Chapter 7: Toxicology Flashcards
Discern the difference between and irritant/corrosive and a toxicant.
Irritant/corrosive: damage only the tissues they contact
Toxicant: has the ability to cause harm to organs or biochemical processes away from the site on the body where exposure occurred.
What are the three routes of exposure.
Dermal, Oral, Respiratory
What is the difference between acute and chronic toxicity?
Acute: small amount of time, large amount of chemical
Chronic: over a long amount of time, small amount of chemical
What is a risk assessment? What is important to know about a substance that might be toxic?
A risk assessment is when you identify the hazard, assess the dose-response, assess the exposure, and then characterize the risk.
It’s important to know how safe is safe.
What was DDT originally used for?
It was used to treat malaria, typhus, other vector born diseases
What are the environmental effects of DDT?
DDT has detrimentally affected wildlife and it has be indicated as a human carcinogen. It has caused live tumors in animals
Describe biomagnification.
Biomagnification is when something from lower on the food chain ingests the carcinogen and it effects something higher up. For example, when DDT was used it got into the water, therefore it got into the fish that birds eat and the birds were then contaminated with the DDT.
What are PCB’s and what were they used for?
PCBs are Polychlorinated Biphenyls. They were used for industrial purposes because they were extremely stable. They have a high boiling point, low electrical conductivity, and high resistance to heat.
How were PCB’s leaked into the environment? What is the most common form of PCB exposure?
PCBs leaked into the environment when discharge of PCB-laden waste from labs were put into waterways, vaporization from paints or landfills, burning, leaks in industrial equipment, and accidental spills or illegal dumplings. The most common form of exposure is through sport fish.
What were at least two environmental disasters that we discussed so far in class?
Dioxin: Times Beach, MO
Vermiculite/Asbestos: Libby, Montana
What were dioxins originally used for – why were they perceived to be so threatening?
Dioxins were never intentionally manufactured. They were more of an unwanted byproduct. Dioxin, at least in Times Beach was used to keep dust down on gravel roads. It is perceived to be so threatening is because it is slow to break down and we can get it though our food. the labs showed guinea pigs that were exposed died- not as much of an issue with other rodents.
What is asbestos? Why is it used commercially/industrially?
Asbestos is a six fibrous silicate mineral. It was used because it is super useful for so many things. It has been used in isolation, textiles, roofing paper, floor tiles, and just about anything you could think of.
What is the most common and dangerous route of exposure to asbestos?
The most dangerous route of exposure to asbestos is through inhalation.
What are asbestos-related diseases? Which diseases’ only causative agent is asbestos?
Some asbestos-related diseases are asbestosis(Chronic, scarring of lung tissue, 20 years worth of exposure, painful and irreversible), Lung cancer, and Mesothelioma, which asbestos is the only causative agent for mesothelioma.
How can asbestos be treated?
Asbestos can be treated with encapsulation, enclosure, and removal.
