HEA 316 Ch. 7

Which of the following statements about LD50 is false?

A substance with an LD50 of 85 is more toxic than one with an LD50 of 30

In assessing health risk, how do investigators typically determine whether or not the substance in question poses a threat to humans?

Animal testing

In modern times, which of the toxic substances discussed in this chapter has been responsible for the largest incidence of deaths and disabling disease?

Asbestos

Name a toxic substance that has been associated with lung cancer.

Asbestos

Name a toxic substance that has been associated with mesothelioma.

Asbestos

Name a toxic substance discussed in this chapter for which no level of exposure can be considered safe.

Asbestos or lead

Cigarette smoking significantly enhances the risk of which two asbestos related disease?

Asbestosis, lung cancer

What policy action did the EPA take in 1993 in order to protect waterfowl from lead poisoning?

Ban on lead fishing sinkers

Name two ways in which lead is currently entering the environment.

Burning of lead-contaminated used oil, emissions from smelters, incineration of municipal refuse

What painful treatment method is prescribed for severe lead-poisoning cases?

Chelation therapy

A chemical that can damage health when exposure to repeated low doses occurs over an extended time period can be said to exhibit (_____?______) toxicity.

Chronic

Lead poisoning in adults due to occupational exposure is most common among those engaged in what kind of work?

Construction workers who renovate or demolish bridges

The most serious effect of lead poisoning is:

Damage to brain and central nervous system

Name a toxic substance that has been associated with disruption of hormonal system.

Dioxin

What was the toxic contaminant in Agent Orange which allegedly caused a variety of ailments among Vietnamese civilians and American servicemen exposed to the chemical during the Vietnam War?

Dioxin

What is the least reliable and most problematic step in the risk assessment process?

Exposure assessment

Bisphenol A has been shown to induce liver cancer in humans even at low levels of exposure.

False

Carrots, beets, and potatoes are more likely to be contaminated with lead than are spinach and lettuce.

False

Dioxin's reputation as an extremely toxic chemical is due to the fact hamsters are quickly killed by very minute doses of TCDD.

False

Elevated levels of mercury have been found in farmed salmon due to contamination of their feed with this toxic substance.

False

Encapsulation is the most commonly chosen asbestos abatement option.

False

Inorganic forms of mercury are more toxic to humans than are organic mercury compounds such as methyl mercury.

False

Lead that is inhaled poses less risk to adults than does lead that is ingested, because most of it is quickly exhaled.

False

Lung damage, especially lung cancer, is the major problem experienced by those who inhale mercury vapors.

False

Mesothelioma is currently the leading cause of asbestos-related death in the U.S.

False

On the dose-response curve, the threshold is the point where the curve flattens out after reaching its maximum effect

False

TCDD (dioxin) has been manufactured for use in hundreds of valuable commercial products.

False

The most common adverse health effect associated with PCB exposure is liver cancer.

False

When taken into living organisms, PCBs accumulate in the bones.

False

Where do PCBs, dioxins, or any of the chlorinated hydrocarbons concentrate in living tissues?

Fat

Where in the body does dioxin accumulate?

Fatty tissues

PCBs, which biomagnify as they move up the food chain, are most commonly taken up by humans when they eat certain kinds of:

Freshwater fish

Which of the following animals is most acutely sensitive to the toxic effects of dioxin?

Guinea pigs

Which of the following options describes the effects of endocrine disruptors?

Immune effects in humans and animals

Which of the following is NOT a step in health risk assessment

Implementation of regulations

Indicate the primary route of entry into the human body for PCBs

Ingestion

Indicate the primary route of entry into the human body for dioxin

Ingestion

Indicate the primary route of entry into the human body for methyl mercury

Ingestion

What is the single most frequent cause of childhood lead poisoning?

Ingestion of lead-based house pain in the form of dust or paint chips

Indicate the primary route of entry into the human body for asbestos

Inhalation

Indicate the primary route of entry into the human body for inorganic mercury

Inhalation, Skin absorption

Indicate the primary route of entry into the human body for lead

Inhalation, ingestion

What is the term used to describe the acute toxicity of a chemical?

