Soil reference materials (RMs) are critical to ensuring the accuracy and consistency of analytical results across laboratories and research institutions. BGS has produced ten new soil RMs, which have been developed by its inorganic geochemistry team to offer a cost-effective alternative to traditional certified reference materials (CRMs), while maintaining confidence in analytical data. The RMs have been released at a lower price point to help improve access to high-quality materials for researchers and laboratories with limited budgets, enabling them to enhance measurement controls and increase confidence in analytical results across a variety of sectors worldwide. 

Developed from a broad selection of parent materials and incorporating a diverse range of textures and organic carbon contents, reference soils BGS110 to BGS119 have each been characterised by a select group of international laboratories using a variety of analytical techniques. The RMs are also accompanied by data sheets that include for 64 major, minor and trace elements, including rarely measured bromine and iodine. More information about the ten new RMs can also be found in the new report, .

Reference materials are the backbone of geochemical analysis, providing confidence in the measurements that a laboratory produces. Our RMs offer reliable benchmarks for analysing samples with similar matrices. Due to their diverse concentrations of economically and environmentally significant elements, these RMs will enable laboratories, PhDÌýresearchers and industry professionals to calibrate instruments, validate analytical methods and ensure data comparability across studies.

Dr Michael Watts, head of BGS Inorganic Geochemistry.

51ÁÔÆæ now has 18 soil RMs (including one for use in and seven for the analysis of ) and five mineral RMs available for purchase through its website.

The inorganic geochemistry team also remains actively engaged in global initiatives to harmonise soil analytical data across laboratories. These efforts support enhanced health outcomes and food security worldwide. BGS produces custom proficiency testing (PT) materials for international PT schemes coordinated by the Food and Agriculture Organization of the United Nations’ (GLOSOLAN). As part of its collaboration with the FAO-UN and other organisations, BGS has delivered laboratory training around the world, including guidance on producing RMs and PT samples. A free, publicly available is accessible via the GLOSOLAN website.

In addition, BGS prepares geological PT samples and CRMs for a number of commercial distributors, supporting both UK and international PT schemes.

To place an order or for more information on our bespoke RM and PT preparation services, please contact the inorganic geochemistry team (inorganicgeochemistry@bgs.ac.uk). (Gamma irradiated soil RMs are available on request for shipping internationally.)

The 51ÁÔÆæ Inorganic Geochemistry Facility (IGF) provides high-quality analytical expertise and specialist services for the production and interpretation of inorganic geochemistry data for commercial, academic and public sector clients worldwide. This year marks the facility 25th ±õ³§°¿/±õ·¡°ä 17025 accreditation, a gold standard that fosters trust in the quality of the facility work.  

What is ISO/IEC accreditation? 

This accreditation is the formal recognition by the UK Accreditation Service (UKAS) that an organisation meets the specific requirements of a standard; in our case, . Our accreditation ensures that all staff operate according to internationally recognised standards, underpinning our credibility, impartiality and confidentiality, whilst instilling confidence in our customers that the services provided by BGS conform to the highest quality. 

Fundamentally, it is the core quality system framework and its management that is accredited, ensuring that all analytical techniques are performed under the same quality assurance requirements. The technical scope of accreditation has evolved over the years, adapting to changes in demand and availability, and currently includes the determination of cation, anion and aqueous parameter concentrations in natural and experimental water samples. 

Maintaining accreditation for 25 years highlights the commitment and consistency of high-quality outputs of the IGF and its staff.  

How it all started 

In August 1999, the then BGS Analytical Geochemistry Laboratory was awarded ±õ³§°¿/±õ·¡°ä 17025 accreditation by UKAS, making the laboratory one of the very few organisations within the UK research community to hold UKAS accreditation at that time. The initial drive to acquire accredited status came from working on samples provided by the Nuclear Industry Radioactive Waste Executive (NIREX), as robust quality assurance was essential for the project. This requirement essentially established the working practices from which the laboratory was able to derive its management system. The work for NIREX heightened the laboratory staff’s appreciation of the benefits of having a comprehensive management system, so it was simply a case of taking small steps to gain formal recognition against ISO/IEC 17025.  

As BGS provides global public-good science and work for commissioning bodies and legislators, it is of paramount importance that we can provide credible, impartial data. The accreditation status of the IGF has proved instrumental in receiving long-term, large-scale projects and will continue to do so where credibility and confidence in results are of the utmost importance. 

