Inactivation of Escherichia coli enhanced by anaerobic microbial iron reduction

Environmental Science and Pollution Research - Microbial iron reduction (MIR) is an important and ubiquitous natural process in the biogeochemical cycling of iron and carbon in anaerobic...     

Green technologies for sustainable environment: an introduction

Environmental Science and Pollution Research -     

Potential health risks of toxic heavy metals and nitrate via commonly consumed bivalve and vegetable species in Ho Chi Minh City,Vietnam

Environmental Science and Pollution Research - This study aimed to evaluate the health risks of cadmium (Cd), lead (Pb), inorganic arsenic (As), and nitrate exposure through the consumption of...     

Strength,durability, and microstructure of self-compacting geopolymer concrete produced with copper slag aggregates

Environmental Science and Pollution Research - Lack of vibrations on fresh concrete negatively influences the compaction and thus the quality of concrete. This is particularly concerning with...     

Extraction,chemical compositions,and cytotoxic activities of essential oils of Thevetia peruviana

Abstract

In this study, The essential oil of flowers, fruits, and leaves of Thevetia peruviana, which were collected in Vietnam, were being reported for the first time. The essential oil of flowers was extracted by different methods: n-hexane extraction, distillation water, and supercritical CO₂ extraction. The compositions of essential oil of different parts of Thevetia peruviana were analyzed by GC-FID and GC/MS systems. Major chemical compositions of essential oil were identified as monoterpenes, sesquiterpenes, terpenoids, and sterol. The activities of total essential oil extracts of the Thevetia peruviana exhibit inhibitory activities against five cancer cell lines.     

Optimization of Fenton oxidation pre-treatment for B. thuringiensis – Based production of value added products from wastewater sludge

Fenton oxidation pretreatment was investigated for enhancement of biodegradability of wastewater sludge (WWS) which was subsequently used as substrate for the production of value- added products. The Response surface method with fractional factorial and central composite designs was applied to determine the effects of Fenton parameters on solubilization and biodegradability of sludge and the optimization of the Fenton process. Maximum solubilization and biodegradability were obtained as 70% and 74%, respectively at the optimal conditions: 0.01 ml H₂O₂/g SS, 150 [H₂O₂]₀/[Fe²⁺]₀, 25 g/L TS, at 25 °C and 60 min duration. Further, these optimal conditions were tested for the production of a value added product, Bacillus thuringiensis (Bt) which is being used as a biopesticide in the agriculture and forestry sector. It was observed that Bt growth using Fenton oxidized sludge as a substrate was improved with a maximum total cell count of 1.63 × 10⁹ CFU ml^?1 and 96% sporulation after 48 h of fermentation. The results were also tested against ultrasonication treatment and the total cell count was found to be 4.08 × 10⁸ CFU ml^?1 with a sporulation of 90%. Hence, classic Fenton oxidation was demonstrated to be a rather more promising chemical pre-treatment for Bt - based biopesticide production using WWS when compared to ultrasonication as a physical pre-treatment.     

Application of GIS and modelling in health risk assessment for urban road mobility

Transport is an essential sector in modern societies. It connects economic sectors and industries. Next to its contribution to economic development and social interconnection, it also causes adverse impacts on the environment and results in health hazards. Transport is a major source of ground air pollution, especially in urban areas, and therefore contributes to the health problems, such as cardiovascular and respiratory diseases, cancer and physical injuries. This paper presents the results of a health risk assessment that quantifies the mortality and the diseases associated with particulate matter pollution resulting from urban road transport in Haiphong City, Vietnam. The focus is on the integration of modelling and geographic information system approaches in the exposure analysis to increase the accuracy of the assessment and to produce timely and consistent assessment results. The modelling was done to estimate traffic conditions and concentrations of particulate matters based on geo-referenced data. The study shows that health burdens due to particulate matter in Haiphong include 1,200 extra deaths for the situation in 2007. This figure can double by 2020 as the result of the fast economic development the city pursues. In addition, 51,000 extra hospital admissions and more than 850,000 restricted activity days are expected by 2020.     

Effect of ultrasonication and Fenton oxidation on biodegradation of bis(2-ethylhexyl) phthalate (DEHP) in wastewater sludge

The presence of bis(2-ethylhexyl) phthalate (DEHP) and its metabolites, i.e. 2-ethylhexanol, 2-ethylhexanal, and 2-ethylhexanoic acid in wastewater sludge (WWS) were investigated during aerobic digestion and Bacillus thuringiensis (Bt)-based fermentation of WWS. Ultrasonication and Fenton oxidation pre-treatment was applied to improve biodegradability of WWS and bioavailability of the target compounds for digestion and fermentation. DEHP and 2-ethylhexanoic acid were observed at higher concentration, meanwhile 2-ethylhexanol and 2-ethylhexanal were observed at lower concentration in WWS. After 20-day aerobic digestion, DEHP removal was 72%, 89%, and 85%, and 2-ethylhexanoic acid removal was 71%, 84%, 79%, respectively for raw, ultrasonicated, and Fenton-oxidized sludges. Bt was found to degrade DEHP, leading to DEHP removal of 21%, 40%, and 30%, respectively for raw, ultrasonicated, and Fenton-oxidized sludges in the fermentation. The results suggested that aerobic stabilization and Bt-based fermentation can remove the phthalates, and pre-treatment of WWS was also effective in improvement of DEHP biodegradation. Hence, Bt-based biopesticide production from WWS can be applied safely when taking into consideration the phthalate contaminants.     

Pollution sources and occurrences of selected persistent organic pollutants (POPs) in sediments of the Mekong River delta, South Vietnam

The Mekong River delta is one of the largest agricultural land in the Southeast Asia. It plays a very important role for agriculture and fisheries in South Vietnam. However, comprehensive studies on the environmental pollution of persistent organic pollutants (POPs) in Mekong River delta have not been carried out in recent years. In this study, we collected sediment samples from the Mekong River to evaluate the contamination and ecological risks caused by several POPs. The contamination pattern of POPs was DDT>PCBs>CHLs>HCHs>HCB. DDTs are the most abundant pollutants, their concentration ranging from 0.01 to 110 ng/g dry wt, followed by PCBs (0.039-9.2 ng/g dry wt). DDTs and PCBs concentrations were higher in sediment from adjacent to urban areas than those from rural and agricultural sites, suggesting urban areas as important point sources of DDTs and PCBs to the river. Ratio of p,p'-DDT/p,p'-DDE was lower compared to those previously reported. However, some samples still had the ratio higher than 0.5, indicating recent input of DDT into the aquatic environments. This result shows that although the magnitude of contamination decreased over time, recent inputs of DDTs to the river still occur. Some sediment samples had concentrations of DDT compounds higher than the standards from the Canadian Environmental Quality Guideline, suggesting continuous monitoring for POPs contamination in the Mekong River is necessary.