APES Chapter 8: Environmental Health and Toxicology - Questions and Answers, Exams of Epidemiology

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APES Chapter 8 QUESTIONS AND

ANSWERS

health - ANSWER>>a state of complete physical, mental, and social well-being

disease - ANSWER>>an abnormal change in the body's condition that impairs physical or psychological function

morbidity - ANSWER>>illness, Diet and nutrition, infectious agents, toxic chemicals, genetics, trauma and psychological stress all play roles in it

mortality - ANSWER>>death, Diet and nutrition, infectious agents, toxic chemicals, genetics, trauma and psychological stress all play roles in it

global disease burden - ANSWER>>Life expectancy increasing as infant mortality decreases. Diabetes is on the increase. One-third of children born in North America today will develop diabetes in their lifetime due to poor diet and little exercise.

WHO projects that psychological conditions could increase their share of the global disease burden from 10% currently to 15%. Depression will be the second largest cause of all years lived with disability.

Tobacco related lung diseases are increasing. Biggest single cause of death worldwide.

Disability-adjusted life years (DALYs) - ANSWER>>combine premature deaths and loss of healthy life resulting from illness or disability Chronic conditions account for premature death and disease in both developed and developing countries today. By 2020, heart disease may become the leading source of disability and disease worldwide. Global cancer rates will increase by 50%.

infectious disease - ANSWER>>Communicable diseases are still responsible for about 1/3 of all disease-related deaths. Majority in countries with poor nutrition, sanitation, and vaccination New diseases test our defenses in developed countries. Better nutrition, clean water, improved sanitation and inoculation of children could eliminate most of the deaths.

pathogens - ANSWER>>are disease-causing organisms They include: Viruses Bacteria Protozoans Parasitic worms including flukes Greatest loss of life in a single year from a pathogen was in 1918 when the flu epidemic killed 50 to 100 million people worldwide. Malaria is a major disease in tropical areas. About 600,000 people die each year.

emergent diseases - ANSWER>>one not previously known, or one which has been absent for at least 20 years. Bird flu Ebola fever HIV

Air travel makes it possible to spread emergent diseases around the globe quickly.

ecological diseases - ANSWER>>animal epidemics White nose syndrome in bats is due to a fungus recently introduced into the eastern US California sea lions have herpes 1 virus spread to them from human sewage. An imported fungus is killing oak, redwoods, and Douglas fir trees in California. Dermo, a parasite of oysters, is spreading rapidly along the east coast due to climate warming.

conservation medicine - ANSWER>>examines how environmental changes threaten the health of humans and natural communities

pesticide resistance - ANSWER>>The protozoan parasite that causes malaria is now resistant to most antimalaria drugs, while the mosquitoes that transmit the protozoan have developed resistance to many insecticides. Natural selection and the ability of organisms to evolve rapidly Human tendencies to overuse pesticides speeds up this process.

antibiotic resistance - ANSWER>>Antibiotics are chemicals that kill or inhibit the growth of bacteria Many people do not finish the full-course, creating resistant strains of bacteria. Antibiotic resistant strains of MRSA are spreading through hospitals in the US and China resulting in thousands of deaths. In the US over 19,000 deaths are estimated to have occurred from over 100,000 MRSA infections. At least half of the 100 million antibiotic doses prescribed in the U.S. every year are unnecessary or are the wrong drug. Antibiotics are routinely fed to U.S. farm animals to stimulate weight gain. These are excreted in urine and feces, and find their way into surface waters where they create more antibiotic resistance.

funding health care - ANSWER>>Heaviest burden of illness borne by poorest people who cannot afford a healthy environment or adequate health care. WHO estimates 90% of all disease burden occurs in developing countries where less than 10% of all health care dollars are spent. Increased financial aid to developing countries could reduce the spread of pathogens and might stabilize population growth since parents whose children have a higher survival rate tend to have fewer offspring.

toxicology - ANSWER>>the study of poisons and their effects on living systems. Dangerous chemicals are divided into two broad categories: toxic and hazards

toxic - ANSWER>>known poisons that damage or kill cells/tissues Can be general or very specific. Often harmful even in dilute concentrations.

