Coastal groundwater aquifer characterization from geoelectrical measurements- A case study at Kalapara, Patuakhali, Bangladesh.

Vertical electrical sounding has been carried out in a coastal area in the southern part of Bangladesh to locate the groundwater aquifers containing fresh water. The Interpex1X1Dv3 computer program was used to process the field apparent resistivity data sets obtained from the vertical electrical sounding.  Geoelectric layers were identified in the context of resistivity and thickness from the vertical electrical sounding data. From the initial parameters layered model was achieved using the inversion technique. Correlation of the obtained layer model with a nearby lithologic log concludes the groundwater aquifer system of the area. From the electrical properties of the subsurface layers, water bearing layers were detected and characterized. Very fine sand geoelectric layer with a thickness varying from 20 to 143 meters is an upper aquifer and has 0.66–14.02 Ωm apparent resistivity value. Fine sand geoelectric layer with 0.21-5.99 Ωm apparent resistivity value is lower aquifer with maximum thickness ~250 meters. From the resistivity value, it is observed that the upper aquifer contains saline to brackish-fresh water while the resistivity value of the lower aquifer indicates that it contains saline water. The water quality of the upper zone varies geographically from the southern to the northern part in the investigated area. The water quality of the upper aquifer is fresh in the northern part of the study while lower aquifer contains saline water there

Exploring impacts and livelihood vulnerability of riverbank erosion hazard among rural household along the river Padma of Bangladesh

Abstract Background Riverbank erosion has both direct and indirect effects on human life and socio-economy of Bangladesh. The present study investigated the riverbank erosion hazard in study area, its impacts on local people and livelihood vulnerability due to land loss. Methods To evaluate the riverbank erosion hazard in the study area, data have been collected from relevant scientific literatures, different government and non-government organizations, informal interview, questionnaire survey and Focused Group Discussion; and analyzed through different computer program and index. Results From the study, it was found that from 1973 to 2011, about 189.4 km2 lands was eroded from the left bank section and only 23.66 km2 was accreted with a net loss of 155 km2. Instead, right bank of the Padma River behaved in the opposite manner with 166.53 km2 erosion and 134.45 km2 accretions. Comparing to the right bank, left bank was more vulnerable to erosion which destroyed the permanent stable lands. However, the value of the newly accreted char land is very low compare to the main land. Thus this hazard creates a great loss in the local economy. Within the studied time range the monetary loss is about 1414.81 million BDT (17,422,937.16 $). Many wealthy farmers of the study area turn into marginal farmer and even landless due to the erosional hazard. Agricultural land becomes barren land by huge siltation and the cropping pattern has been changed significantly. In addition, the infrastructure and property losses are enormous. From the results of vulnerability index (IPCC-VI) it suggests that the most vulnerable areas are identified as Boyra (0.061), Kanchanpur (0.062), Lesragonj (0.064), Azimnagar (0.067), Sutalori (0.071) and Dhulsonra (0.076) because of more sensitivity and less adaptive capacity. On the other hand, Balara (− 0.017) and Balla (− 0.019) are comparatively least vulnerable comparing to the previous sites. Conclusions As, riverbank erosion is one of the most hazardous disasters in the study area; so treating independent separate policies and program for the vulnerable areas might helpful to support the affected community

Water Quality Criteria and Ecological Risk Assessment of Typical Transition Metals in South Asia

Transition metal pollution in rivers in South Asia is more serious than in other regions because of the lack of adequate freshwater management measures. Water quality criteria (WQC) for South Asia is urgently needed to protect regional aquatic environments because of the occurrence of transboundary rivers. The present study established non-parametric kernel density estimation species sensitivity distribution (NPKDE-SSD) models and then derived the acceptable hazardous concentration for protection of 95% of all aquatic species (HC5) and WQC of six typical transition metals in South Asia. The results showed that the order of acute and chronic WQC was Mn > Fe > Cd > Zn > Cu > Hg and Cu > Fe > Cd, respectively. A risk assessment of these metals in the Indus River, the Ganges River, the Brahmaputra River, the Meghna River, and the Bagmati River was also carried out. Based on the results, these major rivers in South Asia were highly polluted with transition metals, with significant ecological risks for a large number of aquatic species. This study can contribute to a better understanding of ecological risks in South Asia and provide a scientific basis for the updating of water quality standards and the increase in overall water quality

A Soil Health Card (SHC) for soil quality monitoring of agricultural lands in south-eastern coastal region of Bangladesh

Abstract Background The present study introduces an alternate tool of laboratory analysis named Soil Health Card (SHC) for soil quality monitoring and routine field observations by farmers. Results Different physicochemical and nutrient contents of soil, i.e. pH, electric conductivity, soil organic matter, organic carbon, total nitrogen, phosphorous, sulfur and boron were assessed by laboratory analysis collected from the different fields of Noakhali district of Bangladesh. These parameters were scored according to the soil fertility standards according to Bangladesh Agriculture Research Council. Results found that, the soil quality of all the studied fields are medium category. Again, a SHC was prepared using soil structure, subsurface compaction, aggregate stability, status of ground cover, soil smell, soil pH, color, organic matter content, drainage capacity, diversity of micro-life, earthworm contents, infiltration rate, soil aeration, crop coverage and leaf color. The result of SHC is interestingly similar to the laboratory experiment results. Conclusions Analyzing these two methods it was found that, the SHC is truly representative, much convenient, precise, coast effective and easily understandable to the marginal farmers. However, SHC can be an alternative to farmer for sustainable farm management

Genetic surveillance in the Greater Mekong subregion and South Asia to support malaria control and elimination.

BackgroundNational Malaria Control Programmes (NMCPs) currently make limited use of parasite genetic data. We have developed GenRe-Mekong, a platform for genetic surveillance of malaria in the Greater Mekong Subregion (GMS) that enables NMCPs to implement large-scale surveillance projects by integrating simple sample collection procedures in routine public health procedures.MethodsSamples from symptomatic patients are processed by SpotMalaria, a high-throughput system that produces a comprehensive set of genotypes comprising several drug resistance markers, species markers and a genomic barcode. GenRe-Mekong delivers Genetic Report Cards, a compendium of genotypes and phenotype predictions used to map prevalence of resistance to multiple drugs.ResultsGenRe-Mekong has worked with NMCPs and research projects in eight countries, processing 9623 samples from clinical cases. Monitoring resistance markers has been valuable for tracking the rapid spread of parasites resistant to the dihydroartemisinin-piperaquine combination therapy. In Vietnam and Laos, GenRe-Mekong data have provided novel knowledge about the spread of these resistant strains into previously unaffected provinces, informing decision-making by NMCPs.ConclusionsGenRe-Mekong provides detailed knowledge about drug resistance at a local level, and facilitates data sharing at a regional level, enabling cross-border resistance monitoring and providing the public health community with valuable insights. The project provides a rich open data resource to benefit the entire malaria community.FundingThe GenRe-Mekong project is funded by the Bill and Melinda Gates Foundation (OPP11188166, OPP1204268). Genotyping and sequencing were funded by the Wellcome Trust (098051, 206194, 203141, 090770, 204911, 106698/B/14/Z) and Medical Research Council (G0600718). A proportion of samples were collected with the support of the UK Department for International Development (201900, M006212), and Intramural Research Program of the National Institute of Allergy and Infectious Diseases