Project highlights

  • Development of advanced analytical technology for environmental monitoring
  • Tracing the origin of environmental pollutants using isotopic analysis methods
  • Training in computer aided design, mass spectrometry, use of portable sampling devices and advanced statistical methods

Overview

Brazil nut trees (Bertholletia excelsa), a protected species that is vital to the forest economies of Amazonian Bolivia, Peru and Brazil, cannot be grown in plantations.  Therefore, nuts are harvested from wild trees in natural forest. The majority of nuts are exported to the EU, UK and USA, providing the only regular income for many rural households in the Western Amazon region and guaranteeing the survival of the forests where trees grow.  As part of import controls to the EU, Brazil nut processing plants are required to certify levels of methyl bromide (CH3Br), a pesticide that is banned in many countries due to its harmful environmental impacts. CH3Br is not known to be used in any of the forests, or adjacent agricultural landscapes where Brazil Nuts are grown, yet levels of 24 to 100 ppb have been reported in Brazil nuts.  At 25 ppm or above nuts no longer qualify as ‘organic’, despite being wild harvested in natural forest away from agrochemical use of CH3Br. At or above 50 ppm, nuts no longer qualify as fit for human consumption. This impacts considerably on the commodity’s price and it is perceived by processing and export companies as the main threat to their industry (greater than climate change or deforestation). The loss of this mainstay on the local community would have devastating impact on the forests as their main value would switch to soya, cattle, or timber, which would entail deforestation.

This project will focus on the development of mass spectrometry techniques and remote sampling methods to trace the source of CH3Br. Specifically, the project will investigate the variation of CH3Br at different scales (in nuts, across the tree, within the surrounding forest, across the Bolivian Amazon).  We will investigate whether the contamination is coming from the local environment (soil, leaf-litter, the trees themselves) or longer distance contamination stemming from pesticide use, and whether levels of CH3Br correlate with any impact on the nutritional or health value of Brazil nuts.  Finally, we will determine potential drivers in variation that could predict long-term threats or mitigation to the Brazil nut market.

The image shows a schematic of a GC-ICP-MS system. A custom heated transfer line connects the two instruments.

Figure 1: A schematic of the gas chromatography (GC) – inductively coupled plasma mass spectrometry (ICP-MS) system that will be used to conduct analysis of methyl bromide. A custom heated transfer line will be developed and extensively validated during year 1 of the project.

CENTA Flagship

This is a CENTA Flagship Project

Case funding

This project is suitable for CASE funding

Host

Loughborough University

Theme

  • Climate and Environmental Sustainability
  • Organisms and Ecosystems

Supervisors

Project investigator

 

Co-investigators

How to apply

Methodology

Bromine has two stable isotopes (79Br and 81Br), the ratio of which varies in nature.  Ratios of 81Br/79Br in nuts and associated environmental samples will be measured to establish the source of CH3Br contamination.  Gas chromatography (GC) will separate CH3Br from the sample matrix, followed by inductively coupled plasma – mass spectrometry (ICP-MS), to provide precise determination of the 81Br/79Br ratio.  Coupling of GC to ICP-MS is relatively niche and has not previously been applied to this sample matrix, thus the first year of the project will focus on construction of the GC-ICP-MS interface, followed by validation using certified reference materials.  Analysis of 81Br/79Br ratios in nuts from the Bolivian rainforest and analysis of any impact on the nutrient and chemical composition will follow in years 2 and 3.  A range of related pollutants (e.g. organophosphates) will be analysed in parallel using remote sampling devices and organic mass spectrometry.

Training and skills

Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and ‘free choice’ external training. One CTC equates to 1⁄2 day session and students must accrue 100 CTCs across the three years of their PhD.

The student will have access to a range of relevant short courses through our MSc Chemistry programmes, plus Doctoral College training courses, aligned with the Vitae Researcher Development Framework.  Project specific training, including operation of mass spectrometry instrumentation, computational design of equipment, data reduction and advanced statistical methods, will be provided at Loughborough. Additional training opportunities in use of liquid chromatography-mass spectrometry (LC-MS, including high resolution accurate mass) for analysis of nutritional and secondary metabolites in Brazil nuts will be provided at Kew, where the student will have access to regular seminars in a range of plant and fungal sciences.

