Iodine In Soil Research Articles

Multiple geochemical factors may cause iodine and selenium deficiency in Gilgit-Baltistan, Pakistan

Deficiencies of the micronutrients iodine and selenium are particularly prevalent where populations consume local agricultural produce grown on soils with low iodine and selenium availability. This study focussed on such an area, Gilgit-Baltistan in Pakistan, through a geochemical survey of iodine and selenium fractionation and speciation in irrigation water and arable soil. Iodine and selenium concentrations in water ranged from 0.01–1.79 µg L−1 to 0.016–2.09 µg L−1, respectively, which are smaller than levels reported in similar mountainous areas in other parts of the world. Iodate and selenate were the dominant inorganic species in all water samples. Average concentrations of iodine and selenium in soil were 685 µg kg−1 and 209 µg kg−1, respectively, much lower than global averages of 2600 and 400 µg kg−1, respectively. The ‘reactive’ fractions (‘soluble’ and ‘adsorbed’) of iodine and selenium accounted for < 7% and < 5% of their total concentrations in soil. More than 90% of reactive iodine was organic; iodide was the main inorganic species. By contrast, 66.9 and 39.7% of ‘soluble’ and ‘adsorbed’ selenium, respectively, were present as organic species; inorganic selenium was mainly selenite. Very low distribution coefficients (kd = adsorbed/soluble; L kg−1) for iodine (1.07) and selenium (1.27) suggested minimal buffering of available iodine and selenium against leaching losses and plant uptake. These geochemical characteristics suggest low availability of iodine and selenium in Gilgit-Baltistan, which may be reflected in locally grown crops. However, further investigation is required to ascertain the status of iodine and selenium in the Gilgit-Baltistan food supply and population.

Ecological and Toxicological Analysis of Iodine Content in Mongolian Soils

Man-made environmental pollution, low iodine content in soils and waters leads to the spread of endemic goiter in animals and humans. The main sources of iodine in the body are food and drinking water, which determines the high dependence of the health of the population that consumes local food on the level of iodine in the soils and natural waters of agricultural landscapes. The article presents the results of cartographic analysis of thematic maps of Mongolia, medical data and data on the content of iodine in soils obtained from open sources. For the Ulaanbaatar region, the authors also used their own field and analytical data on the content of iodine in drinking water obtained in 2015-2017.the hypothesis about the influence of geographical and edaphic conditions on the causes of iodine deficiency in various parts of The country was tested. The average content of iodine in the soils of Mongolia ranged from 0.5 to 3 mg / kg, while the most iodine-deficient areas were identified for the southern and partially Eastern aimags (territories) of the country. The data obtained deserve attention and consideration when organizing the prevention of iodine deficiency in Mongolia.

Iodine fractionation in agricultural and forest soils using extraction methods

Iodine is an essential micronutrient that enters the food chain from soil primarily via plant root absorption. However, only water soluble and exchangeable fractions are usually linked to the bioavailable iodine in soils. Therefore, an assessment of iodine pools in soils via sequential extraction can provide useful information on the availability of iodine for plant uptake. Moreover, studies that deal with iodine content and fractionation in non-contaminated agricultural and forest soils are scarce and unique. Thus, we have evaluated the total iodine content and its concentration in soil fractions extracted from agricultural and forest soil samples by single and sequential extraction methods followed by ICP-MS determination. Our results showed that the total iodine content in Slovak, non-contaminated soils is around the average value of referred inland soil iodine content. Most of the iodine was extracted from organically rich soils of the haplic cambisol rhodic (CMro), cutanic luvisol (LV) and stagnic cambisol (CM) type, with more than 2.5 mg.kg−1 of iodine. Other soils contained less iodine, and its content decreased in the order of haplic chernozem (CH) > fluvisol (FL) > gleyic fluvisol (glFL). The correlation analysis highlighted that organic matter content plays the most important role in soil iodine retention, followed by concentration of amorphous and weakly crystalline forms of aluminum, clay fraction content, aluminum and iron minerals. Most of the iodine in the selected soils was determined in oxide-bound fraction, fraction bound in humic acids, and in soil residue. The other fractions contained less than 10% of the total iodine on average. The water-soluble fraction, which is theoretically the most bioavailable, contained only 4.4% of the total iodine on average. Furthermore, correlation analysis indicates that the changes in iodine fraction distribution are strongly dependent on soil organic carbon content and the content of metal oxyhydroxides. Our results highlight the significance of soil chemistry for iodine distribution and provide useful information for agricultural research and geochemistry, especially regarding the assessment of mobile and bioavailable fractions of iodine for plant uptake from agricultural and forest soils.

