What causes turbidity in water?
Turbidity in water is caused by suspended and colloidal matter such as clay, silt, finely divided organic and inorganic matter, and plankton and other microscopic organisms.
What’s most important when testing turbidity?
A glass of drinking water is expected to be clear. That’s because US government regulations determine the acceptable level of turbidity—or volume of particulates suspended—in the water. Untreated stream water that contains clay, plankton, or organic compounds may appear as a murky brown. Aside from appearing unappetizing, this high degree of turbidity may not be safe to drink.
Water clarity is expressed as level of turbidity (NTU or nephelometric turbidity units) and measured with a turbidity meter. Beyond drinking water and manufacturing water for other beverages, turbidity is helpful in determining water quality for fish and aquatic life. High turbidity can impact water treatment costs, which in turn affects production in industries such as food processing, pharmaceuticals, and many others.
Three tips for measuring turbidity
Determine turbidity as soon as possible after the sample is collected to ensure examination under original conditions.
- Gently agitate samples to ensure a representative measurement. If storage is required, cool to 4°C to minimize microbiological decomposition of solids.
- Keep cells scrupulously clean, inside and out, and discard if scratched or etched. Never handle them near the instrument’s light beam.
- Fill cells with samples and standardsallow sufficient time for bubbles to escape. Because small differences between sample cells can significantly impact measurement, use either matched pairs of cells or the same cell for both standardization and sample measurement.
Learn more about measuring turbidity.
Learn more about water testing.
Shop turbidity meters.