Southwest Bangladesh Research Articles

Coliform Bacteria and Trace Metals in Drinking Water, Southwest Bangladesh: Multivariate and Human Health Risk Assessment

In this study, drinking water sources of tube well (TW), pond sand filter (PSF), rainwater, SIDKO (arsenic treatment plant), and Kuya (open well) were monitored in the southwest coastal area of Assasuni Upazila, Satkhira, Bangladesh. Faecal coliform, total coliform, and trace metals, especially arsenic (As), manganese (Mn), cadmium (Cd), iron (Fe), and zinc (Zn), were measured in drinking water. Totally, 73 water samples were analyzed for faecal coliform and total coliform bacteria, whereas 26 water sources from TWs (22), PSF (2), SIDKO (1) and Kuya (1) were inspected for trace metals. The water samples were free from 46.6% faecal coliform and 39.7% total coliform bacteria, respectively. On the other hand, As content has exceeded both WHO and Bangladesh standards. Due to lack of routine maintenance of As treatment plants (PSF and SIDKO), they are impotent in removing As completely. Besides, multivariate statistical principal component analysis indicts the availability of trace metals in drinking water originated both from natural and anthropogenic sources. Mean values of hazard quotient of As for both adult and children exceeded the standard limit, and hazardous index values both for adults and children were very high which might pose a potential human health risk of the study area. Even, TW above acceptable limit of mean carcinogenic risk values of As intimated cancer risk due to the lifespan drinking of As-contaminated water for both adults and children. Authority should take initiative to find priority-basis sustainable policies ensuring potable water sources in this territory.

Observations and scaling of tidal mass transport across the lower Ganges–Brahmaputra delta plain: implications for delta management and sustainability

Abstract. The landscape of southwest Bangladesh, a region constructed primarily by fluvial processes associated with the Ganges River and Brahmaputra River, is now maintained almost exclusively by tidal processes as the fluvial system has migrated east and eliminated the most direct fluvial input. In natural areas such as the Sundarbans National Forest, year-round inundation during spring high tides delivers sufficient sediment that enables vertical accretion to keep pace with relative sea-level rise. However, recent human modification of the landscape in the form of embankment construction has terminated this pathway of sediment delivery for much of the region, resulting in a startling elevation imbalance, with inhabited areas often sitting >1 m below mean high water. Restoring this landscape, or preventing land loss in the natural system, requires an understanding of how rates of water and sediment flux vary across timescales ranging from hours to months. In this study, we combine time series observations of water level, salinity, and suspended sediment concentration with ship-based measurements of large tidal-channel hydrodynamics and sediment transport. To capture the greatest possible range of variability, cross-channel transects designed to encompass a 12.4 h tidal cycle were performed in both dry and wet seasons during spring and neap tides. Regional suspended sediment concentration begins to increase in August, coincident with a decrease in local salinity, indicating the arrival of the sediment-laden, freshwater plume of the combined Ganges–Brahmaputra–Meghna rivers. We observe profound seasonality in sediment transport, despite comparatively modest seasonal variability in the magnitude of water discharge. These observations emphasize the importance of seasonal sediment delivery from the main-stem rivers to this remote tidal region. On tidal timescales, spring tides transport an order of magnitude more sediment than neap tides in both the wet and dry seasons. In aggregate, sediment transport is flood oriented, likely as a result of tidal pumping. Finally, we note that rates of sediment and water discharge in the tidal channels are of the same scale as the annually averaged values for the Ganges and Brahmaputra rivers. These observations provide context for examining the relative importance of fluvial and tidal processes in what has been defined as a quintessentially tidally influenced delta in the classification scheme of Galloway (1975). These data also inform critical questions regarding the timing and magnitude of sediment delivery to the region, which are especially important in predicting and preparing for responses of the natural system to ongoing environmental change.