Feed-derived iodine overrides environmental contribution to cow milk

Diets worldwide are deficient in iodine, leading to a range of undesirable health effects at the population level. Dairy products are a primary source of iodine in diets for those populations in which iodized salt is not systematically used or available. However, the flows of iodine through dairy agroecosystems are not well understood. The aim of this research was to investigate iodine flows though the dairy agroecosystem, including the influence of atmospheric depositional inputs, environmental variables, season, husbandry, and diet. Three farm-based sampling campaigns were carried out in this investigation, with milk, soil, silage, grass, and feed iodine determined by inductively coupled plasma mass spectroscopy, and nonparametric statistical analysis tests were conducted on data sets obtained. Natural iodine inputs into the environment are dominated by atmospheric deposition, which mainly from sea spray, and thus the location of farms relative to the coast and prevailing wind direction. Herbage and silage produced from grass-based systems strongly correlated with soil iodine, yet there was a strong disconnect between soil, forage, and feed and the milk that results. This was due to the levels of iodine in supplemental feeds being approximately 10-fold higher than those in forage-derived feeds. The practice of feed supplementation, accentuated by summer housing of cows, led to elevated milk iodine.

Short-Term Iodine Dynamics in Soil Solution.

Assessing the reactions of iodine (I) in soil is critical to evaluate radioiodine exposure and understand soil-to-crop transfer rates. Our mechanistic understanding has been constrained by method limitations in assessing the dynamic interactions of iodine between soil solution and soil solid phase over short periods (hours). We use microdialysis to passively extract soil solution spiked with radioiodine (129I- and 129IO3-) to monitor short-term (≤40 h) in situ fixation and speciation changes. We observed greater instantaneous adsorption of 129IO3- compared to 129I- in all soils and the complete reduction of 129IO3- to 129I- within 5 h of addition. Loss of 129I from solution was extremely rapid; the average half-lives of 129I- and 129IO3- in soil solution were 4.06 and 10.03 h, respectively. We detected the presence of soluble organically bound iodine (org-129I) with a low molecular weight (MW) range (0.5-5 kDa) in all soils and a slower (20-40 h) time-dependent formation of larger MW org-I compounds (12-18 kDa) in some samples. This study highlights the very short window of immediate availability in which I from rainfall or irrigation remains in soil solution and available to crops, thus presenting significant challenges to phytofortification strategies in soil-based production systems.

Iodine in Soils and Potatoes Produced in Private Farms of Bryansk and Gomel Regions Located in the Impact Zone of the Chernobyl Accident

Among residents of the Bryansk and Gomel regions of Russia and Belarus, who were exposed to the so-called “iodine attack” as a result of the 1986 Chernobyl Nuclear Power Plant accident, there was a sharp increase in thyroid disease. Therefore, the natural iodine deficiency in soils was an important additional risk factor that could cause adverse reactions primarily among children, for whom the incidence of thyroid cancer in Belarus increased by 76 times. Potatoes belong to one of the main ration-forming foods for local population. In this regard, in 2007–2017, 97 settlements were surveyed in the affected areas, in which samples of local arable soils and potatoes were taken from 138 private subsidence farms (PFs).The iodine content in the studied soils of the private farms of the Bryansk region ranged from 0.11 to 3.5 mg/kg (air-dry weight). The content of iodine in potatoes grown on these soils varied within a considerably wider interval: from 0.002 to 0.119 mg/kg (wet weight), averaging 0.033 mg/kg, which indicates a generally low iodine transfer to this particular product. The data obtained deserve attention when organizing monitoring and carrying out measures for the prevention of iodine deficiency.

Sorption of iodine in soils: insight from selective sequential extractions and X-ray absorption spectroscopy.

The environmental fate of iodine is of general geochemical interest as well as of substantial concern in the context of nuclear waste repositories and reprocessing plants. Soils, and in particular soil organic matter (SOM), are known to play a major role in retaining and storing iodine. Therefore, we investigated iodide and iodate sorption by four different reference soils for contact times up to 30days. Selective sequential extractions and X-ray absorption spectroscopy (XAS) were used to characterize binding behavior to different soil components, and the oxidation state and local structure of iodine. For iodide, sorption was fast with 73 to 96% being sorbed within the first 24h, whereas iodate sorption increased from 11-41% to 62-85% after 30days. The organic fraction contained most of the adsorbed iodide and iodate. XAS revealed a rapid change of iodide into organically bound iodine when exposed to soil, while iodate did not change its speciation. Migration behavior of both iodine species has to be considered as iodide appears to be the less mobile species due to fast binding to SOM, but with the potential risk of mobilization when oxidized to iodate.

