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Global climate changes can alter the suitable geographical range of different crops, leading to possible changes in cropping pattern and its extent in some regions. For example, temperature changes can interact very closely with changes in availability of water and soil nutrients, and crop growth cycle. The consequences of the biophysical impacts of climate changes will be influenced by the human responses to these impacts. There is a strong link between soils and human health, and these soils per se are controlled by climate changes. The human health is very close to both selenium (Se) element and climate changes. It is estimated that about 37-40 % of the total Se emissions to the atmosphere are due to the anthropogenic activities.Those anthropogenic activities, which are sources of Se, include coal and oil combustion, mining activities, the utilization of rock phosphates as a fertilizer and the application of sewage sludge to agricultural land. It was thought that selenium was a toxicant for a long time due to inadequate analytical data. In the recent past, Se has become very important in environmental biogeochemistry because of its influence on human health. Although Se is an essential nutrient for animals and humans, it is also toxic at high doses. Furthermore, the range between Se deficiency, lower than 40 lg day -1 , and toxicity, higher than 400 lg day -1 , is narrow. Selenium deficiency has been linked to several human diseases including multiple sclerosis, muscular dystrophy, heart disease, immune system, cancer and reproductive disorders. On the other hand, Se toxicity can lead to hair and nail loss and disruption of the nervous and digestive systems in animals and humans. Despite the obvious connections between Se element and human health under climate changes, there has not been a great amount of research done in this area. So, more and more studies should be carried out to enhance and protect human health. Therefore, this article reviews the biological and economic dimensions of the effects of Se element on human health under climate changes.

The main goal of this study was to synthesise and characterise different formulations based on alginate and alginate/chitosan microspheres containing nanoselenium (nano-Se) for controlled delivery applications. Nanosize elemental selenium was produced by using probiotic yogurt bacteria () in a fermentation procedure. The structural and morphological characterisation of the microspheres was performed by Fourier transform infrared (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. FTIR and XRD pattern indicated that was an effective cross-linking of selenium nanoparticles within the polymeric matrix in both cases. The SEM images reveal that selenium nanoparticles are mainly exposed on the surface of alginate, in contrast to porous structure of alginate/chitosan/nano-Se, interconnected in a regular network. This architecture type has a considerable importance in the delivery process, as demonstrated by differential pulse voltammetry. Selenium release from both matrices is pH sensitive. Moreover, chitosan blended with alginate minimise the release of encapsulated selenium, in simulated gastric fluid, and prolong the duration of release in intestinal fluid. The overall effect is the enhancement of total percentage release concomitant with the longer duration of action. The authors' formulation based on alginate/chitosan is a convenient matrix to be used for selenium delivery in duodenum, caecum and colon.

No abstract

The classical Rothamsted Experiments allow to contribute to current research. The heavy metal content of soil and hay samples have been measured with ICP-AES from a control and a fertilized plot of the Park Grass Experiment. Today a difference of 1.2 can be observed in the pH levels of the control and fertilized plots; the pH level of the control plot has decreased about 1.0, that of the fertilized plot about 2.2 as a result of 150 years of acid deposition and fertilization. The changes in the pH levels has caused many changes in the heavy metal content of the top layer of the soil. Using different extraction methods (e.g., ammonium acetate, EDTA, and sequential analysis), the heavy metal content of different fractions have been estimated. In the control plot, the Zn, Cd and Pb content increased. In the fertilized plot, the Pb and Cd contents have also increased because of atmospheric deposition and small amounts of lead in the fertilizer. The available form of Cd and Pb increased in both the control and the fertilized plots.