Southeast Bangladesh Research Articles

Heavy metal contamination of freshwater prawn (Macrobrachium rosenbergii) and prawn feed in Bangladesh: A market-based study to highlight probable health risks

An assessment of the dietary risk of heavy metal exposure to humans is important since it is the main source of exposure. This study aimed to estimate the degree of contamination and assess the probable health risk in the prawn food chain. In prawn feed, the concentrations of metals were detected in the following order: Hg > Co > Pb > Cd. The concentrations of heavy metals in prawn were the highest for Co and lowest for Cd. Trace amounts of As and Cr were detected in the analyzed sample. Target hazard quotients for heavy metals for adults were >1 for Pb, Cd, Hg, and Co, and for children, the same were high for Co and Hg, indicating significant health risks upon dietary exposure. All the prawn samples contained nine-fold and fourteen-fold higher concentrations than the maximum acceptable levels for Pb and Hg, respectively (0.5 mg kg−1; WHO/FAO). Human health risk due to the Co exposure is quite alarming as the level of exposure was found to be very high. In the prawn samples intended for human consumption, the hazard index (HI) was highest in the samples obtained from Bagerhat (3.25 in flesh and 3.26 in skin), followed by the samples obtained from Satkhira (2.84 in flesh and 3.10 in skin) and Dhaka City Corporation (2.81 in flesh and 3.42 in Skin); this indicates a potential risk of prawn consumption obtained from Southeast Bangladesh. This is particularly problematic as this area accounts for the majority of prawn production and export of the country.

Mobility aspirations and indigenous belonging among Chakma students in Dhaka

ABSTRACTIn recent decades, indigenous people from the Chittagong Hill Tracts (CHT) in South-east Bangladesh have experienced increased social and spatial mobility. This article investigates how indigenous students from the CHT region who have migrated to Dhaka redefine indigenous belonging. By highlighting the juxtaposition of different forms of mobility (physical and social) the paper responds to a recent trend which has only rarely been the subject of scholarly enquiry. In particular, it examines the experiences of mobility of individual students and explores the ways in which these students justify their quest for higher education to fulfil their aspirations for a better future. The paper also reveals the obstacles students experience in their everyday lives, mainly in the form of stereotypical, often racist talk. It discusses the structural disadvantages indigenous students face as members of ethnic minorities as well as the strategies employed by the students to counter them. Furthermore, the paper illustrates how indigenous students negotiate urban lifestyles and redefine modernity and indigeneity simultaneously and how migrants face exclusion based on static interpretations of people from the CHT as put forward in mainstream discourses as well as by transnational indigenous activist networks. These lead to feelings of alienation between indigenous students and their Bengali Bangladeshi peers, leaving students to increasingly draw on indigenous networks to achieve mobility.

Shoreline changes along the Kutubdia Island, south east Bangladesh using digital shoreline analysis system

A ~65 km coastal stretch has been analyzed to estimate the change dynamics of Kutubdia Island with the help of digital shoreline analysis system (DSAS). This study investigated the reliability of medium resolution satellite imagery for mapping shoreline positions and for estimating historic rates of changes. Nine shoreline positions were extracted on 1972, 1976, 1980, 1989, 1999, 2004, 2009, 2011 and 2014 covering a long term of 42 years period. Rates of shoreline changes were estimated by four statistical methods namely, end point rate (EPR), linear regression rate (LRR), weighted linear regression (WLR) and least median of squares (LMS) by using DSAS and subsequently all the methods were verified with the correlation coefficient (R).The scrutiny of shoreline changes shows that the erosion during the last 42 years has affected the island, with some exception, at the north and west segment where minor accretion has been documented. The average rates of changes estimated for north, south, east and west segment using WLR, LMS, EPR and LRR are Ñ4.0 m/yr, Ñ33.7 m/yr Ñ2.6 m/yr and Ñ5.6 m/yr, respectively. The outcome of this particular analysis might be useful for proper planning and management of Kutubida Island. However, this may also be used in statistical modeling for forecasting the future shoreline position.Bangladesh J. Sci. Res. 27(1): 99-108, June-2014

