01 · Water Quality Parameters

Coming Soon

What this article covers

A river cannot tell you it is sick. Scientists use a set of standard water quality parameters — measurable indicators — to diagnose what is happening below the surface. Each parameter is a window into a different kind of stress.

This article will cover:

• The core physical parameters: temperature, turbidity, colour, odour
• The oxygen story: Dissolved Oxygen (DO) and Biochemical Oxygen Demand (BOD) — and why their relationship is the single most important thing to understand about organic pollution
• Chemical indicators: pH, nitrates, phosphates, total dissolved solids (TDS)
• Biological indicators: faecal coliforms and what they reveal about sewage contamination
• Heavy metals and toxic compounds: lead, arsenic, chromium, mercury — where they come from and at what levels they become dangerous
• Composite indices: how individual parameters are combined into a single Water Quality Index (WQI)

Key concept to anchor on

BOD and DO are inverse partners. When organic waste enters a river, bacteria consume oxygen to break it down — BOD rises, DO falls. When DO drops below 4 mg/L, aquatic life begins to suffocate. This single mechanism explains a large portion of India’s river pollution crisis.

Why this matters beyond science

Parameters are not just numbers for laboratories. They are the language that:

• Tells a volunteer whether the water near their ghat is safe for ritual contact
• Determines whether a stretch of river qualifies for legal action under pollution norms
• Feeds into the dashboards and reports that drive (or fail to drive) government response

Understanding parameters is the foundation of everything else in Pollution Library.

Full article coming soon

This page is a placeholder. The complete article — with detailed explanations, visual aids, and a quick-reference parameter table — is being written.