SEGH Articles

Capacity strengthening in field collections and laboratories for geochemical sampling and public health in Western Kenya

11 March 2019
Here David Samoie, Odipo Osano and Diana Menya discuss geochemical sampling in western Kenya.

‘In late 2018 BGS was awarded funds from NERC via the GCRF funding initiative to supplement on-going activities in developing countries supported by the BGS-ODA programme, with one of the objectives to enhance activities at a local level.  Here David Samoie from the University of Eldoret describes a field collection initiative which he led and organized with this funding support’ – Michael Watts.

This was to be the 5th field sample collection for a joint project between the University of Eldoret (UoE), Moi University (MU) and British Geological Survey (BGS) in collaboration with the International Agency for Research on Cancer (IARC-WHO). The project seeks to explore a potential link between soil geochemistry and the spatial incidence of esophageal cancer and other human/animal health issues in the Great Rift Valley corridor in western Kenya.

Figure 1: Field team collecting geochemical samples

Preparation and Training

For the previous 4 sampling trips, members of the BGS team led 3 separate field teams with two or three field assistants (academic leads from UE and Moi, technician and postgraduate students) to help out in the field and in most Counties a Public Health Officer. Through the activity, training was provided in sampling and initial sample processing procedures for soil, drinking water, crops and urine from rural households, alongside data capture for each site onto field sheets.  Gradually each Kenyan member took on more responsibility with an emphasis on quality assurance. Training included:

  • Detailed planning before and after sampling for sample locations and logistics.
  • Accurate record keeping in the field and cross-checking of samples with field lists.
  • Use of photography as a backup of record in the field – daily back-up of field sheets.
  • Avoiding sample contamination and ensuring sample preservation.

Good isn’t always expensive! The sampling team was trained on the Use of Maps.Me. A free mobile Smartphone software application. This application is a very powerful tool in pre-sampling site planning, route guidance and recording of the geographic coordinates and altitude of the actual sampling site.  Sampling an area of 3835 km2 with an even spatial spread would not have been possible without the support of the software and training. The sampling sites for our first independent field collection using the NERC-GCRF funds were predetermined using soil type/pH maps and locations for previous collections. Thirty selected sampling points were pre-assigned onto the mobile app.  (maps.me) and used to navigate from one site to another, making sure to get as close as practically possible to these predetermined GPS sites.

Sample Locations

Figure 2: Sample locations

Sampling

Armed with smartphones, maps.me app. and other sampling gear the Kenyan team managed to collect 302 samples of Soil, Water, Urine and Plants, from 30 households in Bungoma and Busia counties in Western Kenya. Field data capture sheets were completed, along with water chemical parameters measured at each household.  Soil samples were sieved to 2 mm when found dry and plant samples were washed to remove surface contamination.

At the end of each day, samples were checked against field sheets, water and urine samples stored in cool boxes and plant/soil samples aired where possible. On completion, all samples were taken to the UoE lab for further processing before shipping to the UK. The processing involved air drying of leafy vegetables in a glass house (circa 30oC); peeling and freeze-drying of fruits and root vegetable; pulverizing grains by use of coffee grinders taking care to avoid cross-contamination; and oven drying of soils. The soil samples were packed in zip lock bags, the leafy vegetables in paper bags and the rest of the samples were packed in vacuum-sealed plastic bags.

All samples were cross-checked again to prepare sample lists for export permission by the Kenyan Authorities (KEPHIS).

Waters and urines were refrigerated, soil samples were oven dried at 30oC and then split spilt to provide a reference sample to create an archive at UoE for future student projects and a portion to be sent to BGS for analyses.

Figure 3: Field team collecting geochemical samples and processing samples

 

Our experience - Challenges and Mitigations

  • Impassable roads. Because the sampling points were randomly and evenly spread on the map, sometimes it was hard to reach the actual locations.  The routes suggested by the software app. were sometimes practically impassable and minimal adjustments were to locations were made when required. Certainly, 4x4 vehicles are recommended at all time during sampling.
  • Informed consent and honour of African Culture and taboos were adhered to. We strived to win the confidence of household members and in many occasions, they enthusiastically participated in sample collection at the field and provided the required information.
  • At the time of sampling in January, it was dry season and the roads were more easily passable but very dusty. Travelling for about 200 km every day for 5-6 days on unpaved and dusty roads was testing. The area of sampling also required more precautions for mosquitoes.

 

Benefits of sampling and laboratory experience to UoE

This sampling exercise has greatly benefited UoE lab staff and students to put into practice the training received from BGS for field collections and instigation of quality assurance procedures from collection to lab data output. Via this training in Kenya and through training secondments to BGS funded by Professional Fellowships (CSCUK-ACU) for David Samoei (May-2017) and Doreen Meso (May-2019), the UoE laboratory capacity has been greatly enhanced by this interchange of experience.

The lab has also benefitted greatly with equipment procured for sampling. These include Freeze driers, coffee grinder, balances, sieves, and other expendable laboratory supplies, soon to be joined by equipment to improve capacity in preparing samples for chemical analyses via BGS and a network of jointly funded grants’ applications.

Our future prospects are to undertake more processing of sample collections at UoE, such as basic and fundamental tests like pH, LOIs and chemical extractions to a greater quality of output with guidance from high-end facility labs such as at BGS and other partners in the network. This will greatly reduce the workload in BGS in relation to processing samples from Africa, through building confidence in local capability. These will necessitate further training and exchange of skills to be able to develop data outputs to international standards comparable for publication and to be able to offer paid analytical services within Kenya to provide sustainable and more regular sources of income using our peers as a benchmark.

This collaboration so far has opened opportunities for individuals in our labs, as well as a widening network to bid for joint proposals for a broadening range of research projects in the theme of environmental geochemistry and health – Marriot blog. Continuing collaboration with BGS will help to develop the network of funded projects and to build local capability through practical experience and supplementation of equipment where possible.

Figure 4: Schematic flow of field sampling


Acknowledgements

We acknowledge the funding from the NERC-GCRF funds, via the BGS-ODA programme for this sampling trip and previous support over the last few years. Technical support from the BGS Team (Dr Michael Watts, Dr. Andy Marriot, Dr. Dan Middleton, Olivier Humphrey) especially the ever-present remote assistance, constructive criticism and reminders from Dr. Michael on Whatsapp platform; the  sampling team (David Samoei, Doreen Meso, Job Isaboke, Esilaba Anabwani, Melvive Anyango, Amimo Anabwani, for exacting themselves during whole sampling period; Prof Odipo and Dr. Diana Menya for effective local coordination, pre-visits to the local Health facilities: Public health Officers, Community Health Workers and Community Health Volunteers of Bungoma and Busia Sub-county Hospitals for effective community entry; and the Management of University of Eldoret and Moi University for its support during the whole process.

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