Compare And Contrast Nitrate And Nitrite In Drinking Water
2.23 Nitrate-Nitrogen and Nitrite-Nitrogen in Drinking Water
Nitrate may be naturally occurring, although its presence in drinking water is more often associated with contamination by excessive use of fertilizers (both inorganic and organic), in addition to inappropriate farming practices and sewage. The high nitrate level in drinking water is also associated with the simultaneous presence of bacterial contamination (World Health Organisation, 1996).
The primary health hazard from drinking water with nitrate-nitrogen occurs when nitrate is transformed to nitrite in the digestive system. The nitrite oxidizes iron in the haemoglobin of the red blood cells to form methaemoglobin, which lacks the oxygen-carrying capacity of haemoglobin. This …show more content…
It is one of the most common constituents present in natural waters ranging from zero to several hundred milligrams per litre depending on the source and treatment of the water (Putz, 2003). Calcium is largely responsible for water hardness, and may negatively influence toxicity of other compounds. Elements such as copper, lead and zinc are much more toxic in soft water. Calcium carbonate has a positive effect on lead water pipes, because it forms a protective lead (II) carbonate coating. This prevents lead from dissolving in drinking water, and thereby prevents it from entering the human body. Calcium phosphate is a supporting substance and it causes bone and tooth growth, together with vitamin D. Bones decalcify (osteoporosis) and fractures become more likely if a body is not getting enough calcium. Since a guideline value is proposed for total hardness, no guideline value is proposed for calcium concentration in drinking water (World Health Organisation, …show more content…
It also does not grow and reproduce in the environment. As a result, it is considered to be the species of coliform bacteria that is the best indicator of faecal pollution (Edberg et al., 2000). They also indicate the possible presence of pathogenic bacteria, viruses and protozoans (Kara et al., 2004). Almost all the methods used to detect total coliforms, faecal coliforms and Escherichia coli are enumeration methods that are based on lactose fermentation (American Public Health Association, 1992). The Most Probable Number (MPN) method is a statistical, multi-step assay consisting of presumptive, confirmed and completed phases. In the assay, serial dilutions of a sample are inoculated into broth media.
Analysts score the number of gas positive (fermentation of lactose) tubes, from which the other two phases of the assay are performed and then use the combinations of positive results to estimate the number of bacteria present. Typically, only the first two phases are performed in coliform and fecal coliform analysis, while all three phases are done for Escherichia coli (American Public Health Association,
Nitrate may be naturally occurring, although its presence in drinking water is more often associated with contamination by excessive use of fertilizers (both inorganic and organic), in addition to inappropriate farming practices and sewage. The high nitrate level in drinking water is also associated with the simultaneous presence of bacterial contamination (World Health Organisation, 1996).
The primary health hazard from drinking water with nitrate-nitrogen occurs when nitrate is transformed to nitrite in the digestive system. The nitrite oxidizes iron in the haemoglobin of the red blood cells to form methaemoglobin, which lacks the oxygen-carrying capacity of haemoglobin. This …show more content…
It is one of the most common constituents present in natural waters ranging from zero to several hundred milligrams per litre depending on the source and treatment of the water (Putz, 2003). Calcium is largely responsible for water hardness, and may negatively influence toxicity of other compounds. Elements such as copper, lead and zinc are much more toxic in soft water. Calcium carbonate has a positive effect on lead water pipes, because it forms a protective lead (II) carbonate coating. This prevents lead from dissolving in drinking water, and thereby prevents it from entering the human body. Calcium phosphate is a supporting substance and it causes bone and tooth growth, together with vitamin D. Bones decalcify (osteoporosis) and fractures become more likely if a body is not getting enough calcium. Since a guideline value is proposed for total hardness, no guideline value is proposed for calcium concentration in drinking water (World Health Organisation, …show more content…
It also does not grow and reproduce in the environment. As a result, it is considered to be the species of coliform bacteria that is the best indicator of faecal pollution (Edberg et al., 2000). They also indicate the possible presence of pathogenic bacteria, viruses and protozoans (Kara et al., 2004). Almost all the methods used to detect total coliforms, faecal coliforms and Escherichia coli are enumeration methods that are based on lactose fermentation (American Public Health Association, 1992). The Most Probable Number (MPN) method is a statistical, multi-step assay consisting of presumptive, confirmed and completed phases. In the assay, serial dilutions of a sample are inoculated into broth media.
Analysts score the number of gas positive (fermentation of lactose) tubes, from which the other two phases of the assay are performed and then use the combinations of positive results to estimate the number of bacteria present. Typically, only the first two phases are performed in coliform and fecal coliform analysis, while all three phases are done for Escherichia coli (American Public Health Association,