1
|
Manzeke-Kangara MG, Ligowe IS, Kaninga B, Nalivata P, Kabambe V, Mbewe E, Chishala BH, Sakala GM, Mapfumo P, Mtambanengwe F, Tendayi T, Murwira A, Chilimba ADC, Phiri FP, Ander EL, Bailey EH, Lark RM, Millar K, Watts MJ, Young SD, Broadley MR. Doctoral training to support sustainable soil geochemistry research in Africa. Interface Focus 2024; 14:20230058. [PMID: 39129856 PMCID: PMC11310714 DOI: 10.1098/rsfs.2023.0058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 02/12/2024] [Accepted: 05/22/2024] [Indexed: 08/13/2024] Open
Abstract
Africa's potential for scientific research is not yet being realized, for various reasons including a lack of researchers in many fields and insufficient funding. Strengthened research capacity through doctoral training programmes in higher education institutes (HEIs) in Africa, to include collaboration with national, regional and international research institutions, can facilitate self-reliant and sustainable research to support socio-economic development. In 2012, the Royal Society and the UK's Department for International Development (now the Foreign, Commonwealth and Development Office) launched the Africa Capacity Building Initiative (ACBI) Doctoral Training Network which aimed to strengthen research capacity and training across sub-Saharan Africa. The ACBI supported 30 core PhD scholarships, all registered/supervised within African HEIs with advisory support from the UK-based institutes. Our 'Soil geochemistry to inform agriculture and health policies' consortium project, which was part of the ACBI doctoral training programme network, was implemented in Malawi, Zambia and Zimbabwe between 2014 and 2020. The aims of our consortium were to explore linkages between soil geochemistry, agriculture and public health for increased crop productivity, nutrition and safety of food systems and support wider training and research activities in soil science. Highlights from our consortium included: (i) the generation of new scientific evidence on linkages between soils, crops and human nutrition; (ii) securing new projects to translate science into policy and practice; and (iii) maintaining sustainable collaborative learning across the consortium. Our consortium delivered high-quality science outputs and secured new research and doctoral training funding from a variety of sources to ensure the continuation of research and training activities. For example, follow-on Global Challenges Research Funded Translation Award provided a strong evidence base on the prevalence of deficiencies in children under 5 years of age and women of reproductive age in Zimbabwe. This new evidence will contribute towards the design and implementation of a nationally representative micronutrient survey as an integral part of the Zimbabwe Demographic and Health Surveys conducted by the Ministry of Health and Child Care. The award also generated new evidence and a road map for creating quality innovative doctorates through a doctoral training landscape activity led by the Zimbabwe Council for Higher Education. Although our project and the wider ACBI has contributed to increasing the self-reliance and sustainability of research within the region, many challenges remain and ongoing investment is required.
Collapse
Affiliation(s)
- M. G. Manzeke-Kangara
- Rothamsted Research, West Common, Harpenden, UK
- Department of Soil Science and Environment, University of Zimbabwe, Harare, Zimbabwe
- School of Biosciences, University of Nottingham, Sutton Bonington, UK
| | - I. S. Ligowe
- Department of Crop and Soil Sciences, Lilongwe University of Agriculture and Natural Resources, Lilongwe, Malawi
- Department of Agricultural Research Services, Lilongwe, Malawi
- Department of Forestry and Environmental Management, Mzuzu University, Mzuzu, Malawi
| | - B. Kaninga
- Zambia Agriculture Research Institute, Mount Makulu, Central Research Station, Lusaka, Zambia
- School of Agricultural Sciences, University of Zambia, Great East Road Campus, Lusaka, Zambia
| | - P. Nalivata
- Department of Crop and Soil Sciences, Lilongwe University of Agriculture and Natural Resources, Lilongwe, Malawi
| | - V. Kabambe
- Department of Crop and Soil Sciences, Lilongwe University of Agriculture and Natural Resources, Lilongwe, Malawi
| | - E. Mbewe
- Department of Crop and Soil Sciences, Lilongwe University of Agriculture and Natural Resources, Lilongwe, Malawi
| | - B. H. Chishala
- School of Agricultural Sciences, University of Zambia, Great East Road Campus, Lusaka, Zambia
| | - G. M. Sakala
- Zambia Agriculture Research Institute, Mount Makulu, Central Research Station, Lusaka, Zambia
| | - P. Mapfumo
- Department of Soil Science and Environment, University of Zimbabwe, Harare, Zimbabwe
