Search Results (133)

The windowpane oyster (Placuna placenta) is common in coastal areas of the Philippines, thriving in brackish waters. Its shells underpin the local craft industries. While its meat is edible, only small amounts are consumed locally, most going to waste. Utilization of this potential nutrient source is hindered by the lack of information concerning its organic and mineral content, the possible presence of heavy metal ions, and the risk of microbial pathogens. We report extensive analysis of the meat from Placuna placenta, harvested during three different seasons to account for potential variations. This comprises proximate analysis, mineral, antioxidant, and microbial analyses. While considerable seasonal variation was observed, the windowpane oyster was found to be a rich source of protein, fats, minerals, and carbohydrates, comparing well with the meats of other shellfish and land animals. Following pre-cooking (~90 °C, 25–30 min), the standard local method for food preparation, no viable E. coli or Salmonella sp. were detected. Mineral content was broadly similar to that reported in fish, although iron, zinc, and copper were more highly represented, nevertheless, heavy metals were below internationally acceptable levels, with the exception of one of three samples, which was slightly above the only current standard, FSANZ. Whether the arsenic was in the safer organic form, which is commonly the case for shellfish, or the more toxic inorganic form remains to be established. This and the variation of arsenic over time will need to be considered when developing food products. Overall, the meat of the windowpane oyster is a valuable food resource and its current (albeit low-level) use should lower any barriers to its acceptance, making it suitable for commercialization. The present data support its development for high-value food products in urban markets. Full article

The Angat Reservoir serves as a major water source for Metro Manila, providing most of the region’s domestic, agricultural, and hydropower needs. However, its dependence on rainfall makes it sensitive to climate variability and future climate change. This study assesses potential long-term impacts of climate change on water availability in the Angat watershed using the Hydrologic Engineering Center–Hydrologic Modeling System (HEC-HMS). Historical rainfall data from 1994 to 2023 and projections under both RCP4.5 (moderate emissions) and RCP8.5 (high emissions) scenarios were analyzed to simulate future hydrologic responses. Results indicate projected reductions in wet-season rainfall and corresponding outflows, with declines of up to 18% under the high-emission scenario. Increased variability during dry-season flows suggests heightened risks of water scarcity. While these projections highlight possible changes in the watershed’s hydrologic regime, the study acknowledges limitations, including assumptions in rainfall downscaling and the absence of direct streamflow observations for model calibration. Overall, the findings underscore the need for further investigation and planning to manage potential climate-related impacts on water resources in Metro Manila. Full article

Groundwater remains a critical water source for urban communities, particularly in rapidly urbanizing countries such as the Philippines. However, intensifying anthropogenic pressures have contributed to widespread contamination from heavy metals, nutrients, pathogens, volatile organic compounds (VOCs), and emerging pollutants, including pharmaceuticals and personal care products (PPCPs). This review synthesizes findings from 130 peer-reviewed studies on groundwater monitoring and remediation, emphasizing technological advancements and their application in urban environments. The literature is categorized into five thematic areas: monitoring technologies, contaminant profiles, remediation strategies, Philippine-specific case studies, and alignment with global frameworks. Recent innovations—such as Internet of Things (IoT)-enabled systems, remote sensing, biosensors, and artificial intelligence/machine-learning (AI/ML) models—show strong potential for real-time and predictive monitoring. Despite these advancements, technology adoption in the Philippines remains limited due to regulatory, technical, and infrastructural constraints. This review identifies key research and implementation gaps, particularly in the monitoring of emerging contaminants and the integration of data into policy-making and urban planning. To address these challenges, a conceptual framework is proposed to support more sustainable, technology-driven, and context-sensitive groundwater management in heavily urbanized areas. Full article

This study evaluates the impacts of Solar Radiation Management (SRM) on precipitation-related climate extremes in Southeast Asia. Using simulations from the Geoengineering Large Ensemble (GLENS), we assess spatial anomalies and differences in extreme precipitation indices—number of wet days (RR1), very heavy precipitation days (R20mm), maximum 5-day precipitation (Rx5day), consecutive dry days (CDD), and consecutive wet days (CWD)—relative to historical (1980–2009) and Representative Concentration Pathway 8.5 (RCP8.5) baselines. The results reveal that SRM induces highly heterogeneous precipitation responses across the region. While SRM increases rainfall frequency in parts of Indonesia, it reduces the number of wet days and lengthens dry spells over Vietnam, Thailand, and the Philippines. Spatial variations are also observed in changes to heavy precipitation days and multi-day rainfall events, with potential implications for flood and drought risks. These findings highlight the complex trade-offs in hydrological responses under SRM deployment, with important considerations for agriculture, water resource management, and climate adaptation strategies in Southeast Asia. Full article

