How does pollution make people sick, and how do diseases spread through dirty water?
Topic 8.14 Pollution and Human Health: describe how pollutants and pathogens affect human health and how infectious diseases spread through the environment.
A focused answer to APES Topic 8.14, covering the health effects of pollutants (heavy metals, particulates, toxins), waterborne and infectious diseases (cholera, typhoid, dysentery), pathogens and disease vectors, the difference between acute and chronic effects, dysentery and access to clean water, and prevention, with a worked disease-rate reasoning example.
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What this topic is asking
The College Board (Topic 8.14) wants you to describe how pollutants and pathogens affect human health and how infectious diseases spread through the environment.
Health effects of pollutants
Pathogens and waterborne disease
Prevention
Why this matters
This topic ties the whole of Unit 8 to human wellbeing: the pollutants and pathogens covered earlier are dangerous because of what they do to people. It links directly to sewage treatment (which removes pathogens), to indoor air pollution (Unit 7), and to the toxicology of LD50 and dose-response, completing the pollution-to-health chain.
Try this
Q1. Identify one waterborne infectious disease. [1 point]
- Cue. Any one of cholera, typhoid, or dysentery.
Q2. Explain the difference between an acute and a chronic health effect of a pollutant. [2 points]
- Cue. An acute effect appears soon after a single or short, high exposure; a chronic effect develops slowly from repeated or long-term exposure to lower doses.
Exam-style practice questions
Practice questions written in the style of College Board exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
AP 2022 (style)4 marksSection II (FRQ). (a) Identify one pollutant that harms human health and the effect it causes. (b) Identify one waterborne infectious disease and how it spreads. (c) Explain the difference between an acute and a chronic health effect. (d) Describe one method to reduce waterborne disease.Show worked answer →
A 4-point FRQ on pollution and human health.
(a) Identify (1 point): a pollutant and effect, for example lead (neurological damage), mercury (nervous system damage), or fine particulates (respiratory and heart disease).
(b) Identify (1 point): a waterborne disease such as cholera, typhoid or dysentery, spread through water contaminated with sewage or faecal pathogens.
(c) Explain (1 point): an acute effect appears soon after a single or short high exposure; a chronic effect develops slowly from repeated or long-term lower exposure.
(d) Describe (1 point): provide clean drinking water and sanitation, treat sewage, disinfect water, or control disease vectors.
Markers reward a valid pollutant with its health effect, a valid waterborne disease and its faecal-contamination route, the acute-versus-chronic timing distinction, and a valid prevention method.
AP 2018 (style)1 marksSection I (multiple choice). Cholera, typhoid and dysentery are best described as: (A) chronic diseases caused by heavy metal exposure (B) waterborne infectious diseases spread by faecal contamination of water (C) non-infectious effects of air pollution (D) diseases spread only by mosquitoes. Justify your choice.Show worked answer →
A 1-point MCQ on waterborne disease. The answer is (B).
Cholera, typhoid and dysentery are infectious diseases caused by pathogens that spread when water is contaminated with sewage or faecal matter and then drunk or used. They are not heavy-metal effects (A), not air-pollution effects (C), and not mosquito-borne (D, that describes malaria or dengue). The trap is confusing waterborne faecal-route diseases with vector-borne or chemical health effects.
Related dot points
- Topic 8.11 Sewage Treatment: describe the stages of sewage treatment and explain how they reduce water pollution.
A focused answer to APES Topic 8.11, covering the primary, secondary and tertiary stages of sewage treatment, what each removes, the role of disinfection, sludge handling, why untreated sewage is dangerous, and the link to eutrophication and pathogens, with a worked BOD reduction calculation.
- Topic 8.1 Sources of Pollution: distinguish point and non-point sources of pollution and identify major types of pollutants.
A focused answer to APES Topic 8.1, covering the distinction between point and non-point sources of pollution, examples of each, why non-point sources are harder to control, the major pollutant types, and how this shapes management, with a worked load calculation.
- Topic 8.12 Lethal Dose 50% (LD50): explain what LD50 measures and how it is used to compare the toxicity of substances.
A focused answer to APES Topic 8.12, covering what LD50 means, how it is measured and expressed (mass per body mass), how a lower LD50 means greater toxicity, the role of body mass, the limits of the measure, and its link to the dose-response curve, with a worked LD50 dose calculation.
- Topic 8.13 Dose Response Curve: interpret a dose-response curve and explain the difference between threshold and linear (non-threshold) responses.
A focused answer to APES Topic 8.13, covering how to read a dose-response curve, the difference between threshold and non-threshold (linear) responses, the role of the LD50 and ED50, why some chemicals have no safe dose, the limits of extrapolating from animal studies, with a worked dose-response reading example.
- Topic 7.5 Indoor Air Pollutants: identify the major indoor air pollutants and their sources and explain why indoor air pollution is a serious health risk.
A focused answer to APES Topic 7.5, covering the major indoor air pollutants (carbon monoxide, radon, asbestos, VOCs, particulates from biomass burning, mold, lead), their sources, why indoor air pollution is so dangerous in developing and developed countries, and how to reduce it, with a worked radon risk reasoning example.
Sources & how we know this
- AP Environmental Science Course and Exam Description — College Board (2020)