What does it mean for BGS? 

The IGF conducts internal audits on all activities as well as having independent experts from UKAS carry out an external audit on an annual basis. Overall, the culture in an ISO/IEC 17025-accredited facility is one of professionalism, accountability and a commitment to excellence, creating an environment that supports high-quality data outcomes used by academics and industry.  

51ÁÔÆæ has always been highly regarded in the geoscience community and we often set the standard on how to conduct research. Accreditation to an international standard provides formal recognition to wider industry and the UKAS accreditation is a key part of the IGF identity, instilling a culture that emphasises quality, reliability and continuous improvement. This strong focus on quality at all stages is one of our key strengths and all members of the team understand and adhere to protocols to ensure compliance and the production of high-quality outputs. The culture of continuous improvement encourages feedback and ensures processes are regularly reviewed and updated. 

The accredited status of the IGF has significantly contributed to overseas science partnerships, facilitated BGS-hosted training of laboratory technicians and enhanced capacity-strengthening projects across the globe including Afghanistan, Kenya, Kyrgyzstan, Nigeria, Liberia, Malawi, Saudi Arabia, Tajikistan, Zambia and Zimbabwe.  

Due to our accreditation status, the IGF is a highly sought-after industry placement for undergraduate chemistry students who want to specialise in environmental chemistry. The 12-month industry placement we offer to students from the UK, New Zealand/Aotearoa and Australia equips them with the skills they need to excel in both academic and commercial workplaces, with many of the students going on to work in other accredited laboratories and highly regulated industries. Read more about the success of previous students.  

How will it continue to be relevant in the future? 

The IGF accreditation against ±õ³§°¿/±õ·¡°ä 17025 demonstrates our ongoing commitment to quality assurance, the reliability of results and regulatory compliance, which is crucial for environmental monitoring. The IGF remains adaptable to ensure we can meet future requirements and regulations, and maintains a level of preparedness for future, national-scale programmes. 

About the author

My name is Maureene Auma Ondayo and I am a 51ÁÔÆæ-funded PhD candidate at the University of Eldoret, Kenya, and BGS, with a background in environmental and public health. In this blog I will share my PhD research, investigating major and trace element exposure in the environment. This includes ores, soils, sediment and waters, locally grown staple food crops (maize, leafy vegetables, pulses and tubers), and human samples (hair, nails and urine). My research also incorporates risk factors of exposure to potentially harmful elements (PHEs) and associated health implications among artisanal and small-scale gold mining workers and local residents.  

What is artisanal and small-scale gold mining?  

Artisanal and small-scale gold mining (ASGM) is an informal mining sector that provides subsistence-level livelihoods for many rural communities across the world. In Kenya, ASGM occurs in Migori, Narok, Siaya, Vihiga, Kakamega, Nandi, Kisumu, Turkana, West Pokot, Marsabit, Homa Bay and Kericho counties. It is estimated that ASGM production yields around 5 metric tons per year (worth around £250 million), employing 250 000 workers with more than 1 million dependents. The main environmental and health risks associated with ASGM relate to poor conditions at mining camps and mining operations, which include the extensive misuse of mercury in the production process.   

Mining the gold 

Miners often rely on local knowledge when prospecting for gold after which agricultural land and pristine forests are cleared to make way for the mine. Ores are excavated and broken into smaller pieces using sledgehammers and mills, dispersing large volumes of contaminated dust across nearby environments and communities. Milled ore powder is then wetted and sluiced to extract the gold particles. Panning separates gold-associated sediment particles, then liquid mercury is added, which joins together with the gold to form an amalgam and separates it from the sediment. The amalgam is then burnt on open flames, vaporising the mercury and leaving behind the gold, whilst tailings and wastewater from ASGM are disposed of in nearby farms, residences, playgrounds and waterways. 

These activities expose the workers and local populations to extreme health and safety hazards, with injuries, diseases and premature deaths reported in ASGM areas.  

Hazards of ASGM 

Exposure to potentially toxic elements (PTEs), physical hazards, gaseous emissions, overexertion, physical injuries and poor ventilation inside the mines are the key hazards to human health in ASGM. This exposure results in a wide range of health disorders including:  

• cancers 
• immunity suppression 
• neurological disorders 
• developmental health effects  

Socio-economic issues related to mining activities are also present in local areas, including alcohol and addiction, violence and HIV/AIDs.  

