Chlorination Of Water In Australia Essay
Chemistry Issues Investigation
Issues Question: “Should the chlorination of water be banned in Australia?"
Introduction
Chlorine is a halogen abundant in the natural environment, typically found in the form of ionic chloride compounds. Once isolated into its elemental form, chlorine has a high oxidising potential, resulting in its use as a water disinfectant globally. Although water chlorination has significantly improved public health, recent studies suggest a correlation between the consumption of chlorinated water and an increased risk of certain cancers, leading to the question: “Should the chlorination of water be banned in Australia?"
Chemical Background
Chlorine is a non-metal with high electronegativity. Having a total of 17 electrons, …show more content…
where 7 are in its outer shell, the chlorine ion Cl1- has a stable octet configuration and is isoelectric to inert gases; hence, chlorine is highly reactive, especially in the gas form Cl2, typically forming extremely stable compounds in the natural environment.
To use chlorine in water treatment, it must first be extracted and purified into its elemental form. As the most common compound of chlorine, sodium chloride (NaCl), is found in seawater, chlorine is extracted from brine through electrolysis. Then, it is introduced to the public water systems, most effectively cleaning water in the form of a weak hypochlorous acid.
As shown, this is an equilibrium reaction, where manipulation of the water's pH can increase the concentration of HClO produced. Thus, to ensure that chlorine will most efficiently disinfect water, it is optimal that the water has a pH between 5.5 and 7.5; at a lower pH, more hypochlorous acid is produced. (Lenntech, 2017)
Bacteria in water have cell walls with a net negative charge, effectively repelling other negatively charged particles. However as demonstrated above, the neutrally charged hypochlorous acid acts as an oxidising agent, causing the osmolysis of microbes; HClO dissolves the cell membrane by combining with the electrons present in the cell wall, hence penetrating cell layers and invading the bacteria. (Hadhazy, 2013)
Once inside the bacterium, hypochlorous acid further chemically interacts with its proteins. This interaction causes the proteins to become disfigured, losing their structure and becoming dysfunctional. As proteins are involved in all bodily functions of organisms, deteriorated or malfunctioning proteins causes the bacteria to die.
Context of Issue
Despite being regarded as the driest inhabited continent, Australia is ranked fourth highest in the world for water usage per capita. (Hussey and Dovers, 2007) Currently, the chlorination of water is regarded as an effective method to provide safe drinking water for the public due to the geography of Australia. The Australian climate is largely desert and semi-arid, causing the continent to have a low annual average rainfall measuring at 419 mm in 2012. (Australian Bureau of Statistics, 2012) The dry climate in combination with the geographical distribution of Australia's population along the coast introduces difficulties in water supply, as the population is more spread out.
The chlorination of water should be banned in Australia
Disinfectant by-products (DBPs)
Apart from the bad taste and odour often associated with chlorinated water, it is also responsible for several negative side effects. A major concern regarding the chlorination of water is the disinfection by-products of trihalomethanes (THMs), which form when chlorine reacts with organic and inorganic matter in water. There are four types of THMs, all of which are classified as Group B carcinogens by the Environmental Protection Agency and has been proven to cause cancer in laboratory animals. (U.S. Department of Health and Services, 2014)
When chlorinated water is ingested, THMs encourage the growth of free radicals, which has the ability to destroy or alter vital cells in the body. As the bladder, liver and kidneys are responsible for detoxifying and removing fluid waste from the body, THMs are often associated to the cancer of these organs. (King and Marrett, 1996) Moreover in Western Australia, a study conducted by the University of Sydney revealed, "A positive association was observed between colon cancer and water bromoform concentrations in men." (Rahman et al., 2014) Clearly, there is sufficient evidence to support that the by-products of chlorinated water are health hazards.
