VNUHCM Journal of Earth Science and Environment

Applying multi-criteria analysis tools (AHP, SAW) combined with GIS to analyze the reasonableness of mineral resource exploitation in Phu My town, Ba Ria – Vung Tau province

Cuong Tan Le — 2024-12-31

Mineral resources play a crucial role in infrastructure development and serving socio-economic development but also lead to consequences of non-renewable resource depletion and negative impacts on the environment and society. Therefore, some studies establish appropriate indexes to analyze and evaluate the reasonableness of exploiting mineral resources. This study approaches the multi-criteria analysis method (MCDM) and geographic information system (GIS) to analyze and evaluate the reasonableness of exploiting mineral resources. The reasonableness index is established based on 03 component indexes related to mining conditions, economic and social, and environmental protection, estimated based on 03 sets of criteria and corresponding weights. The study investigated, interviewed 114 relevant subjects, and evaluated 25 mine sites planned to exploit mineral resources in Phu My town, Ba Ria - Vung Tau province. Research results have shown that the reasonableness of each mine site is classified as Very high, high, medium, and low, accounting for 28%, 36%, 24%, and 12%, respectively. Based on the analysis and direct consultation with managers, 03 solutions to improve the reasonableness of exploiting natural resources were proposed. In addition, the research results also support managers and policies in making decisions related to ensuring harmony and reasonableness between exploitation and use of resources with environmental protection.

Building a map of urban ecosystem services in Thu Duc City

Anh Hoang Nguyen — 2024-12-31

The process of urbanization brings numerous positive impacts on economic and social development; however, it also exerts significant effects on the natural environment. Specifically, urbanization has contributed to the disruption of many natural ecosystems, which play a vital role in filtering pollution and safeguarding the living environment. Thu Duc City serves as a case study, where rapid urbanization has led to substantial changes in its natural ecosystems. Many ecosystems have been degraded or lost, reducing their capacity to provide valuable ecosystem services such as carbon sequestration, climate regulation, and pollution mitigation. This study aims to evaluate the condition of natural ecosystems in Thu Duc City and analyze the ecosystem services they provide. The research involves the creating of an ecosystem service map system over the period from 1988 to 2023, employing the Analytic Hierarchy Process (AHP) method in combination with GIS and remote sensing technologies. The study’s findings reveal that the conversion of land use types from agricultural land to urban areas has significantly diminished the capacity of ecosystems to provide essential services. These results provide a critical foundation for urban planning and environmental conservation efforts in the region.

Measuring circularity performance based on the material circularity indicator for a circular economy in the seafood processing plant

Tran Trung Kien — 2024-12-31

In this study, a circular economy model for seafood processing factories was proposed. The proposed solutions are based on previous studies on waste conversion techniques combined with the actual emission status of the factory. Besides, the Material Circularity Indicator (MCI) has been established and applied to the proposed circular economy system to evaluate the efficiency of waste conversion techniques. The MCI index will be used to calculate efficiency and circularity for all discarded waste to evaluate the environmental and economic effectiveness of the circular economy system. Results show that the level of recovery is higher than the level of recycling, but the difference is not too great, which shows that these are potential products, easy to recover without much loss, especially in recycling. Notably, only the water that is imported to be used to wash materials is 80% recycled. So the Fr of water has a value of 0.8. The remaining 7 waste products are 100% raw materials, with no recycled ingredients, so the Fr of these 7 products has a value of 0. The low percentage of input materials from recycled sources is because of the products. This is a waste product. A more concrete finding is that the circular economy model changes many of the fundamentals in the system compared to the current linear economic system. Therefore, some negative impacts will occur if businesses choose to switch to a circular economy system.

Assessment and zoning of economic damage risk due to the inundation in Thu Duc City on the period 2021-2022