My research 

During my PhD, I investigated the environmental and human exposure and health implications among nineteen ASGM communities in Kakamega and Vihiga counties, Kenya. 

I collected soil, sediment, water, locally grown food and human biomarker samples (hair, nails and urine) from ASGM workers and residents of ASGM villages and analysed them for major and trace elements at BGS Inorganic Geochemistry Facility in Keyworth. Further risk factors from PTE exposure and potential health effects among the studied ASGM communities were assessed through interviews.  

Study results 

Kakamega and Vihiga counties are naturally enriched with macro- and micro-elements and the ASGM activities primarily disperse them across surrounding environments and communities. The results show that:  

• soils, sediments and water sources in the ASGM villages were highly polluted by PTEs, including arsenic, mercury, chromium, lead and nickel 
• soil concentrations of arsenic, chromium and nickel in the studied ASGM villages were 154, 9 and 4 times higher than background concentrations, respectively 
• drinking-water samples in the ASGM villages, including springs, shallow wells and mine shafts, were heavily polluted with arsenic, lead and chromium. Very worryingly, we observed mine workers and residents drinking mine-shaft water, the most contaminated water at the ASGMs, when they were extracting the ore!  
• locally grown staple food crops were also contaminated with arsenic, nickel, lead, chromium, cadmium, mercury and aluminium, and were not considered safe for consumption  

The inhalation of gaseous PHEs like mercury during amalgam burning, the consumption of locally grown staple food crops and drinking water, and ingesting PTE-contaminated dust and soils (especially children and pregnant women that exhibit pica, that is, eating non-food items like soil) were the main exposure pathways found in our study. Self-reported potential pollution-related health effects included cancers, neurological effects, respiratory infections, musculoskeletal effects, infectious diseases including HIV/AIDS, and malaria.    

Working with the ASGM community 

A key aspect of my PhD was the multidisciplinary research approach taken to understand the relationships between the environment, diet and public health to effectively assess and communicate human exposure and health risks. We continue to collaborate with ASGM workers, local communities and local health practitioners while sharing our findings.  

On 2 December 2023, we met with county public health administrators to understand how best to present and share the data for interpretation with our key stakeholders. These include: 

• politicians 
• broader county employees 
• the departments of mining, environment, and law enforcement 
• community health workers 
•  the studied ASGM communities in both Kakamega and Vihiga counties 

Additional meetings with public health officers, medical practitioners, environment and agricultural departments and other key stakeholders are planned. This will let us share our results and recommendations on reducing PTE exposure through environmental, occupational and public health safety controls, such as: 

• providing safer drinking water to ASGM communities 
• relocating residences and schools away from ASGM activities  
• controlling dust transfer 
• encouraging regular personal protective equipment (PPE) use 
• alternatives to mercury 
• safer cyanidation operations 
• wet milling 
• technological interventions in ore exploration, excavation, processing and recovery 
• targeted education and training on industrial hygiene 
• public health policy formulation in ASGM in Kenya 

This study characterised PHE exposure pathways and health risks among ASGM communities in the Kakamega gold belt. Our findings are valuable to public health authorities as they inform them of the mitigation actions that are needed to research further, reduce exposure, improve ASGM processes, and protect the environment, food sources and the health of ASGM workers and residents, including policy formulation. 

About the author 

Maureene Auma Ondayo is a 51ÁÔÆæ-funded PhD candidate at the University of Eldoret, Kenya, and BGS, with a background in environmental and public health. 

Co-authors  

Prof Odipo Osano is an environmental toxicologist at the University of Eldoret, Kenya. He has a background in veterinary medicine, public health, and community and laboratory-based environmental epidemiological research.   

Clive Mitchell, BGS Industrial Minerals Geologist.   

Dr Olivier Humphrey, BGS Environmental Chemist.   

Dr Michael Watts, BGS Head of Inorganic Geochemistry and lead for BGS International Geoscience Research and Development.   

The summer of 2023 saw the completion of the twentieth cohort of undergraduate industrial placements within the Inorganic Geochemistry Facility at BGS. These students undertake a twelve-month placement at BGS as paid members of the team, typically during the third year of a four-year undergraduate chemistry degree. The students largely originate from the University of Surrey, where an extensive programme set up by Prof Neil Ward comprises industrial placement experience with key sectors in the UK and around the world, with the goal of improving the employability of graduates. Overall, we have employed thirty-six students at BGS through this scheme since 2003, with several also coming from the universities of Nottingham, Waikato (New Zealand) and Adelaide (Australia).

