1.3 -Toxicology in Public Health and Environmental Health

Who is most impacted by the environment?

Low and middle income countries bear the greatest share of environmental disease

How do contaminants travel in the environment?

• Soil/waste

• Groundwater

• Landfill gas

• Offsite sources

• Exposure routes

What are the routes of exposure to environmental contaminants?

• Inhalation (lungs)

• Ingestion (GI tract)

• Dermal (skin)

• Clinical practice: additional routes such as injection

How are chemicals absorbed through the respiratory tract?

The surface area of lungs is large and allows for rapid uptake and release of certain molecules

For particulate matter (smaller particles), they move deeper into the respiratory system. They move through alveolar cells and are carried to other organs and can also carry absorbed materials

What are chemicals that can be exposed through vaping?

• Nicotine

• Formaldehyde and flavoring diacetyl (both cause lung damage)

• Ultrafine particles

• Heavy metals including lead

• Cancer causing chemicals

When chemicals are absorbed into the skin, the amount absorbed depends on what factors?

• Whether the skin is damaged (cuts, abrasions, etc.)

• Thickness of the outer layer (stratum corneum) of the skin

• Skin temperature (absorption increases with temperature)

• Physical and chemical properties of the chemical

• Concentration of chemical on skin

• Amount of time the chemical on skin

• Location - hair follicles, sweat ducts, sebaceous glands

How are chemicals absorbed through the GI tract?

Through the small intestine as it has a large surface area to facilitate nutrient absorption. Chemicals can also be absorbed into the body through the small intestine

How does the FDA handle dietary supplement products?

FDA is not authorized to review dietary supplement products for safety and effectiveness before they are marketed. However, the FDA is responsible for taking action against adulterated or misbranded dietary supplement products AFTER they reach the market. (bruh)

What are the four parts of the environmental risk assessment?

1. How much chemical is present?

2. How are people exposed and how much?

3. How toxic is it?

4. What is the likelihood of an adverse effect?

Which act regulated many airborne contaminants?

The Clean Air Act

What is one category of regulated contaminants and what does it include?

Criteria Air Pollutants":

• Particulate matter

• Lead

• Ground-level ozone

• Carbon monoxide

• Sulfur dioxide

• Nitrogen dioxide

How small are particulate matters?

Less than 10 microns in diameter

Why are particulate matters the greatest risk?

Because they can cause…

• Premature death in people who have heart or lung disease

• Nonfatal heart attacks

• Irregular heartbeat

• Aggravated asthma

• Reduced lung function

• Increased respiratory symptoms (airway irritation, coughing, or difficulty breathing)

Who are most susceptible to the effects of particle pollution exposure?

Children, older adults, and people with heart or lung diseases

How does lead affect children ages 0-6 years old?

Reduced IQ, learning problems, and behavioral problems

How does lead affect pregnancies?

Lead can be stored in the bones with calcium and during pregnancy, lead can be released with calcium from the mother’s bones and expose the fetus or breastfeeding infant to lead

How does lead affect fetuses and infants?

• Preterm birth or low birthweight

• Damage to baby’s brain, kidneys, nervous system

• Increased leaning and behavioral problems

• Reduced IQ

What are the health effects of breathing ozone?

• Chest pain

• Coughing

• Throat irritation

• Airway inflammation

• Reduced lung function

• Damage to lung tissues

• Can worsen bronchitis, emphysema, and asthma

How can elevated CO levels affect people?

Reduced oxygen to heart and angina (chest pain), affects people who have a reduced ability to get oxygenated blood to the heart

How does sulfur dioxide affect people?

Can make breathing difficult, sensitive individuals include children and those with asthma

How does nitrogen dioxide affect people?

Irritate respiratory airways, aggravate respiratory diseases (particularly asthma), longer exposures may contribute to the development of asthma and increase risk of respiratory infections, and sensitive individuals include children, elderly, and those with asthma