For coastal nations and regions, wave energy provides a localized energy solution, decreasing dependency on external energy sources and fostering the sustainable development of local economies. Effective wave height occurrence (EWHO) represents the availability of wave energy and is a crucial parameter for site selection for optimal wave energy. This paper systematically analyzes the distribution of EWHO in China seas areas using significant wave height (SWH) data in the fifth generation of ECMWF atmospheric reanalysis (ERA5) and key climate indices. Employing methods such as climate statistical analysis, linear regression, significance testing, and trend analysis, the study highlights the temporal and spatial distribution characteristics, variation trends, and correlations with climate indices of EWHO. This research aims to provide technical assistance and decision support for the development of wave energy at sea. The results indicate the following conclusions: (1) The high EWHO in the China seas is predominantly located in northern Nanhai, southern Donghai, and the eastern waters of the Philippine Islands. The EWHO is highest in winter. (2) The growth trend of EWHO is most notable in the sea area east of the line connecting the Ryukyu Islands, Taiwan, and the northeastern Philippines, peaking in spring and being relatively weak in winter. (3) The correlation between NINO3 and EWHO is most significant in Nanhai and the northeastern waters of the Philippines, peaking in February with correlation coefficients ranging from −0.30 to −0.50. Full article

Oncomelania hupensis quadrasi is the intermediate host of S. japonicum, the causative species of schistosomiasis in the Philippines. Conventionally, risk areas are identified by procedures requiring highly skilled personnel and constant surveillance efforts. Recent developments in disease diagnostics explore the utilization of environmental DNA as targets for polymerase chain reactions in disease surveillance. In this study, a low-cost, specific, and efficient SYBR Green-based real-time PCR assay to detect O. h. quadrasi DNA from water samples was developed, optimized, and validated. Primers were designed based on the A18 microsatellite region of O. h. quadrasi. The assay exhibited a detection limit of one copy number per microliter at 99.4% efficiency and R² = 0.999, which specifically amplified O. h. quadrasi DNA only. Validation of this assay in environmental water samples demonstrated 100% PPV and NPV values, suggesting its potential as a tool for identifying risk areas, pathogen-directed surveillance, policy making, and disease control. Full article

Nautilus pompilius, a ‘living fossil’ of the oceans, is crucial to the study of biological evolution and paleontology. However, the species’ habitat has been severely impacted by global climate change. Based on this, species distribution models and conservation gap analyses were conducted under current and future climate scenarios. The results revealed that the current habitats for N. pompilius were primarily located in the coastal waters of Australia, Indonesia, and the Philippines. Under the Representative Concentration Pathway (RCP) 4.5 scenario, suitable habitat is projected to decline by 4.8% in the 2050s and 5.3% in 2100s. This loss is expected to intensify under higher emission scenarios, particularly RCP 8.5, where the reduction could reach 15.4% in the 2100s. Conservation gap analysis indicates that while nearly 30% of suitable habitats fall within marine protected areas (MPAs), many vulnerable regions remain unprotected. Future MPA establishment should strategically address these conservation gaps, particularly in coastal waters such as the Gulf of Carpentaria, the Arafura Sea, and the southern edge of the Timor Sea. This study provides critical insights into the distribution patterns and conservation needs of N. pompilius, emphasizing the urgent need for targeted conservation efforts to protect this endangered species. Full article

This study examines the perceived health impacts of a mining company on residents of Libjo, Dinagat Islands, Philippines, addressing a critical research gap in understanding the perceived health impacts of mining activities in underrepresented regions. The perceived health impacts of mining operations were examined using a qualitative research approach, employing semi-structured interviews. The interview instrument was developed to investigate how mining company activities impact key health determinants, such as water quality, sanitation, income, employment, infrastructure, education, and women’s empowerment. The study was conducted across multiple sites at different distances from the mining area to further investigate the possible distance-based variations. The findings indicate that the mining company has positively impacted several areas, particularly income, employment, infrastructure, education, and women’s empowerment. However, there were mixed perceptions regarding water quality and sanitation. The majority of respondents, particularly those who are near the mining sites, perceived a significant positive impact on health service delivery, attributing it to the company’s support initiatives. Despite these positive impacts, the community expressed concerns about potential negative environmental consequences, such as air and water pollution, deforestation, land degradation, and noise pollution. This study reveals the complex relationship between mining operations and community health, emphasizing the importance of balancing economic benefits and environmental safety. The study further contributes to a deeper understanding of how mining operations affect the community’s health and well-being and their potential distance-based variations. Full article

