Environment and Natural Resources Journal

Spatial Distribution and Trends of Heat Stress in Vietnam

Nhung Vu, Thanh Ngo-Duc — Tue, 30 Jan 2024 00:00:00 +0700

This study investigated the spatial distribution and trend of heat stress in Vietnam using data from 68 meteorological stations between 1979 and 2018. Daily maximum wet-bulb temperature (TWmax), an indicator of heat stress, was computed based on the daily maximum air temperature (Tx) and relative humidity at 13:00 LST (RH13). The results indicate a strong positive correlation (>0.72) between daily TWmax and Tx and a weak relationship between daily TWmax and RH13. Tx and TWmax generally increased across most stations over the study period, while RH13 displayed both negative and positive trends. The heat stress thresholds for each station are defined using the 95^th percentile values of TWmax during the baseline period 1979-1998. We found that most parts of Vietnam experienced an increase in heat stress days, with the interquartile range across all stations spanning from 0.8 to 4.2 days per decade. Among seasons, summer contributed the most (typically 52-80%) to the annual number of heat stress days in most sub-regions, except for the Central Highlands and the South, where spring contributed the most (44% and 41%, respectively). Overall, this study provides useful benchmark values for future research on heat stress in Vietnam.

Fine Scale Modeling for Potential Distribution of Dengue Fever in Tampan District, Indonesia

Eggy Arya Giofandi, Dhanu Sekarjati, Cipta Estri Sekarrini, Yuska Nelva Sari — Mon, 05 Feb 2024 00:00:00 +0700

Larvisiding is one common way used to reduce mosquito density in breeding areas before metamorphosizing into adults. Despite numerous eradication efforts, the outcomes have not met expectations, leading to additional issues such as environmental pollution in urban areas. In the context of dengue hemorrhagic fever (DHF), addressing the challenge of mitigating the endemic outbreak entails formulating an effective strategy through a vector eradication approach. Therefore, this study explored the spatial pattern of DHF and estimated the potential spread of outbreaks. A geographic information system approach, with nearest neighbor analysis and kernel density estimation (KDE), was used to generate information regarding the pattern and potential for transmission of Aedes aegypti mosquitoes. The results showed that in 2019, a random pattern was observed, while in 2020, a clustered pattern of virus spread occurred. Furthermore, in terms of the potential transmission, an exposed zone of 9.73 km² was identified in 2019, and this increased to 15.72 km² in 2020. In this study, several important actions were implemented with a spatial approach, enabling the detection and polarization of events. However, the limitations included not being comprehensive in addressing the hygiene, sanitation, drainage, and population density aspects.

Faunal Diversity and the Ecological Aspects of a Community-Based Fragmented Lowland Rainforest Patch in Western Province, Sri Lanka

Buddhika Abeyrathne, Nilanga Ranatunga, Sahani Chandrasiri, Indrakheela Madola — Thu, 01 Feb 2024 00:00:00 +0700

Wawekale Rainforest Reserve (WRR) is a primary lowland tropical rainforest area in the Western Province of Sri Lanka, established with diversity, but disturbed by human activities such as rubber cultivation, logging, poaching, chemical release, and the collection of firewood. Visual Encounter Surveys (VES) were conducted for 100 hours in the year 2022, which covered wide habitat distribution. The herpetofaunal diversity was measured in the WRR which can indicate broader ecological shifts, environmental changes, or habitat degradation. Water quality was measured in the WRR area to determine the ecosystem health and human impact. The study reports 171 species in 73 families, including two Critically Endangered (1.17%), six Endangered (3.51%), 16 Vulnerable (9.36%), and 14 Near Threatened (8.19%) species according to the IUCN Red List. The study area showed 51 endemic faunal species in Sri Lanka, which represented 29.83% of endemism. Based on the observations conducted on the herpetofauna diversity, the Shannon-Wiener diversity index (H) was calculated and the overall herpetofauna (H’_H) showed high diversity within the forest premises. The water quality of the forest fragment had an influence from anthropogenic activities such as removing forest cover, bathing, washing vehicles, and releasing agro-chemical compounds resulting in high water temperature, basic pH level, high electrical conductivity, and high total dissolved solid conditions. The WRR, designated under protection, exhibits the need for immediate remedial actions to mitigate human-induced pollution and deforestation, emphasizing the critical importance of implementing proactive conservation measures to sustain ecological integrity and preserve biodiversity.

