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

Ahmad, Saeed; Bailey, Elizabeth H.; Arshad, Muhammad; Ahmed, Sher; Watts, Michael; Young, Scott

Abstract

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 lg L-1 to 0.016-2.09 lg 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 lg kg-1 and 209 lg kg-1 , respectively, much lower than global averages of 2600 and 400 lg 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.

Citation

Ahmad, S., Bailey, E. H., Arshad, M., Ahmed, S., Watts, M., & Young, S. (2021). Multiple geochemical factors may cause iodine and selenium deficiency in Gilgit-Baltistan, Pakistan. Environmental Geochemistry and Health, 43(11), 4493-4513. https://doi.org/10.1007/s10653-021-00936-9

• Journal Article Type: Article
• Acceptance Date: Apr 12, 2021
• Online Publication Date: Apr 24, 2021
• Publication Date: Nov 1, 2021
• Deposit Date: Apr 25, 2021
• Publicly Available Date: Apr 26, 2021
• Journal: Environmental Geochemistry and Health
• Print ISSN: 0269-4042
• Electronic ISSN: 1573-2983
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 43
• Issue: 11
• Pages: 4493-4513
• DOI: https://doi.org/10.1007/s10653-021-00936-9
• Keywords: Geochemistry and Petrology; General Environmental Science; Water Science and Technology; Environmental Chemistry; General Medicine; Environmental Engineering
• Public URL: https://nottingham-repository.worktribe.com/output/5495796
• Publisher URL: https://link.springer.com/article/10.1007/s10653-021-00936-9
• Additional Information: Received: 27 September 2020; Accepted: 12 April 2021; First Online: 24 April 2021; : ; : The authors declare that they have no conflict of interest.