| | - F. Mtambanengwe
- Department of Soil Science and Environment, University of Zimbabwe, Harare, Zimbabwe
| | - T. Tendayi
- Department of Soil Science and Environment, University of Zimbabwe, Harare, Zimbabwe
| | - A. Murwira
- Department of Geography, Geospatial Sciences and Earth Observation, University of Zimbabwe, Harare, Zimbabwe
| | | | - F. P. Phiri
- Department of Nutrition, HIV and AIDS, Ministry of Health, Lilongwe, Malawi
| | - E. L. Ander
- School of Biosciences, University of Nottingham, Sutton Bonington, UK
- Inorganic Geochemistry, Centre for Environmental Geochemistry, British Geological Survey, Nottinghamshire, UK
| | - E. H. Bailey
- School of Biosciences, University of Nottingham, Sutton Bonington, UK
| | - R. M. Lark
- School of Biosciences, University of Nottingham, Sutton Bonington, UK
| | - K. Millar
- School of Biosciences, University of Nottingham, Sutton Bonington, UK
| | - M. J. Watts
- Inorganic Geochemistry, Centre for Environmental Geochemistry, British Geological Survey, Nottinghamshire, UK
| | - S. D. Young
- School of Biosciences, University of Nottingham, Sutton Bonington, UK
| | - M. R. Broadley
- Rothamsted Research, West Common, Harpenden, UK
- School of Biosciences, University of Nottingham, Sutton Bonington, UK
| |
Collapse
|
2
|
Chheang L, Khachornsakkul K, Del-Rio-Ruiz R, Zeng W, Thongkon N, Thanasupsin SP, Sonkusale S. Simple distance-based thread analytical device integrated with ion imprinted polymer for Zn 2+ quantification in human urine samples. Analyst 2024; 149:3161-3168. [PMID: 38632945 DOI: 10.1039/d4an00076e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2024]
Abstract
This article presents the development of a distance-based thread analytical device (dTAD) integrated with an ion-imprinted polymer (IIP) for quantitative monitoring of zinc ions (Zn2+) in human urine samples. The IIP was easily chemically modified onto the thread channel using dithizone (DTZ) as a ligand to bind to Zn2+ with methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as well as 2,2-azobisisobutyronitrile (AIBN) as cross-linking agents to enhance the selectivity for Zn2+ detection. The imprinted polymer was characterized using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS). Under optimization, the linear detection range was from 1.0 to 20.0 mg L-1 (R2 = 0.9992) with a limit of detection (LOD) of 1.0 mg L-1. Other potentially interfering metal ions and molecules did not interfere with this approach, leading to high selectivity. Furthermore, our technique exhibits a remarkable recovery ranging from 100.48% to 103.16%, with the highest relative standard deviation (% RSD) of 5.44% for monitoring Zn2+ in human control urine samples, indicating high accuracy and precision. Similarly, there is no significant statistical difference between the results obtained using our method and standards on zinc supplement sample labels. The proposed method offers several advantages in detecting trace Zn2+ for point-of-care (POC) medical diagnostics and environmental sample analysis, such as ease of use, instrument-free readout, and cost efficiency. Overall, our developed dTAD-based IIP method holds potential for simple, affordable, and rapid detection of Zn2+ levels and can be applied to other metal ions' analysis.
Collapse
Affiliation(s)
- Lita Chheang
- Department of Electrical and Computer Engineering, Tufts University, Medford, MA 02155, USA.
- Nano Lab, Tufts University, Medford, MA 02155, USA
- Department of Chemistry, Faculty of Science, King Mongkut's University of Technology Thonburi, Bangkok 10140, Thailand
- Department of Chemistry, Faculty of Science, Royal University of Phnom Penh, Federation of Russia Blvd, Tuol Kork, Phnom Penh, Cambodia
| | - Kawin Khachornsakkul
- Department of Electrical and Computer Engineering, Tufts University, Medford, MA 02155, USA.
- Nano Lab, Tufts University, Medford, MA 02155, USA
| | - Ruben Del-Rio-Ruiz
- Department of Electrical and Computer Engineering, Tufts University, Medford, MA 02155, USA.
- Nano Lab, Tufts University, Medford, MA 02155, USA
| | - Wenxin Zeng
- Department of Electrical and Computer Engineering, Tufts University, Medford, MA 02155, USA.
- Nano Lab, Tufts University, Medford, MA 02155, USA
| | - Nisakorn Thongkon
- Department of Chemistry, Faculty of Science, King Mongkut's University of Technology Thonburi, Bangkok 10140, Thailand
| | - Sudtida Pliankarom Thanasupsin
- Chemistry for Green Society and Healthy Living Research Unit, Faculty of Science, King Mongkut's University of Technology Thonburi, Bangkok 10140, Thailand
| | - Sameer Sonkusale
- Department of Electrical and Computer Engineering, Tufts University, Medford, MA 02155, USA.
