Impact of a dam construction on the intertidal environment and free-living nematodes in the Ba Lai, Mekong Estuaries, Vietnam.

The impact of high siltation and accumulation of organic and waste material in the intertidal of the dammed Ba Lai River in Vietnam as part of the Mekong estuarine system was investigated by means of marine free-living nematodes. Nutrients content (nitrate, ammonium, total phosphorus, total nitrogen), total suspended solids, total organic carbon, coliform, bacteria E. coli, pH, dissolved oxygen, total dissolved solids, methane and hydrogen sulfide concentration, and the nematode communities were characterized in sediment at selected stations along the river above and below the dam.

Epistemic community in transboundary river regime: a case study in the Mekong River Commission regarding mainstream hydropower development.

Despite the importance of transboundary water management, cooperation mechanisms are limited, especially in the case of Mekong River basin where environmental and social aspects are threatened by recent anthropogenic pressures like hydropower development. Existing transboundary mechanism such as the Mekong River Commission (MRC) is challenged to facilitate the cooperation between riparian states. An epistemic community (EC) is considered to effectively influence international governance and is studied as part of transboundary river regimes.

Two-stage anaerobic membrane bioreactor for co-treatment of food waste and kitchen wastewater for biogas production and nutrients recovery.

Co-digestion of organic waste and wastewater is receiving increased attention as a plausible waste management approach toward energy recovery. However, traditional anaerobic processes for co-digestion are particularly susceptible to severe organic loading rates (OLRs) under long-term treatment. To enhance technological feasibility, this work presented a two-stage Anaerobic Membrane Bioreactor (2 S-AnMBR) composed of a hydrolysis reactor (HR) followed by an anaerobic membrane bioreactor (AnMBR) for long-term co-digestion of food waste and kitchen wastewater.

The challenge of unprecedented floods and droughts in risk management.

Risk management has reduced vulnerability to floods and droughts globally, yet their impacts are still increasing. An improved understanding of the causes of changing impacts is therefore needed, but has been hampered by a lack of empirical data. On the basis of a global dataset of 45 pairs of events that occurred within the same area, we show that risk management generally reduces the impacts of floods and droughts but faces difficulties in reducing the impacts of unprecedented events of a magnitude not previously experienced.

Datasets of land use change and flood dynamics in the vietnamese mekong delta.

This paper compiles the data associated with a research article published in STOTEN [1]. The data set represents figures, tables, and images illustrating the temporal and spatial distribution of land use and flood dynamics from 2000 to 2020 in the Vietnamese Mekong Delta (VMD). The MODIS imageries were freely accessed online via the NASA website [2] and processed to land use and flood maps based on the algorithms by Sakamoto et al.

Toxicity of di-2-ethylhexyl phthalate and tris (2-butoxyethyl) phosphate to a tropical micro-crustacean (Ceriodaphnia cornuta) is higher in Mekong River water than in standard laboratory medium.

Plasticizers such as di(2-ethylhexyl) phthalate (DEHP) and tris (2-butoxyethyl) phosphate (TBOEP) are manufactured chemicals produced in high volumes. These chemicals are frequently detected in the aquatic environment and cause toxic effects on organisms. In this study, we assessed the chronic impacts of DEHP and TBOEP, respectively, at the concentration of 100 µg L dissolved in the artificial medium (M4/4) and Mekong River water on life history traits of a tropical micro-crustacean, Ceriodaphnia cornuta, for 14 days.

Statistically examining the connection between dike development and human perceptions in the floodplains' socio-hydrology system of Vietnamese Mekong Delta.

Efforts on socio-hydrology science have been promoted to solve challenges faced by contemporary water management. This study aims to better understand the co-evolution of human-water systems in floodplains. Specifically, farmers' opinions on flooding, dike effects, and living conditions in different dike systems in the Vietnamese Mekong Delta floodplain are compared to explore possible connections between human perceptions and dike development processes by employing in-depth interviews of 7 officials and oral surveys of 100 farmers supported by a literature review.

Land use change in the Vietnamese Mekong Delta: New evidence from remote sensing.

This paper presents the first attempt to capture a comprehensive spatial view of land use change in the Vietnamese Mekong Delta (VMD) for a long period, i.e., from 2000 to 2020.

Groundwater in Southern Vietnam: Understanding geochemical processes to better preserve the critical water resource.

