Transfer of Nutrient and Harmful Elements from Soil to Rice and Health Risk Assessments for the Vietnamese Population

“Transfer of nutrient and harmful elements from soil into rice and health risk assessments for the Vietnamese population” Main and trace element concentrations in paddy soils and corresponding rice plants collected along some transnational-river systems in Vietnam including Red River in the north and Mekong River in the south, and Huong River in the center were investigated to provide an insight into paddy soil characteristics and the element transfers into rice plant, and to assess chronic health risks by potentially harmful elements through rice consumption. The studied paddy soils have similar parent materials consisting of alluvial sediments deposited by inundation and irrigation. Most of the soils are not or only slightly affected by heavy metal(loid)s contamination from anthropogenic activities, except for Cd enrichment by the use of phosphate fertilizer. Elevated arsenic concentrations exceeding the allowable limit of agricultural soil (15 mg kg-1), are found mostly in the northern and the central paddy soils (80%), but at fewer soils in the south (11%). These high concentrations are the result of natural processes related to redox reactions of As-rich sulfide and Fe-oxides/hydroxide phases. Some specific sites close to the river bank and near a fertilizer and chemical factory show a strong enrichment of heavy metals, resulting from industrial wastewater application. Due to similar concentrations of elements in the parent material not polluted by human activities, many trace elements show extremely sharp correlations with each other, which can be arranged into groups. The correlations are mainly caused by variable concentrations of dilution by quartz, bio-opal and organic matter in the soil. These correlations can be used to assess if a soil sample is polluted by a certain element. Soil parameters play an important role in the transferability of elements from soil to rice plant causing a large spread of transfer factors. Although the background concentrations of elements in areas are hardly distinguishable, differences in soil pH-value, the content of organic matter, Fe- and Mn-oxides/hydroxides and clay minerals as well as the fertilizer input are the main reasons for contrasting element concentrations in the rice grains of the three research areas. Particularly, the translocation of the potentially harmful elements As, Cd, and Mn shows intermediate to high transfer factors. In general, concentrations of most elements in the plant parts decrease in the order: shoot >> husk > grain. Exceptions are Ni, Mg, Zn, S, Cu, Mo, and P, which are more easily transported to the grains due to their electrostatic repulsion at the negative cell wall charges or to their formation of soluble organic complexes. Health risks of harmful elements intake from rice consumption are estimated by applying four approaches: (1) Tolerable Upper Intake Level (UL) of total daily consumption – data available for As, Cd, Co, Mn, Mo, Ni, Pb, Sb, and U; (2) allowable Maximum Concentration (MC) of rice - data for As, Cd, and Pb; (3) non-cancer risks (HI) - data for As, Cd, Co, Cu, Mn, Mo, Ni, and Pb; and (4) cancer risk (∑ILCR) - data for As and Pb. The mentioned elements are the riskiest pollutants in rice for the Vietnamese population. For the UL-guidelines, 14% of the total studied samples cause health risks of exposure to As, 32% to Cd, and 21% to Pb. In comparison with the MC-values, 4%, 3%, and 19% of the rice samples exceed these levels of As, Cd, and Pb respectively. Results of non-cancer risks and cancer risks exhibit that all rice grains have the HI-values and ∑ILCR-values surpassing their safe and acceptable thresholds. Manganese occupies the highest portion of HI-index and As is the most potential oral carcinogenic factor. People in the three studied areas are facing the different levels of intoxication risk by these elements. People living in the Red River and Huong River area suffer from higher hazard of As and Cd, but not of Pb. People in the Mekong area are additionally exposed to Pb in rice, 10-times more than in the other areas. To mitigate these health risks, controlling the soil pH-value is a simple way that needs to be considered first

A theoretical study on propagation of guided waves in a fluid layer overlying a solid half-space

Ultrasonic guided waves propagating in a non-viscous fluid layer of uniform thickness bonded to an elastic solid half-space is theoretically investigated in this article. Based on the boundary conditions set for the joined configuration, a characteristic dispersion equation is found and new expressions for free guided waves are introduced. Closed-form solutions of guided waves generated by a time-harmonic load are derived by the use of elastodynamics reciprocity theorems. Through calculation examples, it is shown that the obtained computation of the lowest wave mode approaches the result of the Rayleigh wave in the solid half-space as the layer thickness approaches zero. The aim of the present work is to improve the understanding of wave motions in layered half-spaces for potential applications in the area of bone quantitative ultrasound

Le discours officiel sur l’histoire de l’éducation au Vietnam

Le système éducatif vietnamien contemporain a été fondé peu après l’indépendance en septembre 1945. Appliqué dans les zones sous contrôle Việt Minh, il s’étend au Nord-Vietnam après 1954 et fonctionne en parallèle avec son homologue du Sud-Vietnam jusqu’en 1975, date à laquelle il est mis en place dans tout le pays. Ce système a cependant des racines historiques profondes, et cette communication, après un bref rappel de ces influences, montrera la vision souvent partielle qu’en proposent les ..

