e. clearing forests, expanding suburbs, and hunting
Reduce Spread of Infectious Disease
-increase research on tropical diseases/vaccines
-reduce poverty and decrease malnutrition
-improve water quality, reduce unnecessary antibiotics use
-educate people to take all of antibiotic prescription
-reduce antibiotics to promote livestock growth
-r
Toxic Chemical
-chemical that can cause temporary or permanent harm or death to humans and animals
-top five toxic substances are arsenic, lead, mercury, vinyl chloride, and polychlorinated biphenyls (PCBs)
PCBs
-chlorine-containing organic compounds
-very stable, nonflammable, exist as oily liquids or solids that enter air as vapor under certain conditions
-used to be used as lubricants, hydraulic fluids, and insulators of electrical transformers and capacitator
Mutagens
-chemicals and forms of radiation that cause of increase the frequency of mutations in DNA
-most cause no harm but some lead to cancer or other disorders
Teratogens
-chemicals that cause harm and birth defects to a fetus or embryo
-i.e. ethyl alcohol--why drinking while pregnant can cause low birth weight or various physical/mental problems
-also includes benzene, formaldehyde, lead, mercury
Carcinogens
-chemicals, types of radiation, or certain viruses that can cause or promote cancer
-cancer is when malignant cells multiply uncontrollably creating tumors that can damage the body and lead to premature death
-i.e. arsenic, formaldehyde, PCBs, UV radiatio
Human Immune System
-consists of specialized cells and tissues to protect body agst disease and harmful substances by forming antibodies that render invading agents harmless
-some chemicals (i.e. arsenic) can weaken immune system and leave body vulnerable to attacks by aller
Human Nervous System
-includes brain, spinal cord, and peripheral nerves
-neurotoxins (natural or synthetic chemicals in environment, i.e. PCBs, arsenic, lead) can harm it
-can lead to behavioral changes, learning disabilities, retardation, ADD, paralysis, death
Human Endocrine System
-complex network of glands that release tiny amounts of hormones into bloodstreams
-low levels of hormones regulate bodily systems that control sexual reproduction, growth, development, learning ability, and behavior
-each type of hormone has a unique sha
Mercury
-mercury and compounds are all toxic
-long-term exposure can permanently damage nervous system, kidneys, and lungs
-low levels can harm fetuses or cause birth defects
-released into air from rocks, soil, volcanoes, and ocean vapor
-2/3 of it in atmosphere
Ways Humans Are Exposed to Mercury
-inhale vaporized elemental mercury or particles of inorganic mercury salts
-can eat fish contaminated with methylmercury
-consumption of high-fructose corn syrup
Methylmercury
-especially dangerous neurotoxin
-is very persistent in enviro so can be biomagnified in food chains or webs
-can cause brain damage in fetuses/children and can harm heart, kidneys, or immune system of adults
Toxicology
-study of harmful effects of chemicals on humans and other organisms
Toxicity
-measure of the harmfulness of a substance
-its ability to cause injury, illness, or death in a living organism
Dose
-amount of a harmful chemical a person has ingested, inhaled, or absorbed through skin
Response
-damage to health resulting from exposure to a chemical
Variables Affecting Toxicity
-dose, age of person, genetic makeup
-how well body's detoxification systems work
-solubility, substance's persistence, biomagnification
Children Are More Vulnerable Than Adults
-infants and young children breathe more air, drink more water, and eat more food per unit of body weight
-exposed to toxins in dust and soil when they put dirty fingers or toys in their mouths
-immune system isn't fully developed
Dose-Response Curve
-scientists estimate toxicity of chemicals by determining effects of various doses of the chemical on test organisms and plotting results on these curves
-can determine lethal dose (kills one) and median lethal does (kills 50% test population)
-nonthresho
Case Reports
-provide info about people suffering an adverse health effect or dying after exposure to chemical
-often involves accidental/deliberate poisonings, overdoses, homicides, suicide attempts
-aren't reliable sources for estimating toxicity but can provide clu
Lab Animals to Test Toxicity
-most widely used method
-often use lab-bred mice or rats because systems are fairly similar to those of humans and are small and able to reproduce quickly
-can take many years, many animals, and lots of money to complete
Epidemiological Studies
-compare health of people exposed to a chemical (experimental group) to health of an unexposed group (control)
-goal is to determine if statistical association between exposure to a toxic chemical and a health problem is strong, moderate, weak, or undetec
Four Factors Limiting Epidemiological Studies
-often too few people have been exposed to high enough levels of toxic agent to detect significant differences
-studies take a long time
-closely linking observed effect with exposure to chemical is different because people are exposed to many toxic agent
Pollution Prevention
-supporters say we shouldn't release chemicals that we know or suspect could cause harm into environment
-need to find harmless or less harmful substitutes for toxic and hazardous chemicals or recycle them within production processes
Precautionary Principle
-when there's substantial prelim evidence that something harms humans or the environment, we should take precautionary measure to prevent or reduce such harm
-can use pollution prevention to implement this, but would require assuming that new chemicals an
Risk Analysis
-identifying hazards and evaluating their associated risks (risk assessment), ranking risks (comparative risk analysis), determining options and making decisions about reducing or eliminating risks (risk management), and informing decision makers and the
Three Greatest Threats to Humans of Premature Deaths
-poverty
-born male
-smoking
-rest are primarily lifestyle choices
Cigarette Smoking
-most preventable major cause of suffering and premature death among adults
-causes heart disease, stroke, lung and other cancers, bronchitis, and emphysema
-could also be linked to various mental illnesses
-secondhand smoke is also health hazard
Reduce Threats from Cigarette Smoking
-quit smoking by age 30
-add federal tax on price of cigarettes
-classify and regulate tobacco as a drug
-enact smoking bans
-media coverage about harmful effects
-mandatory health warnings on cigarette packs
Factors Causing People to Misjudge Risks
-fear
-degree of control one has in a situation
-whether a risk is catastrophic vs. chronic
-optimism bias or belief that risks apply to others but not them
-many risky things are highly pleasurable or give instant gratification
Four Principles to Evaluate and Reduce Risks
-compare risks
-determine how much of a risk you are willing to accept
-determine actual risk involved
-concentrate on evaluating and carefully making important lifestyle choices