Toxicology and Human Health Flashcards
6 cards from real Environmental Science practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Toxicology and Human Health flashcards as text
Indoor air pollution is considered a greater health threat in developing countries than in industrialized nations primarily because:
Answer: Widespread use of biomass fuels (wood, charcoal, dung) for cooking and heating in poorly ventilated homes creates extremely high indoor particulate and CO concentrations
About 3 billion people cook and heat with biomass; burning wood, charcoal, and dung in enclosed spaces without proper chimneys creates PM2.5 and CO levels orders of magnitude above WHO guidelines.
Particulate matter (PM2.5) is especially dangerous to human health because:
Answer: Its small size allows it to penetrate deep into the lungs and enter the bloodstream, causing respiratory and cardiovascular disease
Particles 2.5 micrometers or smaller can penetrate to the alveoli, enter the bloodstream, and trigger systemic inflammation linked to cardiovascular disease, stroke, and premature death.
The dose-response concept of hormesis refers to a condition in which:
Answer: A substance shows a stimulatory or beneficial effect at low doses but an inhibitory or toxic effect at high doses
Hormesis describes a biphasic dose-response where low doses are stimulatory or beneficial and high doses are inhibitory or toxic - yielding a J-shaped or inverted U-shaped dose-response curve.
Arsenic in drinking water is a major health problem in Bangladesh and parts of South Asia primarily because:
Answer: Naturally occurring arsenic in deep geological formations leaches into groundwater drawn from tube wells
Arsenic-rich sedimentary deposits in the Bengal Basin release arsenic into groundwater under reducing conditions; millions of tube wells installed to avoid surface water pathogens now tap arsenic-contaminated aquifers.
The primary reason stratospheric ozone depletion increases human health risk is:
Answer: Increased UV-B radiation reaching Earth's surface, elevating risks of skin cancer, cataracts, and immune suppression
Stratospheric ozone absorbs most UV-B (280-315 nm); ozone depletion increases UV-B reaching Earth's surface, raising rates of melanoma, non-melanoma skin cancers, cataracts, and suppressing immune function.
Nitrate contamination of drinking water poses the greatest health risk to:
Answer: Infants under 6 months of age, who are at risk of methemoglobinemia
In infants, gut bacteria convert nitrate to nitrite; nitrite oxidizes hemoglobin to methemoglobin (unable to carry oxygen), causing blue baby syndrome (methemoglobinemia).