Distribution of Selenium in the Soil–Plant–Groundwater System: Factors Controlling Its Bio-Accumulation

Selenium (Se) is an essential micronutrient for humans and animals, but both Se excess and deficiency can cause various health risks. Since Greece is among the European countries where people have very low Se-serum, the present study is focused on the Se distribution in cultivated and non-cultivated plants and relative soil coming from the Neogene basins of Greece (Assopos-Thiva and Attica), aiming to define potential Se-source/es and factors controlling Se bio-accumulation and enrichment in food. The dry weight Se values are relatively low (0.1–0.9 mg/kg) with the highest Se contents in garlic, beet and lettuce from the Assopos basin, where the translocation percentage [(mplant/msoil) × 100] for Se, P and S is much higher compared to non-cultivated Attica basin. There is a diversity between the Se source in soil and coastal groundwater which is used for irrigation in the cultivated Assopos–Thiva basin. The soil pH and oxidizing conditions (Eh) are considered the main driving force to make Se available for plant uptake. Potential sources for Se in Greece are Fe-Cu-Zn-sulphide ores and peat deposits in northern Greece, with a Se content ranging from decades to hundreds of mg/kg. Application of the leaching testing protocol is necessary to select the most appropriate proportion of additives to improve the Se deficiencies in agricultural soil.

Heavy metal contamination of soil based on pollution, geo-accumulation indices and enrichment factor in Phan Me coal mine area, Thai Nguyen province, Vietnam

Soil samples around the Phan Me coal mine area, Thai Nguyen province, Vietnam had been analyzed for Fe, Mn, Cu, Zn, As, Cd, Hg, Pb and Ni. Single pollution index, geo-accumulation index, enrichment factor have been determined and used for assessing the soil quality. In average by pollution index, the soil heavy metal pollution sequence is Cu(PI=4.2)>Cd(3.5)>Zn(3.1) >Pb(1.7)>Ni(1.3). High concentrations of Cu, Zn and Cd in the soil in the study area are thanks to geo-accumulation and enrichment of the metals in the soil. The soil is from moderately to heavily contaminated by Cu, Zn and Cd: Cu and Zn concentrations are 1.5-2.8 times higher than the ecological risk values, and Cd concentration is about 3.5 times higher than allowable limits. The high concentration of Pb is thanks to moderate geo-accumulation and enrichment of Pb, and the soil mostly has Pb concentration higher than the allowable limit in about 1.7 times. There is a sign that the soil is contaminated by Ni: 22% of the samples have Ni concentration higher than the threshold value, however, the enrichment of Ni is only deficient to minimal. The results of the assessment highlight the need for a comprehensive and detailed study program on heavy metal content in different soil resources in a wider area to identify the magnitude and details of the problem associated with heavy metal contamination for the development of a remediation plan and more effective pollution preventing measures.

Heavy metal contamination of soil based on pollution, geo-accumulation indices and enrichment factor in Phan Me coal mine area, Thai Nguyen province, Vietnam

Soil samples around the Phan Me coal mine area, Thai Nguyen province, Vietnam had been analyzed for Fe, Mn, Cu, Zn, As, Cd, Hg, Pb and Ni. Single pollution index, geo-accumulation index, enrichment factor have been determined and used for assessing the soil quality. In average by pollution index, the soil heavy metal pollution sequence is Cu(PI=4.2)>Cd(3.5)>Zn(3.1) >Pb(1.7)>Ni(1.3). High concentrations of Cu, Zn and Cd in the soil in the study area are thanks to geo-accumulation and enrichment of the metals in the soil. The soil is from moderately to heavily contaminated by Cu, Zn and Cd: Cu and Zn concentrations are 1.5-2.8 times higher than the ecological risk values, and Cd concentration is about 3.5 times higher than allowable limits. The high concentration of Pb is thanks to moderate geo-accumulation and enrichment of Pb, and the soil mostly has Pb concentration higher than the allowable limit in about 1.7 times. There is a sign that the soil is contaminated by Ni: 22% of the samples have Ni concentration higher than the threshold value, however, the enrichment of Ni is only deficient to minimal. The results of the assessment highlight the need for a comprehensive and detailed study program on heavy metal content in different soil resources in a wider area to identify the magnitude and details of the problem associated with heavy metal contamination for the development of a remediation plan and more effective pollution preventing measures.

Moving Beyond the Gym: A Content Analysis of YouTube as an Information Resource for Physical Literacy

The Internet, and particularly YouTube, has been found to be and continues to develop as a resourceful educational space for health-related information. Understanding physical literacy as a lifelong health-related outcome and facilitator of an active lifestyle, we sought to assess the content, exposure, engagement, and information quality of uploaded physical literacy videos on YouTube. Two researchers collected 300 YouTube videos on physical literacy and independently coded each video’s: title, media source of upload, content topics related to physical literacy, content delivery style, and adherence to adapted Health on the Net Foundation Code of Conduct (HONcode) principles of information quality. Physical literacy videos that focused on physical activity and behaviors were the strongest predictor of high quality ratings, followed closely by videos covering affective domains (motivation, confidence, and self-esteem) of physical literacy. The content delivery method was also important, with videos utilizing presentations and testimonials containing high quality information about physical activity. Thus, providers of physical literacy and health-related online video content should be aware of and adhere to the expected quality standards. As health information expectations and ethical standards increase, the Internet, and specifically YouTube, has the potential to enhance video resources, virtual networking opportunities, as well as the sharing, dissemination, accumulation, and enrichment of physical literacy information for all.

Controlling factors for the accumulation and enrichment of tight sandstone gas in the Xujiahe Formation, Guang’an Area, Sichuan Basin

Tight sandstone gas characterized by a wide distribution, local enrichment and a complex gas–water distribution has high exploration potential. This study, using the Xujiahe Formation in the Guang’an gas field as an example, aims to determine the main controlling factors of the enrichment of tight gas through comprehensive analyses of the source rock and reservoir characteristics, pressure evolution and structural effects by using various methods including well logging, geochemistry, mercury injection, reservoir physical properties and formation pressure. The results show that the proximal-source, interbedded hydrocarbon accumulation results from a dispersed hydrocarbon supply, which is the root cause of the widely distributed tight sandstone gas. The abnormally high reservoir pressure caused the enrichment of tight sandstone gas even under insufficient hydrocarbon generation dynamics; in addition, natural gas preferentially accumulated in the relatively high-quality reservoirs under the same hydrocarbon supply, which means that differences in the reservoir physical properties control gas charge in the reservoir. Structure controls the gas–water differentiation under the stable tectonic background, and the higher the structure is, the more abundant the gas–water differentiation is, and the easier pure gas reservoirs form. Therefore, the accumulation and enrichment of tight sandstone gas in the Xujiahe Formation is controlled by source rocks, abnormally high reservoir pressure and the physical properties and structure of the reservoir.