Sustainable livelihoods development by utilization of geomorphological resources in the Bai Tu Long Bay,Quang Ninh Province,Vietnam

Located in the humid tropical zone and endowed with carbonate sedimentary formations, Vietnam has unique karst landscapes where caves, limestone, and dolines are common. If well managed, these are valuable geomorphological resources for a sustainable socio-economic development. Although publications on sustainable livelihoods associated with conserving biodiversity and local culture are plentiful, there is still a lack of studies linking livelihood quality with the conservation of geomorphological resources, in particular in karst areas. This study assesses the geomorphological resources in Vietnam’s Bai Tu Long Bay and studies the relationship between livelihood and these resources. The current research area Bai Tu Long Bay is adjacent to the natural World Heritage site of Ha Long Bay in the Vietnamese part of the Gulf of Tonkin. Bai Tu Long is characterized by a karst landscape, which is at the same time similar but also different from Ha Long Bay. A field survey and interviews with 153 households allowed assessing people’s perception of the value of the geomorphological resources and their importance for local income. The results show that Bai Tu Long Bay has abundant, diverse, and unique geomorphological resources, which are valuable for tourism development. However, the local people are unaware of these values likely because they have no direct benefit from them. Further a sustainable development strategy for Bai Tu Long Bay is recommended. The outcome is a proposal for tourism initiatives aiming at realizing more sustainability in the area.     

Primary biosorption mechanism of lead (II) and cadmium (II) cations from aqueous solution by pomelo (Citrus maxima) fruit peels

Environmental Science and Pollution Research - The present work investigates the primary adsorption mechanisms of lead (II) and cadmium (II) cations onto pomelo fruit peel (PFP) from aqueous...     

Spatial and temporal variations of PAHs in surface sediments of estuarine and coast of CanGio wetland,Vietnam

Surface sediments from estuarine and coast of CanGio wetland (CGW) of Hochiminh City, Vietnam, were investigated to identify the spatial and temporal variations of polycyclic aromatic hydrocarbons (PAHs). The total PAHs showed wide variation but similar to patterns observed (F?=?0.901, p?=?0.46) in LongTau (31?±?77 ng/g dry weight, n?=?13), SoaiRap (53?±?81, n?=?4), ThiVai (60?±?62, n?=?10) estuaries, and coastal areas (112?±?211, n?=?9). A decreasing trend in the wet season (F?=?8.8, p?=?0.01) reflected that inland sources such as wastewater discharged and atmospherically transported contaminants contributed to PAHs in sediments. The risk posed by the PAHs in the coastal and estuarine areas of CGW is still negligible. The present study provides baseline data, which can be used for regular monitoring and future strategy of environmental protection for the study area.

     

Correction to: Water‑induced erosion potentiality and vulnerability assessment in Kangsabati river basin,eastern India

Environment, Development and Sustainability -     

Optimization, equilibrium, adsorption behavior and role of surface functional groups on graphene oxide-based nanocomposite towards diclofenac drug

Aquatic contamination of diclofenac (DCF), an emergent non-steroidal anti-inflammatory drug (NSAIDs), can result in adverse effects to many ecosystems through biomagnification. Hence, introducing effective remediation techniques to sequester the pharmaceutical wastes is highly fundamental to prevent their accumulation in the environment. Generally, adsorption has been presented as a green and efficient approach. Herein, we report the characterization and application of the novel magnetic nanocomposite ([email protected]₂O₄) derived from cobalt-based ferrite (CoFe₂O₄) and graphene oxide (GO) for DCF adsorption. For the optimization procedure, the response surface methodology (RSM) was adopted to investigate the impacts of DCF concentration (1.6–18.4 mg/L), DCF dosage (0.08–0.92 g/L), and solution pH (2.6–9.4) to find the optimum conditions for DCF removal, at 10.5 mg/L, 0.74 g/L, and pH 4, respectively. For the adsorption experiments, the kinetic, isotherm, thermodynamic, and intraparticle diffusion models were systematically studied. Moreover, we have elucidated the role of functional groups on the surface of [email protected]₂O₄ in enhancing the adsorption of DCF drug. With good removal efficiency (up to 86.1%), high maximum adsorption capacity (32.4 mg/g), [email protected]₂O₄ can be a potential candidate to eliminate DCF drug from water.     

Real-time black carbon personal exposure levels in microenvironments: Home to home on a round-trip,Hanoi–Singapore

Little is known about personal exposure levels of black carbon (BC), a fraction of PM2.5, specifically in the transport microenvironments. In this study, real-time personal exposure to BC recorded by a portable microAeth AE51 was investigated in microenvironments in a round-trip from Hanoi (Vietnam) directly to Singapore. Personal exposure to BC was monitored in microenvironments at residential flat, in various surface modes of transport (taxi, bus, train), at the airports, and on the airplanes. The study found that personal exposure levels of BC in Singapore were higher than those in Hanoi for the same type of microenvironment in general for most of the microenvironments, except for smoking rooms. The highest exposures in each city were in smoking room in Noi Bai International Airport (NIA) and at bus station in Singapore, reached 98,709 ng/m3 and 44,513 ng/m3, respectively; the lowest personal exposure level was in-flight (approximately 250 ng/m3) for both trips. It is also remarkable that personal exposure to BC in indoor microenvironments was higher than outdoor levels.

Implications: Real-time personal exposure to BC was investigated in microenvironments in a round trip from Hanoi (Vietnam) directly to Singapore. BC personal exposure levels in Singapore were higher than those in Hanoi for the same type of microenvironment except for smoking rooms. Personal exposure to BC levels in indoor microenvironments was higher than in outdoor microenvironments. The highest levels of exposure were 98,709 ng/m3 in the smoking room at Noi Bai International Airport (Hanoi) and 44,513 ng/m3 at the bus station in Changi (Singapore). The lowest BC level was in-flight for both trips, at approximately 250 ng/m3.     

