Cysts in Water Supply: Treating Water Born Disease Causing Protozoa

Although there is no absolute guarantee that a water supply is pathogen free, we can definitely do a lot to reduce the risk of infection by disease causing micro-organisms and ensure that our drinking water meets standards that are considered to be acceptable or at a safe level.

Municipal Water Sources

If your water source is from a municipal, or public water supply in Canada, you can be sure that it is treated and tested to produce micro-biologically safe water. Municipal water treatment systems generally do a good job of providing safe water without the need for additional treatment by the consumer. In some areas, such as Victoria BC, the municipality goes to great lengths to ensure that it's water is at the safest level possible by installing multi-barrier water treatment processes which include a state of the art Trojan UV system. Ultraviolet radiation has been shown to be a very effective solution for the de-activation of biological pathogens such as Cryptosporidium and Giardia (Wilczak et al., 1996).

Surface Water Contamination

If your water source comes from a surface water supply such as creeks, rivers, lakes or shallow wells that may be directly influenced by surface water then there is a very real possibility of contamination and the presence of cysts in water. It is important that you take measures to treat and test your water to protect yourself and your family from contamination by Cryptosporidium and Giardia Lamblia (AKA: Beaver Fever).

Cysts.... Real Pests in Our Drinking Water

Cryptosporidium and Giardia Lamblia are protozoans that may be present in any water that comes in contact with wildlife, and more specifically, feces (ie surface water). Both of these parasites produce a cyst, which is essentially a "suitcase" for the infectious material inside. Cysts in water are very resistant to harsh environmental conditions and most water disinfectant methods. When they are ingested they germinate, reproduce and cause illness. After feeding, the parasites produce new cysts which are passed in feces and in this way become re-introduced to the environment. It has been shown that ingestion of only a few cysts will cause illness in humans.

How to Treat Your Water if it is at Risk

Most of the methods used on a municipal scale been incorporated into smaller devices which are available to private citizens. These devices are usually designed to treat water at the point-of-entry(POE) which is where the water enters the home or at the point-of-use (POU) such as at a kitchen tap.

The most common drinking water disinfectants are chlorine, chloramine, ozone and chlorine dioxide, with chlorine being the most widely used. Chlorine is a strong oxidant and is capable of inactivating bacteria and viruses. Chlorine based disinfectants, however, are not very effective for the control of cysts in water.

UV Light Disinfection

Many studies have been carried out which show that Ultraviolet light disinfection appears to be a highly effective method for inactivating many types of pathogens, including pathogenic protozoa such as Cryptosporidium and Giarda. (Wilczak et al., 1996). Click here for more information about how UV disinfection works

In Conclusion

The bottom line in all of this is your health and safety. If you rely on surface water as your primary source of drinking water you will be best served by a multi-barrier approach which includes mechanical filtration, chlorine-based disinfection and ultraviolet sterilization. It is also highly recommended that you look for products that have been certified by an accredited certification body to meet the standards set out by NSF International (NSF) or the American National Standards Institute (ANSI).