Urinary sodium and iodine concentrations among Belgian adults: results from the first national Health Examination Survey.

BACKGROUND/OBJECTIVES: Iodine deficiency and excessive salt intakes have adverse health consequences. The objective was to measure sodium and iodine concentrations in urine spot samples among a representative sample of Belgian adults and compare those to World Health Organization (WHO) recommendations. SUBJECTS/METHODS: Spot urine samples were collected in 2018 from participants of the Belgian Health Examination Survey. Iodine and sodium concentrations were measured by inductively coupled plasma mass spectrometry and ion selective electrodes respectively. Tanaka and INTERSALT equations were used to predict 24-h urinary sodium excretion using sodium and creatinine concentration in spot samples, sex, and measured height and weight. RESULTS: Median urinary iodine concentration (UIC) among adults (n = 1092) was 93.6 µg/L, indicating mild iodine deficiency according to WHO thresholds. Median UIC among participants who reported thyroid problems over the last year was significantly higher than among those who did not report thyroid problems (104.1 µg/L versus UIC = 92.2 µg/L, p < 0.001). There were no significant differences in median UIC between sexes, age groups, and regions. The average salt intake among Belgian adults (n = 1120) was 8.3 ± 0.1 g/day using the Tanaka equation and 9.4 ± 0.1 g/day using the INTERSALT equation. For both equations, <5% of the population met the recommended WHO upper salt intake level of 5 g/day. CONCLUSIONS: Iodine nutrition in the Belgian adult, nonpregnant population likely indicates mild iodine deficiency as the median UIC was below the WHO threshold for iodine sufficiency. Salt intake was substantially higher than the WHO recommendations. Further policy efforts are needed to optimize iodine and reduce salt intake in Belgium.

Variability of iodine concentrations in the human placenta.

Iodine is an essential trace element, necessary for the production of thyroid hormones, which play a key role in optimal foetal growth and (neuro-) development. To date, iodine deficiency remains a health burden in many countries. We investigated the variability of placental iodine concentrations within and between individuals. We used 20 mother-neonate pairs from the ENVIRONAGE birth cohort, took samples at three standardized locations of the placentas, pooled and digested them, and determined the iodine concentrations using an ICP-MS method as an alternative for the Sandell-Kolthoff method. The variability between and within the three sample regions was calculated using the intra-class correlation coefficient (ICC) from the variance components of mixed models. With the Friedman test, the differences between placental biopsies were assessed. The ICC showed a higher between-placenta (68.6%) than within-placenta (31.4%) variability. Subsequently, we used our optimized method to determine iodine concentrations in 498 mother-neonate pairs, which averaged 26.1 µg/kg. For 96 mothers, the urinary iodine concentrations were also determined, which showed no correlation with the placental iodine storage, as was expected. Future studies are necessary to explore the effects of these placental iodine concentrations in relation to health outcomes of mother and child at birth and later in life.

Kinetics and mechanism of Paraquat's degradation: UV-C photolysis vs UV-C photocatalysis with TiO2/SiC foams.

In this study, the photolytic and photocatalytic removal of the herbicide paraquat is investigated under UV-C (254 nm). For photocatalytic experiments, SiC foams were used with P25-TiO2 nanoparticles deposited by dip-coating. The foams were characterized by scanning electron microscopy and paraquat's degradation under UV-C photolysis or photocatalysis, followed by UV-vis spectroscopy, total organic carbon analyzer, LC-MS and ion chromatography. After 3 h of reactions by photolysis and photocatalysis, 4% and 91% of TOC removal were observed. An analysis of degradation by-products showed a similar degradation pathway with pyridinium ions observed by LC/MS and carboxylic acids (succinate, acetate, oxalate and formate) detected by ion chromatography. In conclusion, these two different photo-degradation processes are able to remove paraquat and produce similar by-products. However, the kinetics of degradation is rather slow during photolysis and it is recommended to combine the UV-C lightning with a TiO2 photocatalyst to improve the mineralization rate.

Sol-gel synthesis of TiO2 nanoparticles: effect of Pluronic P123 on particle's morphology and photocatalytic degradation of paraquat.

We report a facile method to tune TiO2 nanoparticles' morphology by modifying and an acid-catalyzed sol-gel synthesis with Pluronic P123. Synthesized particles were characterized by transmission electron microscopy, BET analysis, and X-ray diffraction spectroscopy. XRD analysis revealed a high anatase content while BET measurements showed that porous volume strongly depends on the amount of P123. We demonstrate that high amounts of P123 increase particle's aspect-ratio from spherical to rod-shape morphology. We evaluated the photocatalytic performances for the removal of methyl viologen (paraquat) and found that best performances are obtained for the following weight ratio P123/TiO2 = 7.5. Furthermore, P25 is less active than synthesized nanoparticles.