Mutation Spectrum of β-Thalassemia and Other Hemoglobinopathies in Chittagong, Southeast Bangladesh

Thalassemia is one of the most common autosomal recessive blood disorders in the world. It shows a variety of clinical expression, starting from asymptomatic to severe blood transfusion dependence. More than 500 alleles have been characterized in or around the β-globin region. Moreover, most geographical regions have their own characteristics, frequency and availability of these alleles, predominantly circulating within the communities present in that particular region. In this study, we explored the spectrum of β-thalassemia (β-thal) alleles present in Chittagong, Southeast Bangladesh. This study comprises β-thal and Hb E (HBB: c.79 G > A) patients from in and around the area of Chittagong. Not only exploring the complete β-globin mutation spectrum of the area, but we also tried to look at the origin of the mutated alleles. The β-thal mutations of Bangladesh show a relatively wide spectrum of alleles, which further demonstrates the heterogeneity of the disease in this country. Although our study showed that the majority of the mutations have their origin in neighboring countries such as India, countries of Southeast Asia, Pakistan, etc., some unusual alleles do not originate in neighboring countries and put a little more diversity in the overall spectrum of β-thal-specific alleles. Overall, this study demonstrates the mutation spectrum related to β-thal in Chittagong, Southeast Bangladesh.

Two Sample Sputum Microscopy and Revised Tuberculosis Case Definition by WHO: Bangladesh Perspective

INTRODUCTION: Three samples of sputum (Spot-Morning-Spot) used for screening patients with suspected pulmonary tuberculosis in Bangladesh. At least two positive samples required for case definition. Cases with single positive smear require additional chest x-ray or culture. The study was done to evaluate utility of two sputum samples for case detection and whether adoption of new case definition (requiring single positive sample) recommended by World Health Organization adds advantage over current case definition for diagnosing smear positive pulmonary tuberculosis. MATERIAL AND METHODS: Retrospective analysis of sputum positive pulmonary tuberculosis cases taken from two separate hospitals in southeast Bangladesh. Frequency, pattern and increment of smear positivity noted in each samples. Smear positive cases reevaluated using proposed case definition and compared with current national definition. RESULTS: Sputum positivity for first, second and third samples was 71.6%, 99.0% and 97.3% respectively (n=408). Incremental new case detection rate was 71.6%. 28.1% and 0.2% in same order. Morning sputum had the highest sensitivity for case detection (99.0%). Incremental new case detection from third sample was negligible and using current case definition of sputum positive tuberculosis in three samples left some inconclusive cases requiring further x- ray or culture for diagnosis pending decision further. Adoption of new case definition reduces number of inconclusive cases and diagnostic delay. CONCLUSION: Two sputum samples adequate for screening of tuberculosis suspects. Adopting new case definition will reduce number of cases left inconclusive with microscopy alone (using current case definition). This will strengthen role of microscopy in tuberculosis detection in low resource setting.DOI: http://dx.doi.org/10.3126/jucms.v2i4.12034 Journal of Universal College of Medical Sciences (2014) Vol.02 No.04 Issue 08Page: 1-6

Mesoscale simulation of a flood producing rainstorm over Rangamati, Bangladesh using MM5 model

Mesoscale simulation of a flood producing rainstorm of 21 June 2004 over Rangamati, Bangladesh has been carried out using the MM5 Model. The model performance was evaluated by examining the different predicted and model derived parameters. The MM5 model suggests that the rainstorm over Rangamati was resulted by the large scale weather circulation associated with active conditions of southwest summer monsoon over the head Bay of Bengal which generated favourable conditions for developing the severe mesoscale convections. The strong confluence of southwesterly low level flow transporting large amount of moisture (which vertically extended up to 350 hPa) from the Bay of Bengal towards southeast Bangladesh and its neighbourhoods appears to be one of the striking features. An elongated vorticity maximum of the order of 30-40×10 -5 s -1 was observed across the Rangamati. A well-defined area of low level convergence (-25×10 -5 s -1 ) is associated with strong divergence (25×10 -5 s -1 ) in the high level (200 hPa) has provided favourable conditions for strong convection. The model simulated realistic pattern of rainfall over Rangamati as compared with TRMM observations. Considering the quantitative comparison of the domain average rainfall with TRMM observations, it is found that the model over predicts by 12% as compared with TRMM observed rainfall.