Understanding factors associated with agricultural mechanization: A Bangladesh case

Bangladesh is heralded as a success story in terms of smallholder agricultural mechanization enabled by appropriate small-scale machinery and policy. Using data collected in 2013 from 630 farm households in the coastal delta of South-West Bangladesh, this study assesses the factors associated with the adoption of small-scale machine types, particularly irrigation pumps, threshers and power tillers (two-wheel tractors). We use a multivariate probit model to account for the interdependence of machine type use and show the likelihood of adoption to be enhanced by the farmers’ economic position, market access and participation in off-farm work. Critically, machinery ownership is not necessary for their use as most farmers hire these machine services. Key policy implications are to facilitate machinery access and use by enabling the development of small-scale machinery and custom hiring services, and enhancing farmers’ income through access to markets, knowledge and off-farm income generating opportunities.

Women’s gainful employment in ‘gher’ farming system (prawn–carp–rice integrated culture) in Bangladesh: trends and determinants

The paper examines trends in women’s gainful employment in ‘prawn-carp’ and ‘high yield variety (HYV) rice’ enterprises of the ‘gher’ farming system and jointly identifies the determinants of employing female and male labor in these enterprises using a farm-level panel data of 90 producers covering a 14-year period (2002–2015) from southwest Bangladesh by applying a multivariate Tobit approach. Results revealed that women’s gainful employment and real wage increased significantly with a substantial reduction in wage gap between female and male labor. The decision to employ female and male labor was found to be positively correlated thereby confirming jointness in decision-making and validity of our chosen approach. Prices and socio-economic factors exerted varied influences on female and male labor demand. Output prices, cultivated area, education, and experience positively increased women’s gainful employment whereas larger family size reduced it. Policy implications include investments in education targeted at the ‘gher’ farming households and land reform policies to consolidate farm size and facilitate smooth functioning of the land market to increase women’s gainful employment.

Herbicidal weed control in drill sown spring wheat under Bangladesh condition

Weeds are considered as one of the major factors responsible for current low wheat yield in Bangladesh. Although chemical weed control is well established in many wheat growing countries, in Bangladesh, the herbicides are typically not used by farmers to manage weeds in wheat. Hence, to evaluate the efficacy of pre- and post-emergence herbicides in mechanized drilled sown wheat, a two-year field study was conducted in southwest Bangladesh. The study evaluated the performance of four pre-emergence herbicides (oxadiargyl 80g, pendimethalin 850 g, pyrazosulfuron 15 g, and mefenacet + bensulfuran methyl 550 g a.i. ha-1) applied at 2 days after sowing (DAS) and four post-emergence herbicides (2,4-D 1400 g, ethoxysulfuron18 g, penoxsulam22.5 g, and fenoxaprop 56 g a.i. ha-1) applied at 20 DAS, on weed control efficacy. A season long weed-free and a season long weedy plots were also maintained to compare the results. The weed control option using a single pre- or post-emergence herbicide was not adequate to control weed effectively when weed infestation was relatively higher. The best yield provided by pre-emergence (pendimethalin and oxadiargyl) and post-emergence (2,4-D and ethoxysulfuron) herbicide treatments were respectively 13-15% and 12-17% lower than the yield (4.1-4.2 t ha-1) of weed-free treatment. Post-emergence herbicides fenoxaprop was the best in controlling weeds; however, due to phytotoxic effects on wheat plants, the plots applied with fenoxaprop produced very low yield (2.6-2.8 t ha-1). Similarly, even after good weed control by the post-emergence application of penoxsulam, phytotoxicity on wheat resulting in low yield. The study suggested that the best weed control option for wheat is to use a pre-emergence (pendimethalin or oxadiargyl) followed by (fb) a post-emergence (2,4-D or ethoxysulfuron) herbicides depending upon weed species which would benefit the farmers by providing high weed control efficacy at lower cost compared to manual weeding.

