Toxicology

Carcinogenic
A cancer causing substance or agent.
Any substance that causes cancer. Substances that produce malignant tumors are carcinogens.
Tetrogenic
Teratogenic
Teratogen- Any substance capable of causing malformation during the development of the fetus, thus, causing birth defects.
Agents which cause structural abnormalities in unborn offspring.
Any substance that causes fetal malformations (birth defects).
Mutagenic
An agent such as a chemical, ultraviolet light, or radioactive element, that can induce or increase the frequency of mutation in an organism.

Mutagen- agents which cause changes in genetic material. Any substance that causes DNA damage, ranging from changes in one or a few base pairs to gross changes in chromosome structure or number.

Poison
A substance that causes injury, illness, or death.

Something destructive or fatal

Acute vs. Chronic exposure
Chronic:
exposure- more than a few
onset of symptoms- one week, years

Acute:
exposure- usually one
onset of symptoms- immediate, minutes, hours

Inhalation
Lungs-
Main absorption site in the lungs are the alveoli. Toxic gases are absorbed by the blood. Liquid aerosols and particulate matter are engulfed by phagocytes and absorbed into the lymphatic’s.
Ingestion
GI tract-
The stomach is a significant site of absorption. In the intestine there is a carrier-mediated transport system for nutrient absorption. Toxicants such as lead, Thalium, and similar substances can be absorbed.
Injection
Dermal
Skin offers barriers against external stimuli. Some toxicants can be absorbed through the skin via the following routes:
-hair follicles
-sweat glands
-sebaceous glands

However, percutaneous absorption occurs through the skin proper- Epidermis and Hypodermis

Lethal Dose (LD 50)
LD 50 is the amount of substance that kills 50% of test animals.

Categories:
Category……..LD 50
Super Toxic- <1 mg/kg
Extremely Toxic- 1-5mg/kg
Highly Toxic- 5-50 mg/kg
Moderately Toxic- 50-500 mg/kg
Slightly Toxic- 500-5,000 mg/kg
Tech. Non-Toxic- 5,000-15,0000 mg/kg
Relatively Safe- >15,000 mg/kg

Dose/Response
HSCI 380 notes
Dose-response relationship:
Response to dose on a log scale; central portion of population curve (16-84%)
TWA – Time Waited Average