Laboratory Enrichment of Radioactive Assemblages and Estimation of Thorium and Uranium Radioactivity in Fractions Separated from Placer Sands in Southeast Bangladesh

The present study reports the likely first attempt of separating radioactive minerals for estimation of activity concentration in the beach placer sands of Bangladesh. Several sand samples from heavy mineral deposits located at the south-eastern coastal belt of Bangladesh were processed to physically upgrade their radioactivity concentrations using plant and laboratory equipment. Following some modified flow procedure, individual fractions were separated and investigated using gamma-ray spectrometry and powder-XRD analysis. The radioactivity measurements indicated contributions of the thorium and uranium radioactive series and of 40K. The maximum values of 232Th and 238U, estimated from the radioactivity of 208Tl and 234Th in secular equilibrium, were found to be 152,000 and 63,300 Bq/kg, respectively. The fraction of the moderately conductive part in electric separation contained thorium predominantly, while that of the non-conductive part was found to be uranium rich. The present arrangement of the pilot plant cascade and the fine tuning of setting parameters were found to be effective and economic separation process of the radioactive minerals from placer sands in Bangladesh. Probable radiological impacts and extraction potentiality of such radioactive materials are also discussed.

Dietetic use of wild animals and traditional cultural beliefs in the Mro community of Bangladesh: an insight into biodiversity conservation

Meeting the demand for regular animal protein, for human consumption, through hunting wild animals is a worldwide, common phenomenon in traditional communities. Hunting, which constitutes an essential part of the tribal culture, is also contributing to the steady loss of faunal diversity. Equally, however, traditional cultural beliefs and taboos which exist in tribal societies are in fact favorable for species conservation. There is increasing global interest surrounding this paradoxical relationship, as well as efforts being made for finding more effective ways of biodiversity conservation and sustainable development within indigenous, tribal communities. This study is a preliminary attempt to explore such a culture and its impact on local biodiversity in the hill forests of southeast Bangladesh, based on a case study of the Mro tribe, the oldest aboriginal group of the country. A total of 45 wildlife species were recorded currently available in the neighbouring forests, from which the Mro harvest for food and other complementary daily uses. Eight species (five mammals and three birds) were revealed to be at risk of disappearance from the region due to over-harvesting. Conversely, long-established ritual taboos were found to be effective in the protection of five species (two mammals, two birds and one reptile). Careful investigation and official recognition of these practices, along with community awareness and stakeholder involvement, may heighten the success of conservation programmes. It is argued that finding alternative protein sources for this marginal local community should be a key incentive for encouraging their involvement in conservation programmes.

Peat Resources, Condition of Deposition as Well as their Utilization, Hakaluki Haor, Moulvibazar and Sylhet District, Bangladesh

The study area is the Hakaluki Haor which is the second largest wet land of Bangladesh. It spans over the districts of Moulvibazar and Sylhet in southeast Bangladesh. The study was focused in the exploration of peat reserve, reconstruction of the paleo-environment as well as the utilization of the peat resources. Peat is found randomly from 0.5 m to 7 m below the surface and 1 m to 11 m thickness at over 40 beels as well as small plain lands of 90 km2 area of Hakaluki Haor. The total reserve of peat is 282 million ton in wet condition and 112 million ton in dry condition. Peat bearing Hakaluki Haor is a low-lying wet land which geological term is synclinal depression. It may be a syncline between two anticlines which was filled with sediments as well as various plant materials derived from the hilly region (anticline) on both sides (west and east) of the Haor. On the other hand vegetation occurred in this depression as aquatic plants which might have been destroyed by large natural disasters or any tectonic reason. As environment dictates the characteristics and the source of sediments, various aspects of the sediment are indicators of condition of peat deposition. Peat has mainly industrial importance as a fuel for power production, traditionally used for cooking, domestic heating and in brick fields, also used as insulator in many industries, agricultural purposes, retaining moisture in soil, raw material in horticulture and colour industries etc. Power plants of about 100 MW capacities may be established in this region based on peat of Hakaluki Haor which may be continued more than one hundred years.