Irrigation Water Quality Assessment of Chitra River, Southwest Bangladesh

Narail Sadar Upazilla is a major agricultural productive region of Narail District, Bangladesh. The crop production here significantly depends on the Chitra River water for irrigation. The present study was undertaken with an aim to evaluate the usability of this river water for irrigation purpose during pre-monsoon, monsoon and post-monsoon. Sampling was conducted three times in each season both in high tide and low tide. The collected samples were analyzed for some physicochemical parameters including pH, electrical conductivity (EC), total dissolved solid (TDS), major cations (Na+, K+, Ca2+ and Mg2+) and major anions (HCO3−, PO43−, SO42−, Cl− and NO3−). The calculated chemical indices’ values for the collected water samples during pre-monsoon indicate that this river water is chemically suitable for irrigation during pre-monsoon with respect to sodium adsorption ratio (SAR), residual sodium carbonate (RSC) and permeability index (PI). The values of all chemical indices declare this river water fitness for use in irrigation both in monsoon and post-monsoon. According to Wilcox diagram, all of the water samples irrespective of tide and sampling stations fall within “permissible to doubtful” category during pre-monsoon while the water samples collected in both tide from all stations fall within “excellent to good” category during monsoon and post-monsoon. The United States Salinity Laboratory (USSL) diagram certifies this river water as C1-S1 (low salinity along with low sodium level) type during monsoon and post-monsoon which makes the river water suitable for use in irrigation in these two seasons while the water is mostly C3-S1, C3-S2 and C3-S3 (high salinity along with low to high sodium level) type in pre-monsoon which makes the river water restricted for use in irrigation in this season.

Total Factor Energy Productivity and Efficiency Changes of the Gher (Prawn-Carp-Rice) Farming System in Bangladesh: A Stochastic Input Distance Function Approach

This paper measures energy performance, Total Factor Energy Productivity (TFEP), technical change (TC) and energy efficiency change (EEC) of the gher (prawn-carp-rice) farming system using a unique panel data of 90 farmers covering a 14 year period (2002–2015) from southwest Bangladesh by employing a stochastic input distance function approach. Results reveal that all inputs contribute significantly to energy productivity of the gher farming system with male labor energy input being the major contributor followed by energy from machineries, seeds and chemicals. Energy performance of the High Yielding Variety (HYV) rice enterprise is highly efficient whereas the prawn enterprise is highly energy inefficient. Furthermore, energy performance of the HYV rice enterprise improved significantly over time. Significant competition exists between HYV rice and prawn enterprises as well as prawn and carp enterprises. Experience and education significantly improve energy efficiency whereas gher area and household size significantly reduces it. TFEP grew at the rate of 2.56% per annum (p.a.) solely powered by technical progress at the rate of 2.57% p.a. Gher system can be sustained in the long-run driven by technical progress and improvements in energy productivity of the HYV rice enterprise. Policy implications include investments in R&D and education targeted at the gher farmers.

Investigating the relationships between climate hazards and spatial accessibility to microfinance using geographically-weighted regression

Microfinance institutions (MFIs) in Bangladesh provide a variety of financial services to poor households that can help them cope with natural disasters (e.g. floods) and adapt to environmental changes (e.g. increasing soil salinity). However, due to the limited geographic range in which MFI branches can provide their services, households located far from a branch typically do not have access to microfinance. In this study, we measured how spatial accessibility (SA) to microfinance varied across 18 sub-districts (upazilas) of southwest Bangladesh, a region heavily affected by climate-related hazards including flooding and high soil salinity. Our objective was to identify if accessibility to microfinance was negatively affected by climate hazards due to, e.g., higher lending risks in hazard-prone areas. For this, we incorporated geospatial data sets related to flood hazard, soil salinity, population density, and transportation infrastructure as explanatory variables for regression modeling of SA. We tested both ordinary least squares (OLS) regression and geographically-weighted regression (GWR) approaches, and found that GWR was better able to predict SA. The GWR model for the SA measure “distance to nearest branch” had the strongest relationship with the explanatory variables (adjusted R2 = 0.717), and in this model (and four of five other models tested), high flood hazard and high soil salinity were negatively correlated with accessibility to microfinance. To increase microfinance accessibility in these climate hazard-prone areas, additional funding for MFI outreach activities (e.g. utilizing national/international climate change funds), reduction of transaction costs, and further experimentation with adapting/packaging MFI services, may be required.

