Toxicity of imidazolium salt with anion bromide to a phytoplankton Selenastrum capricornutum: effect of alkyl-chain length

Room-temperature ionic liquids are regarded as environmentally benign alternatives to volatile organic solvents. However, the product designs for this promising group of compounds should take account, not only the technological needs, but also the eco-toxicological hazards. Therefore, this study aimed to evaluate the toxicity of some important ionic liquids on the growth of the freshwater alga, Selenastrum capricornutum. The ionic liquids examined in this study included 1-propyl-3-methylimidazolium [PMIM], 1-butyl-3-methylimidazolium [BMIM], 1-hexyl-3-methylimidazolium [HMIM] and 1-octyl-3-methylimidazolium [OMIM] with a bromide anion. The susceptibility of alga to ionic liquids was strongly dependent on the alkyl-chain length. According to our results, a longer alkyl-chain resulted in stronger inhibition of algal growth. In general, the toxicity could be summarized as decreasing in the following order: [OMIM]>[HMIM]>[BMIM]>or=[PMIM]. Among the ionic liquids examined, [OMIM] [Br] was found to be most toxic to S. capricornutum, with EC(50) values ranging from 26.3 microM to 54.9 microM after an incubating time of 96 h. Although [BMIM] [Br] and [PMIM] [Br] was relatively less toxic than [OMIM] and [HMIM], their toxicity increased as increasing the incubation time from 48 h to 96 h. This fact indicates that these kinds of ionic liquids may become more toxic after being released and contacted to freshwater ecosystem.     

Sustainability indicators for clean development mechanism projects in Vietnam

The Clean Development Mechanism (CDM) is one of the flexible instruments of the Kyoto Protocol designed to combat climate change so as to bring advantages to developing countries and developed countries alike. Indeed, CDM projects have a two-fold objective: to offset greenhouse gas emissions and to contribute to sustainable development in the host country. However in many cases, the latter objective appears to be marginalized. This is at least partly due to the difficulties surrounding the definition and the measurement of sustainability, in particular in a developing country context. To assess CDM projects’ contribution to sustainable development in the host country, scholars and practitioners need adapted indicator sets. A set of indicators were developed by way of an iterative Delphi approach amongst selected Vietnamese experts. The Delphi approach allowed a systematic collection of the experts’ judgements on the sustainability indicators through a set of sequentially applied questionnaires, interspersed with feedback from earlier responses. This exercise resulted in the selection of a set of 36 indicators, which emphasise economic efficiency, public health and pollution issues. The exercise yielded a locally supported and context-specific set of sustainability indicators that will allow Vietnamese decision-makers to enhance the sustainability of the approved CDM projects. In the future this set should be continually improved through real-life application and further participation from local stakeholders. This study is a first step in a long-term process towards developing an adapted toolkit for sustainability assessment of CDM projects in Vietnam.     

A robust method for collecting and processing the on-road instantaneous data of fuel consumption and speed for motorcycles

ABSTRACT

Using the laboratory-based fuel consumption models for predicting real-world fuel consumption requires the measurement of data under certain conditions to obtain high accuracy of predicted result. Therefore, it is necessary to develop a logging device for measuring the real-time fuel consumption and speed of vehicle on the road. This article presents a study on developing the on-board data logging device to collect real-world data of fuel consumption and speed for motorcycles with the update rate of 1 Hz. The instantaneous speed of the motorcycle was determined based on the rotational speed of the wheel and the wheel radius. Another module was used to determine the instantaneous fuel consumption rate (FR) though measuring the duration injection pulse. The relationship between the duration injection pulse and the injected amount of fuel was established with high correlation coefficient of 0.997. In addition, a filter was designed to remove noise in the dataset collected using the data logging device. The random errors in the speed and the FR profiles were detected and replaced, the percentage of these errors is 1.8% and 2.4%, respectively. The developed method is a precise one for transient fuel consumption and speed measurement. In chassis dynamometer test, the average deviation between steady speed measured by the chassis and the data logging device is only approximately 0.35%. At transient state, the biggest deviation between these two datasets is less than 3.5%. The average FR at steady speed measured by the developed method is slightly different from the one measured by the carbon balance method. The difference is 0.9%, 2.5%, and 0.25% at the speeds of 30 km/h, 50 km/h, and 70 km/h, respectively. Following the transient test cycle, the fuel consumption measured by the developed method is 4.35% lower than that determined by the carbon balance method.

Implications: A robust method for collecting and processing the on-road instantaneous data of fuel consumption and speed was developed for motorcycles. The proposed method can record well the real-world driving data for motorcycles, including the fuel consumption and speed, with the update rate of 1 Hz. The filter was designed to minimize noise while maintaining data integrity of the collected dataset, the percentage of errors in the the speed and the FR profiles is 1.8% and 2.4%, respectively. The proposed method, therefore, can be used as effective tools for future studies relating to the fuel consumption and emission of motorcycles on the road.     