hazards - ANSWER>>dangerous but not toxic Flammable, explosive, irritant, acid, caustic Ecotoxicology deals with the interactions, transformation, fate, and effects of natural and synthetic chemicals in the biosphere.

allergens - ANSWER>>substances that activate the immune system

antigens - ANSWER>>substances that are recognized as foreign by white blood cells and stimulate the production of specific antibodies Other allergens act indirectly by binding to other materials so they become antigenic. For example, formaldehyde and carbon monoxide that cause Sick Building Syndrome

Sick Building Syndrome - ANSWER>>??? formaldehyde and carbon monoxide that cause it

immune system depressants - ANSWER>>pollutants that depress the immune system

endocrine disrupters - ANSWER>>disrupt normal hormone functions Environmental estrogens - environmental contaminants (e.g., BPA, dioxins) which cause reproductive problems in animals even at very low doses some researchers think they are contributing to the obesity crisis

neurotoxins - ANSWER>>metabolic poisons that specifically attack nerve cells; most are extremely toxic and fast acting. Different types act in different ways.

heavy metals - ANSWER>>neurotoxin that kill nerve cells.

Anesthetics and Chlorinated Hydrocarbons - ANSWER>>neurotoxins that disrupt nerve cell membranes.

Organophosphates and Carbamates - ANSWER>>neurotoxins that inhibit signal transmission between nerve cells.

mutagens - ANSWER>>Agents that damage or alter genetic material. Can lead to birth defects or tumors.

teratogens - ANSWER>>specifically cause abnormalities during embryonic growth and development Alcohol - Fetal Alcohol Syndrome

carcinogens - ANSWER>>substances that cause cancer Cancer is the 2nd leading cause of death. 1 in 2 males and 1 in 3 females in the U.S. will have cancer in their lifetime.

diet - ANSWER>>Correlation between a high fat/high salt diet and cardiovascular disease Fruits, vegetables, whole grains, complex carbohydrates, and fiber are beneficial. Sixty percent of all U.S. adults are now considered overweight. U.S. Centers for Disease Control warn one in three U.S. children are at risk of becoming diabetic.

solubility - ANSWER>>one of most important characteristics in determining the movement of a toxin Chemicals are divided into two major groups: Those that dissolve more readily in water Those that dissolve more readily in oil

water soluble compounds - ANSWER>>move rapidly through the environment and have ready access to cells via tissue fluid.

fat soluble compounds - ANSWER>>need a carrier to move through the environment, but once inside the body they penetrate tissues easily and cross cell membranes. They are stored in body fat and persist for many years.

exposure and susceptibility - ANSWER>>Airborne toxins generally cause more ill health than any other exposure. Lining of lungs easily absorbs toxins. Food, water and skin contact are other ways to be exposed to toxins. Largest toxin exposure reported in industrial settings Condition of organism and timing of exposure also have strong influences on toxicity. Children more vulnerable than adults.

bioaccumulation - ANSWER>>selective absorption and storage of toxins Dilute toxins in the environment can build to dangerous levels inside tissues.

biomagnification - ANSWER>>Toxic burden of a large number of organisms at a lower trophic level is accumulated and concentrated by a predator at a higher trophic level. Example: DDT there's roughly ten times as much toxin in each successive trophic level in this system

persistence - ANSWER>>Some chemical compounds are very unstable and degrade rapidly under most conditions, thus their concentrations decline quickly after release. For example, most modern pesticides.

Others are more persistent. The stability of these substances such as metals and BPA can cause problems as these toxins may be stored for a long period of time and spread to unintended victims. lead is very persistent even at low levels

examples of persistent organic pollutants - ANSWER>>Flame retardants (PBDE) are now found in humans and other species everywhere in the world. Harm children's reproductive and nervous systems.

Chemicals used in non-stick plastic coatings (PFOS and PFOA) are infinitely persistent in the environment and found in your blood. Cause liver damage and cancer.

