Environment and Natural Resources Journal

Enzymatic Processing of Grouper Bone Waste as Fish Protein Hydrolysate Potential Bioactive Peptides

Thu, 13 Nov 2025 00:00:00 +0700

Grouper fish is a type of reef fish that has high economic value and is widely used as fillets in the industry. It is estimated that 50% of the total fish catch is not used as food. Fish solid waste has been utilized as a source of protein and essential amino acids with high nutritional value over the last decade. Enzymatic hydrolysis is the most recommended method to produce fish protein hydrolysates. Enzymatic hydrolysis with various enzymes and hydrolysis time can determine the characteristics of the hydrolysate obtained. The results of hydrolysis of fish bone powder using variations of Papain, Bromelain, and alcalase enzymes, along with time variations of 30-300 minutes, showed the highest yield with papain enzymes at a hydrolysis time of 240 minutes. The degree of hydrolysis above 88% was achieved at an incubation time of 120 minutes with papain enzyme and alkalase and 3 hours with bromelain enzyme. The proximate content of protein hydrolysates from fish bones showed a moisture content of between 7% and 15%, an ash content below 0.5%, and a protein content of 0.46%. The results of protein hydrolysis molecular weight analysis using SDS-PAGE revealed that each enzyme yielded peptides at sizes of 5 and 3.4 kDa, which are expected to have potential as bioactive peptides.

Suitability and Evaluation of the Quality of Groundwater Used in Irrigation, Case of the Region of Oum El-Bouaghi (Northeast Algeria)

Wed, 08 Oct 2025 00:00:00 +0700

This study assesses the quality of groundwater for irrigation in the plains of Bir Chouhada, Souk Naamane, and Ouled Zouai, focusing on physico-chemical parameters including Electrical Conductivity (EC), Sodium Adsorption Ratio (SAR), sodium percentage (%Na), and chloride toxicity. Results show EC values ranging from 993 to 9,322 µS/cm, indicating poor to unsuitable water quality for irrigation in most wells. The SAR values vary between 8.86 and 43.6 meq/L, reflecting a high risk of soil sodification. The %Na ranges from 19.18% to 61.41%, with over 66% of samples exhibiting high mineralization. Using Richards classification, 58.78% of samples fall in the highly unsuitable C4S4 class, while Wilcox classification indicates 48.78% of dry season samples as unsuitable for irrigation. Seasonal variation shows slight quality improvement during the wet season, with good-quality water increasing from 4.87% (dry) to 7.31% (wet). Hydrochemical facies analysis identifies 46.34% of samples as calcic chloride type, linked to mineralization from gypsiferous formations. Spatial autocorrelation using Moran’s I reveals moderate positive clustering of SAR (0.21-0.27) and %Na (0.15-0.23), with stable patterns across seasons. Statistical analysis via ANOVA confirms the significance of the model with F=29.48 (p<0.000005) and explains 43% of variation in water quality parameters. These findings highlight the critical challenges of irrigation water quality in the region and underscore the need for integrated management strategies including the use of salt-tolerant crops and soil drainage improvements.

Vegetation Condition and Potential Seed Rain in a Fire-Affected Tropical Forest Ecosystem Dominated by the Endangered Eucalyptus urophylla in Mutis Forest, East Nusa Tenggara-Indonesia

Demak E.R. Damanik, Devi N. Choesin, Endah Sulistyawati — Tue, 21 Oct 2025 00:00:00 +0700

Global deforestation and climate change-induced forest fires disrupt tropical forest functions. On the other hand, fires can be ecologically beneficial by increasing seed rain diversity and regeneration. In the Mutis forest, Indonesia, recurrent fires and deforestation threaten the endangered native species Eucalyptus urophylla. This study compared vegetation and seed rain between burned and unburned areas of the Mutis forest. Vegetation data were collected from 50 plots (10×10 m), in each area by measuring trees with a diameter at breast height (DBH; 1.3 m above ground level) ≥3 cm. Seed rain was collected for seven months using 50 seed traps (Ø 50 cm) in each area. The results showed that Eucalyptus urophylla has a significant ecological role in the both sites, as shown by its highest Importance Value Index (IVI) in both burned (177.05%) and unburned sites (115.70%). Four seed species were found in both sites, i.e., E. urophylla, Olea paniculata, Pittosporum timorense, and Rapanea hasseltii. The most abundant seeds were E. urophylla, 435 seeds at the burned site and 314 seed at the unburned site, indicating their origin from local vegetation. Seed species diversity was low in both burned (Shannon H'=0.21) and unburned (H'=0.39) areas. Therefore, conservation are necessary to maintain the sustainability of this forest. Recommended actions included seed collection in April to May, cultivation of E. urophylla for post-fire restoration, and implementing fire management strategies in the Mutis forest area.

