ENSC 1003 Chapter 8

The Delaney Clause (1958) Replaced by: Food Quality Protection Act

1st: forbade the addition of any known carcinogens to food/drugs 2nd: now just "no reasonable harm" requirement, define as 1 cancer for every 1 million people exposed over a lifetime

Referring to the dose/response curve, the greatest number of individuals respond to this toxin at a dosage of _______ppm

20

A group of cells that grows extremely fast and begins to obstruct other cells' functions is known as

A malignant tumor

Emergent disease

A new disease or one that has been absent for at least 20 years

Which of the following practices contributes least to antibiotic or pesticide resistance?

A person takes the full course of the appropriate antibiotic when she has a bacterial infection

An advantage of testing for toxicity by exposing animals to chemicals is that using animals is

A trusted and usually reliable way to get results

Individuals represented by the middle of the dose/response curve (responding to doses of 20 ppm) are _________for that population.

About average in sensitivity

Bioaccumulation is important because it allows cells to

Accumulate essential nutrients and minerals

Allergens are substances that

Activate the immune system

Mutagens

Agents that damage or alter genetic material. Can lead to birth defects or tumors. (Mustard gas, dyes, heavy metals, pesticides) Results can be passed to future gens

Among the most important characteristics of chemicals in determining their environmental risks is/are

All

Which of the following factors would explain the seemingly irrational behavior of a father who smokes (high risk factor for baby), but throws away his baby's teething rings that may contain phthalates (seemingly low risk factor for baby)?

All of these factors can lead to the relatively irrational behavior demonstrated by the father

The magnificent 7 toxins

Allergens Immune System Depressants Endocrine Disruptors Neurotoxins Mutagens Teratogens Carcinogens

Our bodies minimize the effects of toxic compounds by all of the following except

Antagonistic reactions

Chemical Interactions

Antagonistic, Additive, Synergistic

Some particles or cells cause immune responses when your body's white blood cells recognize them as foreign objects. These are known as

Antigens

Hazardous substances _______ while toxins are ________.

Are dangerous substances; poisonous substances

Chronic effects of a toxin response

Can last a long time or be permanent

_________, rather than ________, are becoming the leading cause of the disability and premature death worldwide.

Chronic conditions such as cardiovascular disease; infectious diseases such as malaria

Fat soluble contaiminants

Commonly biomagnify from lower to higher trophic levels

Endemic

Constant presence of a disease within a population or group

Health organizations now use the ______, a tool to __________.

DALY; judge the total impact of the disease rather than only measuring how many people die.

Radiation can act as a mutagen because it

Damages genetic material in cells

Endocrine disruptors

Disrupt normal hormone functions

Neurotoxins act by

Disrupting nerve cells

Factors affecting toxicity

Dose Amount of exposure Route of entry Timing of exposure Sensitivity of organism

Teratogens cause abnormal growth specifically in

Embryos

Pandemic

Epidemic that spreads across large land areas, even continents (moves around the globe).

Two problems encountered in human health risk assessment are_________ and _________.

Extrapolation of data to low doses;extrapolation of data from nonhuman species to humans

One positive aspect of the current state of world diseases is that domestic and wildlife are not experiencing epidemics.

False

Cardiovascular disease is strongly related to what dietary factors

High salt and fat intake

The biomagnification of of DDT demonstrates that

Higher trophic level organisms can concentrate toxins in a type of "inverse biological pyramid."

Which of the following statements is true?

If a substance is toxic, its toxicity is highly dependent on its form and where it is present in the environment

Morbidity is another word for

Illness

Acute effects of a toxin appear

Immediately after exposure

Historically, which of the following considerations in setting standards for toxic exposure has been emphasized the least?

Including information about how toxins affect natural ecological systems

An LD50 is a dose of a toxic chemical that

Kills half of the population

Synergistic reaction

M1 strengthens (exacerbates) the effect of M2 -asbestos + smoking increases lung cancer risk from 20x to 400x

Infectious diseases such as diarrhea are closely linked to

Malnutrition

As a society, we usually focus attention on health risks that are

Most well publicized and frightening

Tumors can grow because of exposure to

Mutagens

The saying "the dose makes the poison" means that

Nearly anything can be toxic at some level

Diseases usually develop in response to _________ factors.

Nutritional & diet Infectious or toxic Physical, physiological stress (All of these are correct)

If solubility is an important characteristics in toxic material movement in the environment -and body, which of the following statements is true?

Oil-soluble compounds accumulate in the body

If 100 cups of strong coffee contain a lethal dose of caffeine, why don't coffee drinkers eventually die from caffeine overdoses?

Our bodies metabolize the caffeine before lethal concentrations are reached

Carcinogens are substances that cause

Out of control cell growth and tumors

Historically, the greatest threats to human health came from

Pathogenic Organisms

Most people do their own personal risk assessments based upon

Personal biases and preferences as well as logic

The World Health Organization regards health as primarily a matter of ___________ well being.