Phthalates found in plastics mimic estrogen and are linked to reproductive abnormalities and reduced fertility.

synergism - ANSWER>>an interaction in which one substance exacerbates the effects of another

antagonistic reaction - ANSWER>>one material interferes with the effects, or stimulates the breakdown, of other chemicals

addictive reaction - ANSWER>>effects of two chemical occurring together are added to one another

synergistic reaction - ANSWER>>one substance exacerbates the effect of the other For example: Asbestos exposure increases risk of lung cancer 20X; smoking has same risk. But together, they increase risk 400X.

can all be material be poisonous under certain conditions? - ANSWER>>yes. Most chemicals have a safe threshold under which their effects are insignificant.

metabolic degradation - ANSWER>>In mammals, the liver is the primary site of detoxification of both natural and introduced poisons. Sometimes compounds that are harmless can be broken down into products that are harmful.

excretion and repair - ANSWER>>Effects of waste products and environmental toxins reduced by eliminating via excretion. Breathing Urine Tissues and organs often have mechanisms for damage repair by cellular reproduction. Any irritating agent can be potentially carcinogenic because the more times that cells divide, the greater the chance that they will have a mistake (mutation) while copying their DNA. This can lead to cancer.

sensitivity variations - ANSWER>>variations of human sensitivity to a toxin varies creating a bell shaped curve

animal testing - ANSWER>>Most commonly used and widely accepted toxicity test is to expose a population of laboratory animals to measured doses of specific toxins. Humanitarian concerns in using animals Different individuals have different sensitivities to the same toxin. Should we aim to protect the average person or the most sensitive?

LD50 - ANSWER>>dose at which 50% of the animal test population dies dose response cures not symmetrical

Unrelated species can react quite differently to the same toxin due to differences in physiology and metabolism.

These variations make it difficult to estimate the risk to humans.

toxicity ratings - ANSWER>>Moderate toxin takes about (1) g/kg of body weight to produce a lethal dose. Very toxic materials require about 10% of that amount. Extremely toxic materials require 1% of that amount.

Supertoxic chemicals can be lethal in a dose of a few micrograms (an amount invisible to the naked eye). Many carcinogens, mutagens, and teratogens are dangerous at levels far below their direct toxic effect because abnormal cell growth exerts a form of biological amplification. One cell mutated by a toxin can form a tumor that kills the individual.

acute effect - ANSWER>>caused by a single exposure and results in an immediate health problem, irreversible effects if the person survives

chronic effect - ANSWER>>Long-lasting, perhaps permanent. Can be result of single large dose or repeated smaller doses. Also refer to long-lasting exposures as chronic Difficult to study the effects of chronic exposure since aging or other diseases may be acting as well.

thresholds - ANSWER>>The Delaney Clause of the U.S. Food and Drug Act forbids the addition of any amount of known carcinogens to food and drugs.

This standard was impossible to meet and was replaced in 1996 by a "no reasonable harm" requirement defined as less than one cancer for every million people exposed over a lifetime.

Delaney Clause 1958 - ANSWER>>added to the US Food and Drug Act, forbids addition of any amount of know carcinogen to food and drugs, based on the assumption that any exposure to these is an unacceptable risk This standard was impossible to meet and was replaced in 1996 by a "no reasonable harm" requirement defined as less than one cancer for every million people exposed over a lifetime.

wind turbine syndrome - ANSWER>>a psychogenic condition with no physical basis, from people who were against wind turbines claiming to be sick

risk - ANSWER>>possibility of suffering harm or loss

risk assessment - ANSWER>>scientific process of estimating the threat that particular hazards pose to human health Risk Identification Dose Response Assessment Exposure Appraisal Risk Characterization

risk assessment isn't rational - ANSWER>>Interested parties tend to downplay or emphasize risks to suit their agenda. We tend to tolerate risks we choose, while objecting to risks that we cannot control. Most people do not understand probability. Personal experience can be misleading. We have an exaggerated view of our own abilities. Most people consider themselves above average drivers. News media over-report sensational events and under-report mundane events, skewing our perception of their frequency. Irrational fears can lead to overestimation of danger

risk acceptance - ANSWER>>People will tolerate a high probability of an occurrence if the harm caused is low. Great harm is acceptable only at very low levels of frequency. For most people, a 1 in 100,000 chance of dying is a threshold for changing behavior. Environmental Protection Agency assumes that a risk of 1 in 1 million is acceptable for environmental hazards. Risk of dying of lung cancer if you smoke is 1 in 4, while risk of drinking water contaminated with the limit of trichloroethylene is 1 in 10 million. Yet many people are focused on the latter.