Late Holocene pathway of Asian Summer Monsoons imprinted in soils and societal implications

The Asian Summer Monsoons (ASM) represent the main source of precipitation in China and East Asia with about one third of the world population and a region of widespread civilizations. Identifying the temporal and spatial patterns (pathways) of these monsoonal events during the Late Holocene to today has been a matter of debate amongst the scientific community. Here we show that the distribution patterns of the cosmogenic isotope 10Be and oceanic 127I in the topsoil across China exhibit imprints of the main ASM pathways. Our results indicate the monsoon pathway pattern persisted for several millennia or more and suggest a strong bond between 10Be and water vapor transport patterns. Our data also reveal a127I distribution pattern controlled by the ASM pathways, rather than proximity to the sea or bedrock weathering. The persistent pathway of the ASM during the late Holocene, together with higher than average global soil iodine concentration, may have further strengthened the development of civilizations in this region of the world through reduction of iodine deficiency related diseases.

Investigating the use of microdialysis and SEC-UV-ICP-MS to assess iodine interactions in soil solution

Element cycling in the terrestrial environment is heavily reliant upon processes that occur in soil solution. Here we present the first application of microdialysis to sample iodine from soil solution. In comparison to conventional soil solution extraction methods such as Rhizon™ samplers, centrifugation, and high-pressure squeezing, microdialysis can passively sample dissolved compounds from soil solution without altering the in-situ speciation of trace elements at realistic soil moisture conditions. In order to assess the suitability of microdialysis for sampling iodine, the permeability factors and effect of perfusion flowrate on I− and IO3− recovery was examined in stirred solutions. Furthermore, microdialysis was used to sample native soluble iodine at a range of water contents and iodine-enriched soils to investigate iodine soil dynamics. Total iodine concentrations were measured using ICP-MS. Inorganic species and the molecular weight distribution of organically bound iodine were determined by anion exchange and size exclusion chromatography (SEC) coupled to an ICP-MS, respectively. The most effective recovery rates in stirred solution were observed with the slowest perfusion flowrate yielding 66.2 ± 7.1 and 70.5 ± 7.1% for I− and IO3−, respectively. Microdialysis was proven to be capable of sampling dissolved iodine from the soil solution, which accounted for <2.5% of the total soil iodine and speciation followed the sequence: organic-I > I− > IO3−. The use of SEC coupled to (i) UV and (ii) ICP-MS analysis provided detail regarding the molecular weight distribution of dissolved org-I compounds. Dissolved org-I was detected with approximate molecular weights between 0.1 and 4.5 kDa. The results in this study show that microdialysis is a suitable technique for sampling dissolved iodine species from soils maintained at realistic moisture contents. In addition, inorganic iodine added to soils was predominately bound with relatively low molecular weight (<4.5 kDa) soluble organic matter.

Iodine bioavailability in acidic soils of Northern Ireland

Iodine is an essential trace element for humans and grazing animals and is often deficient. Our aim was to investigate the role of soil properties in retaining and ‘fixing' iodine in soils and thereby controlling its phyto-availability to grass. Soils were spiked with labelled 129IO3− and rye grass (Lolium perenne L.) was grown to measure iodine uptake by grass as a function of yield, soil properties and continuous 127I inputs from irrigation water. Iodine-129 added at the start of the uptake trial was rapidly fixed (t1/2 c. 40 h) into non-labile humus-bound forms in soil. The 129I/127I isotopic ratio in grass, compared to the ratio in soil, declined over time confirming progressive 129I fixation into the soil solid phase. The rate of fixation was controlled by soil properties. A model describing iodine dynamics and uptake accounted for c. 75% of the variation in iodine concentration in grass. For most of the soils studied, the main source of iodine in herbage probably arises from the transient availability of periodic rainfall inputs rather than from soil sources. This is expected to improve biofortification strategies.

