Water Pollution

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Water pollution is the contamination of water bodies (like rivers, lakes, groundwater) by substances harmful to living organisms. It occurs when physical, chemical, or biological parameters of water e…

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The two main sources of fresh water are: (i) Surface water – from rivers, lakes, and rainfall runoff; (ii) Groundwater – found in aquifers beneath the Earth's surface, accessed through wells and sprin…

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The hydrological cycle describes the continuous movement of water on Earth: evaporation from oceans and surfaces → condensation into clouds → precipitation (rain/snow) → runoff into rivers/lakes or se…

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Three physical parameters are: (1) Colour – abnormal color indicates contamination; (2) Odour – foul smell suggests organic decay; (3) Turbidity – cloudiness due to suspended particles like silt or wa…

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Three chemical parameters are: (1) Nitrates – from fertilizers, cause methemoglobinemia; (2) Phosphates – lead to algal blooms; (3) Heavy metals (e.g., lead, mercury) – toxic even in small amounts.

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Biological parameters refer to the presence of harmful microorganisms like bacteria (e.g., E. coli), viruses, protozoa, and algae in water. Their presence indicates sewage contamination and poses heal…

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Point sources are specific, identifiable locations like factory outlets or sewage pipes. Non-point sources are diffuse, spread over large areas, such as agricultural runoff or urban stormwater carryin…

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Two natural sources are: (1) Siltation – soil particles washed into water bodies during floods; (2) Leaching of minerals like radium or potassium-40 from rocks into groundwater.