Geographical InvestigationDone by: Krishna Das (14), LE403Experiment Conducted by:Rohan, Martin, Matthew, KrishnaPre-Field Investigation:Research Question:How does human interaction affect the quality of water?HypothesisI believe that the two factors are inversely proportional to each other. This means that the greater the amount of human interaction that the body of water is exposed to, the poorer the quality of water. Similarly the lesser the amount of human interaction the body of water is exposed to, the greater the quality of water. I came up with this hypothesis because water pollution is mainly caused by liquid waste and sewage from residential housing so i figured that human interaction also produces liquid waste thus coming up with the hypothesis.PurposeThe reason why we set out to conduct this experiment is because we wanted to find out more about how much has human interaction affected the environment and we decided to focus our scope into only looking at water quality.
Pre-existing ResearchMultiple websites and articles have conducted research on how urbanisation and human interaction affects water quality and pollution.Some articles states that “industrial wastes, sewage, runoff from farmland, cities, and factory effluents” 1 are all contributing factors that lead to freshwater pollution thus emphasizing the fact that human interaction has caused the quality of water to decrease. Furthermore, many books were published about how human interactions affected freshwater rivers with authors such as Norman E Peters, Michel Meybeck, Deborah V Chapman with their book, Encyclopedia of Hydrological Sciences published online on 15 April 2006.2Field Investigation:Bishan Park:Location 1 at Bishan Park was muddy and located <5m from the river bank. It is located 40m away from the nearest HDB block and 22m to a walkway. The site is also located directly under a pedestrian bridge.Fig 1(a).
Area which we took sample for Bishan Park (Interaction)Site B is located in the middle of the river itself with about 80m in between it and the HDB’s with little pedestrians frequenting the area. Fig 1(b). Area which we took samples for Bishan Park (Without Interaction)Fig 1(c).
Overhead view of where the sample were taken at Bishan ParkNicoll Highway:Fig 2(a). Location where sample of Nicoll Highway (Interaction) was takenFig 2(b). Location where sample of Nicoll Highway (Without Interaction) was takenFig 2(c). Overhead view of the samples were taken at Nicoll HighwayLocation 1 was the closest to human interaction with a road being only 20m away while Location 2 was 50m away from the nearest road. Explanation of LocationsSince Bishan Park and Nicoll Highway are all one body of water, the kallang river, by choosing a location upstream and one downstream, it will show the two extremes in terms of differences of the water quality. As the water from an upstream location such as Bishan Park flows downstream, it crosses many roads, residential buildings and industrial sectors thus exposing the water to large amounts of human interaction making it clear that there will be a large difference between these two locations. Furthermore, at each extreme, we took samples of different distances from HDB houses to further show how human interaction can affect the water on a smaller scale.Fig 3.
Overhead view of the entire river systemData Collection and TestsOver the course of two days, different groups went to different locations to collect samples of water from the river. Day 1On day 1, a pair went to Bishan Park (Upstream) to collect a sample from each site, Fig 1(a) and Fig 1(b). The other pair proceeded to Nicoll Highway (Downstream) to collect 2 samples from each site Fig 2(a) and Fig 2(b).At Bishan Park, the weather was rather humid with temperatures reaching 32 degrees celsius.
The soil around the river was still damp as it had rained 2 days before the day of the investigation. There was moderate cloud cover with little to no winds experienced. Over at Nicoll Highway, the weather was cooler at around 29 degrees celsius with a gentle breeze blowing along the ground. There was little to no cloud cover noticed on the day on the investigation.We used a stratified approach by grouping accessible parts of the river according to the distance from human traffic (Buildings, Roads, Drains etc.
). We then chose the closest site and the furthest site to gather samples. This approach was used both in Bishan Park and at Nicoll Highway.
We calculated the distance from the nearest from of human traffic by using apps called “Google Maps” and “Photo Ruler”. Once our sites were chosen and measured, we were ready to collect the samples.We then coordinated the time of collection of each site at both Bishan Park and Nicoll Highway so that we could minimise the environmental factor that affects the quality of water.Fig 4(a). Sample taken from Bishan Park (Interaction)Fig 4(b). Sample 1 taken from Bishan Park (Without Interaction)Fig 4(c).