Contamination by arsenic and other trace elements in tube-well water and its risk assessment to humans in Hanoi, Vietnam

Concentrations of As and other trace elements and their association were examined in groundwater (n = 25) and human hair (n = 59) collected at Gia Lam District and Thanh Tri District, suburban areas of Hanoi, Vietnam, in September 2001. Concentrations of As in the groundwater ranged from <0.10 to 330 microg/l, with about 40% of these exceeding WHO drinking water guideline of 10 microg/l. Also, 76% and 12% of groundwater samples had higher concentrations of Mn and Ba than WHO drinking water guidelines, respectively. Arsenic concentrations in hair of residents in Gia Lam and Thanh Tri Districts (range 0.088-2.77 microg/g dry wt.) were lower than those in other As-contaminated areas of the world, but were higher than those of people in non-contaminated areas. Concentrations of As and Mn in hair of some individuals from the Gia Lam and Thanh Tri Districts exceeded the level associated with their toxicity and, therefore, a potential health risk of As and Mn is a concern for the people consuming the contaminated water in this area. Cumulative As exposure was estimated to be lower than the threshold levels at the present, which might explain the absence of manifestations of chronic As poisoning and arsenicosis in the residents of Gia Lam and Thanh Tri Districts. To our knowledge, this study revealed for the first time that the residents are exposed not only to As but also Mn and Ba from groundwater in the Red River Delta, Vietnam.     

Polybrominated diphenyl ethers in plastic products,indoor dust,sediment and fish from informal e-waste recycling sites in Vietnam: a comprehensive assessment of contamination,accumulation pattern,emissions, and human exposure

Residue concentrations of polybrominated diphenyl ethers (PBDEs) in different kinds of samples including consumer products, indoor dust, sediment and fish collected from two e-waste recycling sites, and some industrial, urban and suburban areas in Vietnam were determined to provide a comprehensive assessment of the contamination levels, accumulation pattern, emission potential and human exposure through dust ingestion and fish consumption. There was a large variation of PBDE levels in plastic parts of obsolete electronic equipment (from 1730 to 97,300 ng/g), which is a common result observed in consumer plastic products reported elsewhere. PBDE levels in indoor dust samples collected from e-waste recycling sites ranged from 250 to 8740 ng/g, which were markedly higher than those in industrial areas and household offices. Emission rate of PBDEs from plastic parts of disposed electronic equipment to dust was estimated to be in a range from 3.4 × 10^?7 to 1.2 × 10^?5 (year^?1) for total PBDEs and from 2.9 × 10^?7 to 7.2 × 10^?6 (year^?1) for BDE-209. Some fish species collected from ponds in e-waste recycling villages contained elevated levels of PBDEs, especially BDE-209, which were markedly higher than those in fish previously reported. Overall, levels and patterns of PBDE accumulation in different kinds of samples suggest significant emission from e-waste sites and that these areas are potential sources of PBDE contamination. Intakes of PBDEs via fish consumption were generally higher than those estimated through dust ingestion. Intake of BDE-99 and BDE-209 through dust ingestion contributes a large proportion due to higher concentrations in dust and fish. Body weight normalized daily intake through dust ingestion estimated for the e-waste recycling sites (0.10–3.46 ng/day/kg body wt.) were in a high range as compared to those reported in other countries. Our results highlight the potential releases of PBDEs from informal recycling activities and the high degree of human exposure and suggest the need for continuous investigations on environmental pollution and toxic impacts of e-waste-related hazardous chemicals.     

Impact of simulated acid rain on the growth of three species Brassica integrifolia,Brassica rapa,Brassica juncea in Hanoi,Vietnam

Environmental Science and Pollution Research - Over the past decade, the extent and magnitude of acid rain in Vietnam and other Asian countries have become more apparent. In this study, the effect...     

Effects of introducing energy recovery processes to the municipal solid waste management system in Ulaanbaatar, Mongolia

Currently, most developing countries have not set up municipal solid waste management systemswith a viewof recovering energy fromwaste or reducing greenhouse gasemissions. In this article, we have studied the possible effects of introducing three energy recovery processes either as a single or combination approach, refuse derived fuel production, incineration and waste power generation, and methane gas recovery from landfill and power generation in Ulaanbaatar, Mongolia, as a case study. We concluded that incineration process is the most suitable as first introduction of energy recovery. To operate it efficiently, 3Rs strategies need to be promoted. And then, RDF production which is made of waste papers and plastics in high level of sortingmay be considered as the second step of energy recovery. However, safety control and marketability of RDF will be required at that moment.     

Main and added effects of heatwaves on hospitalizations for mental and behavioral disorders in a tropical megacity of Vietnam

Environmental Science and Pollution Research - Vietnam is highly vulnerable to climate change-related extreme weather events such as heatwaves. This study assesses the association between heatwaves...