NSRRC Activity Report 2022

Environmental and Earth Sciences 069 inductively coupled plasma mass spectrometry ( Fig. 2 ). Ga was distributed homogeneously in the endosperm of rice grains, which indicates a potential risk to public health through the consumption of white rice grown in Ga-contaminated soil. The predominant Ga species in the test soils were Ga(OH) 3 , Ga(III)–humic acid [Ga(III)–HA], and Ga(III)–ferrihydrite [Ga(III)– FH], which were identified using XAS ( Fig. 3 ). On day 0 (before rice cultivation), the relative concentrations of Ga(III)–FH, Ga(OH) 3 , and Ga(III)–HA in the soils were 39–56%, 21–38%, and 6–24%, respectively. On day 100 (after rice cultivation), the predominant Ga species in all three soils was Ga(OH) 3 (43–59%); the relative concentrations of Ga(III)–FH decreased in all soils. However, the relative concentrations of Ga(III)–HA decreased in Pc soil but increased in Tn and Tk soils. The decreases in the relative concentrations of Ga(III)–FH in the soils (15–30%) may be attributed to the reductive dissolution of Fe(III) hydroxides under the submerged condition of paddy soils, which contributed to Ga uptake by the roots of rice plants. To the best of our knowledge, this study was the first to explore Ga speciation in soils using Ga K-edge XAS and to indicate the potential risk of Ga contamination of soils. The findings may help devise effective strategies for the reduction of health risks from the consumption of rice grown in Ga-contaminated soils. (Reported by Shan-Li Wang, National Taiwan University) This report features the work of Shan-Li Wang and his colleagues published in J. Hazard. Mater. 424 , 127582 (2022). TLS 17C1 W200 – EXAFS • XAS • Environmental and Earth Sciences, Chemistry Reference 1. K.-Y. Chen, P.-T. Yang, H.-F. Chang, K.-C. Yeh, S.-L. Wang, J. Hazard. Mater. 424 , 127582 (2022). Fig. 2 : (a) Visible image of a grain of rice grown in Tn soil treated with 1.0 mmol kg −1 Ga and (b) the corresponding spatial distribution of Ga in the rice grain observed using laser ablation inductively coupled plasma mass spectrometry. [Reproduced from Ref. 1] Fig. 3 : (a) Ga K-edge X-ray absorption near edge structure (XANES) spectra of the reference compounds, including Ga(OH) 3 , Ga(NO 3 ) 3 , Ga(III)–humic acid [Ga(III)–HA], Ga(III)–ferrihydrite [Ga(III)–FH], and Ga(III)–goethite [Ga(III)–GT], for linear combination fitting. (b) Linear combination fits (solid lines) of the Ga K-edge XANES spectra (open circles) for three soils (Pc, Tn, and Tk) treated with 1.0 mmol kg −1 Ga before (Day 0) and after (Day 100) rice cultivation. [Reproduced from Ref. 1] (b) (a) (b) (a)