Chlorine as a disinfectant in drinking water and its link to Cancer

Based on this rationale, countries with warm temperatures like Nigeria (Africa), will have higher THMs found in drinking water supplies that have been treated with Chlorine due to increased amount of natural organic matter in water sources all year around. The levels of THM will also be higher when rivers or other surface waters are the water source due to increased amount of organic matter. This implies that such countries have a higher risk of cancer resulting from increased exposure to THM.

Chlorine is used as a disinfectant to reduce or eliminate microorganisms such as bacteria and viruses found in most drinking water supplied to communities. Studies show that chlorine on its own is great but the issue is with the by-products that are produced when chlorine is used.

When chlorine interacts with organic matter (such as dead leaves and soil) in untreated water, it forms new chemicals that remain in the water. These are called chlorination by-products or disinfection by-products. It is the chlorination by-products that can increase cancer risk. The most common of these by-products are trihalomethanes (THMs), which include chloroform.

According to Health Canada, the amount of THMs found in drinking water depends on several things, including the season and the water source. For instance, THM levels are generally lower in winter than in summer, because the amount of natural organic matter is lower and less chlorine is needed to disinfect at colder temperatures. THMs are also lower when wells or large lakes are the drinking water source.

Based on this rationale, countries with warm temperatures like Nigeria (Africa), will have higher THMs found in drinking water supplies that have been treated with Chlorine due to increased amount of natural organic matter in water sources all year around. The levels of THM will also be higher when rivers or other surface waters are the water source due to increased amount of organic matter. This implies that such countries have a higher risk of cancer resulting from increased exposure to THM.

The Canadian Cancer Society states that one is exposed to these chlorination by-products when water treated with chlorine is ingested by drinking, inhalation of the water vapour during showering, swimming and other activities.

For decades, researchers have studied the long-term effects of using chlorinated water and it has been shown that when people are exposed to chlorinated water over extended periods of time, it increases their risk of cancer. Identified cancers include bladder, rectal and breast cancers and most studies have shown that women are at a higher risk. More research is still be done.

Sources:

Chlorinated water – Canadian cancer Society -Retrieved Sep 26, 2017 from http://www.cancer.ca/en/prevention-and-screening/be-aware/harmful-substances-and-environmental-risks/chlorinated-water/?region=bc#ixzz4tnuVP5vt

Drinking Water Chlorination – Health Canada – Retrieved Sep 26, 2017 from https://www.canada.ca/en/health-canada/services/healthy-living/your-health/environment/drinking-water-chlorination.html

Tapped Out? Are Chlorine’s Beneficial Effects in Drinking Water Offset by Its Links to Cancer? Retrieved Sep 26, 2017 from https://www.scientificamerican.com/article/earth-talks-tapped-out/

Drinking water chlorination and cancer – a historical cohort study in Finland. Retrieved Sep 26, 2017 from https://link.springer.com/article/10.1023/A:1018420229802

 

 

 

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