Testing water for contaminants involves several physical, chemical, and biological methods to ensure it is safe for drinking or industrial use. Here’s a clear overview:
1. Physical Tests
- Turbidity: Measures cloudiness caused by suspended particles using a turbidimeter.
- Color and Odor: Checked visually or by smelling; unusual color or odor may indicate contamination.
- Temperature & Conductivity: High conductivity may indicate dissolved salts or minerals.
2. Chemical Tests
- pH Measurement: Determines acidity or alkalinity using a pH meter or indicator paper.
- Dissolved Oxygen (DO): Low DO can indicate pollution from organic waste.
- Chemical Contaminants:
- Heavy Metals: Lead, mercury, arsenic, cadmium, etc., tested using atomic absorption spectroscopy or ICP-MS.
- Nitrates/Nitrites: Tested using colorimetric methods.
- Chlorine and Fluoride: Checked using specific reagents.
- Total Dissolved Solids (TDS): Measures overall mineral content using a TDS meter.
3. Biological Tests
- Coliform Bacteria Test: Detects harmful bacteria like E. coli using membrane filtration or most probable number (MPN) method.
- Pathogen Detection: Tests for viruses or protozoa using culture or molecular methods (PCR).
4. Advanced Instrumental Methods
- Spectrophotometry: Measures concentration of specific chemicals.
- Chromatography (GC or HPLC): Detects pesticides or organic pollutants.
- Mass Spectrometry: For precise identification of trace contaminants.