An analysis of the AD1762 earthquake and tsunami in SE Bangladesh

In AD1762, a large earthquake originating within the Arakan Subduction Zone occurred. However, conflicting opinions exist as to whether this earthquake triggered a major regional tsunami in the northern Bay of Bengal (BoB) that struck southeast Bangladesh. This research aims to review and assess the effects of the AD1762 earthquake in Bangladesh and reviews what effects associated tsunamis had along the coast of southeast Bangladesh. Through field visits and investigations, this research confirms the locations of liquefaction, compaction, landslides, co-seismic subsidence, deaths and injuries using the descriptions of historical documents as a guide. The earthquake triggered land-level changes where the soil is young and soft, and these areas are located adjacent to the coast of the BoB and along the banks of the Karnafuli, Halda and Meghna rivers. The earthquake probably generated several submarine sediment slides that triggered local tsunamis that struck different locations (Bansbaria, Bharchhara and Burumchhara) along the Chittagong coast. Following an analysis of the earthquake effects, we consider that a repeat of the AD1762 earthquake would result in significant damage to fragile infrastructure and to vulnerable communities in Bangladesh. Further, we recommend (1) conducting geological and geomorphological studies at key sites to assess the nature and extent of land-level changes; (2) undertaking socially oriented community vulnerability assessments to earthquakes and tsunamis; and (3) implementing a variety of risk-reduction strategies to reduce vulnerability and enhance resilience to future events.

Synoptic Analysis of a Heavy Rainfall Event over Southeast Region of Bangladesh Using WRF Model

Synoptic analysis of the heavy rainfall event of 7 September 2011 was carried out using the Weather Research and Forecasting (WRF) Model. This extraordinary rainfall event was localized over the southeast region of Bangladesh and recorded rainfall was 331 mm at Chittagong and 226 mm at Sandwip within a span of 24-h. The model was run at 9 km horizontal resolution using KF CPS with YSU PBL scheme. The model performance was evaluated by examining the different predicted parameters like mean sea level pressure, upper and lower level circulations, wind shear, relative vorticity, convergence, moisture and rainfall. The rainfall was validated with TRMM 3B42RT and observed rainfall data. The results indicate that the WRF model was able to simulate the heavy rainfall event, and associated synoptic features reasonably well, though there are some biases in the rainfall pattern. The results suggest that the highly localized heavy rain over southeast Bangladesh was the result of an interaction of the large scale monsoon system with cyclonic disturbances and required moisture have been supplied from the Bay of Bengal. The low level flow facilitated strong convergence over the region due to horizontal wind shear, which resulted in maintenance of the storms. Keywords: Heavy Rainfall; WRF Model; Simulation; Validation; TRMM. © 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v5i3.13171 J. Sci. Res. 5 (3), 421-434 (2013)

Opportunities and challenges for the development of prawn farming with fish and rice in southeast Bangladesh: potential for food security and economic growth

Although prawn farming in rice fields is concentrated in the southwest of Bangladesh, the southeast region has been identified as a promising area for prawn culture, owing to favorable resources and agro-climatic conditions. To date, however, relatively few farmers in this area have adopted prawn culture. We examined the opportunities and constraints for the development of prawn farming with fish and rice in southeast Bangladesh. The prospects for prawn-carp polyculture and integrated prawn-fish-rice farming in southeast Bangladesh are positive but require institutional and organizational support, and technical assistance. We conclude that the sustainable development of prawn farming with fish and rice in southeast Bangladesh has considerable potential for increasing incomes and improving the food security of farming households, and more broadly the economic growth of the country through earnings from the export of prawns.

