Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, Leicestershire, UK.
Mountain Agriculture Research Centre Gilgit, Pakistan Agricultural Research Council), Gilgit-Baltistan, Pakistan.
Environ Geochem Health. 2021 Nov;43(11):4493-4513. doi: 10.1007/s10653-021-00936-9. Epub 2021 Apr 24.
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 to 0.016-2.09 µg L, 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 and 209 µg kg, respectively, much lower than global averages of 2600 and 400 µg kg, 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) 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.
碘和硒等微量营养素的缺乏在以土壤中碘和硒含量低为特征的地区尤为普遍，这些地区的人们食用当地生产的农产品。本研究聚焦于巴基斯坦吉尔吉特-巴尔蒂斯坦（Gilgit-Baltistan）这样的地区，通过对灌溉水和耕地土壤中碘和硒的分馏和形态进行地球化学调查来研究这一问题。水中的碘和硒浓度范围分别为 0.01-1.79 µg L 和 0.016-2.09 µg L，均小于世界上其他类似山区报告的水平。所有水样中的主要无机碘形态为碘酸盐，硒形态为硒酸盐。土壤中碘和硒的平均浓度分别为 685 µg kg 和 209 µg kg，远低于全球平均水平 2600 µg kg 和 400 µg kg。碘和硒的“活性”（“可溶”和“吸附”）部分仅占其土壤总浓度的<7%和<5%。超过 90%的活性碘为有机碘，碘化物是主要的无机碘形态。相比之下，66.9%和 39.7%的“可溶”和“吸附”硒分别以有机形态存在，无机硒主要为亚硒酸盐。碘和硒的分配系数（kd=吸附/可溶；L kg）非常低（分别为 1.07 和 1.27），表明可溶碘和硒对淋溶损失和植物吸收的缓冲能力很低。这些地球化学特征表明，吉尔吉特-巴尔蒂斯坦的碘和硒的生物可利用性较低，这可能反映在当地种植的作物中。然而，需要进一步调查才能确定吉尔吉特-巴尔蒂斯坦的食物供应和人口中碘和硒的状况。
