Rice (Oryza sativa L.) plants were cultivated in an experimental field and separated at harvest into different components, including polished rice, rice bran, hull, straw, and root. The contents of iodine in these components and the soil were determined by inductively coupled plasma-mass spectrometry and radiochemical neutron activation analysis, respectively. Iodine content varied by more than three orders of magnitude among the plant components. Mean concentration of iodine in the entire plants was 20 mg kg(-1) dry weight, and the concentration of iodine in the surface soil (0-20 cm depth) was 48 mg kg(-1). The highest concentration of iodine (53 mg kg(-1) dry weight) was measured in root and the lowest concentration (0.034 mg kg(-1) dry weight) in polished rice. While the edible component (polished rice) accounted for 32% of the total dry weight, it contained only 0.055% of iodine found in the entire rice plants. Atmospheric gaseous iodine (5.9 ng m(-3)) was estimated to contribute <0.2% of the total iodine content in the biomass of rice plants; therefore nearly all of the iodine in the rice plants was a result of the uptake of iodine from the soil. The content of iodine in the aboveground part of rice plants was 16 mg kg(-1) dry weight and the percentage of iodine transferred per cropping from the soil into the aboveground biomass corresponded to 0.27% (20 mg m(-2)) of the upper soil layer content.
"Johnson (2003b) concluded that locally grown food from most areas of the world, except coastal areas, are not going to produce sufficient iodine to reach an Adults Recommended Dietary Allowance (RDA) of 150 lg day -1 . Iodine being non-mobile is not concentrated in the seed (Johnson 2003b), therefore, seed crops such as rice (and wheat) cannot be considered as a good source of dietary iodine (Fordyce et al. 2000; Tsukada et al. 2008). "
[Show abstract][Hide abstract] ABSTRACT: A study was carried out across 86 locations of the country to investigate iodine supply potential of soils, grains and underground waters for onward design of an environmental intervention in Pakistan. Wheat crops were the principal crop in this study since it supplies 75 % of calorific energy in an average Pakistani diet. TMAH-extractable iodine in soils provided a geometric mean of 0.66 µg g−1, far lower than the worldwide mean of 3.0 µg g−1 for soil iodine. Bioavailable (water-extractable) iodine concentration had a geometric mean of 2.4 % (of TMAH-extractable iodine). Median iodine concentrations in tube well sourced waters were 7.3 µg L−1. Median wheat grain-iodine concentrations were 0.01 µg g−1. In most of the grain samples, TMAH-extractable iodine was below detection limit of 0.01 µg g−1. The highest wheat grain iodine was measured on a soil having highest TMAH-extractable iodine. An iodine intake of 25.4 µg a day has been estimated based on median wheat grain iodine measured and groundwater consumption compared to world health organisation (WHO) recommendations of iodine intake of 150 µg a day. This nominal intake of iodine is alarming since 60 % of Pakistani households do not consume iodised salt.
[Show abstract][Hide abstract] ABSTRACT: All papers published in the Journal of Radioanalytical and Nuclear Chemistry (JRNC) in the period 2005–2009 (source dataset)
and all papers citing these papers and published in other journals (target dataset) have been compiled. A scientometric analysis
of the datasets has been performed using Hirsch-type statistics. A comprehensive bibliography of the citing papers is presented.
Journal of Radioanalytical and Nuclear Chemistry 07/2010; 285(1):1-168. DOI:10.1007/s10967-010-0571-z · 1.03 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this study, a method for the estimation of plant-unavailable I concentrations in soils was developed. Concentrations of total land potentially plant-available I (i.e., water-soluble and organically bound I) were measured in 141 agricultural soil samples. For total I measurements, pressed powder pellets were prepared from soil samples, and concentrations of I were measured by energy dispersive x-ray fluorescence. Potentially plant-available I contents were measured by inductively coupled plasma mass spectrometry after the soil samples had been extracted with tetramethyl ammonium hydroxide and their soluble and organically bound I concentrations had been measured (TMAH-extractable I). The results showed a high correlation between the total and TMAH-extractable I concentrations. The geometric means of total and TMAH-extractable I in the paddy field samples were 1.9 and 1.1 mg kg(-1) dry weight, respectively, while those in the upland field soil samples were 5.7 and 4.2 mg kg(-1) dry weight, respectively. For the agricultural soils having <5 mg kg(-1) total I, it was estimated that the average concentrations of plant-unavailable I in paddy fields and upland fields were 0.7 +/- 0.2 and 0.7 +/- 0.4 mg kg(-1) dry weight, respectively. The different total I concentrations for the fields from the two agricultural uses could be explained by the differences in their redox conditions; I is mobile under reducing conditions so that it was removed from the paddy fields by leaching from the plowed layer or by I volatilization from the soil.
Soil Science Society of America Journal 09/2010; 74(5). DOI:10.2136/sssaj2009.0423 · 1.72 Impact Factor
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