Assignment Paper on Public Health Essay

Assignment Paper on Public Health Essay

Values stipulated in the water guidelines include aesthetic based effects, the health based effects and the operational considerations. The health based values are important, as they are associated with contaminants, exposure levels, and the availability of the treatments and the analytical technologies. Aesthetic values on the other hand, include turbidity, tastes, and colour of water and help to indicate whether the consumer of the water will see it as drinkable. These values are important in the guidelines since they help in determining whether water has the correct palatability and portability effect to the consumer, that is, it is drinkable as well as portraying colour, taste and other characters that are appealing to the consumer’s senses.Assignment Paper on Public Health Essay

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• The health based guideline value for free chlorine is 5mg/L whereas the aesthetic based guideline value is 0.6mg/L – why are they different?

The health requirement for chlorine is 5mg/L above which the health regulation will indicate that chlorine is being detected in the water and it will compromise quality or the effectiveness of disinfection. At the same time, it will affect the reaction between chlorine and other organic precursors. However, the aesthetic value is based on consumer preference and sensitivity. At 0.6mg/L is the acceptable range for most consumers in terms of tastes and odour related to chlorine. Therefore, the difference exists because aesthetic value is based on consumer preference in terms of taste and odour while 5MG/l relates to the operational range of chlorine that will not be harmful.

• Why are different parameters monitored for source water and customer tap water? Give examples of parameters which require to be monitored in (a) raw water and (b) distribution system (ADWG Ch9/10 will help here)

Different parameters are monitored both at the source and at the customer’s water tap to ensure that surrogates are controlled and at the same time to increase assurance that objectionable characteristics are reduced or are not present. Some parameters that need to be monitored include PH, turbidity, dissolved oxygen, faecal contamination at the source water, treatment failures like free chlorine, HPC, Escherichia coli and turbidity, water stagnation issues like the dissolved oxygen, HPC, the loss of disinfectant residual and total coliforms,  and in case there are disinfection by-products.Assignment Paper on Public Health Essay

• Why is there ‘residual chlorine’ in drinking water?  Why is the residual chlorine measured as ‘free’ residual chlorine in chlorinated systems, but as ‘total’ residual chlorine in chloraminated systems?

The presence of residual in the drinking water is an indication that a sufficient amount of chlorine has been put into the water so that most of the bacteria and viruses that are likely to cause diseases can be inactivated. At the same time, it helps in assuring the users that the water they are drinking or using for animal consumption has been protected from recontamination, as it is transported to their homes and when it will be stored at their homes. Chlorine presence also indicates the portability of water. In the chlorinated systems, the total demand for chlorine is zero since there are no nitrates to react with chlorine. Where the water is not treated, nitrate reacts with chlorine and part of it stays within the system to make the water portable.

• The results for tap water sourced from the Happy Valley system (DWQR p21) indicate that the aesthetic guideline for free chlorine was met 88.1% of the time – is this important? 

The 88.1% of the time as indicated from the tap water of Happy Valley system is indicative of the aesthetic guideline and it is important because it shows that the palatable quality of water that is delivered to the residents of Happy Valley in terms of taste, colour and odour is not completely accepted by the residents. It indicates that 11.1% of the residents think that the waster is not good for consumption and therefore the water management board ought to do something about the matter to make it 100% good. It is also important because it explains the views of the thetic compliance has been fulfilled.

• Which parameters are used in measuring microbial contamination? (ADWG Ch10 will help here)

The parameters that are used to measure microbial contamination include the coliforms group. This group is made up of bacteria that have defined growth as well as biochemical characteristics that are related to faecal contaminants. It entails the total coliforms that can be used in disinfection of water, and it can also be used in treated water in the distribution system both ingress and regrowth as well as in outbreak investigations. Others of the coliform group include the Escherichia coli, and thermotolerant coliforms. Another parameter that can be used to measure microbial contamination includes the presence of enterococci and faecal streptococci. Enterococcus species originates from faecal matter. Faecal streptococci on the other hand are more resistant than the E. Coli and other coliform bacteria, they are resistant to drying and can therefore be used for routine controls and in the distribution systems. Ratio of counts is another parameter that counts thermotolerant coliforms and the faecal streptococci and helps in differentiating contaminations emanating from animals and humans. Others include the direct total bacteria counts and activity tests, heterotrophic bacteria, clostridium perfringens, heterotrophic plate count among others.Assignment Paper on Public Health Essay

• The township of Parachilna achieves only 92% compliance for coliforms and yet 100% compliance for E.coli (DWQR p25). Explain the discrepancy in these results. Should the residents of Parachilna be concerned about these results?

