VNUHCM Journal of Earth Science and Environment

Characteristics of mechanical composition and mineral composition of cultivation land the former Dang Xa – Le Chi area, Gia Lam, Hanoi city

2025-08-12T15:09:19+07:00

The land specialized for vegetable cultivation extending from the former Dang Xa through Le Chi Communes, Gia Lam, is part of the green vegetable belt supplying the inner city of Hanoi. This area is one of the sources of vegetables and fruits for the daily consumption needs of the city. In order to clarifying the characteristics of structure, mechanical composition, mineral composition of cultivation land of the former Dang Xa - Le Chi area, Gia Lam, Hanoi city, the authors have conducted field surveys, dug holes, study the soil profiles through the dug holes and collect soil samples. Combination of analytical methods in the lab such as grain size analysis, the XRD method, scanning electron microscopy (SEM) for fine grain bath, and stereomicroscopy method. The results of the studying soil profiles show that the cultivation land in Dang Xa-Le Chi area compose of mainly young alluvial soil, distributed on the sediments of the Thai Binh Formation. In general, the soil has mainly 2 layers structure: The upper layer: from the surface down to 35-45cm, has the composition of silt, finegrained sand, brown, loose, and organic matter; The lower layer is distributed mainly at a depth of 45-50 cm, the composition of silt-clay is yellow-brown, more solid, in many places containing thin layers with black and yellow-brown laterite spots. For mechanical composition of cultivation land in the study area is mainly loamy soil, heavy silt-clay soil and sandy clay. The mineral composition of coarse-grained bath is mainly quartz, iron hydroxides/oxides with small or little amount of feldspar, rutile, amphibol, micas... In fine-grained batch, quartz also accounts for the majority, followed by illite, kaolinite, montmorillonite, goethite, chlorite. Feldspar and other minerals such as gibsite, amphibol, hematite and calcite account for small amounts. In terms of characteristics of structure, mechanical composition, mineral composition of cultivation land in the study area is quite favorable for the cultivation of short-term, terrestrial crops, including vegetables. The research results will contribute the scientific basis for the sustainable management and development of safe vegetable cultivation areas in the areas.

Survey on the ability to collect honey bee venom (Apis Mellifera ligustica) and evaluate the economic potential for beekeeping

2025-11-18T14:17:05+07:00

Bee’s venom (Apitoxin) is a natural toxin containing more than 18 pharmacologically active compounds, including small peptides and enzymes, which play a major role in protecting bee colonies. In traditional Oriental medicine, bee venom has been used to treat inflammatory diseases and pain due to its anti-inflammatory, anti-abscess, anti-fibrotic and anti-arthritis effects. Currently, in addition to traditional beekeeping for honey, many countries in the world such as Australia, Poland, the US, China, etc. have collected bee venom for use in cosmetics and pharmaceuticals to help treat arthritis, dementia, HIV and in anti-cancer research. This study aims to investigate the ability to collect bee venom and its effects on the health of bee colonies (Apis Mellifera ligustica) and honey productivity, conducted at a location in the suburbs of Thu Duc City. The average amount of venom per bee per collection fluctuates from 3.7µg to 6.7µg per collection. The economic value for beekeepers is estimated at 100-200 thousand VND for a beehive with one venom collection. However, the venom collection process shows that the average mass of beehives in the venom collection boxes decreased by more than 15% compared to the initial data. From there, it can be seen that the impact of venom collection has a negative impact on the health of honey bee colonies. Further research is needed to find a reasonable frequency of venom collection to ensure the health of bee colonies, increasing the economic value of beekeeping.

Application quantile regression method to forecast heat waves in hanoi with 5-day and 10-day forecasts

2025-11-29T06:01:02+07:00

The paper presents the results of applying the quantile regression method to forecast heat waves in Hanoi. The study uses the maximum temperature (Tx) in the months of May, June, July, August and September in 20 years (1999-2018) observed at the Hanoi station and the 5-day and 10-day forecast data of the sub-seasonal to seasonal forecast model (S2S). The above data series is used to build the forecast equations on different quantiles (q10, q25, q50, q75 and q90) and the linear regression equation. The results of the equation testing show that the linear regression equation and the equations at quantiles 10, 25, 50, 75 and 90 are statistically significant. The study evaluates the quality of the equations based on the data series of heat waves in 3 years 2019-2021 with a total of 45 waves corresponding to 179 days (samples) based on the statistical indexes ME, MAE, RMSE and relative error. The results show that the 5-day and 10-day forecasts, the 75th and 90th percentile regression equations improve by over 20% compared to the error of the S2S model and improve the error by about 6% compared to the linear regression method. In addition, the Tx forecast error values of the 75th and 90th percentile models for 5-day and 10-day periods are both below 2.0^oC. Thus, the 75th and 90th percentile regression models can be applied to forecast Tx operations for the Hanoi area.