Composite Layered Double Hydroxide Zn-Al/Magnetic Biochar Modified for Highly Effective Malachite Green Adsorption

Tue, 20 Feb 2024 00:00:00 +0700

One of the main needs of humans is water, one source of water pollutantion is from dyes. Adsorption is the most popular method in removing pollutants as it is proven to be efficient. One of the dyes harmful to living things is malachite green. In this study, malachite green dye was removed using a layered double hydroxide (LDH) Zn-Al/magnetic biochar composite. The XRD, FTIR, BET, and VSM analyses show that the LDH Zn-Al, magnetic biochar, and LDH Zn-Al/magnetic biochar composite were successfully produced. The surface area of the Zn-Al/magnetic biochar composite made up of LDH increased from 9.621 m²/g to 99.473 m²/g. The point of zero charge of LDH Zn-Al and magnetic biochar were at pH 6, whereas the composite of these two materials was at pH 7. For LDH Zn-Al, magnetic biochar, and composite LDH Zn-Al/magnetic biochar, pH 8 is the ideal value for adsorption of malachite green. PSO (pseudo-second order) kinetics is the best-fit model. LDH Zn-Al, magnetic biochar, and LDH Zn-Al/magnetic biochar composite had adsorption capacities of 14.472, 15.552, and 25.907 mg/g, respectively, at a temperature of 60°C. Regeneration showed the LDH Zn-Al/magnetic biochar composite had superior and more effective ability compared to LDH Zn-Al and magnetic biochar.

Monitoring Land Surface Temperature Relationship to Land Use and Land Cover in Hai Duong Province, Vietnam

Bui B. Thien, Asya E. Ovsepyan, Vu T. Phuong — Tue, 13 Feb 2024 00:00:00 +0700

This study utilised remote sensing data and ArcGIS 10.8 software to evaluate changes in land use and land cover (LULC) and their effects on land surface temperature (LST) in Hai Duong Province, Vietnam, from 1992 to 2022. Landsat satellite data were pre-processed and classified using supervised methods for the years 1992, 2010, and 2022. In 1992, vegetation cover accounted for 57.89% of land cover, increasing to 84.49% in 2010, but then decreasing again to 66.67% in 2022. In contrast, the built-up area consistently increased, from 2.88% in 1992 to 29.35% in 2022, as most of the barren land present in 1992 became built-up area in 2022. The LST values were calculated from the thermal bands for the years 1992, 2010, and 2022 and ranged from 16.09°C to 34.27°C, 17.04°C to 36.74°C, and 11.03°C to 28.44°C, respectively. In addition, the Normalized Difference Vegetation Index (NDVI) values were calculated using the near-infrared band and the red band, with values ranging from -0.40 to 0.70 over the study period. A linear regression analysis indicated a shift in the correlation between NDVI and LST from positive to negative. This study highlights the significant transformation that occurred in Hai Duong Province due to rapid population density increases, urban growth and infrastructure development, leading to a decline in greenery. These LULC changes can cause severe environmental damage. These research findings will assist policymakers in formulating management strategies and sustainable land-use plans to minimize potential harm and promote sustainable development in the area.

Assessment of Landslide Susceptibility in the Intermontane Basin Area of Northern Thailand

Kritchayan Intarat, Patimakorn Yoomee, Areewan Hussadin, Wanjai Lamprom — Mon, 12 Feb 2024 00:00:00 +0700

