Earth ScienceEnvironment

Measuring Pollution Levels in Newcastle-upon-Tyne

Abstract

The Ouseburn Valley within Newcastle upon Tyne is an urban tributary that has been placed under pressure as a result of the continuing urban development and changes to its climate. Sourced in Callerton, a region in the north-east close to Newcastle Airport, the tributary flows over approximately 17.5 km and through numerous urban and agricultural environments, forming a catchment of 65 km². A water quality survey was conducted to ascertain the implications of urbanisation upon the tributary, with faecal pollution and its impacts being the primary focus. The results suggest that the source of the pollution comes from Kingston Park and another region situated further downstream. Brief consideration has also been given to methods by which such pollution can be ameliorated. The method proposed within this study is inexpensive and can be used to accurately determine the extent of faecal contamination within any body of water.

Introduction

The Ouseburn is an urban tributary that flows through Jesmond Dene, Gosforth, Kingston Park, and Newcastle Great Park, discharging into the River Tyne via the Ouseburn Valley. Historically, Ouseburn Valley, akin to the rest of Newcastle-upon-Tyne, has been susceptible to pollution from three main sources: poor agricultural practices, mining, and landfill sites[1].

Jesmond Dene is of particular interest, as the Ouseburn intersects with the park at a point where it becomes a popular bathing site. However, prior surveys have demonstrated that during times of high flow, pollution is a serious issue, rendering the water unsuitable for bathing. Sampling was conducted in areas with faecal contamination as the pollutant of interest. Recently, Jesmond Dene received a heritage fund of £6 million, which has been spent upon the construction of a visitor’s centre and landscaping.

Figure 1: a satellite image of Jesmond Dene, Newcastle upon Tyne. Source: Google Maps

The most recent Newcastle City Council project along the Ouseburn is an expansion of Great Park, which is concerned with public infrastructure and residential properties. To better manage the surface water run-off from the surrounding area, a Sustainable Drainage System (SUDS) was built, which was supposed to emulate natural drainage[2], but research has indicated that the system is not operating at its highest capacity. The area which this inquiry will focus upon is Kingston Park, which has been given poor water quality assessments for several years, and the aim of this study is to quantitatively analyse the water within the Kingston Park area to see if coliform populations match the assigned grade. Coliform bacteria are microorganisms that usually occur in the intestinal tract of animals, including humans.

Figure 2 shows a scanning electron micrograph of coliforms, specifically E.coli. Source: Science Photo Library

Literature Review

All of the literature cited and referenced within this study are from reliable authors and organisations, with work having been published in peer-reviewed journals. However, some data, such as that used from the MET Office, is from 2012, and so, may not provide results that are as relevant to this study, as a result of the time of their collection.

Ecological Policies

The Water Framework Directive (WFD) is a “legally binding policy that provides a common framework for water management and protection throughout Europe.”[3] The creation of this directive enabled multiple aspects of water management to be brought together for suitable analysis and policy-making, committing all relevant parties to achieve ‘good ecological and chemical status by 2015’[4]. The implications of the aforementioned WFD are visible within the Ouseburn Valley, with analyses of water quality being carried out at sites recognised as requiring significant improvements within the Northumbria River Basin Management Plan (NRBMP), and suggesting any improvements where necessary. The standards of the WFD will be used to evaluate the quality of samples.

Water Quality and Urban Run-Off

One consequence of urban run-off is the reduced quality of water resulting from pollution from heavy metals such as mercury, which are the result of the area’s mining history, hydrocarbons, and grit, with such occurrences being worsened during periods of high flow and providing the tributary with mephitic smells and an unappealing colour. Mercury is toxic to the central and peripheral nervous systems. The inhalation of mercury vapour can also be corrosive to the immune system and kidneys and the inorganic salts of mercury can irritate and be corrosive to the skin and eyes[5].

During winter months, UK Climate Change Projections predict a 10-20% increase in the levels of precipitation, which naturally leads to more urban run-off and flooding, thus meaning that the problem of pollution becomes greater in the catchment. Contamination of the tributary was accentuated by a BBC report from 1st October 2011[6] describing how detergents had polluted the river, generating ‘mystery bubbles’ of foam that took six hours to clear away.