- Nano Lab, Tufts University, Medford, MA 02155, USA
| |
Collapse
|
3
|
Prywer J, Torzewska A, Mielniczek-Brzóska E. Understanding the role of zinc ions on struvite nucleation and growth in the context of infection urinary stones. Metallomics 2024; 16:mfae017. [PMID: 38599629 PMCID: PMC11095266 DOI: 10.1093/mtomcs/mfae017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Accepted: 04/09/2024] [Indexed: 04/12/2024]
Abstract
Taking into account that in recent decades there has been an increase in the incidence of urinary stones, especially in highly developed countries, from a wide range of potentially harmful substances commonly available in such countries, we chose zinc for the research presented in this article, which is classified by some sources as a heavy metal. In this article, we present the results of research on the influence of Zn2+ ion on the nucleation and growth of struvite crystals-the main component of infection urinary stones. The tests were carried out in an artificial urine environment with and without the presence of Proteus mirabilis bacteria. In the latter case, the activity of bacterial urease was simulated chemically, by systematic addition of an aqueous ammonia solution. The obtained results indicate that Zn2+ ions compete with Mg2+ ions, which leads to the gradual replacement of Mg2+ ions in the struvite crystal lattice with Zn2+ ions to some extent. This means co-precipitation of Mg-struvite (MgNH4PO4·6H2O) and Znx-struvite (Mg1-xZnxNH4PO4·6H2O). Speciation analysis of chemical complexes showed that Znx-struvite precipitates at slightly lower pH values than Mg-struvite. This means that Zn2+ ions shift the nucleation point of crystalline solids towards a lower pH. Additionally, the conducted research shows that Zn2+ ions, in the range of tested concentrations, do not have a toxic effect on bacteria; on the contrary, it has a positive effect on cellular metabolism, enabling bacteria to develop better. It means that Zn2+ ions in artificial urine, in vitro, slightly increase the risk of developing infection urinary stones.
Collapse
Affiliation(s)
- Jolanta Prywer
- Institute of Physics, Lodz University of Technology, ul. Wólczańska 217/221, 93-005 Łódź, Poland
| | - Agnieszka Torzewska
- Department of Biology of Bacteria, Faculty of Biology and Environmental Protection, University of Lodz, ul. Banacha 12/16, 90-237 Łódź, Poland
| | - Ewa Mielniczek-Brzóska
- Institute of Chemistry, Faculty of Science and Technology, Jan Długosz University of Czestochowa, ul. Armii Krajowej 13/15, 42-200 Częstochowa, Poland
| |
Collapse
|
4
|
Zhong J, Liu L, Zhang L, Xu Z, Peng L, Zhao X, Yang Q, Yang T, Xu D, Hong F. Association of Urinary Zinc Concentrations with Dyslipidemia and Its Subtypes: Baseline Data from the Chinese Multi-Ethnic Cohort (CMEC) Study. Biol Trace Elem Res 2022:10.1007/s12011-022-03454-6. [PMID: 36284051 DOI: 10.1007/s12011-022-03454-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 10/17/2022] [Indexed: 11/02/2022]
Abstract
This study elucidates the association between urinary zinc concentration and the risk of developing dyslipidemia and its subtypes in China's ethnic minority residents. Based on the baseline survey data of the Chinese Multi-Ethnic Cohort (CMEC) study, 10,620 subjects were included in the study. Logistic regression analysis evaluated the relationship between urinary zinc concentration and dyslipidemia and its subtypes. After adjustment, compared with urinary zinc concentration quartile 1 (Q1), the odds ratios (ORs) and 95% confidence intervals (95% CIs) of dyslipidemia participants in the quartile 2 (Q2), quartile 3 (Q3), and quartile 4 (Q4) groups were 1.091 (0.963, 1.237), 1.151 (1.051, 1.304), and 1.393 (1.230, 1.579), respectively (P for trend < 0.001). While that of hypertriglyceridemia participants in the Q2, Q3, and Q4 groups were 1.130 (0.979, 1.306), 1.283 (1.113, 1.480), and 1.483 (1.287, 1.709), respectively (P for trend < 0.001). Lastly, the ORs and 95% CIs of hyperbetalipoproteinemia participants in the Q2, Q3, and Q4 groups were 1.166 (0.945, 1.439), 1.238 (1.007, 1.522), and 1.381 (1.126, 1.695), respectively (P for trend < 0.002). This study found that urinary zinc concentrations were not associated with hypercholesterolemia and hypoalphalipoproteinemia. The dose-response relationship was non-linear between urinary zinc concentration and dyslipidemia, hypertriglyceridemia and hyperbetalipoproteinemia (P for trend < 0.001). In the stratified analysis, urinary zinc levels were positively associated with the risk of dyslipidemia, hypertriglyceridemia, and hyperbetalipoproteinemia in male, ≥ 60 years old, Miao nationality, hypertension, diabetes, and BMI ≥ 24.0 kg/m2 subgroups. Our study provides some possible evidence that elevated urinary zinc concentrations are associated with an increased risk of dyslipidemia, hypertriglyceridemia, hyperbetalipoproteinemia.