Diep Ngoc Nguyen — 2024-12-31

Thu Duc City directly under Ho Chi Minh City was established in 2020 on the basis of merging 3 districts (Thu Duc District, District 2 and District 9). Since its establishment, Thu Duc City has faced widespread urban flooding caused by both rain and tides. The impacts of urban flooding cause many adverse influences on people living and trading in the Thu Duc City. Inheriting the study on economic damage due to inundation in Ho Chi Minh City in the period 2016-2019, the project inherits the survey forms to conduct surveys and the flood’s and damage’s formulas to assess economic losses of people living there. The surveys of the inundation and the economic damages caused by floods are implemented in all wards of Thu Duc City in the period 2021-2022. The results of the study show that the distribution of inundation, economic damage level as well as the flood-damage risk level due to the inundation are concentrated in densely populated areas and riverside areas. It also shows that the level of economic damage in the period 2021-2022 is much reduced compared to the period 2016-2019 by about 25-30% and at the low level. The main reasonable of explanation about the reduction of risk level in the period 2021-2022 is the decrease of City’s economic due to the serious disease Covide 19. The citizen’s incomes reduced. Their works are delayed and the movement limitted. So that, the indirect economic damages also significantly being lower than the previous. Through establishing a flood and damage survey form, the study hopes to update more information and contribute a "way" to assess damage caused by floods directly to the urban management agencies of Thu Duc City.

Assessing the effect of operating factors on phosphate removal by electrocoagulation process using Response Surface Methodology

Huynh Thi Ngoc Han — 2024-12-31

This study investigated the electrocoagulation batch model with two aluminum plate electrodes. The effect of operating factors on phosphate removal efficiency by electrocoagulation process using aluminum electrodes was evaluated by Response Surface Methodology (RSM), including current density, pH, initial phosphate concentration, and reaction time. A total of 15 experiments were set up following the Box-Behnken method in Design – Expert 12 software, with three center points. The optimal operating conditions were determined by analyzed collected data in Design – Expert 12 software: current density of 16.7 A/m2, pH 5.6, reaction time of 33.5 min, and initial phosphate (P-PO43-) of 66.249 mg/L. The correlation equation between treatment efficiency and factors was also determined as a quadratic model with R2 = 0.9771. The interaction between the pairs of factors significantly affected P-PO43- treatment efficiency, represented by 3D surface plots. The maximum P-PO43- treatment performance was reached 99.6%. The treatment efficiency of real livestock wastewater was determined and reached a high agreement with the predicted value, 99.7% after 30 min. Generated sludge was evaluated, approximately 6.3±0.76 kg per 1 m3 treated wastewater.

Application of GIS and SWMM model to assess urban flooding in Hung Phu 1 Residential Area of Cai Rang District

Nguyen Thanh Ngan — 2024-12-31

Abstract: Cai Rang District, established in 2004 under Government's Decree No. 05/2004/ND-CP, is a fast-growing urban district in Can Tho City. In recent years, the construction land areas in this district have expanded at a rapid rate, showing that the urbanization level in this region is quite strong. Besides urbanization, Cai Rang District also faces three important environmental problems: climate change, land subsidence, sea level rise. The combination of these problems makes urban flooding in this inner-city district quite serious. One of the areas often affected by urban flooding in Cai Rang District is Hung Phu 1 Residential Area. This paper introduces the preliminary results of the application of GIS and SWMM model to assess urban flooding in Hung Phu 1 Residential Area. The research has shown the main features of urban flooding in the study area, including the degree of flooding, time of flooding, flood volume, flow velocity and locations that are often flooded. The obtained data is an important basis for developing suitable flood reduction solutions and improving the quality of life of the residents in Hung Phu 1 Residential Area.
Keywords: urban flooding, GIS, SWMM model, Cai Rang District, Hung Phu 1 Residential Area.

Application of Remote Sensing & GIS to estimate the changes of surface temperature in Ninh Thuan

Tuy Van — 2024-12-31

Advanced remote sensing technology enables the detailed analysis of surface temperature variations across large areas, overcoming the limitations posed by the number of meteorological stations. This research focuses on applying remote sensing techniques and GIS to create surface temperature maps for Ninh Thuan province during the 2018–2021 period. By employing satellite imagery of Landsat and Sentinel, the study assessed changes in surface temperatures and their relationship with vegetation cover. The findings revealed that surface temperatures in the region ranged from 15.0°C to 44.0°C. Urban areas, residential zones with limited greenery, and vacant lands exhibited higher temperatures, typically between 27.1°C and 35.0°C. In contrast, mountainous areas with dense vegetation showed significantly lower temperatures. The study utilized a method to convert digital values from satellite images into spectral radiance values, which were then processed using computational algorithms to calculate surface temperatures. The NDVI vegetation index was employed to evaluate vegetation density and its correlation with temperature. Over the study period, vegetation cover decreased by 3.5%, while vacant land increased by 1.7%, and residential areas expanded by 0.35%. These shifts in land use contributed to increased thermal radiation and higher surface temperatures. Maps of land cover and surface temperature demonstrated a notable rise in areas with temperatures exceeding 37°C, especially in coastal and lowland regions where urban development and limited vegetation were significant factors. The research validates the feasibility and efficiency of using remote sensing data to monitor surface temperature changes across extensive areas. The results not only offer insights into temperature trends in Ninh Thuan but also provide a critical scientific basis for proposing strategies to mitigate the effects of rising surface temperatures. Such strategies are essential for achieving sustainable development in the face of escalating climate change challenges.

