Chapter 10 Flashcards
Environmental Health
assesses environmental factors that influence our health and quality of life
Physical Hazards
arise from processes that occur naturally in our environment and pose risks to human life or health; some are ongoing like exposure to UV radiation from sunlight; other events include earthquakes, volcanic eruptions, fires, floods, landslides, hurricanes, blizzards and droughts
Chemical Hazards
include many of the synthetic chemicals that our society manufactures, such as pharmaceuticals, disinfectants and pesticides
Biological Hazards
results from ecological interactions among organisms; becoming sick from infection, virus, etc we are suffering parasitism
Cultural Hazards
hazards that result from our place of residence, our socioeconomic status, our occupation or our behavioral choices; AKA lifestyle hazards
Noninfectious disease
diseases not spread from one person to another; such as cancer and heart disease
Infectious disease
invasion by bacteria, viruses, fungi, parasites that do spread from person to person
Injury
damage or harm to the body
Toxicology
the science that examines how poisonous chemicals affect the health of humans and other organisms
Toxicity
the degree of harm a chemical substance can inflict
Toxicant
a toxic substance or poison
Environmental Toxicology
deals specifically with toxic substances that come from or are discharged into the environment
Indoor hazards
cigarette smoke, radon (a radioactive gas that seeps up from the ground) both cause lung cancer; asbestos (used in the past as insulation in walls and other products; lead poisoning from water pipes or leaded paint; PBDE’s: polybrominated diphenyl ethers are used as fire retardants in computers, TV’s, plastics and furniture
Synthetic Chemicals
made from a natural product that are manufactured or imported; these substances find their way into the air, water and soil
Findings of National Water-Quality Assessment Program
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Findings of National Health and Nutrition Examination Survey
data on 148 foreign compounds in Americans’ bodies: there were several toxic persistent organic pollutants restricted by international treaty; depending on the pollutant they were found in 41-100% of the people; exposure to synthetic chemicals begins in the womb
Rachel Carson’s Silent Spring
1962 book that brought exposure to the risks of pesticides and DDT was banned as a result
Natural toxins
toxic substances can exist naturally in the environment; many plants can produce toxins
Toxicants
toxic substances can be classified based on their impacts on health
Carcinogens
substances or types of radiation that cause cancer where malignant cells grow uncontrollably creating tumors and damaging the body
Mutagen
substances that cause genetic mutations in the DNA of organisms; most have little or no effect but some can lead to severe problems
Teratogens
chemicals that cause harm to the unborn and affect the development of human embryos in the womb; can cause birth defects
Neurotoxin
damage the nervous system; includes venoms produced by animals, heavy metals such as mercury or lead and some pesticides
Allergens
overactivate the immune system causing an immune response when one is not necessary
Pathway inhibitors
toxicants that interrupt vital biochemical processes in organisms by blocking one or more steps in important biochemical pathways (ie. endocrine disruptor: mimics the structure of hormone molecules) (i.e. Bisphenol A)
Organism’s natural defenses
some organisms produce biological toxins to deter predators or capture prey ie. venom in poisonous snakes and spiders; skin, scales and feathers resist uptake from the natural environment
Impacts on surface and groundwater
runoff concentrates contaminants; toxic chemicals from urine can make there way into water from wastewater treatment plants; many chemicals are soluable in water so they enter organisms’ tissue through drinking and absorption; aquatic invertebrates, frogs and fish are a good indicator of pollution
Impacts on air
toxic substances released around the world from agriculture, industrial and domestic activities and may be redistributed by air currents
Pesticide drift
air currents can carry pesticides to sites far away from agricultural fields
Global Distillation
toxic substance can be carried great distances especially to Earth’s polar regions because of the natural patterns of global atmospheric circulation; lots of contaminants have been found in penguins, polar bears and people living in Greenland
Bioaccumulation
persistent toxicants accumulate in an organism’s body such that the organism’s tissues have a greater concentration of the substance than exists in the surrounding environment
Biomagnification
toxic substances that accumulate in an organism’s tissues may be transferred to other organisms as predators consume prey; when one organism consumes another the predator takes in any stored toxicants and stores them in its own body; takes place on all trophic levels
