Understanding the impact of hydropower developments in the context of upstream–downstream relations in the Mekong river basin

Hydropower developments along the main stem of the Mekong River and its tributaries cause transboundary effects within the Mekong Basin Region, which comprises parts of six countries. On the one hand, the provision of hydropower triggers economic development and helps to meet the rising energy demand of the Mekong riparian countries, especially China, Thailand, and Vietnam. On the other hand, the negative impact of dam construction, mainly altered water flow and sediment load, has severe impacts on the environment and the livelihoods of the rural Mekong population. Several discrepancies exist in the needs, demands, and challenges of upstream versus downstream countries. Against the common apprehension that downstream countries are powerlessly exposed to mainly negative impacts whereas upstream countries unilaterally benefit from hydropower, the authors argue that upstream–downstream relations are not really clear-cut. This conclusion is based on a consideration of the complex power play between Mekong riparians, with a focus on recent power trade interactions. The article investigates the consequences of hydropower dams for the Mekong region as well as the role of supranational players, such as the Mekong River Commission and the Greater Mekong Subregion Initiative, on the hydropower debate. It is not nations that are the winners or losers in the hydropower schemes in the Mekong, but rather parts of the riparian population: a few influential and powerful elites versus the large mass of rural poor.     

Lignin and polylactic acid for the production of bioplastics and valuable chemicals

Environmental Chemistry Letters - Global warming and plastic pollution result from the massive use of fossil fuels, calling for the development of sustainable bioplastics derived...     

Resource use efficiency and economic losses: implications for sustainable rice production in Vietnam

The study aimed to estimate resource use efficiency and economic losses by using stochastic frontier analysis. The data set were collected in An Giang Province of Vietnam through personal interviews with 199 rice farmers. The results revealed that returns to scale are decreasing. Rice farmers had high levels of output-oriented and input-oriented technical efficiency with the means of 91.92 and 85.39 %, respectively. The mean environmental efficiency was 82.03 %. The mean efficiency of normal inputs was 61.20 %. Among the bad inputs, pesticide and energy were the least efficient ones with the mean values of 51.39 and 45.53 %, respectively, indicating serious overuses of these inputs. As regards normal inputs, capital had the lowest efficiency score at 21.08 %, followed by seed quantity at 26.4 %. Further, the total economic losses were estimated at 8261 thousand VND (380 USD) per hectare, which is equal to the sales of about 1600 kg of rice per hectare or the efforts to increase by 20 % of output level. This study suggests that rice farmers need to contract inputs, particularly environmentally detrimental inputs to improve profits. To improve the productive efficiency, the use of ecological engineering, collective pump and cultivation of three rice crops per year are possible options.     

Accumulation features of persistent organochlorines in resident and migratory birds from Asia

Concentrations of organochlorine contaminants including polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), chlordane compounds (CHLs), hexachlorobenzene (HCB) were determined in the resident and migratory birds, which were collected from India, Japan, Philippines, Russia (Lake Baikal) and Vietnam. Accumulation patterns of organochlorine concentrations in resident birds suggested that the predominant contaminants of each country were as follows: Japan--PCBs Philippines--PCBs and CHLs, India--HCHs and DDTs, Vietnam--DDTs, and Lake Baikal--PCBs and DDTs. The migratory birds from Philippines and Vietnam retained mostly the highest concentrations of DDTs among the organochlorines analyzed, indicating the presence of stopover and breeding grounds of those birds in China and Russia. On the other hand, migratory birds from India and Lake Baikal showed different patterns of organochlorine residues, reflecting that each species has inherent migratory routes and thus has exposure to different contaminants. Species which have breeding grounds around the Red Sea and Persian Gulf showed high levels of PCBs, indicating the presence of areas heavily polluted by PCBs in the Middle East.     

Implementing In-Stream Nutrient Processes in Large-Scale Landscape Modeling for the Impact Assessment on Water Quality

For a long time, watershed models focused on the transport of chemicals from the terrestrial part of the watershed to the surface water bodies by leaching and erosion. After the substances had reached the surface water, they were routed through the channel network often without any further transformation. Today, there is a need to extend watershed models with in-stream processes to bring them closer to natural conditions and to enhance their usability as support tools for water management and water quality policies. This paper presents experience with implementing in-stream processes in a ecohydrological dynamic watershed model and its application on the large scale in the Saale River basin in Germany. Results demonstrate that new implemented water quality parameters like chlorophyll a concentrations or oxygen amount in the reach can be reproduced quite well, although the model results, compared with results achieved without taking into account algal and transformation processes in the river, show obvious improvement only for some of the examined nutrients. Finally, some climate and water management scenarios expected to impact in-stream processes in the Saale basin were run. Their results illustrate the relative importance of physical boundary conditions on the amount and concentration of the phytoplankton, which leads to the conclusion that measures to improve water quality should not only take nutrient inputs into account but also climate influences and river morphology.     

Study of high-frequency electromagnetic field effect on some somatic and neuro-behavioral characteristics in healthy and neurodefective mice

The effect of long-term exposure to high frequency electromagnetic field (HF EMF) on some somatic and neural characteristics was studied in neurodefective Lurcher mutant (+/Lc) and normal wild type mice (+/+). Both newborn and young adult (3 months) animals derived from two strains (C3H, B6CBA) were exposed to HF EMF (870 MHz) from 1st to 21st day or from 91st to 120th day respectively. In animals of both groups and controls we observed the development of body weight. Moreover, in the HF EMF exposed adult B6CBA animals we studied spatial learning ability, motor functions and the CNS excitability. To investigate specific energy absorption rate (SAR) in experimental animals we have done the basic 3D calculations of the electromagnetic energy distribution in the simplified model of the mouse. The HF EMF exposed animals exhibited mild differences of body weight between them and unexposed controls. The long-term exposure to HF EMF did not significantly influence the ability to learn in the Morris water maze. However, significant lower swimming speed was found in the irradiated +/Lc as well as lower motor activity of +/+ in the open field when compared to controls. No significant differences were found between HF EMF irradiated animals and controls in examination of the CNS excitability and motor functions.     

Arsenic-contaminated groundwater and its potential health risk: A case study in Long An and Tien Giang provinces of the Mekong Delta,Vietnam

Environmental Science and Pollution Research - The occurrence of arsenic (As) in groundwater (drilled well water) that were used for drinking, cooking, and personal hygiene and its risks to human...