Benefits to BGS

Each year, we have undergraduates with a fresh perspective keen to put into practice two years of learning at university.  Whilst there is an initial investment in training each year as a host, the students’ enthusiasm and passion quickly leads to effectiveness in the workplace.  The rotation every twelve months results in constant questioning and challenging of staff as to why we undertake laboratory procedures in a certain way, and occasionally leads to some innovative ways of thinking. 

The students are considered part of the wider team and are therefore given their own responsibilities, with guidance. Typically, they are operating complex laboratory instruments (with guidance) within a few months; these can include gamma spectrometers, ion chromatographs, inductively coupled plasma mass spectrometers (ICP-MS) and sometimes multiple instruments – which is not uncommon in industry. In fact, I completed a similar industrial placement myself many years ago at a pharmaceutical company, an industry in which the employment of undergraduate industrial placements is common for the operation of research equipment under the supervision of graduate or postgraduate scientists. This approach is a valuable recruitment tool across industry.

The scheme has also been a helpful recruitment tool. In 2013, Elliott Hamilton was employed as a permanent member of staff; he now oversees the interview and selection of students each year. We have also recruited past industrial placement students onto PhD programmes, with three completed PhD projects at BGS and two currently approaching completion.

Networking is a key benefit of the programme. Through communication between university scientists and BGS, the students learn how to cooperate, sharing ideas, data and learning, and have the opportunity to work with young people with different cultural and educational upbringings to some of our staff.

Benefits to early career scientists

The industrial placement students are given a research project aligned to the ongoing needs of the laboratory and the wider BGS strategy. In general, this will require a new laboratory capability for research or commercial purposes. This activity develops the students’ experience in scientific rigour, reasoning, planning and communication, which is reinforced through oral presentations . Communication learning culminates for the University of Surrey students at their ‘Industry Day’ when they return for their final year of study. They present their experience to the other companies involved in the industrial placement programme, typically pharmaceuticals and the chemical industry, life sciences, environmental science and materials research.

Student responsibilities within the laboratories range from the routine daily tasks that are essential to the functioning of the facility (and in maintaining our accredited status to ISO 17025:2017) to the operation of complex equipment. Crucially, they learn how to multi-task, respond to deadlines on varying scales and deal with pressure points through teamwork and communication.ÌýImportantly, throughout the year the students often clarify what they want to do as a career beyond graduation, with the industrial placement giving them valuable applied skills and knowledge, skills for their CV and the start of their own personal career network. Of the 36 alumni, 16 went onto further postgraduate study, with many others remaining in a science career through professions in teaching, sales or chemistry roles across a range of industrial sectors.

The students

Prof Neil Ward, University of Surrey

Michael Watts at BGS provides an excellent laboratory for students undertaking work-based learning or professional training. This long-standing link with the University of Surrey is highly recognised for the professional level of training the students get, with specific on-the-job experience of quality control systems, project specific analysis of other staff at BGS and the day-to-day experience of working with experts from a variety of professions at BGS. All the students learn about research in a world where it is not just sample analysis that is important; the results are also important in relation to natural environmental and geochemical problems.

Summary

Overall, the industrial placements are an extremely valuable way of refreshing the workforce perspective and approach to wider learning and development of staff. The students have formed a valuable recruitment pool and a wider network as they develop their careers, resulting in a flexible form of workforce to respond to opportunities, which greatly enhances the employability of the students and the development of wider skills for UK scientific research.  The scheme also continues to be invaluable approach to developing the supervisory and line management skills of junior staff, particularly given the diversity of personalities and  levels of resilience and fragility. Overall, it has been extremely satisfying to see these young scientists evolve, develop their self-confidence and start to crystallise their hopes for the future during the course of the 12 months and beyond.

About the author

During the last year, the Inorganic Geochemistry (IG) Facility at the BGS headquarters in Nottingham installed a new laser ablation – inductively coupled plasma – mass spectrometry (LA-ICP-MS) system for the direct solids analysis of trace elements in geological, environmental and industrial materials. The system was selected with the aim of being able to map elemental distribution across these materials. In this blog, we will cover some highlights of working with the laser so far, focusing on our studies with BGS economic geologist Eimear Deady on critical raw minerals from south-west England and mineralogist and petrographer Dr Alicja Lacinska on magnesium carbonate as a means of ‘locking up’ the potentially toxic element chromium.

