Module 3 Toxicology -Environmental Toxicology Lecture Review

Flashcards generated from lecture notes on environmental toxicology, focusing on Hurricane Harvey's impact, heavy metal, and PAH contamination.

What event caused widespread flooding and toxic chemical release in Houston in 2017?

Hurricane Harvey, a Category 4 hurricane that stalled for 6 days and dropped ~50 inches of rain.

What types of contaminants entered floodwaters during Hurricane Harvey?

Sewage, heavy metals, industrial chemicals, petrochemicals, and toxins from Superfund sites.

Why were poorer neighborhoods more impacted by Hurricane Harvey contamination?

They were closer to industrial sites, Superfund sites, and sewage facilities, and had fewer resources to recover.

What defines heavy metals?

Metals with density > 5 g/cm³, though definition varies.

What property of heavy metals has the greatest implications for their effects on organisms?

Their strong affinity for macromolecules (proteins, DNA, etc.).

True or False: Heavy metals are highly toxic because they bind readily with biological molecules.

True.

Through what routes can heavy metals enter organisms?

Ingestion, inhalation, drinking contaminated water, and skin contact.

Why are heavy metals persistent in the environment?

They are non-biodegradable and strongly bind to soils and particles.

What is bioaccumulation and why is it important for metals?

Metals accumulate in organisms over time and magnify up the food chain, increasing toxicity risk.

What human body system is most acutely affected by lead exposure?

The central nervous system.

What are health effects of lead exposure in children?

Reduced IQ, attention problems, hyperactivity, impaired growth, and learning disabilities.

What are common anthropogenic sources of lead in soil?

Vehicle emissions from leaded gasoline, deteriorating lead paint, industrial releases, and toxic waste sites.

What is the primary exposure route for lead?

Oral ingestion (soil, dust, food, water).

How can residents reduce lead exposure from soil?

Cover soil, use raised beds, wash produce, limit bare soil play, remove shoes indoors, wash hands and toys often.

How do polycyclic aromatic hydrocarbons (PAHs) primarily enter the environment?

Through incomplete combustion of fossil fuels.

What is the danger of contacting PAH-contaminated floodwaters?

They can enter the body through ingestion, inhalation, or skin contact, causing both short- and long-term health risks.

What are examples of PAH exposure routes for humans?

Ingesting charred foods, inhaling combustion particles, contact with contaminated soil or water.

What property affects a substance’s ability to cross cell membranes by passive diffusion?

Lipid solubility.

What properties make inhaled toxicants most likely to be absorbed?

Water solubility and small molecular size.

What is the role of the cell membrane in toxicant exposure?

It regulates entry; toxicants cross by diffusion, transport proteins, or endocytosis.

Which neighborhoods were most impacted by Hurricane Harvey contamination?

Low-income and minority neighborhoods near industrial and contaminated sites.

What factors explain why poorer neighborhoods were more affected?

Proximity to industrial pollution, weaker infrastructure, and fewer resources for recovery.

What are long-term implications of Hurricane Harvey for low-income families?

Slower economic recovery, long-term health risks, and greater vulnerability to future disasters.

What is the connection between climate change and hurricanes like Harvey?

Climate change increases severe weather events, raising storm intensity, flooding, and disaster risk.

What are some policies to reduce impacts of future hurricanes?

Stronger regulations on pollution, better infrastructure planning, climate mitigation policies, and community preparedness.

What are PAHs?

Polycyclic aromatic hydrocarbons, toxic chemicals formed by incomplete combustion of fossil fuels.

What are main sources of PAHs?

Burning fossil fuels, tobacco smoke, grilled/charred foods, industrial processes.

What are known health effects of PAHs?

Cancer risk, respiratory issues, and potential reproductive/developmental effects.

What are the main components of soil?

Minerals, organic matter, water, and air.

How does soil composition influence chemical fate?

Particle size, pH, cation exchange capacity, and organic matter affect binding and transport of chemicals.

How do clays and humic substances affect metal binding?

They have negative charges that bind cations and metal ions, reducing mobility but increasing persistence.

What are anthropogenic sources of lead?

Leaded gasoline, deteriorating paint, industrial emissions, waste sites.

What are the main exposure routes for lead?

Ingestion of soil, dust, or contaminated produce; touching contaminated surfaces then hands/mouth.

What are health consequences of lead exposure in children vs adults?

Children: cognitive and developmental issues. Adults: kidney damage, hypertension, neurological issues.

What are the four major routes of toxicant exposure?

Inhalation, ingestion, dermal (skin), injection (less common in environmental exposures).

What determines how much of a toxicant is absorbed?

Dose, duration, route of exposure, and properties like solubility and ionization.

How do income and race influence exposure to pollution?

Lower-income and minority communities are often closer to industrial sites and have fewer resources to relocate.

What are long-term health effects of living near industry?

Chronic respiratory problems, cancer risk, cardiovascular disease, neurological issues.

What social/economic factors influence pollution exposure?

Housing costs, zoning laws, industrial siting, and systemic inequities.