Alternative Water Treatment Methods
Furthermore, developments in technology have produced safer and more efficient methods for water purification. Around the world, many countries have converted to using a potable water delivery system without residual disinfectants. This system involves multiple water treatment facilities with a disinfection step to inactivate pathogens using ozone and/or UV light, effectively eliminating bacteria that chlorine is ineffective against, such as cryptosporidium and giardia, whilst also reducing the disinfectant contact times. (Hadhazy, 2013) To ensure that treated water does not become contaminated during transport, this approach requires more focus upon the distribution system. For example in the Netherlands, the public water system is designed with self-cleaning networks using smaller pipes to lessen water age. (Speight and Rosario-Ortiz, 2016) Below is a comparison of the effectiveness different water treatment types and the associated costs:
Evidently, the costs for other methods of water treatment are similar to chlorination, especially ozone; yet, it is significantly more efficient and does not have harmful DBPs or environment impacts. Overall, the evidence supports that water chlorination should be banned in Australia.
The chlorination of water should not be banned in Australia
Antiseptic Properties of Chlorine
With statistics indicating that water related diseases cause more than 3.4 million deaths annually, the chlorination of water was a significant public health accomplishment of the 20th century.
(World Health Organisation, 2017) Water chlorination has led to the declination of most waterborne epidemics in today's world, due to its elimination of common pathogens such as E. coli, salmonella and listeria. This has severely reduced instances of cholera, dysentery, typhoid fever and gastroenteritic diseases, all of which remain key causes of death in developing countries that cannot afford proper water sanitation. (Water Quality and Health Council, 2017) Hence, although THMs in chlorinated water are possible carcinogens, the health hazards of non-disinfected water are much …show more content…
greater.
Residual Chlorine in Water Systems
Additionally, a benefit of using chlorination to treat water is due to the chlorine residue that provides protection against recontamination. In the water system, once chlorine has killed all bacteria and cannot further react with other matter in the water, it becomes free residual chlorine. This property is particularly useful for water treatment in Australia as it ensures that the water constantly has a disinfectant along its journey before reaching the consumer. When effectively managed, the water system should be at breakpoint, meaning that it would always contain some amount of free chlorine, hence allowing continuous disinfection. (Lenntech, 2017)
Costs of Chlorinated Water
From an economical perspective, chlorine is currently the cheapest method of water treatment available due to its abundance in nature and simple isolation process; it also achieves similar levels of effectiveness for removing pathogens in comparison to other treatment methods. To eliminate bacteria, approximately 0.2-0.4 mg/L of chlorine is required, where 100g of chlorine costs $0.20 AUD. (U.S. Department of Health and Services, 2014)
Hence, it would not be efficient or cost-effective to build new facilities across Australia in order to enforce other methods of water treatment.
Carbon Filter Alternative
Instead, water systems in Australia should remain chlorinated to continue eliminating bacteria within the water supply. However, activated carbon filters should be installed in households, as they can remove chlorine DBPs and chemicals that cannot be removed by chlorine disinfectant.
Currently, several water treatment companies in Australia such as Puratap, Aquasana and Life Saver, provide this technology as separate tap instillations specifically for drinking water in households.
Conclusion
Overall, in regards to the geography of Australia, alternative water treatment methods are most likely not as efficient or cost-effective in comparison to chlorination, as complex water networks must be constructed and are impractical to transport water across Australia. Thus, the chlorination of water should not be banned in Australia, but instead, carbon filters should be installed in households to ensure that possible cancerous by-products of chlorinated water are not consumed.
TOTAL WORDCOUNT - 1200 (excluding in-text referencing) Bibliography
ASM. (2014). Highly Effective TOC Reduction Through the Complete Advanced Reactor Process. [online] Available at: http://www.aquasonicmanagement.com/uv-sonic-ozone-reactor/ [Accessed 12 Mar. 2017].
Australian Bureau of Statistics, (2012). Year Book Australia, 2012. Canberra.
Hadhazy, A. (2013). Science of Summer: How Chlorine Kills Pool Germs. [online] Live Science. Available at: http://www.livescience.com/37122-how-chlorine-kills-pool-germs.html [Accessed 22 Mar. 2017].
Hussey, K. and Dovers, S. (2007). Managing water for Australia. 1st ed. Collingwood, Vic.: CSIRO Pub., p.8.
