Lunyangwa Research Station

Mzuzu, Malawi

Lunyangwa Research Station

Mzuzu, Malawi
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Chidya R.C.G.,Mzuzu University | Matamula S.,Mzuzu University | Nakoma O.,Lunyangwa Research Station | Chawinga C.B.J.,Mzuzu University
Physics and Chemistry of the Earth | Year: 2016

Many people in in the Sub-Saharan region rely on groundwater fordrinking and other household uses. Despite this significance, information on the chemical composition of the water in the boreholes and emperical data on groundwater quality is limited in some rural areas of Malawi. This study was conducted to evaluate the physico-chemical quality of water from boreholes (n = 20) in Zombwe Extension Planning Area (EPA), Mzimba in Northern Malawi to ascertain their safety. Desktop studies and participatory approaches were employed to assess the socio-economic activities and water supply regime in the study areas. The water samples were analysed forpH, conductivity (EC), turbidity, water temperature, nitrate (NO3-), magnesium (Mg), calcium (Ca), zinc (Zn), fluoride (F-), and sulphate (SO42-). In-situ and laboratory analyses were carried out using portable meters and standard procedures. The results were compared with national (Malawi Bureau of Standards - MBS) and international standards (World Health Organization - WHO) for drinking water. The following ranges were obtained: pH (6.00-7.80), EC (437-3128 μS/cm), turbidity (0.10-5.80 NTU), water temperature (27.0-30.60 °C), NO3- (0.30-30.00 mg/L), F- (0.10-8.10 mg/L), Mg (31.00-91.00 mg/L), Ca (20.00-197.10 mg/L), SO42- (10.20-190 mg/L), Fe (0.10-3.60 mg/L) and Zn (0.00-5.10 mg/L). Generally, some parameters tested at several sites (>80%, n = 20) complied with both MBS and WHO limits. No significant differences (p > 0.05) was observed for most parameters (>65%, n = 11). Groundwater contamination was not significant in the area despite some parameters like F-, Ca and SO42- showing higher levels at other sites. Some sites registered very hard water (244.60-757.80 mg/L CaCO3) probably due to mineralization influenced by underground rock material. Further studies are needed to ascertain the groundwater quality of other parameters (like F-, and SO4 2-) which registered higher levels at some sites. Routine monitoring of the groundwater in the study area and entire Malawi is needed for spatio-temporal variation assessment and to ensure good public health. © 2016 Elsevier Ltd.


Stevenson P.C.,University of Greenwich | Kite G.C.,Royal Botanic Gardens | Lewis G.P.,Royal Botanic Gardens | Forest F.,Royal Botanic Gardens | And 4 more authors.
Phytochemistry | Year: 2012