Collapse
Affiliation(s)
- Jianqin Zhong
- School of Public Health, The Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, 550025, China
| | - Leilei Liu
- School of Public Health, The Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, 550025, China
| | - Linyuan Zhang
- School of Public Health, The Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, 550025, China
| | - Zixuan Xu
- School of Public Health, The Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, 550025, China
| | - Lian Peng
- School of Public Health, The Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, 550025, China
| | - Xiaolan Zhao
- School of Public Health, The Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, 550025, China
| | - Qianyuan Yang
- School of Public Health, The Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, 550025, China
| | - Tingting Yang
- School of Public Health, The Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, 550025, China
| | - Degan Xu
- Guiyang Center for Disease Control and Prevention, Guiyang, 550003, China
| | - Feng Hong
- School of Public Health, The Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, 550025, China.
| |
Collapse
|
5
|
Likoswe BH, Lark RM, Phuka J, Maleta K, Joy E, Lowe NM. The potential of spot urine as a biomarker for zinc assessment in Malawian children and adults. Front Nutr 2022; 9:890209. [PMID: 35938137 PMCID: PMC9355503 DOI: 10.3389/fnut.2022.890209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 06/29/2022] [Indexed: 11/13/2022] Open
Abstract
Population-level assessment of zinc deficiency remains a challenge due to the lack of suitable biomarkers. Spot urinary zinc concentration (UZC) has the potential to provide information on population zinc status in large-scale surveys, but there is no established cut-off point indicating deficiency. A strong correlation between this biomarker and an established biomarker such as serum zinc concentration (SZC) in paired samples (i.e., from the same individual), could identify the thresholds indicating zinc deficiency. This study, therefore, aimed to regress spot UZC from school-aged children and women from the Malawi micronutrient survey with paired SZC data using a linear mixed-effects model. The nested variance components indicated no linear relationship between the UZC and SZC data, irrespective of adjustments for inflammation and hydration. Thresholds of urinary zinc excretion that have been suggested by expert panels were applied to the spot UZC data, as a post-hoc analysis. The zinc deficiency prevalence estimates derived from these suggested thresholds were not similar to the estimates from the SZC data, and further research is required to understand whether spot UZC can still provide useful information in population zinc assessment.
Collapse
Affiliation(s)
- Blessings H. Likoswe
- Department of Nutrition and Dietetics, School of Global and Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
- *Correspondence: Blessings H. Likoswe ;
| | - R. Murray Lark
- School of Biosciences, University of Nottingham, Loughborough, United Kingdom
| | - John Phuka
- Department of Nutrition and Dietetics, School of Global and Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Kenneth Maleta
- Department of Nutrition and Dietetics, School of Global and Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Edward Joy
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Nicola M. Lowe
- UCLan Research Centre for Global Development, University of Central Lancashire, Preston, United Kingdom
| |
Collapse
|
6
|
Distribution and Determinants of Serum Zinc, Copper, and Selenium Levels among Children under Five Years from Popokabaka, Democratic Republic of Congo: A Cross-Sectional Study. Nutrients 2022; 14:nu14030683. [PMID: 35277041 PMCID: PMC8839910 DOI: 10.3390/nu14030683] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 01/31/2022] [Accepted: 02/03/2022] [Indexed: 01/27/2023] Open
Abstract
Information about essential trace elements among children in many African countries, including the Democratic Republic of Congo (DRC), is limited. We aimed to measure the distribution and determinants of serum zinc (Zn), copper (Cu), and selenium (Se) concentrations in a representative sample of children under five years old. We conducted a community-based cross-sectional study in Popokabaka, DRC. Blood samples were drawn from 412 children. The serum concentrations of minerals were measured using inductively coupled plasma−mass spectrometry. The median concentrations (P25−P75) of Zn, Cu, and Se were 61.9 µg/dL (52.8−70.2), 145.5 (120.0−167.0) µg/dL and 5.3 (4.3−6.3) µg/dL. The CRP-adjusted prevalence of serum Se deficiency was 84.1% (95% confidence interval [CI] 81.4−87.0) and of Zn deficiency was 64.6% (95% CI 59.8−69.1%). Only a few children were Cu deficient [1.5% (0.6−3.2)]. Evidence of inflammation (C-reactive protein, >5 mg/L) was associated with a lower Se concentration and higher Cu concentration. Furthermore, serum Se concentration was positively associated with linear growth. The average Cu/Zn molar ratio (2:1) was twice that recommended. Children in western Popokabaka had higher Zn and Se levels than their eastern neighbors. Zinc and selenium deficiencies are common among children in Popokabaka and require attention and prioritization.
