Factors Affecting Bulimba Creek's Unrinkability

The water from the creeks and water bodies around Brisbane will be unsafe to drink as the water is polluted and results will not be in the recommended requirements for safe drinking. It is expected that Bulimba Creek is polluted because it is a large water way and therefore it is hard for one committee to maintain the watery way’s health while respecting its biodiversity (BulimbaCreek.org, 2015). It is expected that Waterloo Bay is undrinkable because it is a salt water body (Health-e-waterways.org, 2012). It is expected that Phillips Creek is undrinkable because it is located in an industrial area and surrounded by many shops and petrol stations, which can lead to exposure of chemicals which can pollute the water (BulimbaCreek.org, n.d.).
The aim of the experiments were to investigate and assess the quality of the drinkability of water from creeks and water bodies in Brisbane.
Water samples were collected from Bulimba Creek, Waterloo Bay and Phillips Creek. Tap water from a Brisbane household was used as a control during the experiment. It was predicted that the most drinkable water, and the water which satisfied the most Australian Drinking Water Guidelines (ADWG) would be Bulimba Creek, then Phillips Creek, followed by Waterloo Bay. This is because Bulimba Creek, located around rural Bulimba, is a difficult, biodiverse water way to keep clean. Phillips Creek, with a water sample taken from Carina Heights, is located near many shopping locations which may have an effect upon its water body’s drinkability. Waterloo Bay, located in Wynnum, is a salt water body which would be unfit for human
consumption.
The results from the turbidity demonstrated that Waterloo Bay, Bulimba Creek and Phillips Creek were all polluted. The ADWG standard for turbidity is <9NTU. Turbidity tests the amount of undissolved solids in the water. There is hydrogen bonding in water molecules which is the strongest force of intermolecular attraction. If the water molecules have a stronger attraction between their ions than the other polar molecules in the solution, the solid will stay undissolved. Solids are also likely to remain undissolved if they are a molecular substance because most molecular substance are insoluble. It is usually only molecular substances that have the ability to form hydrogen bonds with the hydrogen in the water samples that will dissolve, as shown in Figure 6 (Smith, D., 2008). Therefore it is evident that there are many undissolved solids in the three water samples because of a weak attraction between the insoluble solids and the water molecules.
Figure 6: Substance Dissolving in Water
This same understanding of forces and solubility though are the same driving forces behind the heavy metal test. None of the three water samples tested contained heavy metals, which adheres to the ADWG guidelines………………………………………………………….
This theory behind forces and solubility also applies to the salinity test completed. Waterloo Bay had a salinity of 20.68ppt which far exceeds the ADWG standard of drinkable water at 0.5 to 1ppt. Bulimba Creek and Phillips Creek’s salinities were however in this suitable range at 0.13ppt (Bulimba Creek) and 0.18ppt (Phillips Creek). Salinity is the concentration of Cl- atoms in a solution ……………………………………….. ………………………………………………………………………………………………………………………………………………………………………………………………..A precipitation reactions occurs when ions with opposing charges are together in an aqueous solution and bond together to form an insoluble ionic solid which is known as a precipitate. By applying the previous theory of………………………………………………………………………………………………………………………………
Equation 1 shows the reaction which occurs during the experiment
Equation 1: Al3+(aq) + NaOH(aq)  Al(OH)3(aq) + Na+(s)
The pH of Waterloo Bay, Bulimba Creek and Phillips Creek disproves the hypothesis, indicated that all three water samples should have qualities which make the water drinkable. All three water samples had an average pH calculated from three measurements which were in the ADWG standard of 6.5 to 8.5pH. Waterloo Bay had a pH of 7.93, Bulimba Creek had a pH of 6.92 and Phillips Creek had a pH of 7.69. A neutral solution has a pH of 7, which is the middle of the desirable drinking water standard. The lower the pH from 7, then the more acidic the water sample is, while the higher the pH the more basic the water is. If water is basic then it contains a higher concentration of OH-, while an acidic solution contains a higher concentration of H+.
However, the qualitative data recorded oppose that the water bodies are clean. Drinkable water is indicated by general observations when the liquid is transparent and odourless. Bulimba Creek had a brown colour from the amount of dirt in the water. Waterloo Bay was cloudy because of the salt found in the water. Phillips Creek was cloudy because of dirt in the water. This colour change reveals the water is unclean because a sign of water pollution is the traces of sediments. The brown and cloudy colour of the water samples indicates there are sediments in the water. The tap water though was transparent and clear. This reveals that by colour, tap water is the only drinkable water and the other three water samples are polluted with other substances.
The results of the smell though are more unreliable than the colour. Bulimba Creek and Phillips Creek both smelt on the bottles they were being held in, and no other smell could be dedicated because of that. Waterloo Bay though smelt of salt as it is a salt water body. The tap water was the only odourless water, indicating it is the only drinkable water as it is expected to match the ADWG.
There were other difficulties associated with the experiment too. There were outliers and modifications made throughout the duration of the experiment. When testing the turbidity of the water samples there was an outlier recorded in the first trial for Bulimba Creek. This may have been caused because the bottle containing the water was not shaken before the test begun. This caused for the substances other than water to remain in the bottle, and so the result was inaccurate. For an accurate result to use in the calculations of Bulimba Creek’s turbidity a fourth trial was run for the water sample.
There were also outliers in the pH test. The amount of outliers in the test could be a result of cross-contamination. Despite the pH meter being rinsed with diluted water to neutralise reading, it is possible that not enough water was used and as a result the meter was measuring the pH of two different samples. To still have accurate results in the pH test the method was slightly modified and instead of three trials being run on each water sample four were instead done.
When testing the salinity of Waterloo Bay another modification also had to be made. Initially 25mL burettes were being used for the experiment but the volume of AgNO3 needed to complete the experiment exceeded this amount. Therefore a 50mL burette was used to test the salinity of Waterloo Bay.
CONCLUSION
The hypothesis, which stated that Bulimba Creek, Phillips Creek and Waterloo Bay would not be drinkable water according to the ADWG because the water bodies are polluted, was supported.
It is evident from this experiment that the three water samples are all undrinkable. To improve the water quality of the water ways there needs to be less insoluble substances found in the water.
The turbidity of the water samples needs to be improved for Waterloo Bay and Bulimba Creek. This can be done by filtering the water. By having non-degradable sediments around the water way the amount of run off entering the water is limited. This would also contribute to improvement of the water’s colour because it would have less insoluble substances such as dirt.
The salinity of Waterloo Bay cannot be improved because it is a salt water body. However to improve the salinity of Phillips Creek and Bulimba Creek the roads and other sediment based structures and the infrastructure of nearby drainage need to be regularly maintained to avoid rocks falling into the water. The salinity levels of the water bodies also has the potential to fluctuate due to periods of rainfall which are able to dilute the concentration of the Cl- in the water
ways.
The experiment can also be improved by testing more drinkability indicators to better gauge the drinkability of the water samples used in the tests. Bulimba Creek also has to be considered to be polluted from the experiment results because of the qualitative data collected and its turbidity. However its results are the closest to the SEQ water guidelines in pH, salinity and contains no heavy metals. This may be a result because of the location the water was collected from, where dirt was abundant.
In conclusion, from the results of the experiment the three water samples tested can be considered to be polluted and undrinkable because although they may meet a few of the SEQ water guidelines, they do not meet them all.