Persistent toxins
Bt toxin used in GM crops has a short persistent time but DDT and PCBs persist for decades; the rate at which a substance degrades depends on its chemistry and other factors like temp, moisture and sun exposure
Threat to ecosystem services
ie. pesticide exposure has been a factor in the decline of honeybee populations; ie. when soils are exposed to harmful chemicals nutrient cycling can be altered
Wildlife studies
scientists study the impacts of environmental hazards on wild animals to help conserve animal populations and also understand potential risks to people
Louis Guillette
alligators in lakes in Florida receiving agricultural runoff had higher rates of reproductive problems; early work tying environmental chemicals to endocrine disruption
Tyrone Hayes
frogs raised in water containing atrazine became feminized and hermaphroditic: developing both testes and ovaries; hormonal problems
Case history
process of observing and analyzing individual patients; have advanced our understanding of human illness
Epidemiological Studies
large-scale comparisons among groups of people, usually contrasting a group known to have been exposed to some hazard against a group that has not
Manipulative Studies
specifically changing factors being studied and seeing how things change; manipulates the independent variable
Animal Testing
the use of non-human animals in experiments that seek to control the variables that affect the behavior or biological system under study.
Dose-response analysis
scientists quanitfy the toxicity of a substance by measuring the strength of its effect or the number of animals affected at different doses; standard method of testing with lab animals in toxicology
Dose-response curve
response quantified by measuring the proportion of animals exhibiting negative impacts and the data is plotted on a graph with dose on the x-axis and the response on the y-axis
LD 50
Lethal-dose 50; label for if 50% of the animals are killed; high LD 50 indicates low toxicity for a substance and a low LD 50 indicates high toxicity
ED 50
Effective-dose 50; if 50% of the animals are effected in some other way such as reproductive abnormalities or growths
Threshold dose
below this threshold doses have no measurable effect; might be expected if an organism’s body can fully metabolize or excrete a toxicant at low doses
Acute Exposure
exposure to a toxicant occuring in high amounts for short periods of time
Chronic exposure
exposure for long periods of time to a toxicant occuring in low amounts
Synergistic effects
an interactive effect that is more than or different from the simple sum of their constituent effects
Endocrine Disruption Issues
substances have been linked to effects on reproduction, development, immune function, brain and nervous system function
Perception vs. Probability of Risk
Our perception of risk does not always match reality; risk of dying 1 in 6 heart disease, 1 in 7 cancer, 1 in 29 smoke;
Quantitative Assessment
the quantitative measurement of risk and the comparison of risks involved in different activities or substances together; used to identify and outline problems
Risk management
decisions and strategies to minimize risk
Cost-benefit analysis
look at scientific and nonscientific concerns before making decisions on whether and how to reduce or eliminate risk; benefits are often economic and costs often pertain to health
EPA
environmental protection agency
CDC
centers for disease control and prevention
FDA
food and drug administration
New product safety testing
industrial research & development -> pre-market testing by industry, government and academic scientists -> consumer use of products -> post-market testing by industry, government and academic scientists -> regulations and bans of unsafe products -> consumer use of safe products
Innocent until proven guilty
products brought to the market after little testing; some fraction of them may cause harm to people
Precautionary principle
bringing substances to market only after extensive testing; some say chemical manufacturers should bear the burden of proof for the safety of their products before they hit the market; the principle that the introduction of a new product or process whose ultimate effects are disputed or unknown should be resisted
EPA’s Toxic Substances Control Act (TSCA)
law by the EPA that regulates synthetic chemicals not covered by other laws
European Union: Registration, Evaluation, Authorization and restriction of Chemicals (REACH)
program that shifts the burden for testing chemical safety from national governments to industry and requires that chemical substances produced or imported in amounts over 1 metric ton per yr to be registered with a new European Chemicals Agency; went into effect in 2007
Stockholm Convention on persistent organic pollutants
came into force in 2004; (PoPs) toxic chemicals that persist in the environment, bioaccumulate and biomagnify up the food chain and can travel long distances