Gender Norms and Agricultural Innovation: Insights from Six Villages in Bangladesh

The ability of development interventions to catalyse and support innovation for—and by— women and men is undermined by lack of specific understanding about how gender norms interact with gender relations and what this means for innovation. This is also the case for Bangladesh despite substantive research and development investments in the past decade that have placed emphasis on gender norms, particularly those inhibiting women and girl’s education, women and girl’s health, and women’s economic empowerment. This paper analyses how men and women in South West Bangladesh perceive gender norms to affect their ability to innovate, adopt, and benefit from new technologies in aquaculture, fisheries and agricultural systems. Our qualitative findings from six villages in 2014 confirm that the engagement of women and men smallholders with agricultural innovation and its opportunities is gender-differentiated. We explore further: how gender norms shape these differences; which gender norms are most significant in the given context, when and for whom; and, finally, when and how are some women and men able to innovate in the context of these norms. In doing so, we highlight how gender norms interact with gender relations and wider structural inequalities to constrain and/or enable innovation for different women and men. We conclude that technical organizations seeking to promote innovation need to go beyond itemizing gender ‘gaps’ to engage more closely with underlying gender norms and the way they influence various women’s, and men’s, motivations, spheres of innovation, and valuations of outcomes.

Influence of surface geology and micro-scale land use on the shallow subsurface salinity in deltaic coastal areas: a case from southwest Bangladesh

Salinity, both in soil and water, is a ubiquitous problem in coastal Bangladesh, particularly in the southwest. Salinity varies at the local scale (5–10 m), but the relative roles of land use and surface geology on salinity variation in near-surface (< 5 m) groundwater are not fully understood. Surface geology, land use and salinity in near-surface (ca. 3 m) groundwater at two small sites (each 0.05 km2) were explored in the southwest coastal region of Bangladesh. The sediments in the near-surface at both sites are fine and hydrometer analyses of cored samples indicate the dominance of silty clay (70%) along with very fine sand (5%), sandy clay (15%) and clay (10%) materials. Salinity variation in near-surface groundwater tends to follow land use rather than surface geology at the scale of our investigations. The study provides evidence of the influence of land use on the near-surface salinity variation and indicates the importance of land-use planning in salinity management in coastal areas.

Impacts and responses to environmental change in coastal livelihoods of south-west Bangladesh

Aquatic ecosystems are of global importance for maintaining high levels of biodiversity and ecosystem services, and for the number of livelihoods dependent on them. In Bangladesh, coastal and delta communities rely on these systems for a livelihood, and the sustainability of the productivity is seriously threatened by both climate change and unsustainable management. These multiple drivers of change shape the livelihood dependence and adaptation responses, where a better understanding is needed to achieve sustainable management in these systems, while maintaining and improving dependent livelihoods. This need has been addressed in this study in the region of Satkhira, in the southwest coast of Bangladesh, where livelihoods are highly dependent on aquatic systems for food supply and income. Traditional wild fish harvest in the rivers and aquaculture systems, including ghers, ponds, and crab points have been changing in terms of the uses and intensity of management, and suffering from climate change impacts as well. By means of six focus groups with 50 participants total, and validated by expert consultations, we conduct an analysis to understand the main perceived impacts from climate and human activities; and the adaptation responses from the aquatic system livelihoods. We find that biodiversity has decreased drastically, while farmed species have increased and shrimp gher farming turned more intensive becoming the main source of income. All these changes have important implications for food supply in the region and environmental sustainability. Dramatic responses taken in the communities include exit the fisheries and migration, and more adaptive responses include species diversification, crab fattening and working more on the pond and gher infrastructure. This study evidences the results of the combination of multiple stressors in productive systems and the barriers to adaptation in aquatic ecosystem dependent communities.

Deconstructing resilience: why gender and power matter in responding to climate stress in Bangladesh

Resilience is increasingly becoming the new buzz word. This paper examines the utility of the concept of resilience for understanding the gendered experiences of women to climate stress, through case study research in South-west Bangladesh. It provides evidence that resilience, as commonly understood, is inadequate for understanding the intersecting vulnerabilities that women face because of embedded socio-cultural norms and practices. These vulnerabilities culminate in a gendered experience of climate stress, where some groups of women are more likely go without education, food and access to good quality water. Such circuits of control highlight the importance of a more radical, transformational, gendered and power sensitive frame for moving beyond coping mechanisms to strategies that deal with the fundamental root causes of vulnerability to climate stress. A failure to do so risks further reinforcing gender inequalities due to the reality of social difference and inequities within local power structures.