Le discours officiel sur l’histoire de l’éducation au Vietnam

Le système éducatif vietnamien contemporain a été fondé peu après l’indépendance en septembre 1945. Appliqué dans les zones sous contrôle Việt Minh, il s’étend au Nord-Vietnam après 1954 et fonctionne en parallèle avec son homologue du Sud-Vietnam jusqu’en 1975, date à laquelle il est mis en place dans tout le pays. Ce système a cependant des racines historiques profondes, et cette communication, après un bref rappel de ces influences, montrera la vision souvent partielle qu’en proposent les ..

10. Sel, soufre et mercure

Pour les hermétistes, les trois principes : soufre, sel et mercure se retrouvaient dans tous les corps, le soufre, le contenu, se réunissant au sel, le contenant, et au mercure, l’ambiance. Écolier vietnamien dans un lycée français, ne sommes-nous pas un mélange de soufre, de sel et de mercure, le soufre étant le jaune de l’œuf, le sel, sa coquille, et le mercure son blanc, comme l’exprime la composition hermétique de l’œuf ? Pour une histoire des élèves Dans l’Indochine française, le système..

Designing learning activities to develop self-directed learning competency in teaching informatics

Currently, there are not many studies on teaching informatics in the direction of developing students’ self-directed learning (SDL) competency. The results of the survey with 235 informatics teachers in 42 provinces/cities across Vietnam showed that although they are very interested in teaching SDL, teachers are still confused about teaching methods and assessments. To improve the effectiveness of informatics teaching as well as develop SDL for students, the study proposed a method of teaching informatics in the direction of designing activities to guide students to create digital products by themselves. The pedagogical experiment on assessing SDL and learning outcomes was conducted on two experimental and control groups, selected from 87 10th grade students, in the first semester of the school year 2022-2023 at Cam Giang High school in Hai Duong, Vietnam. The results of SDL and test scores of the experimental class were higher than that of the control class (with p-value <0.005– this difference is statistically significant). This proves that the method (creating of digital products) is effective, positively affecting students’ learning, helping students develop SDL competency

EFL TEACHERS’ STRATEGIES AND CHALLENGES IN PROMOTING HIGH SCHOOL STUDENTS’ AUTONOMY IN VOCABULARY LEARNING

Learner autonomy is now regarded as a desirable objective in language teaching. The objective of the study was to identify ELT teachers’ strategies in promoting EFL high school students’ autonomy in vocabulary learning. Besides, this research attempts to find out the challenges that ELT high school teachers employ in promoting EFL students’ autonomy in vocabulary learning. A questionnaire and an interview were used in this study to find out the strategies adopted by the teachers in the current research as well as the challenges they face. The findings of this study revealed that English language teachers frequently promoted autonomous learners in their classrooms. They usually implemented different teaching strategies, which can be categorized into three groups involving students in a student-centered atmosphere; playing various roles in the classroom; and equipping students with the strategies to learn vocabulary. Additionally, the results demonstrated that teachers faced challenges such as learners' lack of independent learning abilities, rules and regulations implemented in schools, and teachers' lack of fundamental ways to promote autonomous learning. Finally, it is hoped that the proposed pedagogical implications will contribute to the innovation of promoting learner autonomy in vocabulary learning in the context of high school in the Mekong Delta of Vietnam.  Article visualizations

DESIGNING A GEODATABASE MODEL FOR URBAN INFORMATION SYSTEM AT THE BASIC LEVEL (Case Study in Nguyen Du Ward, Hai Ba Trung District, Hanoi City)

Joint Research on Environmental Science and Technology for the Eart

Factors affecting intention to purchase organic agriculture products among Vietnamese

Globally, customer intention to purchase has become the essential part of the product and organization's success in the market. More recently, the idea has captured the attention of academic and policymakers alike. Therefore, the current article analyses product quality features such as agreeableness, emotional stability conscientiousness, openness to experience and extroversion on the intention to purchase organic agricultural products in the context of Vietnam. The study also analyses the mediating role of customer satisfaction between the association of product quality features and intention to purchase organic products in Vietnam. The present study uses questionnaires to collect data pertaining to the health sector of Vietnam. The current study employs the smart-PLS to analyze the constructs and items' reliability as well as the association among constructs. The results show that product quality features except extroversion have a positive and significant association with intention to purchase organic products in Vietnam. The results also reveal that customer satisfaction significantly and positively mediates among the associations of product quality features and intention to purchase organic products in Vietnam. This study is suitable for policymakers while formulating policies that may directly or indirectly affect customers' intention to purchase organic agricultural products.Luong Thu Thuy (Faculty of Economics, Academy of Finance, Vietnam), Tran Thi Phuong Diu (Faculty of Economics, Academy of Finance, Vietnam), Nguyen Dinh Hoan (Faculty of Economics, Academy of Finance, Vietnam), Vu Viet Ninh (Faculty of Economics, Academy of Finance, Vietnam), Nguyen Thi Thuy Nga (Faculty of Economics, Academy of Finance, Vietnam)Includes bibliographical reference