What is LA-ICP-MS?

The laser in our LA-ICP-MS system samples less than one microgram of material by focusing the equivalent power of a nuclear power-generating station into a spot of light, less than the diameter of a human hair, for a mere ten billionths of a second. This intense burst of energy vaporises the tiny sample; we capture it in a stream of gas and pass it over to our mass spectrometer to analyse.

For those who like technical specifications, the new LA system is an imageGEO193 from Elemental Scientific Lasers, which is designed for high-speed, high-resolution imaging of geological materials. it uses a 193 nm excimer laser, running at 1 to 500 Hz, and a fluence of 0 to 15 J/cm². The mass spectrometer is an 8900 series ICP-MS/MS from Agilent Technologies. This generation of ICP-MS has high sensitivity and high selectivity, allowing us to measure fifty major elements, from per cent levels down to trace element concentrations below one part per million every fifth of a second.

Importantly for users, it can make the laser ablation craters in either a circular or rectangular shape and between 1 and 150 microns across, which makes it ideal for mapping analysis. Solid samples can be used in almost any form, as long as they fit into the ablation chamber, although for mapping they need to have a flat, smooth surface. We would normally use samples that have been prepared in a similar way to those used for scanning electron microscope (SEM) or electron probe work, i.e. samples contained in either polished resin blocks or as thin sections. We use this preparation method because most geological samples are heterogeneous and require a nice cross-section to see what you are analysing.

The laser ablation mapping ablates across the whole surface of the sample, creating transect marks as shown on the SEM image in Figure 3. The process of ablating across the sample is sufficiently shallow that the sample is not disrupted for other future analytical work of a qualitative manner.

Cool applications

Tungsten, tin and antimony mineralisation in south-west England

A key aim of producers should be understanding the full metal budget from ore deposits, in order to achieve a more sustainable approach to mining and the extraction of metals. This ensures they extract all possible metals and are managing the flow of elements into waste. While trace element content in major ore phases can be used to constrain the parameters that control the petrogenesis of mineralised deposits, it also allows us to identify and quantify impurities or indeed bonus elements that may occur in the ore.

The Hemerdon deposit, located in Devon, is the fifth-largest tungsten deposit in the world and is currently under development. One of the aims of this aspect of the research is to use the trace element data to understand the fluids that formed the deposit, the changing geological conditions under which it formed and how that affects ore quality. We also aim to better understand the deportment of minor metals such as bismuth and molybdenum, assessing both their distribution and abundance.

The LA mapping highlighted the variability of the trace element distribution (Figure 4), identifying crystallographic differences that were invisible under reflected light microscopy or SEM.   

Chromium in synthetic magnesium carbonate — the CrCarb project

The move to low-carbon technologies requires the sourcing of industrial, technological and precious metals in quantities higher than ever before. However, an increase in mining without adequate handling and disposal of the waste can cause adverse effects for the environment and society. The CrCarb project focuses on hexavalent chromium, a highly toxic and carcinogenic pollutant originating from the mining and processing of chromium or nickel ores from ultramafic rocks and laterites, and proposes to immobilise the hexavalent chromium in the crystalline structure of carbonate minerals.

LA-ICP-MS mapping was used as part of a multiscale, multi-technique investigation to uncover the presence and distribution of chromium in experimentally produced magnesium carbonates. Preliminary characterisation of these materials using scanning electron microscopy with energy dispersive X-ray spectrometry and wavelength dispersive X-ray spectrometry (SEM EDS-WDS) revealed that chromium distribution is highly variable. As a result, a statistically significant number of particles needed to be analysed to observe and understand any trends in the element distribution, which LA-ICP-MS mapping enabled us to do (Figure 5).

Funding

Our thanks to the Innovation Flexible Fund, whose support allowed us time to optimise the new system and undertake some case studies with colleagues both within BGS and beyond.

About the authors

If you would like us to help you with one of your own projects, contact one of the authors below and we will get back to you!

This BGS ArcGIS web application was created to develop a predictive soil geochemistry map of western Kenya. The interactive app provides to the agri-community using BGS’s measured data combined with machine learning.

The original data, relating to land use, crops grown, drinking water source/usage and any local health problems, was generated from field collections between 2016 and 2019 during the BGS ODA-I programme, as part of a geochemistry and health project to investigate the spatial incidences of diseases within the Rift Valley (e.g. oesophageal cancer; micronutrient deficiencies). You can read more about the project and our time in western Kenya in our previous blogs on and .