Collapse
|
7
|
Watts MJ, Menya D, Humphrey OS, Middleton DS, Hamilton E, Marriott A, McCormack V, Osano O. Human urinary biomonitoring in Western Kenya for micronutrients and potentially harmful elements. Int J Hyg Environ Health 2021; 238:113854. [PMID: 34624595 DOI: 10.1016/j.ijheh.2021.113854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/20/2021] [Accepted: 09/30/2021] [Indexed: 11/15/2022]
Abstract
Spot urinary elemental concentrations are presented for 357 adults from Western Kenya collected between 2016 and 2019 as part of a wider environmental geochemical survey. The aim of this study was to establish population level urinary elemental concentrations in Western Kenya for micronutrients and potentially harmful elements for inference of health status against established thresholds. For elements where thresholds inferring health status were not established in the literature using urine as a non-invasive matrix, this study generated reference values with a 95% confidence interval (RV95s) to contextualise urinary elemental data for this population group. Data are presented with outliers removed based upon creatinine measurements leaving 322 individuals, for sub-categories (e.g. age, gender) and by county public health administrative area. For Western Kenya, reference values with a 95% confidence interval (RV95s) were calculated as follows (μg/L): 717 (I), 89 (Se), 1753 (Zn), 336 (Mo), 24 (Cu), 15.6 (Ni), 22.1 (As), 0.34 (Cd), 0.47 (Sn), 0.46 (Sb), 7.0 (Cs), 13.4 (Ba and 1.9 (Pb). Urinary concentrations at the 25th/75th percentiles were as follows (μg/L): 149/368 (I), 15/42 (Se), 281/845 (Zn), 30/128 (Mo), 6/13 (Cu), 1.7/6.1 (Ni), 2.0/8.2 (As). 0.1/0.3 (Cd), 0.05/0.22 (Sn), 0.04/0.18 (Sb), 1.2/3.6 (Cs), 0.8/4.0 (Ba) and 0.2/0.9 (Pb). Urinary concentrations at a population level inferred excess intake of micronutrients I, Se, Zn and Mo in 38, 6, 57 and 14% of individuals, respectively, versus a bioequivalent (BE) upper threshold limit, whilst rates of deficiency were relatively low at 15, 15, 9 and 18%, respectively. Each of the administrative counties showed a broadly similar range of urinary elemental concentrations, with some exceptions for counties bordering Lake Victoria where food consumption habits may differ significantly to other counties e.g. I, Se, Zn. Corrections for urinary dilution using creatinine, specific gravity and osmolality provided a general reduction in RV95s for I, Mo, Se, As and Sn compared to uncorrected data, with consistency between the three correction methods.
Collapse
Affiliation(s)
- Michael J Watts
- Inorganic Geochemistry, Centre for Environmental Geochemistry, British Geological Survey, Nottingham, UK.
| | - Diana Menya
- School of Public Health, Moi University, Eldoret, Kenya.
| | - Olivier S Humphrey
- Inorganic Geochemistry, Centre for Environmental Geochemistry, British Geological Survey, Nottingham, UK
| | - DanielR S Middleton
- Environment and Lifestyle Epidemiology Branch, International Agency for Research on Cancer, Lyon, France
| | - Elliott Hamilton
- Inorganic Geochemistry, Centre for Environmental Geochemistry, British Geological Survey, Nottingham, UK
| | - Andrew Marriott
- Inorganic Geochemistry, Centre for Environmental Geochemistry, British Geological Survey, Nottingham, UK
| | - Valerie McCormack
- Environment and Lifestyle Epidemiology Branch, International Agency for Research on Cancer, Lyon, France
| | - Odipo Osano
- School of Environmental Sciences, University of Eldoret, Eldoret, Kenya
| |
Collapse
|