Application of Integrated-Weight Water Quality Index in Groundwater Quality Evaluation

Groundwater is one of the most crucial freshwater resources in many parts of the world. However, the growth of the population and different economic activities have negatively impacted groundwater quality. This study aims to assess the groundwater quality in An-Giang province, Vietnam, from 2017–2020 and investigate its suitability for drinking via a new integrated-weight water quality index (IWQI). The samples were collected at thirteen wells in dry and rainy seasons and analyzed for eleven physicochemical parameters, including pH, total dissolved solids (TDS), total hardness, nitrate (NO3ˉ), ammonium (NH4+), iron (Fe), manganese (Mn), arsenic (As), mercury (Hg), lead (Pb), and coliform. These values were compared to the Vietnamese standard. The entropy weight method and the Criteria Importance Though Inter-criteria The correlation weighting method was integrated to compute the weights in IWQI. The results showed that NH4+and coliform concentrations were consecutively higher than the standard over the study period. No detection of As, Hg, and Pb concentrations in groundwater was in 2019 – 2020. There were significant statistical differences between parameters from 2017–2020 in the dry and rainy seasons. The results of IWQI revealed that about 40% of the total samples in 2020 were categorized as unsuitable for drinking. IWQI values range from 72 to 7973 in 2020, 12 to 3020 in 2019, 21 to 1115 in 2018, and 53 to 2246 in 2017. Most samples with high IWQI values are located near the burial pits of African fever-infected swine. The findings of this study could provide further information about the changes in groundwater quality from 2017–2020 in An Giang province, Vietnam, and the IWQI method can be proposed for other studies to evaluate groundwater quality effectively. Doi: 10.28991/CEJ-2022-08-11-020 Full Text: PD

Health Risk Assessment for the Exposure of Workers to BTEX at the Gasoline Stations

The study was conducted to assess the health risks of workers due to exposure to toxic gases including benzene, toluene, ethylbenzene, m, p-xylene, o-xylene, formaldehyde and acetaldehyde at gasoline retail stations. In this study, data on the  concentrations of the toxic gases were collected from the previously published studies in the qualified scientific journals. The health risk assessment was followed by the process of the United States Environment Protection Agency (U.S. EPA). The results show that the concentrations of benzene, toluene, ethylbenzene, m, p-xylene, o-xylene, formaldehyde, and acetaldehyde were in the range of 12.40 - 357.5, 12.47 - 574.17, 2.05 - 156.5, 4.57 - 218, 2.36 - 77.04, 3.64 - 153.93 and 1.27- 27.83 µg/m3 , respectively. Life time cancer risk for gasoline station workers due to exposure to benzene, ethylbenzene, formaldehyde, and acetaldehyde was calculated in the ranges of 2.13x10-5 - 6.14x10-4 , 4.96x10-7 - 3.79x10-5 , 4.81x10-6 - 2.03x10-4 , and 7.99x10-7 - 1.75x10-5 , respectively. For non-carcinogenic  compounds, the hazard index due to benzene, toluene, m, p-xylene, o-xylene were respectively in the range of 0.13 - 3.81, 7.97x10-4 -  0.04, 0.01 - 0.70 and 0.01 - 0.25. The findings revealed that there is high risk of cancer and non-cancer for the workers working at the gasolines stations if they are not taking good preventive measures. The calculation showed that the limit levels of benzene, toluene, ethylbenzene, xylene, formaldehyde and acetaldehyde should be reduced to 5.82x10-4 , 15.64, 4.13x10- 3 , 0.31, 7.57x10-4 and 1.59x10-3 mg/m3 , respectively to meet the safety levels for the workers at the gasoline stations. Keywords: benzene, toluene, ethylbenzene, xylene, formaldehyde, acetaldehyde, life-time cancer risk, healt

Physico-chemical properties of fourteen popular cocoa bean varieties in Dongnai-highland Vietnam