There are several factors that determine water quality and are assessed according to set criteria: chemical, biological and physical. By using biological methods, the aim of this inquiry is to identify areas with poor water quality and to suggest possible ways in which it can be improved.

Method

Apparatus:

  • 1 pair of forceps
  • 1 spatula
  • 8 or more petri dishes
  • 250 ml of membrane lauryl sulphate broth solution (MLSB)
  • 450 ml of Ringer’s solution
  • 1 Bunsen burner and 1 heatproof mat
  • Sterile tips for pipettes
  • Pipettes
  • 20 small vials
  • Digital temperature probe or a thermometer (if available, an autoclave can also be used)
  • An incubator

Coliforms (bacteria present within the digestive system of animals) are often used to measure water quality and have frequently led to alterations to public health policy. Escherichia coli (E.coli) is the most commonly used indicator of faecal contamination because it’s amongst the easiest to detect with inexpensive methods. Moreover, it is found in the digestive systems of humans and animals and is found within their faecal matter. As previously mentioned, meanders within the Ouseburn are frequently used as a recreational place, therefore, it is paramount that the water is not detrimental to health. This study shall determine whether water quality (as determined by concentrations and populations of E.coli) adheres to WFD standards, or is a threat to human health.

In order to provide a method of high quality, the method of this study was coordinated with the document ‘The Microbiology of Drinking Water’ by the Environmental Agency, as this ensures comparisons can be drawn with WFD targets. The method of identifying faecal contamination is Membrane Filtration, which will enable both the cultivation and isolation of the bacteria on a lauryl sulphate broth placed on the membrane (MLSB) at 44 degrees Celsius for 18 hours. Although the membrane filtration technique is an accepted method of measuring microbial quality, there are limitations. One example of such a limitation would be the fact that within a nutrient-rich environment, there is a possibility that other thermotolerant coliforms may develop and proliferate[7]. However, the test can be repeated if such a problem occurred.

Figure 4: MF filtration method (top left), the methodology for serial dilution (top right) and the autoclave preparation (bottom)

Testing needs to occur 24 hours after collecting the sample, so as to mitigate the effects of deterioration. The preparation requires the production of Ringer’s solution, which is isotonic (having the same osmotic pressure as cells, thus resulting in no intracellular swelling or shrinking), and is used to disperse bacteria so as to increase the accuracy of the counting process. The isotonic nature of the solution is paramount as it will prevent lysis (the rupture of the cell membrane) or crenation (the shrinking of the cell) which are the result of water entering or leaving the cells via osmosis respectively. MLSB is a medium for membrane filtration and will be used to enumerate the number of E.coli and coliforms within the water sample, and it is easy to use and economical for this study.

Figure 5: a diagram showing the behaviour of cells in hypertonic (exerting a greater osmotic pressure than the cell cytoplasm), hypotonic (exerting a lower osmotic pressure than the cytoplasm) and isotonic solutions. Source: Wikipedia article “Tonicity”

Due to the fact that the cultivation of specific coliforms is imperative for this method, preventing cross-contamination must be achieved. This is done through sterilising all of the necessary apparatus at high temperatures and pressures using an autoclave (or using a Bunsen burner on inoculating equipment), as shown in figure 4. Other equipment, like Petri dishes, are sterilised when they are produced, and so do not require any further modifications prior to their use.

Due to Ringer’s solution having no osmotic impact upon coliform organisms, it is ideal to use for the spreading of the aforementioned organisms across the petri dish and as an agent for serial dilution. Serial dilution enables more manageable results to be obtained because otherwise, the E.coli would be too multitudinous to count.

Serial Dilution Methodology

  1. Ringer’s solution is manufactured prior to the experiment, which was done by filling one 1 litre flask with purified water and adding a Ringer tablet (a Ringer tablet of quarter strength was used here).
  2. 1 ml of the sample was transferred to one 9 ml sample of Ringer’s solution, which created the first dilution and was labelled accordingly, using a sterile pipette.
  3. 1 ml of the first dilution was then transferred to the next sample of Ringer’s solution to create the next dilution. This was also labelled accordingly.
  4. Step 3 was repeated for another sample of Ringer’s.
  5. Duplicates of each dilution were created so as to maximise accuracy.