ICP-MS Determination of Sub-µg g-1 Levels of Iodine in Soil and Sediments Using Purified Ammonia Reagent for Sample Decomposition

ICP-MS Determination of Sub-µg g-1 Levels of Iodine in Soil and Sediments Using Purified Ammonia Reagent for Sample Decomposition

Features of iodine deficiency in the territory of the Republic of Belarus

A medium-scale map of iodine deficiency in the territory of the Republic of Belarus was created for the first time. The map characterizes in detail a spatial variation of iodine concentration in soils of Belarus. The article analyzes a spatial specificity of the ecological situation formed as a result of heterogeneity of the iodine content in soils. Using the means of a specialized GIS, the area of high iodine deficiency was identified at the level of administrative regions. The identified area was further differentiated in terms of different level of ecological risk due to a natural soil iodine deficiency. As a result of such geoinformation analysis, the areas of moderate, significant and greatest risks were established in the territory of Belarus. These regions should become the objects of high priority monitoring and are directly in need of targeted preventive measures.

LEACHABILITY OF IODINE FROM SOILS OF DIFFERENT LAND USES AS AFFECTED BY SELECTED AMENDMENTS

Iodine is an essential microelement required by humans and animals. Leaching of soils under intensive rains has threatened the fertility status of iodine in soils. Therefore, four discrete amendments were used for the mitigation of iodine leaching from soils. For this study, soils collected from four land uses were mixed with the amendments (gypsum, lime, fly ash, charcoal and sawdust) at the rate of 0, 2.5% and 5% (w/w) in PVC columns. Potassium iodide (KI) was applied to the soil at rate of 100 mg kg-1 and 200mg kg-1. Iodine was determined in water after three leaching events. Results indicated that soil of each land use had apparently influenced the leachability of iodine. Lower amount of iodine was released from the barren and pasture soils as compared to the soils of agriculture and forest land uses. Application of amendments significantly reduced the leaching of iodine from soil. Application of KI increased iodine concentration in the leachate. Across all soils, reduction of iodine leaching or retention of iodine among soil amendments varied in the order charcoal > sawdust > fly ash > gypsum > lime. Overall charcoal and sawdust efficiently reduced iodine leaching than other three amendments. The pH values of the leachate were oppositely associated with the iodine retention of soil. Iodine concentrations in soils were related to the amount of soil organic matter. This study has shown that the retention of iodine in soils could potentially be ameliorated by a suitable soil amendment

A Rapid Acid Digestion Technique for the Simultaneous Determination of Bromine and Iodine in Fifty‐Three Chinese Soils and Sediments by ICP‐MS

Bromine and iodine are important tracers for geochemical and environmental studies. In this study, a rapid acid digestion (HNO3 + HF) with ammonia dilution for the simultaneous determination of bromine and iodine in soils and sediments using ICP‐MS was developed. The recoveries of Br and I were controlled by the synergic effect of temperature and time. It took only 15 min at 140 °C for the complete recovery of Br and I in sediment (GSD‐2) and soil (GSS‐24) reference materials, which is a process that needs 2–6 h at 90 °C. A serious loss of Br and I was found at a higher digestion temperature of 190 °C. A 5% v/v NH4OH dilution effectively eliminated the memory effects and stabilised the signals of Br and I. Moreover, ammonia dilution also avoided the corrosiveness of HF on the sample introduction system and torch of ICP‐MS. Tellurium is a more suitable internal standard element than In in the ammonia medium. To avoid the adsorption of residues of dissolution on Te, addition of Te should be carried out after centrifuging the solution. The developed method was successfully applied to determine Br and I in fifty‐three Chinese soil and sediment reference materials. This simple method shows great potential for the rapid determination of Br and I in large batches of geological and environmental samples commonly analysed for mineral exploration and environmental geochemistry studies.

Iodine soil dynamics and methods of measurement: a review.

Iodine is an essential micronutrient for human health: insufficient intake can have multiple effects on development and growth, affecting approximately 1.9 billion people worldwide. Previous reviews have focussed on iodine analysis in environmental and biological samples, however, no such review exists for the determination of iodine fractionation and speciation in soils. This article reviews the geodynamics of both stable 127I and the long-lived isotope 129I (t1/2 = 15.7 million years), alongside the analytical methods for determining iodine concentrations in soils, including consideration of sample preparation. The ability to measure total iodine concentration in soils has developed significantly from rudimentary spectrophotometric analysis methods to inductively coupled plasma mass spectrometry (ICP-MS). Analysis with ICP-MS has been reported as the best method for determining iodine concentrations in a range of environmental samples and soils due to developments in extraction procedures and sensitivity, with extremely good detection limits typically <μg L-1. The ability of ICP-MS to measure iodine and its capabilities to couple on-line separation tools has the significance to develop the understanding of iodine geodynamics. In addition, nuclear-related analysis and recent synchrotron light source analysis are discussed.