Physical, mental, & social

Epidemic

Rapid spread to large number of people in a given population

Toxic substances are dangerous because they

React or interfere with specific cell function

Highly persistent toxic chemicals

Retain their toxicity as they cycle through the food chain and environment

Bioaccumulation is a term that describes the way cells

Selectively absorb and store molecules

Which of the following tissues are more likely to develop cancers?

Skin, because there is a high cellular reproduction rate to replace injured cells

Which of the following is not a problem with generalizing the results of LD50 to humans?

Smaller species generally have reactions that are more sensitive

The dose/response curve shows that

Some exposure is necessary before most individuals respond

Toxicity ratings

Supertoxic -- lethal in a dose of a few micrograms (radioactive waste/dioxins) Extremely toxic -- 0.001 g/kg of body weight Very toxic -- 0.1 g/kg body weight Moderately toxic -- 1 g/kg of body weight to produce lethal dose

A chemical interaction in which one substance exacerbates the effects of another is termed

Synergism

Fetal alcohol syndrome is caused by exposure to a(n)

Teratogen

Detection of toxic chemicals depends upon

The sensitivity of measuring techniques and how many chemicals are present

Malaria is caused by a parasite that is transmitted by mosquitoes

True

Pathogenic organisms are those that cause diseases.

True

The DALY combines premature deaths and loss of healthy lives resulting from illness or injury.

True

Toxins can be dangerous in very small concentrations.

True

Individuals represented by the right end of the dose/response curve (responding to doses between 30 and 40 ppm) are ______ to the chemical.

Very insensitive

Individuals represented by the left end of the dose/response curve (responding to doses between 0 and 10 ppm)

Very sensitive

ecological diseases (animal epidemics)

White nose syndrome - bats (fungus introduced to U.S. from Europe) Herpes 1 virus - California sea lions (from human sewage) Imported fungus - oaks/redwoods/douglas firs in CA Dermo parasite - oysters/clams (spreading rapidly along East Coast due to warming water)

Diseases such as the recent outbreak of cholera and Ebola are

all of these characteristics of diseases such as cholera and ebola

antibiotic resistance

at least 1/2 of the 100 million antibiotic doses prescribed in the U.S. every year are UNNECESSARY or they are for they WRONG DRUG (i.e. there are 3 different strains of the UTI bacteria)

Teratogens

cause abnormalities during embryonic growth & development Alcohol - Fetal Alcohol Syndrome Thalidomide (used for morning sickness in 50's-60's) - Flipper babies

mortality

death

endocrine disruptors

disrupt normal hormone functions Environmental estrogens - enviro contaminents (BPA, dioxins) that cause reproductive problems in animals even at very low doses Xenoestrogens - synthetic, mimic effect of true estrogen and interact w/cellular receptor sites; can send UNINTENDED signals (possible genetic mutations in next generation)

additive reaction

effects of M1 and M2 are added to one another

Conservation Medicine

examines how environmental changes threaten the health of humans and natural communities

metabolic degradation

in mammals - liver primary site of detoxification for natural/introduced poisons -BUT sometimes harmless compounds can be broken down into harmful ones (benzopyrene in cigarette smoke broken down into cancer-causing carcinogen)

Neurotoxins

metabolic poisons that specifically attack nerve cells Heavy metals (mercury, lead, zinc) - kill nerve cells Anesthetics & Chlorinated Hydrocarbons - disrupt nerve cell membranes Organophosphates & Carbamates - inhibit signal transmission between nerve cells (DDTs, pesticides)

Antagonistic reaction

one material interferes with the effects/stimulates breakdown of other chemicals

Immune System Depressants

pollutants that depress the immune system rather than activate it- pesticides, herbicides, PCBs - opposite of an allergen)

risk

probability of suffering harm or loss

risk assesment

scientific process of estimating the threat that particular hazards pose to human health 1. Identify risk 2. Dose response assesment 3. Exposure appraisal 4. Risk characterization -NOT rational OR scientific -For most people, [1 in 100,000] chance of dying is threshold for changing behavior -For environmental protection agency, [1 in 1,000,000] is acceptable for enviro. hazards

Bioaccumulation

selective absorption and storage of toxins -dilute toxins in the environment can build to dangerous levels inside tissues

persistance

stable chemicals that do not degrade rapidly (metals, BPA); can cause problems as toxins may be stored for long time and spread to unintended victims -Flame retardants (PBDE polybrominated diphenyl ethers), harm child reproductive/nervous systems -Non-stick plastic coatings (PFOS perfluorooctane sulfonate, PFOA perfluorooctanic acid), causes liver damage and cancer; found in blood; women 100x more sensitive then men -Phthalates (found in plastics, deodorants food pkging, toys, medical devices), mimic estrogen, linked to reprod. abnormalities, reduced fertility

toxicology

study of poisonous substances and their effects on living systems

antigens

substances recognized by white blood cells as FOREIGN, stimulating the production of specific antibodies to fight them off

Carcinogens

substances that cause cancer (the 2nd leading cause of death) - 1 in 2 males, 1 in 3 females in U.S. will have cancer in their lifetime

resistance

the ability not to be affected by something

biomagnification

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 (ex/ DDT in water->zooplankton->small fish->lg. fish->birds - magnified at each level)