Wheal Maid field trip

Our aim

It was important to us that the design of both our parts, and our filter, and the intended implementation for the project was a reflection of a real-world problem. This insight was largely given to us by the RRI framework, as it stressed the significance of society's role in science and it underlined the problem with innovating in an isolated manner. Motivated by our desire to base our science on our own data taken outside of the lab, we went on a field trip.

Wheal Maid forms part of the Consolidation Mine, part of the Cornwall and West Devon Mining Landscape World Heritage Site. Wheal Maid was mined until the 1870s, and then became site for taking fine-grained mineral processing waste (tailings) from the mill facilities at the former Mount Wellington tin mine during the 1970s and 80s. The waste was taken to a valley infill at Wheal Maid consisting of two lagoons separated by three dams and contains approximately 220,000m³ of tailings. An investigation by the Environmental Agency to conduct an inspection into environmental quality, which took place in 2007, concluded that Wheal Maid is a contaminated site (Carrick District Council, 2008). For this reason we decided to conduct our primary field work at this site, collecting water samples from these lagoons.

Figure 1: Wheal maid Lagoon.

Figure 2: Wheal maid pond.

Figure 3: OSM map of Wheal Maid site with plotted sampling sites. (Geoplaner.com , 2017)

Figure 3 and 4 show the nature of the land and indicate that a stream runs through or under the Wheal Maid site and joins up with the Carnon river. This river contributes to the Restronguet creek, leading to the Carrick Roads before ending in the English Channel. This highlights the issue of potential contaminants and pollutants leaching out of the waste site and into the water that will be carried out through the land and to the sea.

Figure 4: Zoomed out OSM map of Wheal Maid site with plotted sampling sites. (Geoplaner.com , 2017)

A protocol was designed to enable efficient collection and filtration of the samples at the site before they were to be transported back and placed in a cold store for analysis.

Methods

The field trip

14th July 2017 12:35am – arrived at the site A PhD student from the School of Mines at Falmouth University, Tomasa Sbaffi, met us to help us with sampling as she had regularly sampled this site and knew it well. We sampled one of the lagoons and the pond in the East.

We sampled the lagoon by taking 1L of water from each of the 4 sites (A-D) as shown by the diagram. Additionally sampled the Pond by taking 1L from each of the 4 sites (E-H).

Figure 5: Satellite map of Wheal Maid site with plotted sampling sites. (Google Maps, accessed: July 2017)

We then filtered 150ml of each sample in to 3 falcon tubes using yellow 100 um filter and then preceded to filter them further through a smaller 0.2 um filter. We treated the blanks containing Mili Q water as controls and processed them the same way as the samples. The pH of all of the samples was tested using litmus paper which all came out as ~pH 3. The samples were sealed in bags and transported back to Exeter to be placed in a cold room to await further analysis.

Figure 6: Laura Simpson filtering samples from the lagoon using a syringe, filter and falcon tubes.

Figure 7: Jake using litmus paper to measure the pH of the water samples from the different sites.

Results

The Figures 8 and 9 were created using Vidana software to determine the percentage decrease in size of the lagoon and the pond since the Google Maps satellite photo was taken in 2017. This could be due to a number of factors such as seasonality which is likely to concentrate the metal ions and pollutants in the water making the water more harmful to the environment.

Figure 8: The percentage cover of the lagoon, sampled on 14th July 2017, is 22% of the percentage cover of the lagoon in the 2017 Google Maps image. The lake has therefore declined by around 78% in area (and therefore in volume) since the picture was taken. This area was determined from the location of the sampling sites around the edge of the lake and visually from Figure 2. (Geoplaner.com , 2017) (Vidana, 2017)

Figure 9: The percentage cover of the pond sampled on 14th July 2017, is 23% of the percentage cover of the lagoon in the Google Maps 2017 image. The lake has therefore declined by around 77% in area since the picture was taken. This area was determined from the location of the sampling sites around the edge of the lake and visually from Figure 2. (Geoplaner.com , 2017) (Vidana, 2017)

Analysis of samples

We prepared the samples and ran them on the ICP-OES machine in the Geography department at the University of Exeter.

Standard Operating Procedures for sample analysis using the ICP-OES

Risk assessment for diluting acids used in SOP

Risk assessment for handling metal ion standard solution used in SOP

Results

Table 1: pH of the lagoon and pond sites at Wheal Maid

Statistical test

An ANOVA (analysis of variance) was performed on the pH of the samples after storage from the different water bodies to see if there was a statistical difference between the two.

Table 2: ANOVA statistic output testing the variation in pH of the lagoon and pond sites at Wheal Maid.

The ANOVA test (p=0.640) was not significant, therefore we can accept the null hypothesis that the there is no variation in the mean pH of the two sites as p>0.05. This means that these sites are of a similar pH and can be used as replicates when determining the metal ion composition or mine waste water, as they are so similar.

Metal ion composition ICP-OES results

Figure 10: Dissolved metal ion composition of samples taken from the Lagoon and Pond sites at Wheal Maid. Stars indicate which elements are found to have higher concentrations than the drinking water standards. (Defra, 2017) (Lenntech.com , 2017) (US EPA, 2015)

Discussion and Conclusion

Metals we have binding proteins for that are above drinking water standards

• Copper

o DM Pond

o TRM Lagoon 2 & pond

• Cobalt

 no known standard

• Iron

o TRM Lagoon 2 & pond

• Magnesium

 no known standard

• Nickel

o DM Lagoon 2 & pond

o TRM Lagoon 2 & pond

These results will be used to inform which metal binding proteins we can use in our constructs.

References

Leung, H, Duzgoren-Aydin, N., Au, C., Krupanidhi, S., Fung, K., Cheung, K., Wong, Y., Peng, X., Ye, Z., Yung, K. and Tsui, M. (2016). Monitoring and assessment of heavy metal contamination in a constructed wetland in Shaoguan (Guangdong Province, China): bioaccumulation of Pb, Zn, Cu and Cd in aquatic and terrestrial components. Environ Science and Pollution Research, 24, p. 9079–9088.

Screen shots of % cover credit: Hedkey, J. (2017). Vidana. Marine spatial ecology lab.

Screenshots of maps credit: Geoplaner.com. (2017). GPS Geoplaner online. [online] Available at: http://www.geoplaner.com/ [Accessed 07 Aug. 2017]

Defra (2017). Drinking water inspectorate. [ebook] London, pp.1-5. Available at: http://Dwi.defra.gov.uk/consumers/advice-leaflet/standards.pdf.

Lenntech.com. (2017). WHO's drinking water standards. [online] Available at: http://www.lenntech.com/applications/drinking/standards/who-s-drinking-water-standards.htm [Accessed 12 Sep. 2017].

US EPA. (2015). National Primary Drinking Water Regulations | US EPA. [online] Available at: HTTPS://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations [Accessed 12 Sep. 2017].