Cambridge IGCSE Environmental Management: Water (0680)

This guide covers Topic 3 Water, the third of seven topics in Cambridge IGCSE Environmental Management (0680) for the 2027–2029 series. Where Topic 1 (Natural resources) dealt with rocks, minerals and energy and Topic 2 (Land) dealt with soil and agriculture, Topic 3 turns to water as both a resource and a source of environmental and health risk — how it is sourced and supplied, how it becomes polluted, the diseases linked to it, how marine species are farmed once overfishing has depleted wild stocks, and two further marine pollution problems, oil and plastic, that close out the topic’s six sub-topics.

Where this fits in 0680

Topic 3 sits at the midpoint of the seven-topic syllabus and connects forward to later topics: water pollution’s causes (industrial and agricultural practices) echo themes from Topics 1 and 2, while water-related disease control strategies anticipate the public-health-and-population thinking that recurs later in the course. The syllabus is explicit throughout Topic 3 about what is and is not required — several learning outcomes are marked “limited to” a defined list, which is a strong signal of exactly what examiners can ask.

Syllabus coverage

CAMBRIDGE IGCSE ENVIRONMENTAL MANAGEMENT 0680 — TOPIC 3: WATER

• 3.1 Water sources and supply — the water cycle (stores: salt water in oceans, fresh water in ice sheets/glaciers, ground water, the atmosphere, lakes and rivers; transfers: precipitation, interception, surface run-off, infiltration, through-flow, ground water flow, transpiration, evaporation, condensation); sources of fresh water (atmosphere, surface water, ground water, desalinated ocean water); the world’s five oceans; the definition of potable water; the stages of water treatment (screening, sedimentation, filtration, chlorination); global inequalities in access to potable water and sewage treatment; desalination by distillation and reverse osmosis, with its benefits and limitations; the uses of a multipurpose dam (flood control, hydro-electric power, irrigation, storage, transport, recreation, tourism, fish farming) and its benefits and limitations
• 3.2 Water pollution — sources of water pollution (domestic waste, sewage, plastic waste, industrial processes, agricultural practices); impacts on people and the environment (infectious bacterial disease such as cholera, accumulation of toxic substances, bioaccumulation, biomagnification up a food chain, acid rain’s effect on aquatic organisms, eutrophication from leaching and nutrient enrichment); strategies for improving water quality (improved sanitation, sewage treatment, pollution control and legislation)
• 3.3 Water-related diseases — how mosquitoes spread malaria (the female Anopheles mosquito as vector, transmission of the malaria Plasmodium parasite to and from humans); strategies to control malaria (personal protection and vector control) and cholera (handwashing, sanitation, potable water supply, vaccination); the benefits and limitations of these control strategies
• 3.4 Marine aquaculture — the impacts of exploiting marine species (overfishing, overharvesting, effects on target and bycatch species and on food chains); the definition of marine aquaculture as farming marine species (fish, crustaceans, seaweeds) in captivity — knowledge of specific species is not required for that definition outcome; the impacts of marine aquaculture itself (reduced exploitation of natural fisheries, increased food supply, risk of escape and disease, effects on local food webs, nutrient enrichment from waste, energy usage, and being a source of food for farmed species); and a nine-item list of strategies for managing the harvesting of marine species (boat/net size limits, increased mesh size, sustainable methods such as pole and line, quotas, closed seasons, limited fishing days, protected areas, conservation laws, and international agreements)
• 3.5 Oil pollution — the causes of oil pollution on marine and coastal ecosystems (off-shore/on-shore extraction, pipelines, shipping, tank-cleaning at sea, refineries); its impacts on birds, marine mammals, fish, crustaceans, seaweeds, coral reefs and beaches (again, knowledge of specific species is not required); prevention strategies (MARPOL, the International Convention for the Prevention of Pollution from Ships, double-hulled tankers, risk assessments, regular maintenance); and strategies for minimising spill impacts (improved navigation, booms and sorbents, detergent sprays, skimmers, controlled burning)
• 3.6 Plastic pollution — conventional, bio-, biodegradable and non-biodegradable plastics; microplastics (formed when larger plastics break down, and defined as less than 5mm in length); the impacts of plastic pollution on marine ecosystems (visual pollution, entanglement, being mistaken for food, bioaccumulation and biomagnification); and management strategies (alternative packaging, avoiding single-use plastics, safe disposal, recycling, legislation and enforcement)

Water sources and supply (3.1)

This is the most content-dense sub-topic and the one most likely to combine a diagram-based question (the water cycle’s stores and transfers) with an evaluative one (desalination or multipurpose dams). Learn the water cycle as two linked lists — stores versus transfers — rather than a single diagram to memorise, since exam questions can ask for either in isolation. For desalination, be able to explain both methods (distillation’s boil-condense cycle versus reverse osmosis’s pressure-and-membrane process) and to weigh cost and energy use against water security. For multipurpose dams, the eight listed uses double as the structure for “discuss the benefits and limitations” answers — each use is a potential benefit, and each has a documented limitation (for example, hydro-electric power versus disruption to river ecosystems and downstream communities).