King, W. and Marrett, L. (1996). Case-control study of bladder cancer and chlorination by-products in treated water (Ontario, Canada). Cancer Causes and Control, [online] 7(6), pp.596-604. Available at: https://www.ncbi.nlm.nih.gov/pubmed/8932920 [Accessed 11 Mar. 2017].
Lenntech, (2017). Chlorine as disinfectant for water. [online] Lenntech.com. Available at: http://www.lenntech.com/processes/disinfection/chemical/disinfectants-chlorine.htm [Accessed 15 Mar. 2017].
Puratap, (2014). What will a Puratap remove from my tap water?. [online] Puratap.com.au. Available at: https://www.puratap.com.au/knowledge-centre/What-will-a-Puratap-remove-from-my-tap-water [Accessed 12 Mar. 2017].
Rahman, M., Cowie, C., Driscoll, T., Summerhayes, R., Armstrong, B.
and Clements, M. (2014). Colon and rectal cancer incidence and water trihalomethane concentrations in New South Wales, Australia. BMC Cancer, [online] 14(1). Available at: https://bmccancer.biomedcentral.com/articles/10.1186/1471-2407-14-445 [Accessed 8 Mar. 2017].
Speight, V. and Rosario-Ortiz, R. (2016). Can drinking water be delivered without disinfectants like chlorine and still be safe?. [online] The Conversation. Available at: https://theconversation.com/can-drinking-water-be-delivered-without-disinfectants-like-chlorine-and-still-be-safe-55476 [Accessed 19 Mar. 2017].
U.S. Department of Health and Services, (2014). Disinfection By-Products. Atlanta: Centers for Disease Control and Prevention.
Water Quality and Health Council, (2017). Chlorine and Drinking Water: Here's to Your Health. [online] Waterandhealth.org. Available at: http://www.waterandhealth.org/drinkingwater/before.php3 [Accessed 24 Mar. 2017].
World Health Organisation, (2017). WHO World Water Day Report. [online] Geneva. Available at: http://www.who.int/water_sanitation_health/takingcharge.html [Accessed 14 Mar.
2017].
Issues Question: “Should the chlorination of water be banned in Australia?"
Introduction
Chlorine is a halogen abundant in the natural environment, typically found in the form of ionic chloride compounds. Once isolated into its elemental form, chlorine has a high oxidising potential, resulting in its use as a water disinfectant globally. Although water chlorination has significantly improved public health, recent studies suggest a correlation between the consumption of chlorinated water and an increased risk of certain cancers, leading to the question: “Should the chlorination of water be banned in Australia?"
Chemical Background
Chlorine is a non-metal with high electronegativity. Having a total of 17 electrons, …show more content…
where 7 are in its outer shell, the chlorine ion Cl1- has a stable octet configuration and is isoelectric to inert gases; hence, chlorine is highly reactive, especially in the gas form Cl2, typically forming extremely stable compounds in the natural environment.
To use chlorine in water treatment, it must first be extracted and purified into its elemental form. As the most common compound of chlorine, sodium chloride (NaCl), is found in seawater, chlorine is extracted from brine through electrolysis. Then, it is introduced to the public water systems, most effectively cleaning water in the form of a weak hypochlorous acid.
As shown, this is an equilibrium reaction, where manipulation of the water's pH can increase the concentration of HClO produced. Thus, to ensure that chlorine will most efficiently disinfect water, it is optimal that the water has a pH between 5.5 and 7.5; at a lower pH, more hypochlorous acid is produced. (Lenntech, 2017)
Bacteria in water have cell walls with a net negative charge, effectively repelling other negatively charged particles. However as demonstrated above, the neutrally charged hypochlorous acid acts as an oxidising agent, causing the osmolysis of microbes; HClO dissolves the cell membrane by combining with the electrons present in the cell wall, hence penetrating cell layers and invading the bacteria. (Hadhazy, 2013)
Once inside the bacterium, hypochlorous acid further chemically interacts with its proteins. This interaction causes the proteins to become disfigured, losing their structure and becoming dysfunctional. As proteins are involved in all bodily functions of organisms, deteriorated or malfunctioning proteins causes the bacteria to die.