A thorough understanding of groundwater geochemical characteristics and dominant hydro(bio)geochemical processes in the aquifers is valuable for sustainable groundwater protection. With this respect, this study provides a comprehensive assessment of hydrogeochemical characteristics of groundwater in sedimentary aquifers of the Southern region of Vietnam. The dataset comprised 291 water samples collected in rainy and dry seasons from 155 wells, and their chemical compositions of dissolved ions (Ca, Mg, Na, K, HCO, Cl, SO, NO, NH, Fe, total dissolved solids) and pH.

Impact of biomass burnings in Southeast Asia on air quality and pollutant transport during the end of the 2019 dry season.

At the end of the dry season, March and April in Southeast Asia (SEA), agricultural refuse burnings occur over the region, mainly in the countries of Myanmar, Thailand, Laos, Cambodia and Vietnam, in preparation for the wet rice plantation. In this study, the impact of biomass burnings at the height of the burning period in March 2019 in mainland SEA on air quality and pollutant transport is modelled using the Weather Research Forecast WRF-Chem air quality model with emission input from the National Center for Atmospheric Research (NCAR) Fire Emission Inventory from NCAR (FINN). FINN is derived from satellite remote sensing data and species emission factors.

Continuous flow sequencing bed biofilm reactor bio-digested landfill leachate treatment using electrocoagulation-persulfate.

Landfill leachate contains many complex components that have a negative impact on the environment when improperly discharged. This study is the first to treat landfill leachate (after continuous flow sequencing bed biofilm reactor (CF-SBBR) bio-digested) using electrocoagulation (EC) combined with persulfate (PS) on Al and Fe electrodes. The effect of some of the key parameters on the COD, Color, TOC and TN removal efficiencies as part of the EC-PS process were studied using the PS concentration, reaction time, initial pH, current density, and aeration rate.

How the saline water intrusion has reshaped the agricultural landscape of the Vietnamese Mekong Delta, a review.

Once a key factor behind Vietnam's successful Doi Moi (restoration) economic reforms, the rice-centered agriculture of the VMD is now confronted by the new pressure of climate change impacts, including the intensifying salinity intrusion (SI). The SI menace has partly triggered the delta-wide emergence of new adaptive livelihood models across the VMD, including the prawn rice rotational crop (PRRC) that is arguably the most prominent. Research on the SI-driving factors is rapidly increasing in numbers, yet little synthesis has been done.

Toward the Circular Economy of Rare Earth Elements: A Review of Abundance, Extraction, Applications, and Environmental Impacts.

Rare earth elements (REEs) are increasingly critical to the high-technology and low-carbon economy. With a shift to sustainable socioeconomic development that aims to be less fossil fuel dependent, global demand for REEs continues to rise, despite their uncertain supply chain and high environmental impact of production. Here, we review recent research on REEs, including global reserve assessment, REE-based applications, major REE production pathways, environmental impacts, and the potential to leverage circular economies within the REE industry.

High organic removal of landfill leachate using a continuous flow sequencing batch biofilm reactor (CF-SBBR) with different biocarriers.

Landfill leachate contains many pollutants that have a negative effect on the environment when improperly discharged. Thus the treatment of landfill leachate is a crucial issue, especially in the bigger cities in developing countries. In this study, landfill leachate is treated using a continuous flow sequencing biofilm batch reactor (CF-SBBR) with different biocarriers (non-carrier (NC), kaldness (K1), mutag biochip 30™ (MB), and sponge polyurethane (SP)).

Recycling of aquaculture wastewater and sediment for sustainable corn and water spinach production.

This study develops a method to reuse aquaculture wastewater and sediment from a catfish pond in order to increase agricultural productivity and protect the environment. Material flow analysis (MFA) is a central concept of this study that involves collecting catfish pond wastewater (CPW) and reusing it to irrigate five water spinach (Ipomoea aquatic) ponds before discharging it into a river. Typically, catfish pond sediment (CPS) was collected and composted to produce organic fertilizer for cornfields.

Intensifying saline water intrusion and drought in the Mekong Delta: From physical evidence to policy outlooks.

This paper assesses the recently intensified saline water intrusion (SI) and drought in the Vietnamese Mekong Delta (VMD). While the existing literature predominantly points the cause of drought to the hydropower dams in the upstream of the Mekong Basin, we contribute new physical evidence of the intensification of saline water intrusion (through backwater effect) in the VMD caused by three anthropogenic drivers: riverbed incision (due to both riverbed mining and dam construction), sea level rise and land subsidence. Thereupon, we highlight that it is critical to not underestimate the impacts from the localized factors, especially the riverbed-mining which can incise the channel by up to 15 cm/year and amplify the salinity intrusion.