Membrane Filtration

First and foremost, the Petri dishes should be labelled to avoid future confusion between different samples (the underside should be labelled). Techniques that keep the dishes aseptic were used when the packaging was removed. In order to provide an environment encouraging bacterial growth, the 0.45 micrometre gridded membrane pads within petri dishes were soaked in 2.5 ml of MLSB. To prevent any confluent growth, any excess MLSB was removed after 20 minutes. The most diluted sample was spread over the pad and the vacuum pump was then turned on.

The vacuum pump was used to evenly disperse the bacteria over the membrane pad in the Petri dish. This was then repeated for all dilutions, which were then placed in trays with appropriate labels and incubated for 18 hours at 44 degrees Celsius. The samples were then left at room temperature for 20 minutes so as to enable any colour changes to occur. The colonies appeared both yellow and pink, which rendered them easy to count.

Results

In order to account for the effects of dilution factors, the equation by which results are calculated is as follows (calculating the number of colonies within each sample, which for this study was 100 ml):

Units of coliform per 100 ml = (100 x number of colonies x dilution factor) / Volume of filtered sample

The mean CFU (coliform units) per 100 ml of the samples collected shows that a substantial quantity of faecal contamination is present at the sample site, Kingston Park (23,445 CFU/100 ml).

Discussion

The results obtained by this study indicate that the highest levels of faecal pollution occur in Kingston Park. The level of pollution could have detrimental impacts upon the surrounding riparian and aquatic environments, and thus causing harm to wildlife concomitant with sulphur dioxide pollution[8] and creating an aesthetically displeasing and malodorous environment. Some of the impacts mentioned above have already appeared within the area in recent years.

Figure 3 shows the Environmental Agency assessment of the entirety of the Ouseburn between 2002 and 2006, and it suggests that substantial levels of pollution occur between Three Mile Bridge and Brunton bridge. Combined with this inquiry, it can be demonstrated that in between the aforementioned locations, Kingston Park plays a considerable role in the water quality degradation, with vast quantities of faecal pollutants entering the river.

Table 1: an assessment of the water quality within the Ouseburn Valley, 2002-2006, using the Environment Agency General Quality Assessment (GQA) Scheme criteria[9]

From To Sample km 2002 2003 2004 2005 2006
Source Airport steam Woolsington 3.8 C D D D D
Airport steam Bent Hill Brunton Bridge 2.2 C C C C B
Bent Hill Great North Road Three Mile Bridge 2 C D D D D
Great North Road Castle Farm Castle Farm 2.4 C B C C C
Castle Farm Jesmond Dene Jesmond Dene 1.8 C B C C C
Jesmond Dene Tidal limit Jesmond Dene 1 C B C C C
Tidal limit Tyne N/A 1 N/A N/A N/A N/A N/A

The possible contributors to the high levels of faecal pollution have already been discussed. However, some of the causes (such as the future council projects and increasing urbanisation) are difficult to verify without data

Table 2: March to April precipitation data [10]

Year Month Total Precipitation (mm) Average CFU/100ml at Kingston Park
2009 April 36.8 4983
2010 April 12.4 2737
2011 April 7.2 2009
2012 March 15.0 6569

These high results also correspond to the average across March 2012, with high flows corresponding to 38,200 CFU/100 ml, and low flows corresponding to 7,450 CFU/100 ml (see figure 6)

Figure 6 is a bar chart showing the average CFU/100 ml of the Ouseburn Valley the Ouseburn Valley at high and low flows in March 2012 [11]

Conclusions

The results of this study indicate that the stretch of the Ouseburn within Kingston Park consistently shows levels of faecal contamination sufficient to possibly cause harm to biodiversity and human lives, although it is not likely that bathing in the waters of the area will be a public health hazard. However, as higher levels of precipitation result in larger volumes of water travelling through urban environments as surface run-off, the coliform levels within the water used for recreational purposes (due to it being easily accessible) will steeply rise, and may eventually pose more serious threats than before.

