In other words, turbidity refers to the clarity of water. To measure the turbidity of water, a beam of light must be emitted into the water and the amount of light passing through will be calculated in nephelometric turbidity units (NTU). It is recognized that a turbidity of 5 NTU represents visibly turbid water. At 25 NTU, the water becomes blackish. Moreover, the number of nephelometric turbidity units can vary from less than 1 NTU to more than 1000 NTU. In other words, turbidity refers to the amount of suspended solids (TSS) that can be found in the water.
Many factors can cause turbidity in water, such as heavy rainfall that shakes the water and carries contaminants by runoff, various human activities, or even wildlife activites. Suspended matter causing turbidity can be organic particles such as animal or plant matter, or inorganic particles such as silt, clay, and many others.
The mixture of suspended particles can give the water a cloudy appearance, odors and a bad taste. In addition, the presence of TSS can increase the transport of microorganisms and thus hinder disinfection. To counter this problem, it may be necessary to increase the amount of disinfectant used for water disinfection.
The wide variety of particles that can cause turbidity makes it difficult to identify the risks associated with its consumption. Since these suspended particles, mainly colloids, agglomerate contaminants and reduce the effectiveness of disinfection, there may be health risks associated with drinking water with high turbidity.
In Canada, turbidity guidelines vary depending on the type of treatment used and can range from 0.1 uTN to 1 uTN. For more details, we invite you to read the Health Canada guidelines in this document or to write to us directly.