Context of Issue
Despite being regarded as the driest inhabited continent, Australia is ranked fourth highest in the world for water usage per capita. (Hussey and Dovers, 2007) Currently, the chlorination of water is regarded as an effective method to provide safe drinking water for the public due to the geography of Australia. The Australian climate is largely desert and semi-arid, causing the continent to have a low annual average rainfall measuring at 419 mm in 2012. (Australian Bureau of Statistics, 2012) The dry climate in combination with the geographical distribution of Australia's population along the coast introduces difficulties in water supply, as the population is more spread out.
The chlorination of water should be banned in Australia
Disinfectant by-products (DBPs)
Apart from the bad taste and odour often associated with chlorinated water, it is also responsible for several negative side effects. A major concern regarding the chlorination of water is the disinfection by-products of trihalomethanes (THMs), which form when chlorine reacts with organic and inorganic matter in water. There are four types of THMs, all of which are classified as Group B carcinogens by the Environmental Protection Agency and has been proven to cause cancer in laboratory animals. (U.S. Department of Health and Services, 2014)
When chlorinated water is ingested, THMs encourage the growth of free radicals, which has the ability to destroy or alter vital cells in the body. As the bladder, liver and kidneys are responsible for detoxifying and removing fluid waste from the body, THMs are often associated to the cancer of these organs. (King and Marrett, 1996) Moreover in Western Australia, a study conducted by the University of Sydney revealed, "A positive association was observed between colon cancer and water bromoform concentrations in men." (Rahman et al., 2014) Clearly, there is sufficient evidence to support that the by-products of chlorinated water are health hazards.
Alternative Water Treatment Methods
Furthermore, developments in technology have produced safer and more efficient methods for water purification. Around the world, many countries have converted to using a potable water delivery system without residual disinfectants. This system involves multiple water treatment facilities with a disinfection step to inactivate pathogens using ozone and/or UV light, effectively eliminating bacteria that chlorine is ineffective against, such as cryptosporidium and giardia, whilst also reducing the disinfectant contact times. (Hadhazy, 2013) To ensure that treated water does not become contaminated during transport, this approach requires more focus upon the distribution system. For example in the Netherlands, the public water system is designed with self-cleaning networks using smaller pipes to lessen water age. (Speight and Rosario-Ortiz, 2016) Below is a comparison of the effectiveness different water treatment types and the associated costs:
Evidently, the costs for other methods of water treatment are similar to chlorination, especially ozone; yet, it is significantly more efficient and does not have harmful DBPs or environment impacts. Overall, the evidence supports that water chlorination should be banned in Australia.
The chlorination of water should not be banned in Australia
Antiseptic Properties of Chlorine
With statistics indicating that water related diseases cause more than 3.4 million deaths annually, the chlorination of water was a significant public health accomplishment of the 20th century.
(World Health Organisation, 2017) Water chlorination has led to the declination of most waterborne epidemics in today's world, due to its elimination of common pathogens such as E. coli, salmonella and listeria. This has severely reduced instances of cholera, dysentery, typhoid fever and gastroenteritic diseases, all of which remain key causes of death in developing countries that cannot afford proper water sanitation. (Water Quality and Health Council, 2017) Hence, although THMs in chlorinated water are possible carcinogens, the health hazards of non-disinfected water are much …show more content…
greater.
Residual Chlorine in Water Systems
Additionally, a benefit of using chlorination to treat water is due to the chlorine residue that provides protection against recontamination. In the water system, once chlorine has killed all bacteria and cannot further react with other matter in the water, it becomes free residual chlorine. This property is particularly useful for water treatment in Australia as it ensures that the water constantly has a disinfectant along its journey before reaching the consumer. When effectively managed, the water system should be at breakpoint, meaning that it would always contain some amount of free chlorine, hence allowing continuous disinfection. (Lenntech, 2017)
Costs of Chlorinated Water
From an economical perspective, chlorine is currently the cheapest method of water treatment available due to its abundance in nature and simple isolation process; it also achieves similar levels of effectiveness for removing pathogens in comparison to other treatment methods. To eliminate bacteria, approximately 0.2-0.4 mg/L of chlorine is required, where 100g of chlorine costs $0.20 AUD. (U.S. Department of Health and Services, 2014)
Hence, it would not be efficient or cost-effective to build new facilities across Australia in order to enforce other methods of water treatment.