Tephrosia vogelii Hook. f. (Leguminosae) is being promoted as a pest control and soil enrichment agent for poorly-resourced small-scale farmers in southern and eastern Africa. This study examined plants being cultivated by farmers and found two chemotypes. Chemotype 1 (C1) contained rotenoids, including deguelin, rotenone, sarcolobine, tephrosin and α-toxicarol, required for pest control efficacy. Rotenoids were absent from chemotype 2 (C2), which was characterised by prenylated flavanones, including the previously unrecorded examples (2S)-5,7-dimethoxy-8-(3-hydroxy-3-methylbut-1Z-enyl) flavanone, (2S)-5,7-dimethoxy-8-(3-methylbut-1,3-dienyl)flavanone, (2S)-4′-hydroxy-5-methoxy-6″,6″-dimethylpyrano[2″, 3″:7,8]flavanone, (2S)-5-methoxy-6″,6″-dimethyl-4″, 5″-dihydrocyclopropa[4″,5″]furano[2″,3″:7,8] flavanone, (2S)-7-hydroxy-5-methoxy-8-prenylflavanone, and (2R,3R)-3-hydroxy-5- methoxy-6″,6″-dimethylpyrano[2″,3″:7,8]flavanone. The known compounds (2S)-5-methoxy-6″,6″-dimethylpyrano[2″, 3″:7,8]flavanone (obovatin 5-methyl ether) and 5,7-dimethoxy-8-(3-hydroxy- 3-methylbut-1Z-enyl)flavone (Z-tephrostachin) were also found in C2. This chemotype, although designated Tephrosia candida DC. in collections originating from the World Agroforestry Centre (ICRAF), was confirmed to be T. vogelii on the basis of morphological comparison with verified herbarium specimens and DNA sequence analysis. Sampling from 13 locations in Malawi where farmers cultivate Tephrosia species for insecticidal use indicated that almost 1 in 4 plants were T. vogelii C2, and so were unsuitable for this application. Leaf material sourced from a herbarium specimen of T. candida contained most of the flavanones found in T. vogelii C2, but no rotenoids. However, the profile of flavonol glycosides was different to that of T. vogelii C1 and C2, with 6-hydroxy-kaempferol 6-methyl ether as the predominant aglycone rather than kaempferol and quercetin. The structures of four unrecorded flavonol glycosides present in T. candida were determined using cryoprobe NMR spectroscopy and MS as the 3-O-α-rhamnopyranosyl(1 → 6)-β-galactopyranoside-7-O- α-rhamnopyranoside, 3-O-α-rhamnopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-galactopyranoside, 3-O-α-rhamnopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-galactopyranoside-7-O-α-rhamnopyranoside, and 3-O-α-rhamnopyranosyl(1 → 2)[(3-O-E-feruloyl)-α- rhamnopyranosyl(1 → 6)]-β-galactopyranosides of 6-hydroxykaempferol 6-methyl ether. Tentative structures for a further 37 flavonol glycosides of T. candida were assigned by LC-MS/MS. The correct chemotype of T. vogelii (i.e. C1) needs to be promoted for use by farmers in pest control applications. © 2012 Elsevier Ltd. All rights reserved.


Belmain S.R.,University of Greenwich | Amoah B.A.,University of Greenwich | Nyirenda S.P.,Lunyangwa Research Station | Kamanula J.F.,Mzuzu University | And 2 more authors.
Journal of Agricultural and Food Chemistry | Year: 2012

Tephrosia vogelii has been used for generations as a pest control material in Africa. Recently, two chemotypes have been reported based on the occurrence (chemotype 1) or absence (chemotype 2) of rotenoids. This could have an impact on the efficacy and reliability of this material for pest control. We report that chemotype 2 has no pesticidal activity against Callosobruchus maculatus Fabricius (family Chrysomelidae) and that this is associated with the absence of rotenoids. We present a first report of the comparative biological activity of deguelin, tephrosin, α-toxicarol, and sarcolobine and show that not all rotenoids are equally effective. Tephrosin was less toxic than deguelin which was less active than rotenone, while obovatin 5-methyl ether, the major flavonoid in chemotype 2 was inactive. We also report that in chemotype 1 the occurrence of rotenoids shows substantial seasonal variation. © 2012 American Chemical Society.


Hurst R.,University of East Anglia | Siyame E.W.P.,Human Resources University | Young S.D.,University of Nottingham | Chilimba A.D.C.,University of Nottingham | And 14 more authors.
Scientific Reports | Year: 2013

Selenium (Se) is an essential human micronutrient with critical roles in immune functioning and antioxidant defence. Estimates of dietary Se intakes and status are scarce for Africa although crop surveys indicate deficiency is probably widespread in Malawi. Here we show that Se deficiency is likely endemic in Malawi based on the Se status of adults consuming food from contrasting soil types. These data are consistent with food balance sheets and composition tables revealing that >80% of the Malawi population is at risk of dietary Se inadequacy. Risk of dietary Se inadequacy is >60% in seven other countries in Southern Africa, and 22% across Africa as a whole. Given that most Malawi soils cannot supply sufficient Se to crops for adequate human nutrition, the cost and benefits of interventions to alleviate Se deficiency should be determined; for example, Se-enriched nitrogen fertilisers could be adopted as in Finland.