Schistosomiasis japonica is an infectious parasitic disease caused by infection with the blood fluke Schistosoma japonicum, which is endemic in China, small pockets of Indonesia, and the Philippines. Of the three countries, the prevalence of infection is the highest in the Philippines, despite decades of mass drug administration (MDA). As a zoonosis with 46 potential mammalian definitive hosts and a snail intermediate host, the control and eventual elimination of S. japonicum requires management of these animal hosts in addition to new interventions for the human hosts, including health education and water, sanitation, and hygiene (WASH) infrastructure. In this review we examine the status and epidemiology of S. japonicum in the Philippines with an overview of the current control program there and what needs to be accomplished in the future to control and eliminate this disease in the country. Full article

Maritime accidents frequently occur in the Philippine archipelagic waters, often resulting in significant loss of life. These incidents highlight the urgent need for improvements in the country’s maritime safety systems. By utilising accident data from the Philippine Coast Guard and the GISIS IMO databases, spatial analytical approaches were employed to determine incident distribution patterns and resulted in an overall depiction of the likelihood component of risk across the country’s territorial waters. Kernel density and hotspot analysis revealed areas where incidents were concentrated and where statistically significant hotspots occurred. The Maxent tool was used to develop risk likelihood models for the incident locations using environmental rasters representing wind speed, significant wave height, depth, surface current, land distance and port distance. Model performance metrics including the AUC, TSS and Kappa were used to compare the two datasets and provide confidence on model robustness. Variable contribution figures showed that land distance is the most influential variable, with the majority of high-risk areas predominantly located near population centres. The resulting maps provide an intuitive and informative depiction of the characteristic patterns of maritime accidents in the country, identify areas of high risk requiring immediate attention and offer valuable insights to support strategies for improving and enhancing the country’s maritime safety. Full article

This study examines the effects of transitioning to hydrogen production in the National Capital Region (NCR) and Palawan Province, Philippines, focusing on technology, environment, and stakeholder impact. This research, conducted through a July 2022 survey, aimed to assess public awareness, knowledge, risk perception, and acceptance of hydrogen and its environmentally friendly variant, green hydrogen, infrastructure. Disparities were found between urban NCR and rural Palawan, with lower awareness in Palawan. Safety concerns were highlighted, with NCR respondents generally considering hydrogen production safe, while Palawan respondents had mixed feelings, particularly regarding nuclear-based hydrogen generation. This report emphasizes the potential ecological advantages of hydrogen technology but highlights potential issues concerning water usage and land impacts. It suggests targeted public awareness campaigns, robust safety assurance programs, regional pilot projects, and integrated environmental plans to facilitate the seamless integration of hydrogen technology into the Philippines’ energy portfolio. This collective effort aims to help the country meet climate action obligations, foster sustainable development, and enhance energy resilience. Full article

The Silway River has historically failed to meet safe fecal coliform levels due to improper waste disposal. The river mouth is located in General Santos City, the tuna capital of the Philippines and a leading producer of hogs, cattle, and poultry. The buildup of contaminants due to direct discharge of waste from chicken farms and existing water quality conditions has led to higher fecal matter in the Silway River. While there were technical reports in the early 2000s about poultry farming, this is the first study where fecal coliform from poultry farming was detected in the Silway River using highly sensitive protocols like qPCR. This study characterized the effect of flow velocity and physicochemical water quality parameters on chicken fecal contamination. Gene markers such as Ckmito and ND5-CD were used to detect and quantify poultry manure contamination through microbial source tracking (MST) and environmental DNA (eDNA) profiling. The results of this study showed the presence of chicken fecal bacteria in all stations along the Silway River. The results revealed that normal levels of water quality parameters such as temperature, pH, and high TSS concentrations create favorable conditions for chicken fecal coliforms to thrive. Multiple regression analysis showed that flow velocity and DO significantly affect chicken fecal contamination. A lower cycle threshold (Ct) value indicated higher concentration of the marker ND5-CD, which means higher fecal contamination. It was found that there was an inverse relationship between the Ct value and both velocity (R² = 0.55, p = 0.01) and DO (R² = 0.98, p = 0.2), suggesting that low flow velocity and low DO can lead to higher fecal contamination. Findings of fecal contamination could negatively impact water resources, the health of nearby residents, and surrounding farms and industries, as well as the health and growth of fish. Full article