epigenome - ANSWER>>scientists are finding that a complex set of chemical markers and genetic switches consisting of DNA and its associated proteins and other small molecules, regulations gene function in ways that can affect multiple generations

establishing health policy - ANSWER>>It is difficult to separate the effects of multiple hazards and evaluate their risks accurately, especially when exposures are near the threshold of measurement and response. In setting standards, we should consider: combined effects of exposure different sensitivities effects of chronic as well as acute exposure Not reasonable to be protected from every contaminant no matter how small the risk We must consider the effects on other organisms that define and maintain our environment.

BPA - ANSWER>>Bisphenol A, key ingredient in polycarbonate plastics and epoxy resins, used for everyday items, chemical amounts found in most humans, not confirmed but possible that people get disease from it, limit is 50 micrograms of BPA per kilogram of body weight, can get into food sources

environmental health - ANSWER>>focuses on external factors that cause disease, including the elements of the natural, social, cultural, and technological worlds in which we live

women's education and child survival - ANSWER>>according to WHO, half of all gains in child survival are brought about by increases in women's education

protozoans - ANSWER>>single-celled animals

pandemics - ANSWER>>worldwide epidemics

Severe acute respiratory syndrome (SARS) - ANSWER>>pandemic in 2003, thought to have started in Chinese markets, rapid transmission around the world to 31 countries

HIV - ANSWER>>largest recent death toll from an emergent disease was from this, immune-deficiency, 35 mil people infected, 2.5 million die from its complications

white nose syndrome - ANSWER>>ecological disease, bats have fungus grow on their face and wings which wakes them during hibernation and can make them lose a month's worth of fat

Chytridiomycosis - ANSWER>>ecological disease, kills frogs and toads, seen in Australia and spread, fungal infection, hot temperature can kill the fungus

Dermo - ANSWER>>ecological disease affecting oysters in North America, from a protozoan parasite

Toxoplasma gondii - ANSWER>>ecological disease, single-celled protozoaan infects cats and other mammals can cause birth defects in humans

MRSA - ANSWER>>bacteria in Staphylococcus, cause of strep, now becoming resistant to types of penicillins, frequent in places where many antibiotics are used

ecotoxicology - ANSWER>>deals with the interactions, transformation, fate, and effects of natural and synthetic chemicals in the biosphere.

CERCLA (Comprehensive Environmental Response, Compensation , and Liability Act) - ANSWER>>EPA is responsible for monitoring 275 substances regulated by this

sick building syndrome - ANSWER>>headaches, allergies, chronic fatigue, and other symptoms caused by poorly vented indoor air contaminated by mold spores, CO, nitrous oxides, formaldehyde, and other toxins

neoplastic - ANSWER>>tumor

fetal alcohol syndrome - ANSWER>>symptoms including craniofacial abnormalities, developmental delays, behavioral problems, and mental defects

persistent organic pollutants (POPs) - ANSWER>>extremely widespread over the globe, accumulate in food webs and reach toxic concentrations in long-living top predators such as humans, sharks, raptors, swordfish, and bears

PFOS and PFOA - ANSWER>>types of POPs, members of a chemical family to make nonstick, waterproof, and stain-resistant products, reported to be infinitely persistent in the environment

Phthalates - ANSWER>>type of POPs, found in cosmetics, deodorant, and many plastics, used for food packaging, children's toys, and medical devices, can be toxic to lab animals, kidney and liver damage and possibly some cancers, can be endocrine hormone disrupters and cause reproductive issues

Perchlorate - ANSWER>>type of POP, waterborne contaminant left over from propellants and rocket fuels, polluted water used for irrigation has gotten into crops and humans, can interfere with the thyroid gland and metabolism

atrazine - ANSWER>>type of POP, most widely used herbicide in America, applied on corn and cereal grains, also on fields and trees, disrupts endocrine hormone functions in mammals, spontaneous abortions, low birth weights, and neurological disorders, low amounts can be very harmful, found in rain and surface waters

body burden - ANSWER>>accumulation of persistent toxins in the body, acquired from air, water, diet surroundings