LD50

If a preciously healthy individual suddenly began complaining of severe stomach pains, vomiting, and constant fatigue, appeared unusually irritable and quarrelsome, and lost his/her appetite, an alert observer might suspect the possibility of poisoning with what toxic substance

Lead

Name a toxic substance that has been associated with anemia.

Lead

Name a toxic substance that has been associated with gout.

Lead

Name a toxic substance that has been associated with learning disabilities.

Lead

What is regarded as the most important environmental health problem affecting American children?

Lead

Which two of the following toxic substances are capable of crossing the placental barrier and causing severe fetal damage in humans?

Lead and Mercury

What specific public health concern was the main factor in EPA's decisions to phase out the use of leaded gasoline?

Learning disabilities in children

What is currently the leading cause of asbestos-related death?

Lung Cancer

What constitutes the largest source of dioxin entering the environment at present?

Medical waste incinerators

Name a toxic substance that has been associated with Mad Hatters' Disease

Mercury

Name a toxic substance that has been associated with Minamata Disease.

Mercury

Name a toxic substance that has been associated with fetal brain damage.

Mercury

Prospecting methods employed by gold miners in Brazil are resulting in what serious public health problem?

Mercury poisoning

What ailment is considered a "marker disease" for asbestos exposure due to the fact that asbestos is the only known cause of this illness?

Mesothelioma

What are the two main health concerns underlying government asbestos abatement mandates?

Mesothelioma, lung cancer

"Minamata Disease" killed or seriously disabled hundreds of Japanese who had inadvertently eaten fish contaminated with:

Methyl mercury

For purpose of regulation, what assumption regarding carcinogens currently prevails for assessing cancer risk?

No threshold level

"Chloracne" is the first and most characteristic symptom of poisoning with which of the following?

PCBs

Of all the human-made contaminants found in the modern environment today, which is the most widespread?

PCBs

The 1976 Toxic Substances Control Act specifically banned the production and use of what substance?

PCBs

Which of the following is now banned from production, sale, and distribution in the U.S.?

PCBs

Name a toxic substance that has been associated with chloracne.

PCBs, dioxin

Cite one reason why human exposure to lead has declined in recent years.

Phase-out of leaded gasoline, reduction in use of lead-soldered cans

Name a source of human exposure to bisphenol-A.

Plastic food or drink containers, baby bottles, sippy cups, plastic tableware

What is considered to represent the single most frequent cause of lead poisoning among American children?

Swallowing paint chips or paint dust

Why is testing for chronic toxicity more difficult, time consuming, and expensive than testing for acute toxicity?

Symptoms may take months or years to manifest themselves: tests are usually carried out for a time period equivalent to the average lifespan of the rats or mice: symptoms are often similar to other common health complaints and may be misdiagnosed

Which of the following statements regarding toxicity is correct?

The lower the LD50, the more toxic a substance is

On a dose-response curve, what is the term used to indicate the point at which the preciously horizontal line begins to curve upward?

Threshold

Asbestosis develops only after years of exposure to high concentrations of asbestos fibers.

True

Dioxin is very stable chemical, persisting in soils for man years after deposition.

True

In spite of the fact that PCBs were developed strictly for industrial use, they have become very widespread throughout the natural environment.

True

Ingesting asbestos with drinking water, as opposed to inhaling asbestos fibers, does not appear to increase the risk of asbestos-related disease.

True

Lead-base housepaint is still causing lead-poisoning cases among children.

True

Mercury is an example of a toxic substance that bioaccumlates as it moves up the food chain.

True

Occupational exposure to mercury fumes is widespread among dentists and dental hygienists.

True

Only friable asbestos presents serious health concerns in public buildings,

True

PCBs are very useful synthetic organic chemicals that have been used in a wide range of industrial products.

True

The 1986 Asbestos Hazard Emergency Response Act only requires schools to inspect for the presence of asbestos but also to carry out an abatement plan if asbestos-containing materials are found.

True

The food most directly associated with increasing human body levels of PCBs is freshwater fish.

True

The recommended method for disposal of asbestos wastes following and abatement project is burial in a sanitary landfill.

True

There is no convincing evidence that PCBs cause any chronic health problems in humans.

True