An assessment of health management practices and occupational health hazards in tiger shrimp (Penaeus monodon) and freshwater prawn (Macrobrachium rosenbergii) aquaculture in Bangladesh

Diseases have been recognized as the major obstacle to the shrimp (Penaeus monodon) and prawn (Macrobrachium rosenbergii) aquaculture production in Bangladesh. This study provides an assessment of shrimp and prawn diseases/syndromes, health management practices, and occupational health hazards associated with the handling of chemical and biological products to prevent and treat shrimp and prawn diseases. A survey was conducted using a semi-structured questionnaire with 380 shrimp and prawn farmers in the southwest of Bangladesh during February and June of 2016. The farms were categorized on the basis of the three cropping patterns: shrimp polyculture, prawn polyculture, and shrimp and prawn polyculture. Eight different diseases and/or symptoms were reported by the surveyed farmers. The white spot disease and the broken antenna and rostrum symptom were the most common in shrimp and prawn species, respectively. In total, 35 chemical and biological products (4 antibiotics, 15 disinfectants, 13 pesticides, 2 feed additives and probiotics) were used to treat and/or prevent diseases in the all farm categories. The major constraints for disease management were limited access to disease diagnostic service, inadequate product application information and lack of knowledge on better management practices. Handling chemicals and preparation of medicated feed with bare hands was identified as a potential occupational health hazard. This study suggests improvements in farmers’ knowledge and skill in disease diagnostics and health management practices, and appropriate handling of potentially hazardous chemicals.

Physical and Social Assessment of the Waterlogged Area and Suitability of the “Inclusive and Adaptive Tidal River Management Technique” to Alleviate Waterlogging in Southwest Bangladesh

Abstract Bangladesh has often been considered as the land of extremes in terms of natural processes. The statement is justified by the presence of world’s largest delta, one of the largest river systems carrying a huge amount of water and sediment discharge as well as prevalence of a number of natural hazards. These characteristics make the region very dynamic and sensitive to changes. Bangladesh is one of the most densely populated countries in the world and human development activities to accommodate the large population have caused major disruptions to the dynamics of the natural system. The study focuses on such a case where anthropogenic activities, such as polderization, dam construction etc. have disrupted the natural land building process and have caused persistent waterlogging in the southwest region of Bangladesh. The rivers in the region are naturally characterized by active deposition of sediment in riverbed causing reduced drainage capacity. Moreover, construction of coastal polders that de-linked the flood plains from the rivers, and diminished upstream flow during the dry season deteriorated the sedimentation problem in the region. The study delineates different hydrological parameters and characteristics of the deposited sediments along with identification of social vulnerabilities. The investigated hydrological and sedimentological characteristics refer to the existing sediment management as well as provide a framework for the future development works in the pre-identified TRM sites. Based on the findings, the suitability of Inclusive and Adaptive Tidal River Management (TRM++) technique was assessed.

Production Economics and Profitability Analysis of Aquaculture in Southwest Bangladesh

Production Economics and Profitability Analysis of Aquaculture in Southwest Bangladesh