Partners and collaboration

The collaboration between Loughborough and Kew was established through chemistry student placements and will be extended through the complementary facilities and expertise on this project. Kew have been working with rural communities in the Bolivian Amazon since 2013 and it is through this work that they became aware of the problem of CH3Br in Brazil Nuts. Loughborough have a track record of developing advanced mass spectrometry instrumentation and deployment of sampling systems for remote toxicological monitoring; expertise vital to identify the source of CH3Br.  CASE partners Tahuamanu (Bolivia) are processors of Brazil nuts and will provide access to data and samples.

Further details

For further information about this project, please contact Dr Amy Managh ([email protected]) or Dr Matthew Turner ([email protected]). For general information about CENTA and the application process, please visit the CENTA website: https://centa.ac.uk/. For enquiries about the application process, please contact the School of Science ([email protected]).

If you wish to apply to the project, applications should include:

  • A CV with the names of at least two referees (preferably three and who can comment on your academic abilities)

Applications to be received by the end of the day on Wednesday 11th January 2023. 

Possible timeline

Year 1

Training in mass spectrometry.  Testing of total bromine and essential element levels in commercial Brazil nut samples using ICP-MS.  Design and validation of an interface to couple gas chromatography to ICP-MS.

Year 2

Isotope ratio analysis of Brazil nut samples using the validated GC-ICP-MS interface and nutritional and chemical composition analysis of Brazil nuts (GC-MS, LC-MS, ICP-MS).  Training in advanced statistical methods for data reduction.  Deployment of remote environmental sampling devices.  Publication on the technological aspects of trace isotopic analysis.

Year 3

Isotope ratio analysis of environmental (soil, water, air) samples using GC-ICP-MS.  Analysis of related organic pollutants in nut and environmental samples using APCI-MS.  Publication focussed on pesticide residues found in Brazil nuts and the surrounding environment.

Further reading

Craig, G., Managh, A.J., Stremtan, C., Lloyd, N.S., Horstwood, M.S.A. (2018). Doubling Sensitivity in Multicollector ICPMS Using High-Efficiency, Rapid Response Laser Ablation Technology. Analytical Chemistry, 90 (19), pp 11564–11571.

Heaney, L.M, Ruszkiewicz, D.M, Arthur, K.M., Hadjithekli, A., Aldcroft, C., Lindley, M.R., Thomas, C.L., Turner, M.A., and Reynolds, J.C. (2016) ‘Real-time monitoring of exhaled volatiles using atmospheric pressure chemical ionisation on a compact mass spectrometer, Bioanalysis, 8(13), pp. 1325-1336.

Douglas, D.N., Managh, A.J., Reid, H.J., Sharp, B.L. (2015). High-Speed, Integrated Ablation Cell and Dual Concentric Injector Plasma Torch for Laser Ablation-Inductively Coupled Plasma Mass Spectrometry. Analytical Chemistry, 87 (22), 11285-11294

Horst, A., Holmstrand, H., Andersson, P., Andersson, A., Carrizo, D., Thornton, B.F., and Gustafsson, O. (2011) ‘Compound-specific bromine isotope analysis of methyl bromide using gas chromatography hyphenated with inductively coupled plasma multiple-collector mass spectrometry’, Rapid Communications in Mass Spectrometry, 25, pp. 2425–2432.

COVID-19

The use of remote sampling devices and collaboration with partners mean that it is not essential for the student to travel.  Practical experimentation in the laboratories at Loughborough University will be essential, but this is unlikely to pose a problem over a three year project.  Apart from a short period during the first lockdown, these research laboratories have remained fully open with effective social distancing in place.  The project also involves substantial periods of computer based work, such as design of equipment and data processing, that would enable progress to continue in case of a stringent lockdown.