Cocoa (Theobroma cacao L.) is a major, crucial economic, global crop and has been maintained several nutritional benefits. The exporting volume of Vietnamese cocoa bean is increasing in the world cocoa trade. The beans of fourteen popular cocoa varieties that are commonly cultivated in Trang Bom (Dong Nai, Vietnam) were characterized for their physico-chemical qualifications on the background of post-fermented cocoa beans and dehydration in the region of Trang Bom-Dong Nai. The physical properties were determined based on mass ratio and bean’s dimension (lengh, width and thickness) as well as chemical (proximate) composition (total crude protein, ash, moisture, and lipid). These values were analysed using AOAC methods. The largest-size beans were found for the TD8 variety (1.5 g of mass, 25.02 mm of length, 14.28 mm of width and 7.96 mm of thickness). The moisture content of the cocoa beans was in the range between 5.64 and 6.99 (% wb) and the ash content in the range between 3.67% and 2.47% (wb). Noticeably, the fat content ratio (the most important value of cocoa bean) found in 8 varieties (TD1, TD2, TD5, TD9, TD11, TD12, TD13, TD14) was over 50%, thus these varieties are worthy chemical component especially for exported cocoa bean and industrized cultivation (extending the cultivation producing area)

Common mutations in G6PD of Vietnamese-Kinh deficient patients

This study was conducted to identify the common mutations occurring within the G6PD gene in the G6PD - Vietnamese deficient patients, which may be the main causative mutations of the G6PD deficiency in Vietnamese-kinh. Sequencing was performed to detect mutations in the coding region of G6PD gene for 30 Vietnamese-Kinh G6PD deficient patients. Seven sets of primers were designed to amplify and sequenced 13 coding regions of G6PD gene. Seven known types of mutations were detected. Each patient had at least one mutation in his G6PD gene. The most common mutation is the silent mutation 1311C>T with frequency of 56.66%. With the high frequency, the 1311C>T mutations are suggested as potential markers for G6PD deficiency in Vietnamese-kinh population.Keywords: G6PD deficiency, Vietnamese-Kinh, 1311C>T, Viangchan, CantonAfrican Journal of Biotechnology Vol. 12(12), pp. 1318-132

Extended state observer based load frequency controller for three area interconnected power system

In this paper, we develop a new extended state variable observer based LFC scheme for three-area interconnected power systems. The extended state observerbased load frequency controllers are developed which utilize disturbance estimation techniques. The propose control approach assures that the fluctuating things of the load frequencies reaches to a safer range and the load frequencies can also be made at a very minimal not to have an effect on power quality and power flow in multi-area interconnected power system. The results of the simulations using MATLAB/SIMULINK done did not only address that the proposed newly control method works effectively but also change powerfully the parameter variations of the interconnected areas of the power system. Especially, it works very well to limit disturbances impact on interconnected areas in the system. Therefore, the performance of interconnected power system under different multi-conditions is simulated with the new control method to demonstrate the feasibility of the system

Health Risk Assessment for the Exposure of Workers to BTEX at the Gasoline Stations

The study was conducted to assess the health risks of workers due to exposure to toxic gases including benzene, toluene, ethylbenzene, m, p-xylene, o-xylene, formaldehyde and acetaldehyde at gasoline retail stations. In this study, data on the concentrations of the toxic gases were collected from the previously published studies in the qualified scientific journals. The health risk assessment was followed by the process of the United States Environment Protection Agency (U.S. EPA). The results show that the concentrations of benzene, toluene, ethylbenzene, m, p-xylene, o-xylene, formaldehyde, and acetaldehyde were in the range of 12.40 - 357.5, 12.47 - 574.17, 2.05 - 156.5, 4.57 - 218, 2.36 - 77.04, 3.64 - 153.93 and 1.27- 27.83 \u3bcg/m3, respectively. Life time cancer risk for gasoline station workers due to exposure to benzene, ethylbenzene, formaldehyde, and acetaldehyde was calculated in the ranges of 2.13x10-5 - 6.14x10-4, 4.96x10-7 - 3.79x10-5, 4.81x10-6 - 2.03x10-4, and 7.99x10-7 - 1.75x10-5, respectively. For non-carcinogenic compounds, the hazard index due to benzene, toluene, m, p-xylene, o-xylene were respectively in the range of 0.13 - 3.81, 7.97x10-4 - 0.04, 0.01 - 0.70 and 0.01 - 0.25. The findings revealed that there is high risk of cancer and non-cancer for the workers working at the gasolines stations if they are not taking good preventive measures. The calculation showed that the limit levels of benzene, toluene, ethylbenzene, xylene, formaldehyde and acetaldehyde should be reduced to 5.82x10-4, 15.64, 4.13x10-3, 0.31, 7.57x10-4 and 1.59x10-3 mg/m3, respectively to meet the safety levels for the workers at the gasoline stations