The Irawan Watershed in Puerto Princesa, Philippines, is an important resource that supports domestic, agricultural, and industrial water needs. This study applies the Water Evaluation and Planning (WEAP) model to project the impacts of climate change on future surface water availability, integrating the findings into an Integrated Water Resource Management (IWRM) framework. Using bias-corrected General Circulation Models (GCMs) under four shared socioeconomic pathways (SSPs), this study examines scenarios from low to high emissions (SSP126, SSP245, SSP370, and SSP585) for the assessment of potential variations in water supply. The results indicate a significant vulnerability to water availability, especially under SSP370 and SSP585, where climate warming is pronounced, leading to significant reductions in streamflow. Conversely, SSP126 suggests relatively stable conditions with less pronounced hydrological changes. The study also explores the socioeconomic drivers that affect water demand, including population growth and land use changes that influence agricultural water needs. The findings underscore the urgency of using adaptive management strategies to conserve water resources in the face of these anticipated challenges. Key recommendations include optimizing water use efficiency in all sectors, establishing protective zones around natural ecosystems, implementing climate-resilient infrastructure, and promoting community engagement in water management. These measures are critical for enhancing water security and promoting sustainable development within the watershed, contributing to the broader goals of Sustainable Development Goal (SDG) 6. This study offers decision-makers and resource managers an evidence-based framework for integrating hydrological modeling into IWRM, providing valuable insights to navigate the complexities of climate change and ensure the long- term sustainability of water resources in the Philippines. Full article

Constructed wetlands (CWs) are man-made ecosystems that mimic the properties of natural wetlands. They are being utilized to treat various types of wastewater, from domestic to agricultural, municipal, commercial, and industrial effluents. Despite their economic viability and environmental benefits, their widespread adoption is challenged with several uncertainties, including public support, technology learning, and the impacts of climate change. This study proposes a valuation framework that considers these uncertainties to analyze the feasibility of CWs. Using existing CWs in the Philippines as a case, this study employs the real options approach to (1) evaluate the feasibility of CW projects using cost–benefit analysis, (2) calculate the value of postponing decisions to implement CWs projects using real options analysis, and (3) identify the optimal investment decisions for CWs considering the opportunity costs of waiting and uncertainties in public support and the impacts of climate change. Results found that the project is feasible with a net present value of USD 88,968. Yet, the real options value at USD 208,865 indicates that postponing the project may be a more optimal decision. Considering the cost of waiting, the valuation identified the threshold at 5.56% to immediately implement the project. The calculated values increase with uncertainty in public support but decrease with uncertainty in climate change’s impacts. Yet, these uncertainties prolong the decision to implement CW projects until they are resolved. The findings from this case study provide a basis for recommendations to support the adoption of CWs as nature-based water treatment for a more sustainable future. Full article

Carrageenans are valuable marine polysaccharides derived from specific species of red seaweed (Rhodophyta) widely used as thickening and stabilizing agents across various industries. Kappaphycus alvarezii, predominantly cultivated in tropical countries, is the primary source of kappa-carrageenan. Traditional industrial extraction methods involve alkaline treatment for up to three hours followed by heating, which is inefficient and generates substantial waste. Thus, developing improved extraction techniques would be helpful for enhancing efficiency and reducing environmental impacts, solvent costs, energy consumption, and the required processing time. In this study, we explored innovative extraction methods, such as ultrasound-assisted extraction (UAE) and supercritical water extraction (SFE), together with other extraction methods to produce kappa-carrageenan from a new strain of K. alvarezii from the Philippines. FTIR-ATR spectroscopy was employed to characterize the structure of the different carrageenan fractions. We also examined the physicochemical properties of isolated phycocolloids, including viscosity, and the content of fatty acids, proteins, and carbohydrates. For refined carrageenan (RC), both the traditional extraction method and the UAE method used 1 M NaOH. Additionally, UAE (8% KOH) was employed to produce semi-refined carrageenan (SRC). UAE (8% KOH) produced a high yield of carrageenan, in half the extraction time (extraction yield: 76.70 ± 1.44), and improved carrageenan viscosity (658.7 cP), making this technique highly promising for industrial scaling up. On the other hand, SFE also yielded a significant amount of carrageenan, but the resulting product had the lowest viscosity and an acidic pH, posing safety concerns as classified by the EFSA’s re-evaluation of carrageenan as a food additive. Full article