By. George P. Nassos
One of the most critical environmental issues is that of freshwater. There is a limited quantity, and it is becoming more limited as the global population continues to grow. Agricultural and industrial use consists of about 90% of the available freshwater but the quality does not have to be as clean as drinking tap water which requires disinfectants.
Water disinfection is a crucial process that ensures the safety of our drinking water by eliminating harmful pathogens. However, while the primary goal of disinfection is to protect public health, the chemicals used in this process can inadvertently create harmful byproducts. These contaminants pose potential risks to human health and highlight the complex balance between disinfection and the formation of secondary pollutants.
Chlorine is the most widely used disinfectant in water treatment. Its effectiveness in killing bacteria, viruses, and protozoa makes it a staple in ensuring safe drinking water. However, when chlorine reacts with natural organic matter present in water, it forms a group of byproducts known as trihalomethanes (THMs) and haloacetic acids (HAAs).
- Trihalomethanes (THMs): THMs, including chloroform, bromodichloromethane, dibromochloromethane, and bromoform, are formed during the chlorination process. Long-term exposure to THMs is associated with an increased risk of cancer, particularly bladder cancer, and potential reproductive issues.
- Haloacetic Acids (HAAs): HAAs, such as monochloroacetic acid, dichloroacetic acid, and trichloroacetic acid, are another group of byproducts resulting from chlorination. These compounds have been linked to liver and kidney damage, as well as developmental and reproductive problems.
The Environmental Working Group (www.ewg.org) provides a drinking water quality report for most municipalities. It shows results of tests conducted by the water utility and provided to the Environmental Working Group by a state’s EPA. The results show the concentration level of the contaminant along with the legal limit if one exists. The results are also compared to a health guideline which is usually much lower than the legal limit.
Some of the other disinfectants include chloramine which is a combination of chlorine and ammonia, ozone, and chlorine dioxide which is used as an alternative to chlorine. They form other contaminants in the drinking water.
The byproducts formed during water disinfection processes have raised concerns due to their potential health impacts. While the levels of these contaminants are usually regulated and kept within safe limits, prolonged exposure to even low concentrations can pose risks.
Many disinfection byproducts have been identified as potential carcinogens. Long-term exposure to these chemicals, even at low concentrations, can increase the risk of various cancers, particularly bladder, liver, and kidney cancers. Studies have shown that certain disinfection byproducts can interfere with reproductive health and fetal development. Others can cause damage to vital organs such as the liver, kidneys, and thyroid gland. This organ toxicity can lead to long-term health issues and compromise the overall well-being of affected individuals. Mitigation strategies include optimizing disinfection processes, advanced treatment technologies, and regular monitoring and regulation.
The disinfection of drinking water is a critical public health measure that prevents waterborne diseases. However, the formation of disinfection byproducts presents a complex challenge that requires careful management. By understanding the sources and health impacts of these contaminants, and by employing effective mitigation strategies, we can continue to enjoy safe and clean drinking water while minimizing potential health risks.
We are fortunate that most municipalities follow EPA guidelines and have systems in place to measure the quality of drinking water and take the necessary steps to bring it within compliance. That may not be true of the Food and Drug Administration (FDA) that regulates the quality of bottled water.