Environmental Q1: Environmental Health and Toxicology

A person has experienced acute exposure to a toxic substance if _____.

there was high exposure for short periods of time

Why are the "dirty dozen" persistent organic pollutants (POPs) so dangerous? They are all toxic to some degree. They are persistent in the environment. They bioaccumulate. All of these are reasons POPs are considered so dangerous. They are known animal carcinogens or endocrine disruptors.

All of these are reasons POPs are considered so dangerous.

Which of the following is the most sensitive to toxicants?

Fetus

This biological hazard kills hundreds of thousands of people each year, is transmitted by a mosquito, and invades red blood cells.

Malaria

Despite health and safety concerns of some chemicals, why are these chemicals still available for use?

Many of them are widespread and perform important functions in our lives.

If the lethal toxicity threshold for a certain chemical is 50 mg/kg, how many test animals will die when given a dose of 10 mg/kg?

None will die.

Which of the following statements is true of biomagnification

The concentration of toxin can more than double at each level of the food chain.

According to the precautionary principle, how should we treat new chemicals?

The responsibility for proving that a new chemical is safe should fall to those who advocate its use.

Why do many people feel that flying in an airplane is a riskier activity than driving a car?

They feel they have control over voluntary activities such as driving but are not in control of the consequences of flying in an airplane.

Why are endocrine disruptors so dangerous?

They interfere with the body's endocrine (hormone) system, which regulates metabolism, growth, and reproduction.

What determines the toxicity of a chemical?

Type of exposure Age of the individual being exposed Health condition of the individual being exposed The dose (amount) of the toxic substance the individual is exposed to

What are known or likely carcinogens?

Ultraviolet light Unselected Alcohol X rays Chemicals in cigarette smoke

A mutagen is __________.

any substance that causes genetic mutations in the DNA of organisms

Sunflowers can be used to "soak up" and remove toxic chemicals from the soil. This is an example of __________.

bioremediation

A chemical hazard that causes cancer is a(n) _____.

carcinogen

Chemical pesticides and PCBs do the greatest harm to top predators such as gulls and ospreys because __________.

concentrations of toxins become intensified as these substances move through food chains

Factors such as smoking, use of harmful drugs, sunbathing, and overeating are termed _____ hazards.

cultural

When testing the toxicity of a substance, the _____ is the amount of substance a test animal receives.

dose

A __________ curve, plotted on a graph, shows the relationship between increasing dosages of a chemical and some measure of health.

dose-response