Biogeochemical transfer and dynamics of iodine in a soil–plant system

Abstract

Radioactive iodide (125I) is used as a tracer to investigate the fate and transport of iodine in soil under various leaching conditions as well as the dynamic transfer in a soil-plant (Chinese cabbage) system. Results show that both soils (the paddy soil and the sandy soil) exhibit strong retention capability, with the paddy soil being slightly stronger. Most iodine is retained by soils, especially in the top 10 cm, and the highest concentration occurs at the top most section of the soil columns. Leaching with 1-2 pore volume water does not change this pattern of vertical distributions. Early breakthrough and long tailing are two features observed in the leaching experiments. Because of the relatively low peak concentration, the early breakthrough is really not an environmental concern of contamination to groundwater. The long tailing implies that the retained iodine is undergoing slow but steady release and the soils can provide a low but stable level of mobile iodine after a short period. The enrichment factors of 125I in different plant tissues are ranked as: root > stem > petiole > leaf, and the 125I distribution in the young leaves is obviously higher than that in the old ones. The concentrations of 125I in soil and Chinese cabbage can be simulated with a dual-chamber model very well. The biogeochemical behaviors of iodine in the soil-cabbage system show that cultivating iodized cabbage is an environmentally friendly and effective technique to eliminate iodine deficiency disorders (IDD). Planting vegetables such as cabbage on the 129I-contaminated soil could be a good remediation technique worthy of consideration.

Iodine Fortification Plant Screening Process and Accumulation in Tomato Fruits and Potato Tubers

“…A couple of recent publications investigated the movements of iodine in the soil, and the percentages of iodine lost from the soil after an enrichment experiment, by means of a radioactive isotope (Weng et al , 2009). The authors concluded that the percentages of iodine lost from the soil by leaching and volatilization were a small fraction of the iodine persisting in the soil, respectively, from 4.5 to 6% and from 4.2 to 4.7% in a sandy soil (Weng et al 2009).…”

“…A couple of recent publications investigated the movements of iodine in the soil, and the percentages of iodine lost from the soil after an enrichment experiment, by means of a radioactive isotope (Weng et al , 2009). The authors concluded that the percentages of iodine lost from the soil by leaching and volatilization were a small fraction of the iodine persisting in the soil, respectively, from 4.5 to 6% and from 4.2 to 4.7% in a sandy soil (Weng et al 2009). Nevertheless, the residual iodine in the soil, particularly fixed in organic forms, as well as the iodine eluviated into surface and groundwater, and the volatilized fractions, could be considered positively to raise the general iodine level in the food chain in the iodine-deficient areas to control IDD ).…”

High-Resolution Continuum Source Atomic Absorption Spectrometry with Microwave-Assisted Extraction for the Determination of Metals in Vegetable Sprouts

“…Engineered agricultural crops with tailored concentrations of phytonutrients are now regarded as a promising strategy for disease prevention (Johns and Eyzaguirre 2007). Biofortification of carrots or tomatoes is an example of this enrichment protocol with iodine, performed through the addition of compounds containing this element such as KI and KIO 3 Broadley 2005, 2009;Weng et al 2009) to the soil. Iodine, whose deficiency affects 30 percent of the world population, is added universally to table salt; however, total losses before consumption are significant.…”

Iodine biofortification of vegetable plants—An innovative method for iodine supplementation

“…In this study, we have cultivated iodine-containing vegetables directly by adding algal organic iodized fertilizer into soil and thus realized iodine biofortification of edible vegetable. Using microscopy [18] and localization techniques, we have identified and analyzed the distribution of intracellular iodine which revealed the absorption mechanism of iodine by edible vegetable. The findings show that iodine biofortification is a promising approach for eliminating IDD.…”