Chilimba A.D.C.,University of Nottingham | Chilimba A.D.C.,Lunyangwa Research Station | Young S.D.,University of Nottingham | Black C.R.,University of Nottingham | And 4 more authors.
Scientific Reports | Year: 2011

Selenium is an essential element in human diets but the risk of suboptimal intake increases where food choices are narrow. Here we show that suboptimal dietary intake (i.e. 20-30gμSeperson g -1 d g -1) is widespread in Malawi, based on a spatial integration of Se concentrations of maize (Zea mays L.) grain and soil surveys for 88 field sites, representing 10 primary soil types and >75% of the national land area. The median maize grain Se concentration was 0.019mkg g-1 (range 0.005-0.533), a mean intake of 6.7gμSeperson g -1 d g -1 from maize flour based on national consumption patterns. Maize grain Se concentration was up to 10-fold higher in crops grown on soils with naturally high pH (>6.5) (Eutric Vertisols). Under these less acidic conditions, Se becomes considerably more available to plants due to the greater solubility of Se (IV) species and oxidation to Se (VI).


Joy E.J.M.,University of Nottingham | Joy E.J.M.,British Geological Survey | Broadley M.R.,University of Nottingham | Young S.D.,University of Nottingham | And 5 more authors.
Science of the Total Environment | Year: 2015

Food supply and composition data can be combined to estimate micronutrient intakes and deficiency risks among populations. These estimates can be improved by using local crop composition data that can capture environmental influences including soil type. This study aimed to provide spatially resolved crop composition data for Malawi, where information is currently limited.Six hundred and fifty-two plant samples, representing 97 edible food items, were sampled from >. 150 sites in Malawi between 2011 and 2013. Samples were analysed by ICP-MS for up to 58 elements, including the essential minerals calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), selenium (Se) and zinc (Zn).Maize grain Ca, Cu, Fe, Mg, Se and Zn concentrations were greater from plants grown on calcareous soils than those from the more widespread low-pH soils. Leafy vegetables from calcareous soils had elevated leaf Ca, Cu, Fe and Se concentrations, but lower Zn concentrations. Several foods were found to accumulate high levels of Se, including the leaves of Moringa, a crop not previously been reported in East African food composition data sets.New estimates of national dietary mineral supplies were obtained for non-calcareous and calcareous soils. High risks of Ca (100%), Se (100%) and Zn (57%) dietary deficiencies are likely on non-calcareous soils. Deficiency risks on calcareous soils are high for Ca (97%), but lower for Se (34%) and Zn (31%). Risks of Cu, Fe and Mg deficiencies appear to be low on the basis of dietary supply levels. © 2014The Authors.


Chilimba A.D.C.,University of Nottingham | Chilimba A.D.C.,Lunyangwa Research Station | Young S.D.,University of Nottingham | Black C.R.,University of Nottingham | And 2 more authors.
Field Crops Research | Year: 2012

Suboptimal dietary Se intake is widespread in Malawi due to low levels of plant-available Se in most soils and narrow food choices. The aim of this study was to determine the potential for biofortifying maize using Se-enriched fertilisers in Malawi. The response of maize to three forms of selenate-Se fertiliser was determined. Crops were treated with a liquid drench of Na2SeO4(aq) (0-100gSeha-1), a compound NPK+Se fertiliser (0-6gSeha-1), or Se-enriched calcium ammonium nitrate (CAN+Se; 0-20gSeha-1). Experiments with Na2SeO4(aq) and NPK+Se were conducted at six field sites, and at a subset of three sites with CAN+Se, in 2008/09 and 2009/10 (i.e. 30 experimental units). The increase in grain Se concentration was approximately linear for all Se forms and application rates (R2>0.90 for 27 of the 30 experimental units). On average, whole-grain Se increased by 20, 21 and 15μgSekg-1for each gram of Se applied as Na2SeO4(aq), NPK+Se and CAN+Se, respectively. Grain and stover yields were unaffected by Se applications. An application of 5gSeha-1 to maize crops in Malawi would increase dietary Se intake by 26-37μgSeperson-1d-1 based on national maize consumption patterns. Agronomic biofortification with Se in Malawi is feasible in theory through the existing national Farm Input Subsidy Programme (FISP) if deemed to be economically and politically acceptable. © 2011 Elsevier B.V.


