Turbidity (NTU)

What is it?

Water turbidity measures how cloudy a sample of water is as a result of suspended particles. Since these particles occur as a result of both sediment erosion and plankton growth, turbidity can indicate the general state of stream processes for a location.

Why is it important?

Turbidity in open water may be caused by growth of phytoplankton or human activities such as construction, mining and agriculture which enter the bodies of water water due to rain storm runoff. In lakes and rivers, high turbidity levels can mean very little light is reaching the bottom, which can prevent growth of submerged plant life and as such affect aquatic species which are dependent on them for nutrients. High turbidity levels can also affect the ability of fish gills to absorb dissolved oxygen.

What does it mean?

Here turbidity is measured using a nephelometer which uses a light beam (source beam) and a light detector (usually at a 90° angle) set to one side of the source beam. The units of turbidity from a calibrated nephelometer are called Nephelometric Turbidity Units (NTU).

  • 1 NTU: Common turbidity measurement for tap water.
  • 1 NTU: Common regulatory limit for drinking water quality.

Water Rangers Protocol

While we do not currently have a test for this in our kit, you can certainly look at water clarity as an indicator. Typically a turbidimeter or turbidity sensor is used for this test.