Effects of resource availability,predators, conspecifics and heterospecifics on decorating behaviour by the majid crab <Emphasis Type="Italic">Tiarinia cornigera</Emphasis>

Utilization of algae for decorating by the intertidal majid crab Tiarinia cornigera was examined by laboratory experiments in relation to availability of algae, presence of a predator, and the presence of conspecific and heterospecific crabs. Different availabilities of decorating materials had a positive correlation on decorating amount by juveniles, while the correlation was not so clear in subadults. The amount of decorating decreased with increasing density of conspecific crabs in the presence of a predator, but there was so clear relationship in the absence of a predator. The decrease in decorating under high density could be due to intraspecific aggression, because the superior crab, in fighting, was found to be decorated with more algae. Tiarinia cornigera was found to be superior to the co-occurring different majid species Micippa platipes in fighting. When T. cornigera and M. platipes were housed together, the former was decorated with more algae than the latter in the presence of a predator, but in the absence of a predator, the amount of algae was not different. Thus, presence of a predator may motivate intraspecific competition in T. cornigera as well as interspecific competition between T. cornigera and M. platipes for decorating materials.     

Monitoring the levels of brominated and organophosphate flame retardants in passenger cars: Utilisation of car air filters as active samplers

Filters in residential and office air conditioning(A/C) systems have been used as sampling devices for monitoring different pollutants.However,cabin air filters(CAFs) in the A/C system of passenger cars have not been utilised for this purpose.In this study,we collected22 used CAFs from passenger cars in Hanoi,Vietnam to analyse for 8 polybrominated diphenyl ethers(PBDEs) and 10 organophosphate esters(OPEs).All the analytes were detected in more than 50% of samples with the exception of BDE153 and BDE154.The average concentrations of ∑_(10)OPEs and ∑_8 BDEs in the captured dust were 2600 and 40 ng/g,respectively with Tris(1-chloro-2-propyl) phosphate(TCIPP) and BDE209 as the dominant congener in OPE and BDE groups,respectively.CAFs are a potential tool to qualitatively assess the levels of semi-volatile chemicals in suspended dust in cars as a screening step for exposure assessment of those chemicals.     

Metal speciation in sediment and bioaccumulation in <Emphasis Type="Italic">Meretrix lyrata</Emphasis> in the Tien Estuary in Vietnam

The concentrations of seven toxic metals (cadmium (Cd), nickel (Ni), chromium (Cr), arsenic (As), lead (Pb), copper (Cu), and zinc (Zn)) were determined in sediments and the soft tissues of a bivalve species (Meretrix lyrata) collected from the Tien Estuary in Tien Giang Province, South Vietnam. The total metal concentrations in sediments (mg/kg dry weight) increased as Cd (0.06) < Cu (5.0) < Pb (13.9) < As (16.3) < Ni (24) < Cr (50) < Zn (62). Speciation analysis revealed that these metals existed mainly in the residual fraction (43–94%), followed by the Fe-Mn oxide-bound (5–35%) and organic/sulfide-bound (0.6–9.2%) fractions. The metal concentrations in M. lyrata (mg/kg dry weight) were in the ranges of 1.3–1.9 (Cd), 1.5–2.8 (Ni), 1.8–3.4 (Cr), 11–16 (As), 0.3–0.6 (Pb), 6.9–8.7 (Cu), and 95–128 (Zn), which are safe for human consumption. The order of the mean biota-sediment accumulation factor (BSAF) of the metals in the non-residual fractions of the sediment for M. lyrata was Cd > Cu > As > Zn > Cr > Ni > Pb. The Risk Assessment Codes (RACs) suggest that the highest mobility of Cd (with RAC = 37%) poses greater environmental risk to aquatic biota. Correlation analysis results show that M. lyrata can be used as a biomonitor of Cd and Cu pollution in the exchangeable, acid-soluble, and non-residual sediment fractions.     

Evolutionary social and biogeophysical changes in the Amazon,Ganges–Brahmaputra–Meghna and Mekong deltas

Policy-making in social-ecological systems increasingly looks to iterative, evolutionary approaches that can address the inherent complexity of interactions between human wellbeing, provision of goods, and the maintenance of ecosystem services. Here, we show how the analysis of available time-series in tropical delta regions over past decades can provide important insight into the social-ecological system dynamics in deltaic regions. The paper provides an exploratory analysis of the recent changes that have occurred in the major elements of three tropical deltaic social-ecological systems, such as demography, economy, health, climate, food, and water. Time-series data from official statistics, monitoring programmes, and Earth observation data are analysed to explore possible trends, slow and fast variables, and observed drivers of change in the Amazon, Ganges–Brahmaputra–Meghna and Mekong deltas. In the Ganges–Brahmaputra–Meghna delta zone, increasing gross domestic product and per capita income levels since the 1980s mirror rising levels of food and inland fish production. In contrast, non-food ecosystem services, such as water availability, water quality, and land stability appear to be deteriorating. In the Amazon delta, natural and anthropogenic perturbations are continuously degrading key ecosystem services, such as carbon storage in biomass and soils, the regulation of water balance, and the modulation of regional climate patterns. In the Mekong delta, rapid economic development, changing land-use practices, and salinity intrusion are progressively putting more pressure on the delivery of important provisioning services, such as rice and inland aquaculture production, which are key sources of staple food, farm incomes, and export revenue. Observed changes in many key indicators of ecosystem services point to a changing dynamic state and increased probability of systemic threshold transformations in the near future.