Rates of shoreline change along the coast of Bangladesh

Bangladesh, at the confluence of the sediment-laden Ganges and Brahmaputra Rivers, supports an enormous and rapidly growing population (>140 million in 2011), across low-lying alluvial and delta plains that have accumulated over the past few thousand years. It has been identified as one of the most vulnerable places in the world to the impacts of climate change and sea-level rise. Although abundant sediment supply has resulted in accretion on some parts of the coast of Bangladesh, others are experiencing rapid erosion. We report a systematic assessment of rates of shoreline change over a 20-year period from 1989 to 2009, using Landsat satellite images with pixel resolution of 30 m on the ground. A Band ratio approach, using Band-5 divided by Band-2, discriminated the water line on images that were largely cloud-free, adequately registered, and at comparable tidal stages. Rates of shoreline change were calculated for >16,000 transects generated at 50 m intervals along the entire mainland coastline (>1,100 km) and major islands, using the End Point Rate (EPR) method in the Digital Shoreline Analysis System (DSAS) extension in ArcGIS®. Erosion characterises most of the seaward margin of the Sundarbans in western Bangladesh. Retreat rates of up to 20 m/yr are typical, with little evidence that local devastation of the mangrove fringe by Cyclone Sidr in November 2007 had resulted in uncharacteristic long-term rates of retreat where it made landfall. Erosion exceeded accretion in the Barguna Patuakhali coastal zone, most of which eroded at up to 20 m/yr, but with truncation of the southern tip of the Patharghata Upazila at up to 100 m/yr. In Bhola, erosion at rates of up to 120 m/yr were observed along much of the coast, but in the Noakhali Feni coastal zone, similar rates of erosion were balanced by rapid accretion of the main promontory by more than 600 m/yr. Rates of change were more subdued in the Chittagong and Cox’s Bazar coastal zones of southeast Bangladesh. Islands in the Meghna estuary were especially dynamic; Hatiya Island accreted along some of its shoreline by 50 km2 between 1989 and 2009, but lost 65 km2 through erosion elsewhere, resulting in the island moving south. Similar trends were observed on adjacent islands. The overall area changed relatively little across the entire coastline over the 20-year period with accretion of up to 315 km2, countered by erosion of about 307 km2.

14C dating of deep groundwater in the Bengal Aquifer System, Bangladesh: Implications for aquifer anisotropy, recharge sources and sustainability

Environmental isotopes and 14C dating were applied to estimate ages and recharge sources of deep groundwater (⩾150 m bgl) in south-east Bangladesh. With one exception, deep groundwater is shown to have been recharged more recently than 10 Ka (range 3–9 Ka, mean 7.6 Ka), under climatic conditions indicated by δ18O and δ2H as similar to the present day. Groundwater age distributions have been used to infer the scale of aquifer hydraulic anisotropy. 2D groundwater flow modelling is able to reproduce the observed vertical profiles of groundwater age, as determined at two locations, when the aquifer is assigned a permeability anisotropy (Kx/Kz) of at least 103. Under these conditions, deep groundwater originates as recharge in the hill regions at the eastern boundary of the basin. Recharge rates estimated from the groundwater ages are close to an estimate of the current rate of deep groundwater abstraction. Cautious development and careful monitoring are therefore necessary, as excessive deep groundwater pumping could draw dissolved arsenic from the shallow levels of the Bengal Aquifer System (BAS) and contaminate the deep groundwater resource.

Book Review: Oceans of Crime: Maritime Piracy and Transnational Security in Southeast Asia and Bangladesh

Book Review: Oceans of Crime: Maritime Piracy and Transnational Security in Southeast Asia and Bangladesh

A note on water quality associated with slaughter premises in Bangladesh

Water quality used for washing carcasses and abattoir premises was assessed at two sites in southeast Bangladesh. In addition, the effect of discharging untreated washings from slaughter premises on water purity in the receiving waterways was assessed from pH, dissolved oxygen and electrical conductivity measurements. Premises effluents did not have a significant effect on the physico-chemical properties of the water in the receiving canals, as determined from the difference between the 4 m upstream and 4 m downstream samples, relative to the entry point of the effluent. When a water shortage occurred at one of the premises, water was sourced for washing the carcasses and premises from a canal that was also used for conveying municipal effluent. The discharge water from the premises at this time had a pH, dissolved oxygen content and conductivity of 7.93, 1.84 mg/L and 6.06 mS/cm respectively, and this would be a threat to survival of freshwater animal life.

