SEGH Articles

Ecosystem services to alleviate micronutrient malnutrition in Sub Saharan Africa

20 May 2011
Ecosystem Services concepts have great potential for linking biogeochemistry, health and policy formulation for poverty alleviation.

Mineral malnutrition due to environmental and cultural factors is widespread in sub-Saharan Africa (SSA).  A multi-national research consortia led by the University of Nottingham (UoN) undertook a pump priming project to explore if Ecosystem Services could provide an effective conceptual framework to link biogeochemical cycles of dietary minerals and poverty.  The project initially focussed on iodine, selenium and zinc in Malawi and Zambia.  Through data integration, feasibility studies, networking and capacity building we addressed three target themes: Biogeochemistry, Nutrition, and Economics.

Biogeochemistry: we developed a new GIS (ArcGIS) framework linking soil and land-use data has been submitted for open-access peer review publication.  New geochemical data for soils and vegetation were incorporated from an aligned project (UoN) and other spatial data (e.g. DFID FarmLime, BGS). Through integration of soil types in GIS, we have found that the population Se intake from maize is typically 6-7 µg Se per day, which represents ~10% of the dietary requirements for Se. Since maize provides the majority of dietary energy to the rural poor of SSA, this study revealed for the first time that chronic Se deficiency is endemic for the majority of the population and is largely influenced by input from soil.

Major knowledge gaps still exist.  Further  sampling, capacity building and data integration activities were therefore planned at a workshop in Lilongwe in September 2010 with multiple government departments and regional academics for future funding application.









Nutrition: a feasibility study was completed to study the spatial variation in I, Se and Zn dietary intake and status  in Malawi as a case study.  The National Health Sciences Research Committee of the Malawi Ministry of health granted ethical approval for dietary and biomarker surveys and intake analyses across several villages.  Importantly, sensitisation visits to the villages and farmers was undertaken by extension services, Ministry of Health and PI's.  Data showing strong geochemical control of intake and status, and these will be submitted for publication later in 2011. 

Economics: a novel Ecosystem Services framework was developed based on: modelling soil-to-diet relationship using mineral / dietary-energy units; food choices and land-use; quantifying relationship between disease burdens and poverty at population levels. Economic analyses were formalised using World Health Organisation Disability Adjusted Life Years (DALYS), which incorporated a willingness to pay for intervention.   Such analyses provide a useful policy tool at national and regional scales. 

For example: despite limited data, a pilot analysis estimated that 3,955 healthy life years (DALYS) per 1m population per year are lost each year in Malawi due to Zn deficiency alone, mostly due to infant mortality.  This represents an economic loss to Malawi of >1% GDP per year.  Economic analyses for I, Se and other elements requires more data. 

This work was funded via the Ecosystem Service Poverty Alleviation programme by UK DFID-NERC.

Project partners included: British Geological Survey, University of East Anglia, Genius Consultancy, University of Sabanci, University of Adelaide, University of Otago, University of Malawi, University of Zambia, Ministry of Agriculture & Health (Malawi).

Dr Martin Broadley, University of Nottingham.





Keep up to date

Submit Content

Members can keep in touch with their colleagues through short news and events articles of interest to the SEGH community.

Science in the News

Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health

  • Editorial 2018-12-11
  • Chemical fractionation of heavy metals in fine particulate matter and their health risk assessment through inhalation exposure pathway 2018-12-11


    Samples of PM2.5 were collected from an urban area close to a national highway in Agra, India and sequentially extracted into four different fractions: water soluble (F1), reducible (F2), oxidizable (F3) and residual fraction (F4) for chemical fractionation of arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), nickel (Ni) and lead (Pb). The metals were analyzed by inductively coupled plasma optical emission spectroscopy in each fraction. The average mass concentration of PM2.5 was 93 ± 24 μg m−3.The total concentrations of Cr, Pb, Ni, Co, As and Cd in fine particle were 192 ± 54, 128 ± 25, 108 ± 34, 36 ± 6, 35 ± 5 and 8 ± 2 ng m−3, respectively. Results indicated that Cd and Co had the most bioavailability indexes. Risk Assessment Code and contamination factors were calculated to assess the environmental risk. The present study evaluated the potential Pb hazard to young children using the Integrated Exposure Uptake Biokinetic Model. From the model, the probability density of PbB (blood lead level) revealed that at the prevailing atmospheric concentration, 0.302 children are expected to have PbB concentrations exceeding 10 μg dL−1 and an estimated IQ (intelligence quotient) loss of 1.8 points. The predicted blood Pb levels belong to Group 3 (PbB < 5 μg dL−1). Based on the bioavailable fractions, carcinogenic and non-carcinogenic risks via inhalation exposure were assessed for infants, toddlers, children, males and females. The hazard index for potential toxic metals was 2.50, which was higher than the safe limit (1). However, the combined carcinogenic risk for infants, toddlers, children, males and females was marginally higher than the precautionary criterion (10−6).

  • Effects of steel slag and biochar amendments on CO 2 , CH 4 , and N 2 O flux, and rice productivity in a subtropical Chinese paddy field 2018-12-07


    Steel slag, a by-product of the steel industry, contains high amounts of active iron oxide and silica which can act as an oxidizing agent in agricultural soils. Biochar is a rich source of carbon, and the combined application of biochar and steel slag is assumed to have positive impacts on soil properties as well as plant growth, which are yet to be validated scientifically. We conducted a field experiment for two rice paddies (early and late paddy) to determine the individual and combined effects of steel slag and biochar amendments on CO2, CH4, and N2O emission, and rice productivity in a subtropical paddy field of China. The amendments did not significantly affect rice yield. It was observed that CO2 was the main greenhouse gas emitted from all treatments of both paddies. Steel slag decreased the cumulative CO2 flux in the late paddy. Biochar as well as steel slag + biochar treatment decreased the cumulative CO2 flux in the late paddy and for the complete year (early and late paddy), while steel slag + biochar treatment also decreased the cumulative CH4 flux in the early paddy. The biochar, and steel slag + biochar amendments decreased the global warming potential (GWP). Interestingly, the cumulative annual GWP was lower for the biochar (55,422 kg CO2-eq ha−1), and steel slag + biochar (53,965 kg CO2-eq ha−1) treatments than the control (68,962 kg CO2-eq ha−1). Total GWP per unit yield was lower for the combined application of steel slag + biochar (8951 kg CO2-eq Mg−1 yield) compared to the control (12,805 kg CO2-eq Mg−1 yield). This study suggested that the combined application of steel slag and biochar could be an effective long-term strategy to reduce greenhouse gases emission from paddies without any detrimental effect on the yield.