Application of a rice husk-derived biochar in soil immobilization of iodide (I−) and iodate (IO3 −)

Purpose Radioiodine is an inevitable product of nuclear fission during nuclear fuel reprocessing and nuclear accident and finally is brought back to surface soil by fallout. Iodine is very active and mobile in soil and may adversely affect human health due to bioaccumulation through the food chain. The aim of this study was to evaluate the immobilization efficiency of biochar on the mobility of iodine (I−) and iodate (IO3 −) in soil near Qinshan Nuclear Power Plant.

Socio-demographic characters, distribution and transformation of iodine in soil, plant and wheat grains at District Diamer, Gilgit-Baltistan, Pakistan.

Iodine deficiency in soils and plants is a common problem in the hilly areas and has still been ignored. The aim of the current study is to investigate associated health issues, socio-economic characteristics and people's perception regarding iodine deficiency. Furthermore, a follow-up study was conducted to determine iodine and nutrients concentration in soil and crops at District Diamer, Gilgit-Baltistan, Pakistan. A descriptive and empirical analysis was examined. Most importantly, male was significantly observed as more affected for iodine deficiency than female, as contrary to the literature, socio-economic factors such as households' income and awareness (education) are reported as negative and significant contributor to reduce the iodine deficiency among the people irrespective of the gender. Majority of people (84%) heard about the iodine, but about 51.6% people argue that iodine has no effect on the human body and 56% of the respondents do not know why iodine is necessary for human. It was found that 11.5% of the community was affected from the IDD and majority of them were females. Wheat crops were the principal crop since it supplies 75% of calorific energy in an average Pakistani diet. The concentrations of iodine in soil samples range from 4.21 to 5.45mgkg-1. The concentration of iodine in wheat crop plant sampled were considerably varied as Boner>Gais>Goher Abad with 1.12, 0.91 and 0.81mgkg-1. respectively. Likewise, grain iodine concentration was varied as Gais>Boner>Goher Abad with 0.126, 0.102 and 0.078mgkg-1, respectively. This study exposed that community using the cereal crops could face iodine deficiency in their diet which can cause endemic goiter among the population and control the iodine deficiency by empowering the rural community to raise the income level and providing the awareness to the people.

Effects of incubation time and filtration method on Kd of indigenous selenium and iodine in temperate soils

In this study, the effects of incubation time and the method of soil solution extraction and filtration on the empirical distribution coefficient (Kd) obtained by de-sorbing indigenous selenium (Se) and iodine (I) from arable and woodland soils under temperate conditions were investigated.Incubation time had a significant soil- and element-dependent effect on the Kd values, which tended to decrease with the incubation time. Generally, a four-week period was sufficient for the desorption Kd value to stabilise. Concurrent solubilisation of soil organic matter (OM) and release of organically-bound Se and I was probably responsible for the observed decrease in Kd with time. This contrasts with the conventional view of OM as a sink for Se and I in soils. Selenium and I Kd values were not significantly affected by the method of soil solution extraction and filtration.The results suggest that incubation time is a key criterion when selecting Se and I Kd values from the literature for risk assessments. Values derived from desorption of indigenous soil Se and I might be most appropriate for long-term assessments since they reflect the quasi-equilibrium state of their partitioning in soils.