Water pollution (3.2)

The five sources of pollution and the impacts that follow from them are tightly linked in this sub-topic, so revise them as cause-and-effect pairs rather than two separate lists. Bioaccumulation and biomagnification are frequently confused: bioaccumulation is a toxin building up within a single organism over time, while biomagnification is that concentration increasing further as it passes up a food chain from prey to predator. Eutrophication is worth learning as a full causal chain — nutrient enrichment from agricultural or sewage sources leads to algal bloom, which blocks light and depletes oxygen as it decomposes, harming aquatic life — since “explain” answers that only name eutrophication without tracing this chain lose marks.

Water-related diseases (3.3)

Malaria and cholera are the two diseases named in the syllabus, and each has a distinct transmission mechanism and control strategy set that should not be mixed up: malaria is vector-borne (mosquito to human, human to mosquito) and controlled through personal protection and vector control, while cholera is waterborne and controlled through sanitation, safe water treatment and vaccination. “Discuss the benefits and limitations” questions on control strategies reward naming a specific limitation (for example, insecticide resistance limiting spraying programmes, or vaccination access gaps) rather than a generic “it is expensive” answer.

Marine aquaculture (3.4)

With five learning outcomes against three and four for its water-pollution and disease neighbours, this is actually one of the larger sub-topics in Topic 3, and within it only the outcome defining marine aquaculture itself (3.4.2) says species-specific knowledge is not required. Cover the reasons wild marine stocks are exploited (overfishing, overharvesting), the distinction between target and bycatch species, the impacts of aquaculture itself (not just of wild exploitation) on food webs, disease risk and energy use, and the full nine-item list of strategies for managing the harvesting of marine species — not just the definition of aquaculture in isolation.

Oil pollution (3.5)

Learn causes and impacts as linked pairs, then keep prevention strategies (MARPOL, double-hulled tankers, risk assessments, regular maintenance) separate in your mind from strategies for minimising the impact of a spill that has already happened (navigation systems, booms and sorbents, detergent sprays, skimmers, controlled burning) — a “describe strategies for prevention” question and a “describe strategies for minimising impact” question draw on two different lists.

Plastic pollution (3.6)

New for this cycle. Distinguish conventional plastics (fossil-fuel-derived, generally non-biodegradable) from bioplastics (made fully or partly from biological raw materials, which can themselves be biodegradable or not) — being made from biological material does not automatically mean a plastic biodegrades. Microplastics are defined by a specific numerical threshold (less than 5mm) as well as by how they form (larger plastics breaking down), and their impacts on marine ecosystems (visual pollution, entanglement, being mistaken for food, bioaccumulation and biomagnification) pair with named management strategies (alternative packaging, avoiding single-use plastics, safe disposal, recycling, legislation and enforcement).

Common mistakes

• Confusing bioaccumulation with biomagnification — one is within an organism, the other is up a food chain.
• Listing multipurpose dam uses without pairing each with a limitation when a “discuss” question is set.
• Mixing up malaria and cholera control strategies — vector control applies to malaria, not cholera, and vice versa for sanitation-based measures.
• Adding species-specific detail where the syllabus says it is not required – both the marine-aquaculture definition (3.4.2) and the impacts of oil pollution (3.5.2) state that knowledge of specific species is not required.
• Stopping revision at marine aquaculture (3.4) and treating Topic 3 as running only 1st-to-4th — two more sub-topics, oil pollution and plastic pollution, follow it and are equally examinable.

How to approach it

Work through 3.1–3.6 as a chain: source and supply of water, how it becomes polluted, the diseases that follow from poor water quality, how the pressure on wild marine resources (a consequence of both overfishing and pollution) is being addressed through aquaculture, and finally two more specific marine pollution problems — oil and plastic — each with its own causes, impacts and management strategies. Practise past-paper “discuss the benefits and limitations” questions specifically for desalination and multipurpose dams, since these two sub-topics are the most frequently examined evaluative questions in Topic 3, but do not neglect oil and plastic pollution on the assumption that the topic ends at marine aquaculture.

Related resources

• Cambridge IGCSE Environmental Management: Land (0680)
• Cambridge IGCSE Environmental Management: Natural Resources (0680)

Official syllabus

Cambridge Assessment International Education, Cambridge IGCSE Environmental Management 0680 syllabus for 2027, 2028 and 2029: https://www.cambridgeinternational.org/Images/718156-2027-2029-syllabus.pdf (verified 2026-09-02).