Micronutrient and pollution transfer in East African lake catchments: impacts on the food-water-energy security nexus

(WATTS_PBGS19ARIES)

Micronutrient and pollution transfer in East African lake catchments: impacts on the food-water-energy security nexus

(WATTS_PBGS19ARIES)

Project Description

Supervisors

Dr Michael Watts (British Geological Survey)

Professor Will Blake (University of Plymouth)

Dr Andrew Marriott (British Geological Survey)

Professor Odipo Osano (University of Eldoret, Kenya)

Background

Subsistence farmers in Africa are often dependent on food grown within a limited area. Therefore, their health is often associated with geochemical factors that influence the soil-to-crop transfer of essential micronutrients (MN) for health (e.g. zinc). Food production and quality is compromised by soil erosion and downstream transport of sediments to waterbodies where sediment and associated nutrients/pollutants impact water security. Resources to manage soils sustainably can be limited, resulting in weathering and erosion of soil into waterways/catchments, such as Lake Victoria. Little is known about the loss of MN from weathering of soils and whether these are more prone to poor soil management (organic retention). Loss of fine soil particles may result in transfer of micronutrients or naturally occurring/anthropogenic potentially harmful elements (PHEs) into water courses/catchments with implications for ecological health. The Winam Gulf catchment of Lake Victoria is an exemplar of these processes as a regionally important source of food both from land and water.

Research Aims & Objectives

– Quantify the nutrient/micronutrient and erodibility status of soil across the Winam Gulf catchment under a range of land use histories and terrain.
– Link sediment in transit within the system to specific spatial and land use defined source areas and processes (surface versus subsurface/gully erosion) using environmental forensic/tracer tools.
– Integrate geospatial evidence with a GIS-based risk modelling framework permitting scenario testing of future changes in land use on MN and PHE flux.

To achieve these aims, the student will receive training in field, lab and data/statistical techniques in two phases:
1. Using on-going data capture, evaluate the potential apportionment of sediment chemistry to sources and locations from baseline soil geochemistry and sediment data collected by UK-Kenyan partners, with additional analyses on archived samples for source apportionment.
2. The student will undertake sampling in Kenya representative of differing land-use (varying timescales of land clearance) subject to different scales of soil erosion, accounting for soil geochemistry over two field seasons to better understand the chemistry and physical parameters influencing leaching of MNs/PHEs.

The candidate should have an earth/environmental science or chemistry degree and willing to travel for fieldwork in Kenya.

The successful candidate will be registered for a PhD in the University of Plymouth’s School of Geography, Earth and Environmental Sciences.

References

  • Joy, EJM, Broadley, MR, Young, SD, Black CR, Chilimba, ADC, Ander, EL, Barlow, TS and Watts, MJ*. (2015). A spatially refined food composition table for Malawi, Science of the Total Environment, 505, 587-595, DOI:10.1016/j.scitotenv.2014.10.038.
  • Watts MJ*, Joy EJM, Broadley MR, Young SD, Ander EL, Chilimba ADC, Gibson RS, Siyame EWP, Kalimbira and Chilima B. (2015). Iodine source apportionment in the Malawian diet, Scientific Reports, 5 1521. DOI: 10.1038/srep15251
  • Middleton DRS, Watts MJ*, Beriro DJ, Hamilton EM, Leonardi GS, Fletcher T, Close RM, Polya DA. (2017). Arsenic in residential soil and household dust in Cornwall, south west England: potential human exposure and the influence of historical mining, Environmental Science: processes and impact, DOI:10.1039/c6em00690f.
  • E Oyoo-Okoth, W Admiraal, O Osano. (2013). Contribution of soil, water and food consumption to metal exposure of children from geological enriched environments in the coastal zone of Lake Victoria, Kenya, International Journal of Hygiene and Environmental Health, 216, 8-16.
  • Blake, Boeckx et al. (2018). A deconvolutional Bayesian mixing model approach for river basin sediment source apportionment, Scientific Reports, 8: 13073

Open for applications

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