Language Learning Strategies Employed by Non-English Majors at Nong Lam University, Vietnam

Learning strategies have a strong effect on students’ success in foreign language learning. In fact, they are considered tools for active and self-directed engagement, which is vital for developing communicative competence. Language learning strategies also enable students to take responsibility for their own learning progress. This study was carried out to identify the preferred language learning strategies which are most frequently employed by non-English major students at Nong Lam University, Ho Chi Minh City, Vietnam. The research was conducted with 725 undergraduate students with a descriptive quantitative method. The data was collected using a Vietnamese questionnaire adapted from Strategy Inventory for Language Learning (SILL) originally developed by Oxford (1990). The Statistical Package for Social Sciences (SPSS) version 22.0 software was used to analyze the data obtained from the questionnaire. The findings revealed that non-English majors used language learning strategies at a medium level of frequency. They didn’t equally use all 6 strategies in their learning, which probably impeded their progress of language learning. The most frequently used strategies by the learners were metacognitive strategies, followed by memory, affective, cognitive compensation and social strategies as the least preferred ones. Pedagogical recommendations for lecturers are also discussed in the paper

Groundwater Quality Assessment Using Groundwater Quality Index and Multivariate Statistical Methods and Human Health Risk Assessment in a Coastal Region of the Vietnamese Mekong Delta

This study aimed to evaluate the suitability of groundwater for drinking purposes and assess the associated human health risks for different age groups in a coastal province of Mekong Delta, Vietnam. Twenty groundwater samples were collected in Soc Trang Province, and various water quality parameters were analyzed. The data were employed to calculate entropy-weighted groundwater quality index (EWQI), principal component analysis (PCA), cluster analysis (CA), and non-carcinogenic and carcinogenic risks for adult and children health. The results revealed that groundwater in some locations, especially in GW19, was polluted by hardness, total dissolved solids, NH4+, Cl-, Fe, total coliform, and E. coli. In addition, 5 principal components from the PCA results could explain 84.5% of the total variation of groundwater quality, which also suggested that the potential groundwater pollution sources were geochemical processes, agricultural activities, domestic and industrial wastewater, seawater intrusion, and excessive nitrogen fertilizer application. The CA results showed that monitoring locations can be divided into 4 clusters based on their similarities in groundwater quality, and the most polluted group was found at cluster IV (GW19). The computed EWQI values ranged from 20.05 to 738.52, with approximately 45% of total samples classifying good to excellent water quality. The sampling points with undrinkable quality are mainly located in the northeast and center of the province. The ratio of children and adults under the threat of adverse health effects due to drinking groundwater contained non-carcinogenic substances (NH4+, NO2-, NO3-, Cd, Cu, F-, Mn, and As) ranged from 5 to 40%, and children had higher risks compared to adults. Additionally, the consumption of As-contaminated groundwater also poses carcinogenic risks for children, female and male adults ranging from 4.80×10-6 to 1.33×10-4. The findings of this study can provide helpful information for policymakers in the development of long-term water management strategies to protect community health

Seed Health and Quality of Rice Seeds Produced by Farmer and Growing in Cho Moi District, An Giang Province, Vietnam

This study was conducted at Laboratory in An Giang University; the varieties examined were collected from farmer households in 2018 – they were varieties that the farmer stored for the next crop (Winter-Spring) from Autumn-Winter crop in Cho Moi district, An Giang Province, Vietnam. The research evaluated the quality of seed rice, which is provided and planted by the farmer. As a result, this study showed that almost all of the varieties of seed rice from farmer households indicated the ratio of filled-grain, the germination, and the determination of seedling healthy, which are lower than certified variation. Besides, the samples of seed rice from farmer household have more infected fungal; especially the samples with higher in a filled-grain ratio is less infected by fungi, there were 12 types of seed borne-fungi in rice varieties from the farmer (in Cho Moi district), included: Alternaria padwickii, Rhizoctonia solani, Aspergillus oryzae, Bipolaris oryzae, Cercospora janseana, Curvularia lunata, Fusarium moniliforme, Pyricularia oryzae, Sarocladium oryzae, Tilletia barclayana, Fusarium graminearum, and Ustilaginoidea viren