IELTS vocabulary: Water Pollution

Water pollution appears in Task 2 prompts about environmental protection and industrial regulation, in Part 3 discussions following a Part 2 cue card about nature, a river or lake you know, or a place you've travelled, and occasionally in General Training letters about a local waterway. Candidates often default to describing water as simply "polluted" or "dirty," a description that's accurate but tells an examiner nothing about where the contamination comes from, what specific harm it causes, or what a specific fix would look like. This topic is also frequently confused with the separate issue of water scarcity — an inadequate supply of water — when contamination and scarcity are different problems requiring entirely different vocabulary and solutions. This article works through water pollution specifically: the nature of the problem, its sources, its effects, and the solutions that address it, kept distinct throughout from the neighbouring topics of air pollution and water scarcity.

Start with vocabulary for the problem itself, since precision here sets up everything that follows. "Water pollution" is the general term for the contamination of a water source — river, lake, ocean, or groundwater — with harmful substances. "Contamination" refers more specifically to the presence of a particular harmful substance in water, useful when an essay wants to name what exactly has entered the water rather than describing pollution only in general terms. "Waterborne disease" refers to illness transmitted through contaminated water, such as cholera or dysentery, and remains a leading cause of preventable illness in areas without reliable water treatment — a term that lets an essay connect an environmental problem directly to a measurable public health outcome. "Eutrophication" is a more technical but genuinely valuable term: the process by which a body of water becomes overly enriched with nutrients, typically nitrogen and phosphorus, leading to excessive plant and algae growth that can ultimately suffocate the ecosystem beneath it.

Vocabulary for sources lets an essay name a specific origin, which matters because different sources call for entirely different regulatory responses. "Agricultural runoff" refers to fertilisers and pesticides washing from farmland into nearby waterways, often a larger but less visible source of pollution than more obviously identifiable sources. "Industrial discharge" describes waste released directly from factories into rivers or coastal waters, historically the most heavily regulated source but not necessarily the largest. "Untreated sewage" refers to human waste released into waterways without adequate processing, a persistent problem in areas with ageing or insufficient infrastructure. "Plastic waste" and "microplastic pollution" (tiny plastic fragments, often broken down from larger debris, that are now found even in remote water sources) are worth knowing as a specific, currently high-profile source distinct from chemical contamination — plastic pollution is primarily a physical and ingestion hazard to marine life, whereas chemical contamination from runoff or discharge poisons water more directly.