Chilimba A.D.C.,University of Nottingham | Chilimba A.D.C.,Lunyangwa Research Station | Young S.D.,University of Nottingham | Black C.R.,University of Nottingham | And 2 more authors.
Field Crops Research | Year: 2012

The environmental fate and possible residual effects of applied selenium (Se) are important issues when considering sustainable biofortification of food crops to improve human health. Our objectives were to assess residual effects of Se biofortification of maize in Malawi using a combination of 74Se-labelling studies and measurements of KH 2PO 4-extractable soil Se. Stable 74Se isotope trials showed recovery rates in maize grain of 6.5 and 10.8% from 10gSeha -1 applied to two contrasting sites, Chitedze and Mbawa; the 74Se label comprised 69 and 81% of the grain Se content respectively. However, in the following 'residual' year, only 2.0 and 0.78% of Se uptake in grain came from the 74Se-labelled fertiliser originally applied, amounting to <0.1% of the original fertiliser application. In a second trial, residual phosphate-extractable Se in the soil measured at harvest in the year of application (0-100gha -1) at six sites across Malawi varied with soil type but comprised 3.5 and 4.8% of that applied, at Chitedze and Mbawa respectively. However, a second maize crop grown in the same plots in the following cropping season accessed only 0.23 and 0.19% of the original Se application, constituting less than 5% of the phosphate-extractable fertiliser Se measured in the soil at harvest in the previous (fertilised) year. Thus, residual benefits from Se application were measureable but extremely small, probably due to rapid loss of soluble selenate after application or fixation into unavailable organic forms. © 2012 Elsevier B.V.


PubMed | University of Otago, Community Health science Unit, British Geological Survey, Loughborough University and 2 more.
Type: | Journal: Scientific reports | Year: 2015

The aim of this study was to characterise nutritional-I status in Malawi. Dietary-I intakes were assessed using new datasets of crop, fish, salt and water-I concentrations, while I status was assessed for 60 women living on each of calcareous and non-calcareous soils as defined by urinary iodine concentration (UIC). Iodine concentration in staple foods was low, with median concentrations of 0.01 mg kg(-1) in maize grain, 0.008 mg kg(-1) in roots and tubers, but 0.155 mg kg(-1) in leafy vegetables. Freshwater fish is a good source of dietary-I with a median concentration of 0.51 mg kg(-1). Mean Malawian dietary-Iodine intake from food, excluding salt, was just 7.8 g d(-1) compared to an adult requirement of 150 g d(-1). Despite low dietary-I intake from food, median UICs were 203 g L(-1) with only 12% defined as I deficient whilst 21% exhibited excessive I intake. Iodised salt is likely to be the main source of dietary I intake in Malawi; thus, I nutrition mainly depends on the usage and concentration of I in iodised salt. Drinking water could be a significant source of I in some areas, providing up to 108 g d(-1) based on consumption of 2L d(-1).


PubMed | British Geological Survey, Lunyangwa Research Station and Loughborough University
Type: | Journal: The Science of the total environment | Year: 2014

Food supply and composition data can be combined to estimate micronutrient intakes and deficiency risks among populations. These estimates can be improved by using local crop composition data that can capture environmental influences including soil type. This study aimed to provide spatially resolved crop composition data for Malawi, where information is currently limited. Six hundred and fifty-two plant samples, representing 97 edible food items, were sampled from >150 sites in Malawi between 2011 and 2013. Samples were analysed by ICP-MS for up to 58 elements, including the essential minerals calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), selenium (Se) and zinc (Zn). Maize grain Ca, Cu, Fe, Mg, Se and Zn concentrations were greater from plants grown on calcareous soils than those from the more widespread low-pH soils. Leafy vegetables from calcareous soils had elevated leaf Ca, Cu, Fe and Se concentrations, but lower Zn concentrations. Several foods were found to accumulate high levels of Se, including the leaves of Moringa, a crop not previously been reported in East African food composition data sets. New estimates of national dietary mineral supplies were obtained for non-calcareous and calcareous soils. High risks of Ca (100%), Se (100%) and Zn (57%) dietary deficiencies are likely on non-calcareous soils. Deficiency risks on calcareous soils are high for Ca (97%), but lower for Se (34%) and Zn (31%). Risks of Cu, Fe and Mg deficiencies appear to be low on the basis of dietary supply levels.

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