Human–wildlife conflicts and management options in Bangladesh, with special reference to Asian elephants (Elephas maximus)

In this study, we explored the interaction between humans and Asian elephants (Elephas maximus). We analysed local mitigation techniques and propose possible measures to reduce human–elephant conflicts. For four protected areas in Bangladesh, we investigated how people interact with elephants and other crop-damaging species. Crop-damaging species differed from site to site, but elephants were generally the most frequent offenders. Although some people were able to control crop damage caused by other wildlife, damage caused by wild elephants was mostly uncontrollable. Forest villagers were somewhat tolerant of damage caused by other wildlife but they were not tolerant of damage caused by wild elephants. Tolerance of crop damage caused by wildlife other than wild elephants tended to increase with distance of respondents from protected areas. Non-tolerance of crop damage caused by wildlife was more common in southeast Bangladesh than in the north. Habitat destruction, caused by high population growth and poverty, appeared to be a major cause for increasing human–elephant conflict. There is an urgent need for adoption of an umbrella strategy (e.g. estimate the size of elephant populations, develop landscape-scale conservation plans and create forest buffer zones under community-based natural resource management schemes) in the use of conflict mitigation as a conservation tool for Asian elephants.

Traditional practice of palm husbandry in the southeastern region of rural Bangladesh: status and potentials

An exploratory study was conducted in Feni, in southeast Bangladesh, to determine the status and potentials of palm husbandry in the rural economy. A total of 48 households in the study area were interviewed using a semi-structured questionnaire. The farmers were categorized into five groups based on their landholdings. Palms comprised the highest percentage (53%) of homegarden species. The most common palm was betel nut (Areca catechu). This species was distributed over five different geographical sites, of which roadsides were most common. Farmers with medium landholdings had the greatest number of palms. Farmers typically received considerably less compensation than distributors higher in the marketing chain who handled their product. Juice or sap from the wild date palm (Phoenix sylvestris) gave the highest net average profit per liter and annual income per tree. Landless farmers gain the highest proportion of their mean annual income from palm husbandry.

Geological structure, sedimentation conditions, and petroleum potential of sedimentary basins in Southeast Asia

Sedimentary basins located in the continent-to-ocean transition zones with an active tectonic regime are extremely different in terms of both geological structure and composition of rocks with the hydrocarbon-hosting potential. Oil-and-gas fields in such zones are confined not only to the deltaic, coastal-marine, and submarine-slope sandstones, as well as limestones and dolomites of buried carbonate banks, but also to silicic and volcanic rocks. Such fields have been discovered in weathering crusts of granite plutons, metamorphic rocks of the basement, fissured basalts, and other magmatic rocks. This is demonstrated vividly by the Southeast Asia region, including Indonesia, Malaysia, Vietnam, Bangladesh, and other countries, where fore-arc, back-arc, inter-arc, and marginal-rift sedimentary basins are assigned to petroliferous areas.

Malaria in southeast Bangladesh: A descriptive study

Malaria in Asia is thought to be grossly under-reported and this is evident from previously published statistics from Bangladesh. Malaria screening data from four Upazillas was analysed alongside census data to assess the trends in malaria incidence over time and distribution of malaria by age and gender. Malaria incidence in this area has decreased by around two thirds since 2003, although control measures were not significantly increased until 2005. Malaria occurred in people of all ages with the highest incidence being in young adults. This is consistent with higher occupational exposure in this group. The probability of being screened for malaria decreased with age suggesting significant numbers of adults with malaria may be being missed.