Samples 2 taken from both Bishan Park (Interaction) and Bishan Park (without Interaction)Day 2We repeated the experiment at the same sites at Bishan Park and Nicoll Highway at the same time of day. The weather did not change much on the second day with the only major difference being that there was now moderate cloud cover at Nicoll Highway.Day 3One day 3, we all gathers to conduct multiples tests on the samples of water collected. Luminosity TestWe first started out by conducting a luminosity test on all the samples collected. We did this by first:Pouring 50ml of sample water into a clean beakerAfter dimming all the light and closing the curtains, we then poured the 50ml sample into a clear glass containerWe then placed a phone with the application “Lux Meter” directly under the glass jar.
The application allows us to determine the amount of light passing through the water sample and reaching the sensor.Using another phone, we turned on the flashlight and shone the light directly above the sensor.After recording the level of light measured in terms of Lux (lx), we poured away the 50ml sample and washed both the measuring beaker and the glass jar with tap water. We then repeated steps 1-5 using different samples of water from each location and site. Fig 5(a). Sample is being poured into measuring cylinder while reading is taken at eye levelFig 5(b).
Set-up used to determined level of clarity in the waterEquipment Used:Glass JarTap water2 PhonesBeakerNewspapers Sample WaterResults from the test:Water Control (Tap Water) / lxBishan Park (Interaction) /lxBishan Park (Without Interaction) /lxNicoll Highway (Interaction) /lxNicoll Highway (Without Interaction) /lxDay 137083208348620822792Day 2NIL3186353219932704Average3708319735092037.52748Table 1. Difference in clarity of water across each sampleAnalysis of Results:As seen from Table 1, the non-residential area of Bishan Park sample of water allowed the most amount of light to pass through it at 3509lx . It it closely followed by the sample of water taken at the residential area of Bishan Park at 3197lx. Just by looking at these two samples, we can see a difference of 312lx between the 2 samples of water.
For comparison, 300 lux is the amount of light during a thunderstorm at midday while 400 lux is the average light level during sunrise and sunset. Thus the samples so show a significant difference in the clarity of the water even though it is on such a small scale and since the sample closer to HDB housing is less clear, there is a correlation between the distance between HDB housing affecting the clarity of the water. There is little difference in the clarity of the water between the 2 days we took the samples thus showing that results were almost no other factors involved when taking the samples. Furthermore, when comparing samples between Nicoll Highway and Bishan Park, it is clear that both sample taken at bishan park had better water clarity than those taken at nicoll highway as there is a difference of up to 1471.
5 lux with the smallest difference in clarity being 449 lux. This shows that the clarity of water downstream at nicoll highway was much worse than that upstream at bishan park as seen from Fig 5(d).The cause of the pollution of the water could be due to many factors which include liquid waste generated from housing and solid waste created due to construction.
Since the river does pass through a major residential district in Singapore, Toa Payoh, there is a lot of exposure to the liquid waste generated by these districts thus it could have cause the water to be less clear. Fig 5(c). Application used to measure lux levelFig 5(d). Graph used to depict the clarity of water with each different locationpH Test:After conducting the Luminosity Test, we moved on to conduct a pH test of the samples of water. Here are the steps we followed to conduct the test:Firstly, 10ml of sample water were poured into a clean measuring cylinderNext, a piece of universal indicator paper was dipped into the sample for 2 seconds before it was lifted out.After cleaning off excess water, the colour of the universal indicator paper was compared to the resultFig 6(a). Universal Indicator paper used to test the pHResults:Water Control /pHBishan Park (Interaction) /pHBishan Park /pHNicoll Highway (Interaction) /pHNicoll Highway /pHDay 176667Day 2-7667Table 2. Difference in pH level across each sampleAnalysis of Results:As seen from Table 2 and Fig 6(b), the change in the value of the pH is miniscule with the largest difference being only 1 pH.
Although the difference is small, it still makes sense as Nicoll Highway (Non-residential) was predicted to be the cleanest and thus should have the most neutral pH value which it did have. The sample predicted to have a pH value that was furthest off from neutral was Nicoll Highway (With Interaction). Although there is a difference, it was not enough to differentiate it from a sample such as Bishan Park (Without Interaction). From this, we can determine that Human interaction has a miniscule impact on the pH of the water sample as the table does not provide a clear view on the relationship between Human interaction and the pH of the water sample.Fig 6(b). Graph depicting the pH levels across each sampleFiltration TestOnce we were finished with the pH test, we proceeded to filter the water samples to visually determine the amount of impurities that the samples contained.
