Toxicology and Dosage Quiz

Toxicology

• Toxic substances negatively affect normal human physiological function. Examples include lead, mercury, alcohol, and hexavalent chromium.
• Acute toxicity is a relatively short-term effect.
• Chronic toxicity results from repeated exposure over a long period.
• Routes of entry include ingestion (eating or drinking), inhalation (breathing), skin absorption, and injection (puncture or cuts).

Dosage

• Dosage is the amount of a chemical administered per unit of body weight.
• Lethal Dose (LD50) is the dosage of a toxic chemical that kills 50% of test animals (mg/kg).
• Routes of entry for LD50 include ingestion, skin absorption, and injection.
• Lethal Concentration (LC50) is the concentration of a toxic chemical in air that kills 50% of test animals (PPM or mg/m³). The route of entry is inhalation.

Target Organ Chemicals

• Hepatotoxins affect the liver. An example is carbon tetrachloride.
• Neurotoxins affect the nervous system. An example is lead.

Reproductive Toxins

• Mutagens cause permanent DNA changes. Example includes radioactive materials and benzene.
• Teratogens cause damage to a developing fetus, which cannot be passed to future generations. Examples are nicotine and alcohol.
• Ototoxins affect hearing and balance. Examples are styrene and certain drugs (antibiotics).

Biological Hazards

• Biological hazards include viral and bacterial infections.
• Symptoms, transmission methods, and the target organs of various infections are also included.

Common Terms

• Brucellosis: A bacterial infection with symptoms like fever and joint pain and is transmitted through cattle.
• Leptospirosis: A zoonotic bacterial disease (transmitted through animals) characterized by fever and joint pain. It is caused by bacteria Leptospira. Transmission can be through infected animal urine.
• Tuberculosis: A bacterial infection primarily affecting the lungs.
• Hepatitis A and B: Viral infections; hepatitis A & B have various aspects and descriptions as well.
• Q fever: A bacterial infection transmitted from animals. Primary reservoirs are cattle, sheep, and goats.
• Siderosis: Inhalation of metal fumes (magnesium and zinc during welding), which can cause lung issues.
• Byssinosis: Lung problems caused by inhaling cotton dust.
• Presbycusis: Age-related hearing loss.
• NIHL: Noise-induced hearing loss.

Biosafety Levels

• Biosafety levels (BSL) are categorized into levels 1 to 4, indicating the potential hazards' severity.
• BSL 1 involves minimal hazards.
• BSL 4 includes the highest possible hazards.
• Biosafety cabinets are classified into three classes, varying in protection levels.
• COVID-19 is a BSL 4, class 3 level hazard.

Ventilation

• Two main types of ventilation exist, including dilution ventilation and local exhaust ventilation (LEV).
• Dilution vent mixes contaminants with fresh air to reduce concentration to below the Occupational Exposure Limit (OEL).
• LEV removes contaminants at their source.
• Hood design is a key component of LEV systems.

Noise

• Any unwanted sound is categorized as noise.
• Noise levels are measured in decibels (dB).
• OSHA sets guidelines for noise exposure limits.
• The noise addition rule helps determine combined noise levels.

Noise Dosage Calculation

• The formula to determine the noise dosage involves adding the individual noise exposure times to the total allowed exposure time for a given dB level.
• The permissible noise exposure time is based on decibel levels.
• Exceeding the time limit for a given decibel leads to over-exposure.

Radiation

• Ionizing radiation produces ionization in matter; nonionizing radiation does not.
• Types of ionizing radiation include alpha (least penetrative), beta (more penetrative), gamma (highly penetrative), and X rays (less penetrative than gamma).
• Alpha particles are highly dangerous if inhaled or swallowed.
• Gamma rays are the most penetrative.
• Non-ionizing radiation includes UV, infrared, and radio frequencies.

Control Measures

• Control measures to reduce radiation exposure include duration, distance, and shielding.
• The Nuclear Regulatory Commission (NRC) regulates radioactive material exposure.

Units of Measurement

• Radioactivity is measured in becquerels (Bq) or curies (Ci).
• Exposure is measured in roentgens (R).
• Dose is measured in sieverts (Sv).

Radiation Distance Equation

• The inverse square law describes how radiation intensity changes with distance.
• The formula shows that intensity is inversely proportional to the square of the distance.