Scenario-Based Land Cover and Land Use Change Modeling in Mae Chang Watershed, Lampang Province, Thailand

Fri, 17 Oct 2025 00:00:00 +0700

The Mae Chang watershed is part of the headwaters of the Wang River, located in Lampang Province in Northern Thailand. Resource pressures at forest-agriculture-extractive frontiers make this landscape crucial for studying land-habitat conversion and guiding sustainable land-use planning. Thus, this study interpreted LULC (1989, 2005, 2013, 2021) and projected LULC for 2029 and 2037 under BAU, conservation (CON), and development (DEV) scenarios using TerrSet’s LCM-MLP with local drivers, isolating intervention effects by contrasting CON/DEV (with constraint and incentive (CI) layers) against BAU (no CI). From 1989 to 2021, deciduous forest declined 23.3% (-249.01 km²), from 1,070.41 to 821.40 km² (65.40→50.18% of the watershed; -15.2 percentage points), while field crops increased by 104.7%, perennial crops by 97.3%, mines/pits by 240.8%, and urban areas by 28.8% based on human activity. Sub-model accuracies ranged 53-92%, and validation achieved Kstandard 0.824, Kno 0.861, Klocation 0.893, exceeding the success threshold. The three future scenarios yielded similar projected areas in both 2029 and 2037 but there were location differences. The deciduous forest area in 2029 and 2037 declined by 22.3% and 31.5%, respectively for all scenarios compared with 2021. The CON scenario outperformed BAU/DEV because strict no-conversion constraints in protected forests and restricted area effectively prevent ongoing deforestation, offering a practical simulation-based tool to support and implement land-use policies at local and regional scales. These findings provide a validated, transferable framework that isolates policy effects and supports evidence-based land-use planning in tropical headwatersheds.

Assessment of Wood Properties of Hevea brasiliensis Clones Grown in Zamboanga Sibugay Philippines for their Potential Applications

Oliver S. Marasigan, Marina A. Alipon — Mon, 20 Oct 2025 00:00:00 +0700

The potential utilization of 25 year old rubber tree (Hevea brasiliensis [Wild. ex A.Juss.] Müll. Arg.) clones (PB 260 and RRIM 600) were assessed based on their anatomical, physical, and mechanical properties. Anatomical features were evaluated using IAWA standards, while physical and mechanical properties were determined following ASTM D143-2019. Five trees per clone were collected from Naga, Zamboanga Sibugay. Results showed that PB 260 exhibited fiber dimensions significantly greater than RRIM 600, with 6.42% longer fibers, 9.42% larger fiber diameters, and 22.47% wider lumens. However, PB 260 had thinner cell walls by 13.33%. Vessel dimensions of PB 260 were also significantly higher, with 14.05% longer and 11.83% wider vessels. For physical properties, RRIM 600 showed higher basic relative density (0.53), tangential shrinkage (4.91%), and volumetric shrinkage (7.58%) compared to PB 260 (0.48, 4.52, and 7.21%, respectively). However, PB 260 had higher green moisture content (126.14%) than RRIM 600 (102.15%). Mechanical testing revealed RRIM 600 had higher strength, attributed to its higher basic relative density and thicker cell wall thickness. RRIM 600 is recommended for construction, flooring, and cabinetry, while PB 260 is suitable for medium grade furniture, carving, and pallets. The study highlights the potential of H. brasiliensis clones as alternative raw materials for the Philippine wood industry.