We used some coffee filter paper that we bought and created an apparatus that would filter the water sample.Equipment used:Glass JarWater sample Styrofoam cup (act as a funnel)Coffee filter paperNewspaperProcedure:Placed the Styrofoam cup on top of the glass jar and poked a hole through the bottom of the cup to allow the filtered water the pass throughPlaced the coffee filter paper above the mouth of the styrofoam cup Pour the water samples into the filter paper until the glass jar at the bottom was completely fullAfter observing the residue left on the filter paper, change the filter paper, wash and dry both the cup and the glass jar.Repeat steps 3 and 4 for each sampleFig 7(a). Newspaper used to cover the floor in case of a spillFig 7(b). Set-up used to filter water samplesFig 7(c).
Coffee filter paper used to filter the samplesResults:Bishan Park (Interaction): Fig 7(d). Set-up before filtration Fig 7(e). Set-up after filtrationFig 7(f). Residue left on filter paperMinimal residue was noticed with only dust and small insects that were visible.
Weight of Residue:0.7 grams (Day 1)0.8 grams (Day 2)Bishan Park (Without Interaction):Fig 7(g). Set-up after filtration Fig 7(h). Residue after filtrationAlmost no residue was seen on the filter paper at first glance however, after closer inspection, few dirt particles were seen on the filter paper.Weight of Residue:0.1 grams (Day 1)0.
1 grams (Day 2)Nicoll Highway (Interaction):Fig 7(i). Set-up before filtration Fig 7(j)Residue after filtrationThe water sample was initially a dark green colour. Once filtered, large amount of algae was seen on the filter paper and the filtrate became clear. There was so much algae that some water could not filter through the filter paper as it was blocked by the algae.Weight of Residue:2.5 grams (Day 1)3.
0 grams (Day 2)Nicoll Highway (Without Interaction):Fig 7(k). Setup before filtration Fig 7(l)Residue left after filtrationWater sample was not as contaminated as compared to the residential area in Nicoll Highway however, residue was still noticeably large with algae and dirt particles present.Weight of Residue:1.4 grams (Day 1)1.
1 grams (Day 2)Analysis of Results:As seen from the photographs, the water sample at Nicoll Highway (Residential) was the most contaminated with the largest amount of algae and dirt particles. It was followed by the Non-Residential zone of Nicoll Highway with less algae but still large compared to the sites at Bishan Park. The third most contaminated water sample was at Bishan Park (Residential) which contained little residue but had some dirt present while the least contaminated was at Bishan Park (Non-Residential) which had almost no residue visible. This is probably due to the fact that there is more exposure to human waste nearer to Residential areas and more exposure downstream. This causes more nitrate waste (NO3) to contaminate the water in the river which cause an increase growth of algae as the algae requires nitrates to thrive. Furthermore, the closer the sample to a HDB house, the higher the concentration of waste as less soil would be present between the river and the house thus fewer waste would be dispersed into the soil making the water more polluted thus showing how our hypothesis still stands true after this test.
Fig 8(a). Visual depiction of the difference in the Weight of the ResiduePost-Field Investigation:Conclusion:To conclude, the luminosity test showed us how the water quality was affected on a microscopic scale proving that human interaction made the clarity of the water worse while the pH test did not reveal much information about whether interaction affects the pH of the water while the filtration test did show how human interaction did cause an increased growth in algae and greater presence of dirt in the water sample. Thus, i believe that, using evidence from the data we have collected, our hypothesis is correct, that the greater the amount of Human Interaction a body of water is exposed to, the worst the quality of that body of water.Bibliography:https://www.greenfacts.org/en/water-resources/l-2/4-effect-human-actions.htm1http://onlinelibrary.wiley.com/doi/10.1002/0470848944.hsa096/abstract?systemMessage=Please+be+advised+that+we+experienced+an+unexpected+issue+that+occurred+on+Saturday+and+Sunday+January+20th+and+21st+that+caused+the+site+to+be+down+for+an+extended+period+of+time+and+affected+the+ability+of+users+to+access+content+on+Wiley+Online+Library.+This+issue+has+now+been+fully+resolved.++We+apologize+for+any+inconvenience+this+may+have+caused+and+are+working+to+ensure+that+we+can+alert+you+immediately+of+any+unplanned+periods+of+downtime+or+disruption+in+the+future.2https://www.sciencelearn.org.nz/resources/440-human-impact-on-rivers3