One proposed solution to ameliorate this issue would be to introduce reed beds into the local environment. This is because the reed beds would cleanse the water prior to its interaction with the water, and using natural methods to re-introduce the water cycle into urban environments is an initiative that Ouseburn, and surrounding wards of Newcastle, are taking in an effort to become a blue-green city[12]. In addition, this solution would not interfere with the natural landscape, thus maintaining the aesthetics of the region. Many people are concerned with whether reed beds would be able to cleanse the vast volumes of water that enter the watercourse during times of high flow.

Further Improvements

As an independent study, only one location was chosen from which to gather samples due to its easy accessibility and close proximity to my place of residence. Therefore, to form a more holistic and accurate portrayal of the water quality of the entire Ouseburn river, more sample stations should be established at different points along the river’s course. Moreover, more samples could be collected at different times of the year, allowing a quantitative analysis of water quality to be conducted to measure the extent to which it varies throughout the year.

As mentioned in the introduction, there are several factors that influence the quality of water, and in this study, only the biological factor was the cynosure. Therefore, a chemical analysis of the volume of carbon dissolved in the water, along with other pollutants, could be conducted to ascertain a more complete indication of the water quality within the Ouseburn Valley, as well as how such chemicals may impact the surrounding soil profiles.

References

  1. ‘Creative Districts Around the World’ Lenia Marques and Greg Richards. Available at Creative districts around the world lenia marques – Google Scholar
  2. National SUDS Working Group 2004: Interim Code of Practice for Sustainable Drainage. Available at Microsoft Word – CIRIA CONTRACT103 – NSWG SUDS ICoP [FOR PRINTER 2].doc (susdrain.org)
  3. ‘Water Framework Directive: A New Directive for a Changing Social, Political and Economic European Framework’ Kaika M. 2003. Available at The Water Framework Directive: A New Directive for a Changing Social, Political and Economic European Framework: European Planning Studies: Vol 11, No 3 (tandfonline.com)
  4. ‘The EU water framework directive: measures and implications’ Water Policy 3, 125-142. Available at The EU water framework directive: measures and implications – ScienceDirect
  5. ‘WHO: Mercury and Health.’ Available at https://www.who.int/news-room/fact-sheets/detail/mercury-and-health
  6. ‘River Ouseburn Foam: Cleaning Liquid Theory’ (BBC Report 1st October 2011). Available at https://www.bbc.co.uk/news/uk-england-tyne-15136332
  7. Bartram J. and Ballance, R. (1996) ‘Water Quality Monitoring.’ Available at (PDF) Water quality monitoring: a practical guide to the design and implementation of freshwater quality studies and monitoring programmes (researchgate.net)
  8. ‘Effect of SO2 on lichen and bryophytes around Newcastle upon Tyne’ OL Gilbert (1969). Available at 344756 (wur.nl)
  9. Matthew J. Rennie (2012) “Water Quality Survey of the Ouseburn” p.26. RennieM.pdf (ncl.ac.uk)
  10. Durham Precipitation Data, MET Office (2012). Weather and climate change – Met Office
  11. ENVIRONMENTAL AGENCY, NEWCASTLE UNIVERSITY, NEWCASTLE CITY COUNCIL, OUSEBURN CATCHMENT STEERING GROUP, NORTHUMBRIAN WATER LTD & AONE 2009. Ouseburn and North Gosforth Integrated Urban Drainage Study. Data Available at Environmental health and pollution | Newcastle City Council
  12. ‘The Blue-Green Path to Urban Flood Resilience’ Thorne C., Ahilan S. et al (2020). Available at The blue-green path to urban flood resilience | Blue-Green Systems | IWA Publishing (iwaponline.com)

About the Author

Andrew is 17 years old and studies Biology, Geography and Mathematics. In his spare time, he enjoys learning new subjects, with particular interests in organic chemistry, machine learning and environmental science. When he isn’t studying, Andrew enjoys reading and playing badminton

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