Innovation Compact System Usage for Household Water Treatment: A Case Study on Water Quality in Coastal Central Java

Fri, 14 Nov 2025 00:00:00 +0700

In many coastal regions of Central Java, Indonesia, access to safe drinking water remains limited owing to often contaminated groundwater sources. This study evaluated the performance of a compact household water treatment system integrating aeration, filtration, adsorption, and ultraviolet (UV) disinfection. Water samples from 15 wells across Kendal, Semarang, and Demak were tested for 13 parameters, including turbidity, total dissolved solids (TDS), color, ammonia, iron, manganese, dissolved oxygen (DO), and total coliforms, analyzed by ISO/IEC 17025-accredited laboratories. The treatment significantly improved water quality, reducing turbidity from 14.00 to 4.96 NTU (65%), TDS from 738.6 to 336.35 mg/L (54%), color from 21.93 to 9.15 TCU (58%), and ammonia from 1.82 to 1.02 mg/L (44%); meanwhile, DO increased from 5.48 to 8.24 mg/L (33%). The Drinking Water Quality Index scores of samples from 80% of the sites improved from “very poor” (>200) to “good” (<100), indicating untreated water transformation from non-potable to potable. However, microbiological safety remained a limitation, with total coliforms reduced by 52% (from 230 to 110 CFU/100 mL) but failing to meet the 0 CFU/100 mL standard. Therefore, additional heat treatment or UV contact time extension from 3 to 6 h is recommended to achieve full microbial compliance. This study demonstrates the effectiveness of the treatment system in significantly improving physical and chemical quality, while highlighting the need to optimize its microbial disinfection capacity. Its affordability and simplicity make it a promising decentralized solution for underserved communities.

Forecasting Dengue Fever Incidence in Thailand Using ARIMA: Implications for Public Health Planning

Punpaphatporn bunprom, Issara Siramaneerat, Pimnapat Bhumkittipich — Thu, 30 Oct 2025 00:00:00 +0700

Dengue fever remains a significant public health concern in Thailand, characterized by recurrent outbreaks and considerable morbidity. Understanding and forecasting temporal patterns of dengue incidence are essential for effective prevention and control strategies. This study analyzed monthly dengue fever incidence in Thailand from 2013 to 2024 and forecasted trends for 2025-2026 using the Autoregressive Integrated Moving Average (ARIMA) model. Data were obtained from the Bureau of Epidemiology, Department of Disease Control, and Ministry of Public Health. The optimal ARIMA (1,0,1) model was selected based on diagnostic criteria including the Autocorrelation Function (ACF), Partial Autocorrelation Function (PACF), and the Ljung-Box test. Model performance was evaluated using the Mean Absolute Percentage Error (MAPE), yielding 43.40%, and indicating moderately accurate predictions for planning purposes. The model successfully captured seasonal trends, with dengue incidence typically peaking mid-year. Forecasts for 2025-2026 indicate periodic fluctuations, with December 2026 projected to have the highest incidence (7,336 cases) and January 2025 the lowest (2,401 cases). While the ARIMA model demonstrated utility in forecasting general trends, its limitations include the inability to incorporate external variables such as climate, vector control programs, vector control efforts, or viral serotype shifts. Despite this, the findings provide actionable insights for public health planning and resource allocation aimed at mitigating future dengue outbreaks in Thailand.

Spatiotemporal Trends in Temperature and Rainfall in Northwestern Vietnam (2009-2024)

Xuan Duc Do — Mon, 17 Nov 2025 00:00:00 +0700

The present study sought to optimize the data from eleven Regional Hydro- Meteorological Station in the Northwestern Vietnam. The study results indicated that that the average temperature has tended to increase, which is lower than the average global surface temperature. Still, the maximum temperature, and lowest temperature are higher than the global average (values 0.6, 0.3, and 3.0°C, respectively). The rainy season (23.7°C) generally exhibits warmer temperatures than the dry season (16.9°C). There is a positive correlation between temperatures in consecutive months during both the dry and rainy seasons (r values): 0.75 (September, October), 0.53 (October, December), 0.51 (May, June) 0.46 (August, October), 0.45 (November, December), and 0.38 (April, May), respectively. There is negative correlation between the temperatures of months that are in the same season but far apart, R-values -0.61 (February, December), -0.58 (February, November), -0.56 (April, September), -0.31 (April, October), respectively. The total rainfall and total minimum rainfall showed decreasing trend were 127 mm, and 2.8 mm, respectively. By contrast, total rainfall max tends to increase by 230 mm. The highest rainfall was concentrated from May to October (1,219 mm). Higher correlation values for rainfall were observed in winter (January to March, and October to December), at 0.65, 0.78, 0.85, 0.93, 0.94, and 0.99 compared to summer (April to September), with r values of 0.29, 0.36, 0.57, 0.42, and 0.45, respectively. In a year, positive correlations between temperature and rainfall predominate most months of spring (January, February, and March), autumn (July, August, and September), and winter (October, November, and December), R-values: 0.59, 0.36, 0.44, 0.53, respectively, while negative correlations are more common in April, May, and June (summer) with the r values of -0.33, -0.16, and -0.25, respectively. The present study may provide a valuable and future climate, and rainfall projections.