Iodine biofortification of wheat, rice and maize through fertilizer strategy

Iodine (I) deficiency is distinct from other micronutrient deficiencies in human populations in having a high endemic prevalence both in well-developed and in developing countries. The very low concentration of iodine in agricultural soils and cereal-based foods is widely believed to be the main reason of iodine deficiency in humans, especially in developing countries. In the present study, the possibility of using iodine containing fertilizers for agronomic biofortification of cereal grains with iodine was studied. The aim was to establish the best application method (to the soil or as foliar spray), the best form of iodine (potassium iodate or potassium iodide) and the optimal dose of iodine. Additionally, experiments were conducted to study transport of iodine in plants and localization of iodine within the grains. Experiments were conducted both under greenhouse conditions and in the field on wheat (Triticum aestivum) grown in Turkey and Pakistan, on rice (Oryza sativa) grown in Brazil, Thailand and Turkey and on maize (Zea mays) grown in Turkey. The iodine concentration in the grain, localization of iodine in different grain fractions of wheat (i.e., endosperm, bran and embryo) and iodine concentration of both brown rice and polished rice was analyzed. In short-term experiments, the translocation of iodine from older into younger leaves was also studied. Inductively coupled plasma mass spectrometry (ICP-MS) was used for analysis of iodine in plant and soil samples. In greenhouse experiments on wheat, soil-applied potassium iodide (KI) and potassium iodate (KIO3) at increasing rates (i.e., 0, 0.1, 0.25, 1, 2.5, 5, 10 and 20 mg I kg−1 soil) both iodine forms substantially increased iodine concentration in the shoot, with the highest shoot iodine resulting from the KI treatments. However, these soil treatments did not affect iodine concentrations in the wheat grain, with the exception of the highest iodine rates (i. e., 10 and 20 mg I kg−1 soil) which also depressed the grain yield. In contrast to the soil applications, foliar spray of KI and KIO3 at increasing rates during heading and early milk stages did enhance grain iodine concentrations up to 5- to 10-fold without affecting grain yield. Including KNO3 or a surfactant to the iodine containing foliar spray further increased the grain iodine concentration. In a short-term experiment using young wheat plants, it was found that iodine is translocated from older into younger leaves after immersion of the older leaves in solutions containing KI or KIO3. Adding KNO3 or a surfactant in the immersion solution also promoted leaf absorption and translocation of iodine into younger leaves. Field experiments conducted in different countries confirmed that foliar application with increasing rates of iodine significantly increased grain iodine concentrations in wheat, brown rice and maize. This increase was also found in the iodine concentration of the endosperm part of wheat grains and in polished rice. The results of the present study clearly show that foliar application of iodine containing fertilizers is highly effective in increasing grain iodine concentrations in wheat, rice and maize. Presented results suggest that iodine is translocated from shoot to grain by transport in the phloem. Spraying KIO3 up to the rate of 0.05% w/v is suggested as the optimal form and rate to be used in agronomic biofortification with iodine. The substantial increase in grain iodine concentrations could contribute to the prevention of iodine deficiency in human populations with low dietary iodine intake. The reasons behind the higher effectiveness of foliar-applications compared to the soil applications of iodine fertilizers in improving grain iodine concentration are discussed.

Variation in the mineral element concentration of Moringa oleifera Lam. and M. stenopetala (Bak. f.) Cuf.: Role in human nutrition.

BackgroundMoringa oleifera (MO) and M. stenopetala (MS) (family Moringaceae; order Brassicales) are multipurpose tree/shrub species. They thrive under marginal environmental conditions and produce nutritious edible parts. The aim of this study was to determine the mineral composition of different parts of MO and MS growing in their natural environments and their potential role in alleviating human mineral micronutrient deficiencies (MND) in sub-Saharan Africa.MethodsEdible parts of MO (n = 146) and MS (n = 50), co-occurring cereals/vegetables and soils (n = 95) underneath their canopy were sampled from localities in southern Ethiopia and Kenya. The concentrations of seven mineral elements, namely, calcium (Ca), copper (Cu), iodine (I), iron (Fe), magnesium (Mg), selenium (Se), and zinc (Zn) in edible parts and soils were determined using inductively coupled plasma-mass spectrometry.ResultsIn Ethiopian crops, MS leaves contained the highest median concentrations of all elements except Cu and Zn, which were greater in Enset (a.k.a., false banana). In Kenya, Mo flowers and MS leaves had the highest median Se concentration of 1.56 mg kg-1 and 3.96 mg kg-1, respectively. The median concentration of Se in MS leaves was 7-fold, 10-fold, 23-fold, 117-fold and 147-fold more than that in brassica leaves, amaranth leaves, baobab fruits, sorghum grain and maize grain, respectively. The median Se concentration was 78-fold and 98-fold greater in MO seeds than in sorghum and maize grain, respectively. There was a strong relationship between soil total Se and potassium dihydrogen phosphate (KH2PO4)-extractable Se, and Se concentration in the leaves of MO and MS.ConclusionThis study confirms previous studies that Moringa is a good source of several of the measured mineral nutrients, and it includes the first wide assessment of Se and I concentrations in edible parts of MO and MS grown in various localities. Increasing the consumption of MO and MS, especially the leaves as a fresh vegetable or in powdered form, could reduce the prevalence of MNDs, most notably Se deficiency.