On completing our fieldwork trips, we brought the collected samples back to the BGS headquarters at Keyworth, Nottingham, and analysed them at the Inorganic Geochemistry Laboratories. We created a dataset that compiled soil prediction maps for 56 chemical elements (mg/kg), pH and organic matter content (per cent) using machine learning (Random Forest) analysis. The predictive maps, displayed as raster files with a spatial resolution of 500 m, were based on the 452 soil samples collected from discrete sampling locations across western Kenya and relevant environmental covariate data, such as elevation and rainfall.

Once all of the predictive layers were created, they were entered into an , accessible ‘free’ online via a PC or mobile device. Stakeholders in Kenya from the academic and outreach sectors were consulted during development and tested the web tool, making useful suggestions for refinements to better communicate both the tool and the data itself directly to farmers. Future developments will enable us to continue to add more data and expand the area, subject to funding.

The ArcGIS map will have other research uses for BGS grant-funded projects, in particular a Royal Society International Collaboration grant to study dynamics for land-to-lake transfers within the Winam Gulf catchment of Lake Victoria resulting from soil degradation. This tool can also provide valuable information to agricultural extension services regarding areas where fertility may be at greater risk due to soil degradation and contribute to source apportionment models for transfers into the lake basin.

The publication of our web tool will enable BGS to seek wider stakeholder input to the tool to stimulate new developments, ideally with new funding. For example, combining this data with health incidence statistics could provide investigation assistance regarding the spatial influence of geochemistry on health conditions (e.g. oesophageal cancer and micronutrient deficiency) and exposure to geogenic potentially harmful metals with chronic health implications.

Acknowledgements

This research was supported by the BGS-NERC grant  ‘Geoscience for sustainable futures’ and BGS/ programmes for financial support. It was delivered via the BGS Eastern Africa Official Development Assistance (ODA) Research Platform and the activities were coordinated by Michael Watts (BGS), Odipo Osano (University of Eldoret) and Diana Menya (Moi University).

We would like to thank the many people who assisted in the collection of samples, including the public health officers from each county administrative area and, in particular, the field and laboratory staff from the University of Eldoret (UoE), Moi University (Moi U) and BGS.

University of Eldoret

David Samoie, Doreen Meso, Charles Owano, Melvine Anyango and Job Isaboke.

Moi University

Esilaba Anabwani and Amimo Anabwani.

Queen’s University Belfast

Daniel Middleton.

51ÁÔÆæ

Andrew Marriott, Amanda Gardner, Elliott Hamilton, Nicholas Porter and Sophia Dowell.

About the author

The first year of my PhD has been very exciting, although not without its challenges. In November 2019, one month into my PhD, I travelled to Kenya for the first time. This fieldwork provided initial training in sample collection via the project. With the help of our counterparts at the University of Eldoret, I had the opportunity to scope out some potential experimental soil erosion plots in the Oroba Valley, Nandi County, western Kenya (Figure 1).

The escarpment area of western Kenya is rapidly being converted from native forest into farmland, with the Oroba valley representing differing time periods for land clearance between one and more than 80 years. It was clear from our visit that the local residents were feeling the effect of soil erosion in the area, with one family having recently lost their crop due to heavy rainfall washing away the terraces they had built earlier in the year. This land degradation is not only devastating for the farmers in the area, but the soil also has the potential for loss of nutrients and transfer of metals into the river catchment, with consequences for aquatic biogeochemistry in the Winam Gulf of Lake Victoria.

The analysis of these pilot samples indicated that the valley would be an ideal area to model soil erosion processes occurring over differing timescales, within the Lake Victoria catchment. In March, I travelled back to Kenya with Dr Olivier Humphrey to revisit the Oroba valley and begin reference site sampling. During this trip I also had the opportunity to scout out some interesting areas with differing land management practices, for more intensive soil erosion plots in the future.

Unfortunately, this field trip had to be cut short by a couple of days because of the global lockdown due to COVID-19 and a need to return to the UK.ÌýHowever, I was fortunate enough to have collected the planned 10 soil cores to a depth of 30 cm (Figure 2) enabling me to continue work through the summer and autumn of 2020.