In mountainous terrain, landslides are common, particularly in intermontane basin locations. Such regions can adversely affect both human beings and the environment. In the assessment of landslide susceptibility, machine learning (ML) algorithms are increasingly popular due to their compatibility with geospatial data and tools. Herein, this study evaluated the performance of four ML algorithms: namely, random forest (RF), gradient boost (GB), extreme gradient boost (XGB), and stacking ensemble (STK). These algorithms were implemented to create a practical model of landslide susceptibility. The site under investigation is in the province of Chiang Mai, an intermontane basin area in northern Thailand where populations are settled. To address issues of multicollinearity, the variance inflation factor (VIF) was used. Eight out of fourteen factors were selected for examination; hyperparameters of each model were tested to acquire the best combination. Results indicated that the STK model outperforms all other models, providing evaluation metrics (precision, recall, F1-score, and overall accuracy) of 82.92%, 81.18%, 82.04%, and 81.75%, respectively. The area under the receiver operating characteristic (ROC) curve also reveals the high efficiency of the model, achieving 0.8928. However, further analysis of the appropriate model or base learner is necessary for achieving even higher predictive results.

Interaction between Rhizobacteria and Andrographis paniculata Under Water Limitation

Wed, 14 Feb 2024 00:00:00 +0700

Drought stress is a major agricultural problem that leads to increased accumulation of ethylene in plants. It also has negative effects on plant productivity and growth. Andrographis paniculate is an important herb widely used in medical applications to inhibit diseases caused by viruses. In order to improve the production quality and growth of the A. paniculata, ACC-deaminase plant growth-promoting rhizobacteria were isolated from rice rhizosphere soil. All bacterial isolates were screened for their plant growth-promoting properties, including ACC deaminase, IAA production, biofilm formation, and exopolysaccharide production. Among the bacterial isolates, Rh-01 and Rh-22 exhibited positive results (cutting-edge) in all tests and were identified as Paenibacillus polymyxa Rh-01 and Stenotrophomonas maltophilia Rh-22, respectively. These strains were selected for further pot experiment study. Our results revealed that treatment with chemical fertilizer showed the highest potential to promote A. paniculata seedlings under normal moisture conditions. However, under water limitation conditions, the application of ACC-deaminase plant growth-promoting rhizobacteria led to a higher chlorophyll content compared to the control treatment. In addition, under normal irrigation conditions, plant growth promoting rhizobacterial increased relative water content and total biomass. In terms of plant stress markers, the proline content in Andrographis paniculate’s seedling stage was low under water limitation conditions. In conclusion, to enhance the growth of A. paniculate seedlings during water limitation stress, a combination of microbial biofertilizers and chemical fertilizers is beneficial.

Evaluation of Tolerance and Uptake of Cd and Mn for Microfungi Aspergillus flavus, Aspergillus oryzae, and Aspergillus terreus Isolated from Landfill Soil Collected from Bangar, La Union Philippines

Mon, 04 Mar 2024 00:00:00 +0700

Excessive deposition of heavy metals into the environment due to anthropogenic activities necessitates an eco-friendly clean-up strategy. Among microorganisms, limited studies have been made on the mycoremediation potential of microfungi. This paper evaluated three landfill microfungal isolates of Aspergillus species for tolerance and uptake to Cd and Mn. Culture media optimization was also performed for the evaluation of the tolerance index and heavy metal analysis of soil samples from the landfill site. Among the nine heavy metals analyzed, Mn and Fe were detected in relatively high amounts, while Cd, Ni, and Cu were detected in a moderate range. Luxuriant mycelial growth of A. oryzae (MK120548.1) and A. flavus (MH864264.1) was observed in potato dextrose agar while A. terreus (MH047280.1) grew best in potato sucrose agar. In terms of tolerance index, A. oryzae (MK120548.1) and A. flavus (MH864264.1) demonstrated high tolerance to Cd up to 10 mg/kg. A. oryzae (MK120548.1) showed high tolerance to Mn up to 1,000 mg/kg while A. flavus (MH864264.1) exhibited a very high 10,000 mg/kg tolerance. In terms of metal uptake, A. oryzae (MK120548.1) showed the highest metal uptake of up to 654 mg/kg of Cd, while A. terreus (MH047280.1) exhibited the highest metal uptake of 997 mg/kg ofMn. With these findings, A. oryzae (MK120548.1), A. flavus (MH864264.1), and A. terreus (MH047280.1) have considerable mycoremediation potential. Bioremediation studies in conjunction with plants can be explored to further assess the potential of these Aspergillus species.