Carbon Filter Alternative
Instead, water systems in Australia should remain chlorinated to continue eliminating bacteria within the water supply. However, activated carbon filters should be installed in households, as they can remove chlorine DBPs and chemicals that cannot be removed by chlorine disinfectant.
Currently, several water treatment companies in Australia such as Puratap, Aquasana and Life Saver, provide this technology as separate tap instillations specifically for drinking water in households.
Conclusion
Overall, in regards to the geography of Australia, alternative water treatment methods are most likely not as efficient or cost-effective in comparison to chlorination, as complex water networks must be constructed and are impractical to transport water across Australia. Thus, the chlorination of water should not be banned in Australia, but instead, carbon filters should be installed in households to ensure that possible cancerous by-products of chlorinated water are not consumed.
TOTAL WORDCOUNT - 1200 (excluding in-text referencing) Bibliography
ASM. (2014). Highly Effective TOC Reduction Through the Complete Advanced Reactor Process. [online] Available at: http://www.aquasonicmanagement.com/uv-sonic-ozone-reactor/ [Accessed 12 Mar. 2017].
Australian Bureau of Statistics, (2012). Year Book Australia, 2012. Canberra.
Hadhazy, A. (2013). Science of Summer: How Chlorine Kills Pool Germs. [online] Live Science. Available at: http://www.livescience.com/37122-how-chlorine-kills-pool-germs.html [Accessed 22 Mar. 2017].
Hussey, K. and Dovers, S. (2007). Managing water for Australia. 1st ed. Collingwood, Vic.: CSIRO Pub., p.8.
King, W. and Marrett, L. (1996). Case-control study of bladder cancer and chlorination by-products in treated water (Ontario, Canada). Cancer Causes and Control, [online] 7(6), pp.596-604. Available at: https://www.ncbi.nlm.nih.gov/pubmed/8932920 [Accessed 11 Mar. 2017].
Lenntech, (2017). Chlorine as disinfectant for water. [online] Lenntech.com. Available at: http://www.lenntech.com/processes/disinfection/chemical/disinfectants-chlorine.htm [Accessed 15 Mar. 2017].
Puratap, (2014). What will a Puratap remove from my tap water?. [online] Puratap.com.au. Available at: https://www.puratap.com.au/knowledge-centre/What-will-a-Puratap-remove-from-my-tap-water [Accessed 12 Mar. 2017].
Rahman, M., Cowie, C., Driscoll, T., Summerhayes, R., Armstrong, B.
and Clements, M. (2014). Colon and rectal cancer incidence and water trihalomethane concentrations in New South Wales, Australia. BMC Cancer, [online] 14(1). Available at: https://bmccancer.biomedcentral.com/articles/10.1186/1471-2407-14-445 [Accessed 8 Mar. 2017].
Speight, V. and Rosario-Ortiz, R. (2016). Can drinking water be delivered without disinfectants like chlorine and still be safe?. [online] The Conversation. Available at: https://theconversation.com/can-drinking-water-be-delivered-without-disinfectants-like-chlorine-and-still-be-safe-55476 [Accessed 19 Mar. 2017].
U.S. Department of Health and Services, (2014). Disinfection By-Products. Atlanta: Centers for Disease Control and Prevention.
Water Quality and Health Council, (2017). Chlorine and Drinking Water: Here's to Your Health. [online] Waterandhealth.org. Available at: http://www.waterandhealth.org/drinkingwater/before.php3 [Accessed 24 Mar. 2017].
World Health Organisation, (2017). WHO World Water Day Report. [online] Geneva. Available at: http://www.who.int/water_sanitation_health/takingcharge.html [Accessed 14 Mar.
2017].