This summer has been somewhat mixed: the lockdown has not enabled me to undertake follow-up fieldwork in June and October, yet I have been able to progress with the laboratory analyses. These included chemical analyses of the samples, with emphasis on gamma spectroscopy to determine the radionuclide inventories of both Cs-137 and unsupported Pb-210 in the collected soil cores.

The data can then be used to determine the extent of soil redistribution processes. The use of these radionuclides as soil erosion tracers have limitations in the southern hemisphere, so I am investigating the possibility of using Pu-239 and Pu-240 as alternative tracers of soil redistribution. To do this, alongside members of the BGS Inorganic Geochemistry team, I will be developing a working method for the pre-concentration and rapid analysis of plutonium isotopes on the inductively coupled plasma mass spectrometer. This will then allow me to determine the best method for quantifying soil redistribution processes and relate the extent of soil erosion with the soil-micronutrient losses and ultimately soil land-to-lake transfers of metals/nutrients to the Lake Victoria catchment.

This work is a progression from previous geochemistry and health work in western Kenya and is interlinked with a Royal Society international collaboration through to 2022 to identify lake-to-land transfers resulting from land-use changes and soil erosion, subsequent impacts on fisheries and the growing aquaculture industry in Lake Victoria.ÌýUltimately, this work will inform consequences for agricultural productivity, nutritional potential of staple foods and aquatic biogeochemistry, with a link to mitigation steps tested by colleagues in Tanzania.

About the author

My name is Sophia and I am a BUFI PhD student based within the BGS Inorganic Geochemistry Facility in Keyworth. My research is entitled ‘‘. This PhD is in partnership with the University of Plymouth and is funded by the NERC . Before beginning my PhD, I completed a BSc in chemistry at the University of Surrey, during which I completed a placement year within the BGS Inorganic Geochemistry team (see my ) and this is what first sparked my interest in environmental geochemistry.

Chemical reactions in soils are difficult to monitor due to the speed with which they start and finish, but measuring them is necessary to increase our understanding of how nutrients and toxic compounds are transferred into plants.

There are a number of techniques capable of collecting and measuring dissolved compounds in water within soil, but the complex nature of soil demands methods that can collect samples faster and at smaller scales without disturbing the natural chemistry of the soil. Microdialysis — originally developed for use in neuroscience and pharmacokinetics — is a new technique that uses small probes to sample compounds dissolved in soil solution (Figure 1), without the need to dig up soil and potentially alter its chemical properties. BGS Inorganic Geochemistry Facility is at the forefront of developing microdialysis as a soil sampling technique, with the ability to assess rapid chemical reactions with unparalleled temporal and spatial resolution without significantly disturbing in situ physicochemical soil properties.

We first began developing the application of microdialysis during Olivier Humphrey PhD (completed in 2019) at the Centre for Environmental Geochemistry (BGS/University of Nottingham), where he was investigating (full paper). This marked the first occasion of continuous sampling of soil solution to investigate the short-term behaviour of an essential micronutrient, the results of which could inform future food fortification studies aimed at alleviating hidden hunger (aligned with the United Nations Sustainable Development Goal 2: ‘zero hunger’). The use of microdialysis to investigate soil-elemental speciation dynamics has been further developed by Elliott Hamilton during his PhD (completed in 2020), which will be summarised in a future blog.

We have since been awarded a Royal Society of Chemistry grant to continue this research, and have developed a project aimed at establishing harmonised methods for both microdialysis sampling in soils and subsequent data interpretation. Despite the potential advantages of microdialysis, considerable effort is required to develop and progress the analytical chemistry and theoretical frameworks to apply the technology to soil solution multi-elemental analysis. By providing accurate and precise data on the bioavailability of beneficial and harmful elements in soil, substantial progress can be made within soil science, botany and agricultural sciences. A better understanding of what is beneath our feet can only help us in tackling real world problems (incorporating the SDGs); microdialysis truly has the potential to pave the way in finding the solutions to widespread food security and nutrition issues, as well as aiding the promotion of sustainable agriculture and good health and well-being. We aim to establish microdialysis as a tool capable of assessing fine-scale, rapid soil chemistry interactions to better inform existing geochemical models that influence phytoremedial and crop biofortification strategies globally, and look forward to updating you in the future as this exciting technique is developed further.

About the authors

Matthew Ogley, a placement student from the University of Surrey, is currently working in the Inorganic Geochemistry facility to support the research efforts being made on microdialysis, as well as undertaking routine analyses in the laboratories.