Ecological service of aquatic ecosystems: A potential case in Tan Hung district, Long An

2025-12-23T10:51:21+07:00

The study was carried out in Tan Hung district, Long An province, to measure the value of services offered by aquatic habitats, which are typical of wetland ecosystems in the Dong Thap Muoi region. The study utilized the market value survey approach, together with information gathered from management agencies, to calculate the value of all four types of services provided: regulating services, cultural services, and support services. According to the findings, ecological services in the surveyed areas were worth roughly 74 billion VND annually. Regulating services, including flood regulation, water purification, and sediment transport, generated around 48 billion VND each year. Cultural services, including entertainment and tourism, are projected to be worth approximately 19 billion VND each year. In addition, each of the remaining services, such as supply services (water and food resources) and support services (habitat, biodiversity), contributes around 3 billion VND annually. The results of the study emphasize the relevance of flood features in the Dong Thap Muoi region in sediment movement, water resource regulation, and the direct impact on agricultural, aquaculture, and fishing activities, which are the region's major economic activities. Furthermore, Lang Sen Wetland Reserve offers enormous potential for tourism development, creating value and contributing to the long-term growth of the local economy.

Treatment of malachite green in the wastewater of a shrimp farming activity using a H2O2/UV-LED system

2025-12-24T15:01:18+07:00

The free-radical- based advanced oxidation method is a method that can oxidize organic substances into simple molecules such as CO₂ and H₂O due to the formation of free radicals with strong oxidizing power. In this study, we investigated the decomposition of Malachile green (MG) compound in the wastewater of a shrimp farming activity by using H₂O₂/UV-LED system. The study showed that MG decomposition efficiency reached approximately 90% after 60 minutes of the UV irradiation in the presence of H₂O₂ with concentrations of 12 g.L^-1 and 24 g.L^-1. It led to the decomposition process of MG into benzophenone derivatives, and smaller and colorless molecules. Fluctuations in chemical and physical parameters related to wastewater quality during the decomposition process of MG compound were also investigated. The results showed that the oxidation of MG by H₂O₂ under UV irradiation reduced the concentration of total dissolved substances in the wastewater, while increasing its dissolved oxygen content by 2-4 times. The sutdy also showed that H₂O₂ promoted the decomposition of MG faster and more completely. The results revealed the role of advanced oxidation process in the valorization of MG by UV and H₂O₂.

The water quality, ecological and public health risk assessment of the wastewater collected at supper intensitive shrimp farming ponds in My Xuyen district, Soc Trang province

2025-12-25T06:44:48+07:00

Although shrimp farming industry brings high export value, it generates high amount of waste, including sludge and wastewater, due to periodic water exchanges, shrimp cultivation and shrimp pond preparation. In this study, we collected wastewater samples at three shrimp ponds in My Xuyen district, Soc Trang province to analyze and evaluate their water quality. Risk impact of chemical components in shrimp pond wastewater on the environment and the public in the ảea was assessed through calculating the WQI index, using semi-quantitative risk assessment methods and risk matrix methods. The results show that the WQI values of the wastewater samples are in the range of 10 and 100. The wastewater samples meet class B water standards according to the QCVN 40:2011/BTNMT, and as well as meeting the National technical regulation on brackish water shrimp culture farm according to the QCVN 02 - 19: 2014/BNNPTNT. The results showed that the water samples had a low WQI index for COD and BOD indicating that those ponds contain a lot of degradable organic matters. The existence of organic substances and harmful pathogens in shrimp pond wastewater is the cause of environmental and human health issues at moderate-to-high risk levels. There are three main factors that affected the wastewater quality, and they account for 58,6 %, 22,3 % và 9,7 %, respectively.