Applying the Mann-Kendall method to test the change trend of rainfall and temperature in Bac Lieu province 1980-2022

Pham Thi Minh — 2024-12-31

In this study, the Mann-Kendall method and linear regression analysis were used to assess trends in rainfall and temperature changes in Bac Lieu province, based on daily data from the Bac Lieu meteorological station and four additional rainfall stations (Bac Lieu, Phuoc Long, Ganh Hao, and Dong Hai). The results indicated a statistically significant increasing trend in temperature, including daily average, maximum, and minimum temperatures, at the 95% confidence level. Specifically, the average daily temperature rose by approximately 0.03°C per year, the maximum temperature increased by 0.02°C per year, and the minimum temperature increased by 0.0306°C per year. This trend resulted in a narrowing gap between maximum and minimum temperatures, leading to longer periods of warmer nights. Rainfall also showed an increasing trend at all four stations. At Bac Lieu, Phuoc Long, and Dong Hai stations, rainfall increased by about 7.5 mm/year, 11.5 mm/year, and 12.8 mm/year, respectively, with statistical significance at the 95% confidence level. However, the rainfall trend at Ganh Hao station was not statistically significant. Additionally, the linear regression analysis indicated a greater rate of increase in rainfall compared to the Sen trend analysis.

The trend of salinity changes at coastal stations in The Mekong Delta during the period 1996-2018

Nguyễn Thị Huyền Trân — 2024-12-31

The Mekong Delta (MKD) is increasingly suffering from the adverse effects of saline intrusion, primarily due to climate change-sea level rise (SLR), upstream hydropower development, and mangrove forest degradation. This study focuses on using statistical methods to assess salinity changes, by determining the frequency of salinity through ANOVA variance analysis and frequency analysis based on data series from 1996 to 2018 at monitoring stations. The results show that the increasing trend of salinity (at Binh Dai, Ben Trai, Loc Thuan, Huong My, Son Doc, An Thuan, Hung My, Tra Vinh, Cau Quan, Long Phu, Dai Ngai, Phuoc Long, Ganh Hao, CaMau) accounts for 70%, while the decreasing trend of salinity (at Hoa Binh, Vam Kenh, Tra Kha, Tran De, Soc Trang, Song Doc) accounts for 30%. Regarding to frequency analysis, at a frequency of 90%, the stations (Phuoc Long, Ganh Hao, Ca Mau, Song Doc) exceed 33‰, and at a frequency of 95%, the stations (Tran De, Phuoc Long, Ganh Hao, Ca Mau, Song Doc) exceed 33‰. The study's results, which determine the trend of salinity changes, provide a database for further in-depth research as well as support for disaster management efforts concerning local saline intrusion.

A study on the application of phytoremediation ecological technology of heavy metals in water using E. fluctuans: A medicinal plant adapting to climate change

An The Huynh — 2024-12-31

Phytoremediation can be used as a different approach to absorb heavy metals because of environmentally friendly and potential cost-effective. E. fluctuans is one species of herbaceous, semi-aquatic, widely distributed in Vietnam, South and Southeast Asia, and tropical Africa. Its leaves, used as edible vegetables, are also used in traditional medicine to treat a number of ailments. This paper aims to test the effectiveness of E. fluctuans in removing heavy metals from the aquatic environment. The experiments were performed using healthy, young, and acclimatized E. fluctuans. Water containing 0.5 mg/L cadmium, 0.5 mg/L arsenic, 2 mg/L lead, 5 mg/L zinc, and 5 mg/L copper concentrations were experimented with 100 g of E. fluctuans in 30-liter foam containers. The experiments were repeated three times. Throughout the course of the trial, water samples were tracked and their heavy metal concentrations were examined every 10, 20, and 30 days. Through the use of inductively coupled plasma-mass spectrometry, the heavy metals were identified. After 30 days, E. fluctuans could remove Cd at 83.4%, As at 60.8%, Pb at 60.4%, Zn at 40.5%, and Cu at 58.7%. Thus, the E. fluctuans show a high potential for effectively extracting heavy metals from industrial effluent.

