Bioaccessibility of selenium after human ingestion in relation to its chemical species and compartmentalization in maize.

Selenium is a micronutrient needed by all living organisms including humans, but often present in low concentration in food with possible deficiency. From another side, at higher concentrations in soils as observed in seleniferous regions of the world, and in function of its chemical species, Se can also induce (eco)toxicity. Root Se uptake was therefore studied in function of its initial form for maize (Zea mays L.), a plant widely cultivated for human and animal food over the world. Se phytotoxicity and compartmentalization were studied in different aerial plant tissues. For the first time, Se oral human bioaccessibility after ingestion was assessed for the main Se species (Se(IV) and Se(VI)) with the BARGE ex vivo test in maize seeds (consumed by humans), and in stems and leaves consumed by animals. Corn seedlings were cultivated in hydroponic conditions supplemented with 1 mg L(-1) of selenium (Se(IV), Se(VI), Control) for 4 months. Biomass, Se concentration, and bioaccessibility were measured on harvested plants. A reduction in plant biomass was observed under Se treatments compared to control, suggesting its phytotoxicity. This plant biomass reduction was higher for selenite species than selenate, and seed was the main affected compartment compared to control. Selenium compartmentalization study showed that for selenate species, a preferential accumulation was observed in leaves, whereas selenite translocation was very limited toward maize aerial parts, except in the seeds where selenite concentrations are generally high. Selenium oral bioaccessibility after ingestion fluctuated from 49 to 89 % according to the considered plant tissue and Se species. Whatever the tissue, selenate appeared as the most human bioaccessible form. A potential Se toxicity was highlighted for people living in seleniferous regions, this risk being enhanced by the high Se bioaccessibility.

Soil chemistry and meteorological conditions influence the elemental profiles of West European wines.

Elemental profiles of wines have been used successfully to distinguish their geographical provenience around the world; however, underlying mechanisms are poorly understood. In this study, Ba, Ca, Mg, Mn and Sr contents were determined in 215 wines from several West European wine-growing areas using an easy-to-perform analysis based on ICP-OES. Major environmental and wine-making parameters (soil type as "calcareous" or not, rainfall, temperature and wine color) were used to explain variations within the dataset. The combined effects of wine-making processes (expressed by wine color) and soil type explained 28.5% of total variance. The effect of climatic conditions explained 24.1% of variance and could be interpreted as intensity of drought stress. Finally, carbonate occurrence in soils and climatic conditions systematically influenced the elemental composition of the wines. These findings provide insights into the mechanisms underlying elemental fingerprinting and allow prediction of which wine-growing regions can easily be distinguished based on elemental profiles as a marker of the terroir in viticulture.

Seawater quality assessment and identification of pollution sources along the central coastal area of Gabes Gulf (SE Tunisia): Evidence of industrial impact and implications for marine environment protection.

Temperature, pH and trace elements (F, P, Cr, Cu, Zn, Cd, and Pb) contents were determined in 16 stations as well as in 2 industrial and 2 domestic discharge sources, in the central coastal area of the Gulf of Gabes. Compared to the northern and southern areas of the study area, the highest contents of contaminants were reached in the central area which hosts the coastal industrial complex. The seawater in this central area was also found to be acid and of higher temperature. Based on the Water Pollution Index results, an increasing degradation gradient of the seawater quality was revealed from northern and/or southern stations to central ones, categorized as 'strongly to seriously affected'. Phosphogypsum wastes dumped by the Tunisian Chemical Group (GCT) seem to have continuously degraded the seawater quality in the study area. A rapid intervention is needed to stop the effects on the marine environment.