Decolorization of Treated Municipal Wastewater for Non-Potable Reuse Using a Household UV/H2O2 Process

Chanoknan Phumphuang, Kwannate Manoonpong, Pijit Jiemvarangkul — Wed, 29 Oct 2025 00:00:00 +0700

Color remaining in treated municipal wastewater can limit its acceptance for non-potable reuse. This study evaluated a simple UV/H₂O₂ step for decolorization of secondary effluent from three Bangkok Metropolitan Administration (BMA) wastewater treatment plants. Experiments were performed in a 0.75 L batch reactor equipped with a single low-pressure UV lamp (254 nm, 16 W); H₂O₂ doses of 33, 100, 167, and 333 mg/L were tested at ambient 25-30°C and unadjusted pH. Reaction times were 0-10 minutes with sampling at 0, 3, 5, and 10 min. Color (ADMI) decreased rapidly in the first minutes: >65% removal at 5 min for 100 mg/L H₂O₂, and a maximum of 76% at 10 min for 333 mg/L H₂O₂. Linearized kinetic fits showed that a pseudo-second-order model (R²≈0.953-0.966) described the data better than pseudo-first-order (R²≈0.909-0.921), indicating apparent bimolecular behavior under the tested conditions. A screening-level reagent cost based on commercial 50% w/w H₂O₂ pricing was 5.8 THB/m³ at 100 mg/L (≈0.179 USD/m³ using 32.4 THB: USD). These results demonstrate that a household-scale UV/H₂O₂ configuration can provide fast decolorization of municipal secondary effluent under short contact times, with a simple kinetic descriptor and an initial cost benchmark relevant to building-level non-potable reuse.

Population Density Estimation of Hornbills in the Eastern Part of Huai Kha Khaeng Wildlife Sanctuary, Thailand

Wed, 12 Nov 2025 00:00:00 +0700

Hornbills belong to the Bucerotidae Family, and almost all species within this family are vulnerable to extinction. This study examined the population density of four hornbill species in the eastern part of the rainforest of the Huai Kha Khaeng Wildlife Sanctuary. The species studied were the Great Hornbill (Buceros bicornis Linnaeus 1758), Rufous-necked Hornbill (Aceros nipalensis Hodgson 1829), Wreathed Hornbill (Rhyticeros undulates Shaw 1811), and Tickell’s Brown Hornbill (Anorrhinus tickelli Blyth 1855). Moreover, the study investigated factors influencing hornbill density using distance sampling with point transect methods, as well as the unmarked package in R. The survey was conducted along four 9-km survey lines, covering a total of 36 km, using 45 survey points with 200-m spacing between points. In total, 180 points were surveyed, with each point observed for 10 min. The study was replicated twice, covering an area of approximately 600 km², with surveys conducted from November 2023 to January 2024, and again from March 2024 to October 2024. The results showed the following hornbill population densities (individuals/km²): Great Hornbill 10.16±0.07 (n=108), Rufous-necked Hornbill 5.95±0.07 (n=74), Tickell’s Brown Hornbill 4.42±0.03 (n=61), and Wreathed Hornbill 1.52±0.01 (n=22). Factors that significantly influenced hornbill density included elevation, slope, average precipitation, average temperature, and montane forest. These findings contribute to the understanding of hornbill ecology and population dynamics. The results can guide management strategies and promote public awareness of habitat conservation.