The explanation for the discrepancies between coliform and E. Coli in Parachilna can be derived from the fact that unlike E. Coli,  which is widely present in human and animal faeces, it is not found in other niches apart from faecal contamination. This therefore explains why it was 100% compliant. Coliform on the other hand found in faecal contamination, is also found naturally in the environment and therefore may not meet the 100% compliance. Since coliforms are not pathogens, they cannot be found in bottled water. This therefore means that they are not useful determinants of faecal contamination. The people of Parachilna should therefore not be concerned by the noncompliance of the coliforms.

• In the Barossa system (DWQR p20) the min value for coliforms recorded is 0 and the max value is 31. Given these results, explain why the average and median results are both also 0

Since this explains the water system in Barosa system, the whole system is not contaminated with coliforms. Thus, the median and minimum values read at zero. However, in case the water has contaminants, the maximum expected coliform in the water system is 31.

• What is THM, and why might it be important to measure it in drinking water?

THMs (trihalomethanes) are disinfection by-products that form once chlorine has been added to water that has high levels of organic particles like vegetations and decaying leaves. High HTMs are mostly found in areas with surface based water supply. It is important to test THMs in drinking water because if the levels exceed the required acceptable concentrations of 0.1mg/L, it can be dangerous to the health of the consumers. At the same time, drinking water that has a lot of THMs may in time lead to a person getting cancer.Assignment Paper on Public Health Essay

1. Why is it important to measure TDS?

TDS stands for total dissolved liquid and it is a meter that is used to analyse the quality of fresh water. TDS should be measured because when it reaches a certain level say 1000mg/l, the water is considered unfit to be consumed by human beings. TDS also measures taste of the water to determine if it is undesirable, that is, salty, metallic or even bitter. It is also used in measuring filter performance thereby determining when the filter should be changed. Also hardness of water can be detected as well as identifying whether the levels of minerals are constant for aquaculture. It helps measure hydroponics, pools and spas.

1. What is the ‘rule of thumb’ figure used to convert electrical conductivity into total dissolved solids? Why does this conversion not always give a true picture of the TDS in a water sample?

The conversion factor is usually 0.67 which is multiplied by the approximate concentration usually given as (TDS) ppm = Conductivity µS/cm x 0.67.  This conversion does not give the true picture of the TDS in the water sample because it is a gravitational analysis, which bases its assumption on the fact that a given sample would be measured to dryness and each party uses its own range to get the figures.

1. Numerous country systems are never able to meet the aesthetic guideline values recommended for total hardness (DWQR p30). What issues might customers experience as a result of the utility’s inability to meet this guideline?

Generally, failure for the utility to meet the aesthetic guidelines indicates that many of the consumers will not be comfortable drinking the water, as they will think that it is impure. At the Same time, the consumers will think that it smells and tastes bad. It may also affect their clothing,  as it may leave stains if it does not contain the water’s true colour.Assignment Paper on Public Health Essay

1. What does total hardness measure? Why does it have an aesthetic guideline but not a health based one?

Total hardness of water is the sum of calcium and magnesium ions concentrations that generally are expressed as the calcium carbonate equivalent. This being the case, total hardness measures the amount of calcium and magnesium that water may be having. Total hardness has an aesthetic guideline because it relates to the hardness that the consumer expects and is as a result of the source of the water. It is also based on aesthetic guidelines because it makes it difficult for consumers to obtain lather easily from it and can lead to undesirable deposits in hot water pipes and other fittings, and this can be expensive to remove. Health based requirements deal with the composition of water and the necessary steps that the water management takes to ensure that the water is safe for consumption by the consumer.Assignment Paper on Public Health Essay