Implementation of a constructed wetland for the sustainable treatment of inland shrimp farming water.

In the Mekong delta, inland-based shrimp breeding requires significant inflow of high-quality freshwater. In turn, discharge of substantial loads of poor-quality effluents negatively impacts adjacent water bodies and favors disease outbreaks. This project describes the implementation of a laboratory-based continuous closed recirculation aquaculture system composed of a constructed wetland (CW) with horizontal subsurface flow as a water treatment filter for mesohaline conditions, functioning under high loading rate (HLR = 1.

Long-Term Heavy Metal Retention by Mangroves and Effect on Its Growth: A Field Inventory and Scenario Simulation.

The ability of mangroves in taking up and storing heavy metal (HM) helps in reducing HM pollution. However, HMs likewise adversely affect the growth of mangroves. We assess the effects of the long-term soil HMs enrichment on the growth of forest in the Can Gio Mangrove Forest (Southern Vietnam) in different environmental conditions of soil salinity, ground elevation, and tree density based on a novel set of measured data.

Combination of data-driven models and interpolation technique to develop of PM10 map for Hanoi, Vietnam.

The degradation of air quality is the most concerned issue of our society due to its harmful impacts on human health, especially in cities with rapid urbanization and population growth like Hanoi, the capital of Vietnam. This study aims at developing a new approach that combines data-driven models and interpolation technique to develop the PM concentration maps from meteorological factors for the central area of Hanoi. Data-driven models that relate the PM concentration with the meteorological factors at the air quality monitoring stations in the study area were developed using the Multiple Linear Regression (MLR) and Artificial Neural Network (ANN) algorithms.

Combining semi-quantitative risk assessment, composite indicator and fuzzy logic for evaluation of hazardous chemical accidents.

In this study, a combination of semi-quantitative risk assessment, composite indicator and fuzzy logic has been developed to identify industrial establishments and processes that represent potential environmental accidents associated with hazardous chemicals. The proposed method takes into consideration the root causes of risk probability of hazardous chemical accidents (HCAs), such as unsafe onsite storing and usage, inadequate operation training, poor safety management and analysis, equipment failure, and factors affected by the potential consequences of the accidents, including human health, water resources, and building and construction. These issues have been aggregated in a system of criteria and sub-criteria, demonstrated by a list of non-overlapping and exhaustive categorical terms.

The Role of Mangroves in the Retention of Heavy Metal (Chromium): A Simulation Study in the Thi Vai River Catchment, Vietnam.

In this study, chromium (Cr) retention by the mangroves in the Thi Vai catchment located in the south of Vietnam was simulated using a coupled model of the hydrodynamic model Delft3D with Cr transport and a model for the uptake of Cr by mangroves. This coupled model was calibrated and validated using data from four hydrodynamic stations and data from phytoremediation studies. To analyze the effect of mangroves on reducing Cr pollution, three scenarios were run by the model.

Interactive effects of extreme temperature and a widespread coastal metal contaminant reduce the fitness of a common tropical copepod across generations.

Tropical coastal areas are increasingly exposed to temperature extremes from marine heatwaves and contaminants from anthropogenic activities. The interactive effects of these environmental changes on marine life are understudied. We investigated the direct and cross-generational effects of copper (Cu) on F0 and F1 generations of the common tropical copepod Pseudodiaptomus annandalei under extreme temperatures (30 and 34 °C).

New approach of water quantity vulnerability assessment using satellite images and GIS-based model: An application to a case study in Vietnam.

Water deficiency due to climate change and the world's population growth increases the demand for the water industry to carry out vulnerability assessments. Although many studies have been done on climate change vulnerability assessment, a specific framework with sufficient indicators for water vulnerability assessment is still lacking. This highlights the urgent need to devise an effective model framework in order to provide water managers and authorities with the level of water exposure, sensitivity, adaptive capacity and water vulnerability to formulate their responses in implementing water management strategies.

Integrated farming system producing zero emissions and sustainable livelihood for small-scale cattle farms: Case study in the Mekong Delta, Vietnam.

This study proposes an integrated cattle breeding and cultivation system that provides zero emission and sustainable livelihood for the community in rural areas. The proposed integrated farming system improves agricultural productivity and environmental and sanitation conditions, minimizes the amount of waste, and increases the family income up to 41.55%.