The Evaluation of Chlorpyrifos Ethyl Degradation in Tea-Planting Soil in Bao Loc, Lam Dong using Biomix Biodegradation Model Supplemented with Penicillium chrysogenum N2

MINH BAO TRAN — 2024-12-31

This study investigates the capability of treating chlorpyrifos ethyl (CE) – a common pesticide – using a biomix composting model in tea-growing soil in Bảo Lộc, Lâm Đồng, Vietnam. Lâm Đồng, with the largest tea cultivation area in the country, spanning 23,000 hectares and producing 71,000 tons of tea annually, faces significant soil pollution due to excessive pesticide use, particularly CE. Chlorpyrifos ethyl is a potent neurotoxin with high persistence in soil and slow degradation. The biomix compost, consisting of tea soil, straw, peat, and lignin-degrading fungi, was prepared with initial parameters: 60% moisture, pH 6.95, 21.03% organic carbon, 1.29% total nitrogen, and a carbon-to-nitrogen ratio (C/N) of 16.30. Penicillium chrysogenum N₂, a lignin-degrading fungus with 173.2 U/kg activity, was added to the biomix at a 5% ratio to enhance CE degradation. Results showed that CE degradation efficiency ranged from 96% to 99% after 30 days, with CE concentrations from 10ppm to 150ppm, under optimal conditions of 60% moisture, 37°C temperature, and pH 6. The study also monitored the changes in the physicochemical properties of the biomix, indicating that temperature, moisture, and pH variations were conducive to microbial growth and CE degradation. These findings underscore the practical potential of microbial composting in treating pesticide pollution, contributing to environmental protection and sustainable agricultural development.

The study of composting sludge from supper-intensive shrimp farming ponds to make organic fertilizer for the cultivation of Lactuca Sativa

Quốc An Nguyễn — 2024-12-31

Aquaculture, especially shrimp farming, is bringing significant economic benefits to coastal residents in the Mekong Delta region in general and Ben Tre province in particular. Alongside the benefits, the shrimp farming industry is also discharging a massive amount of waste, including wastewater and sludge after each farming cycle, which is significantly impacting the environment. This study employed the aerobic composting method to decompose organic matter using a combination of shrimp pond sludge and coconut coir pith as the composting materials. The research results showed that after 65 days of composting, the total nitrogen content reached 7.51 g/kg; TOC content reached 10.9%; organic matter content was 18.8%; phosphorus content was 1030 mg/kg; available potassium reached 7.2 g/kg; with a pH of 8.19. The C/N ratio after composting was 19.7, which is very suitable for plant growth. Additionally, the obtained organic fertilizer was used to grow Lactuca Sativa to evaluate the fertilizer's effectiveness in improving soil nutrients. Monitoring the growth results of lettuce showed that the organic fertilizer positively influenced plant growth, but attention must be paid to the fertilization rate due to the high salinity in the fertilizer (EC = 12 mS/cm). With a simple process and low investment costs, the method of treating pond sludge through aerobic composting would bring environmental benefits and save fertilizer costs for the farming community.

Risk assessment of groundwater contamination and usage restrictions zoning in Tay Ninh province

Linh Khánh Lưu — 2024-12-31

The upper-middle Pleistocene (qp2-3) aquifer in Tay Ninh province is the primary source of supply for drinking and domestic purposes. In this study, the risk of contamination (RC) was calculated and zoned considering groundwater vulnerability assessment (GOD) and contamination danger index (POSH) in the GIS environment. At the same time, to zone the groundwater quality according to the purpose of use, the study applied the groundwater quality index (GWQI) from the analysis results of 60 water samples in the study area. The results show that the risk of contamination is divided into 3 zones: low, medium, and high, accounting for 63.9%, 26.9%, and 9.1% of the distribution area of the upper-middle Pleistocene aquifer, respectively. The study shows that agricultural areas have a high risk of contamination, while industrial areas have a medium risk of contamination. This result is considered an important tool to support managers in protecting, controlling pollution, limiting exploitation and use activities, and sustainably managing groundwater.