Hydrochemistry in coastal aquifer of southwest Bangladesh: origin of salinity

In the coastal region of Bangladesh, groundwater is mainly used for domestic and agricultural purposes, but salinization of many groundwater resources limits its suitability for human consumption and practical application. This paper reports the results of a study that has mapped the salinity distribution in different aquifer layers up to a depth of 300 m in a region bordering the Bay of Bengal based on the main hydrochemistry and has investigated the origin of the salinity using Cl/Br ratios of the samples. The subsurface consists of a sequence of deltaic sediments with an alternation of more sandy and clayey sections in which several aquifer layers can be recognized. The main hydrochemistry shows different main water types in the different aquifers, indicating varying stages of freshening or salinization processes. The most freshwater, soft NaHCO3-type water with Cl concentrations mostly below 100 mg/l, is found in the deepest aquifer at 200–300 m below ground level (b.g.l.), in which the fresh/saltwater interface is pushed far to the south. Salinity is a main problem in the shallow aquifer systems, where Cl concentrations rise to nearly 8000 mg/l and the groundwater is mostly brackish NaCl water. Investigation of the Cl/Br ratios has shown that the source of the salinity in the deep aquifer is mixing with old connate seawater and that the saline waters in the more shallow aquifers do not originate from old connate water or direct seawater intrusion, but are derived from the dissolution of evaporite salts. These must have been formed in a tidal flat under influence of a strong seasonal precipitation pattern. Long dry seasons with high evaporation rates have evaporated seawater from inundated gullies and depressions, leading to salt precipitation, while subsequent heavy monsoon rains have dissolved the formed salts, and the solution has infiltrated in the subsoil, recharging groundwater.

Improving the Livelihood for Marginalized Women’s Households in Southwest Bangladesh through Aquaculture

Improving the Livelihood for Marginalized Women’s Households in Southwest Bangladesh through Aquaculture

Women’s Participation in Aquaculture in Southwest Bangladesh

Women’s Participation in Aquaculture in Southwest Bangladesh

Benefits of stocking white spot syndrome virus infection free shrimp (Penaeus monodon) post larvae in extensive ghers of Bangladesh

Shrimp farming is an important income generating activity for hundreds of thousands of small scale farmers operating extensive ghers in Bangladesh. White spot syndrome virus (WSSV) has caused major shrimp production losses globally including Bangladesh. This study investigated the benefits of stocking WSSV infection free (WSSVF) Penaeus monodon post larvae (PL) to extensive gher holders of southwest Bangladesh and considered different parameters of the farming system. The longitudinal observational study included 636 gher holders comprising two distinct PL user types; 312 gher holders had stocked polymerase chain reaction (PCR) tested WSSVF and 324 non-tested (NT) PL. Data on explanatory and outcome variables were collected fortnightly during April–October 2015. The major findings were: (i) gher holders who stocked WSSVF PL had significantly higher survival, less disease, higher shrimp production and increased profitability compared to NT PL users, (ii) WSSVF PL stocking had an influence in strengthening the resilience, overall management and economic performance of the extensive gher holders.The study showed that WSSVF PL users had significantly small ghers, higher levels of better management practices (BMP) compliance such as nursery rearing of PL, double netting at inlet, periodic sampling, net fencing and bird netting, significantly higher application rates and usage amount of inputs (lime, inorganic fertilizer, feed) compared to NT PL users. It also found that gher size, water depth, stocking density, stocking frequency, cropping patterns affected levels of shrimp survival, production and disease incidence of the overall population. The results suggested that improving the availability of WSSVF PL through a PCR testing service, production of specific pathogen free PL and limit/stop the sale of WSSV infected PLs could significantly increase shrimp production of extensive gher holders.

Water quality of small-scale desalination plants in southwest coastal Bangladesh

AbstractSouthwest coastal Bangladesh has an acute scarcity of safe drinking water. Both the government and non-government organizations are now promoting reverse osmosis based small scale desalination plants (SSDPs) to ensure safe drinking water. The aim of this study was to assess the physico-chemical and bacteriological quality of the desalination plants (DPs) installed in southwest coastal Bangladesh. Water samples were collected from the inlet and outlet of 10 DPs. The product water mostly complied with water quality standards. High levels of total dissolved solids (TDS) and electrical conductivity (EC) in feed water were reduced significantly after the treatment, although 10% and 20% of the product water samples respectively did not comply with the WHO drinking water standards for those parameters. Compliance of product water with the WHO and Bangladesh drinking water standards for chloride, bicarbonate and sodium were found in respectively 80%, 90% and 70% of the samples, although their concentrations in all the feed water samples were higher than both of the standards. About one-third of the DPs did not meet the drinking water standard for sodium, which may be an important health concern for the people consuming this water. Apart from one of the DPs, all of them complied with the standard for faecal coliform and Escherichia coli. Results suggest that proper maintenance of the SSDPs is necessary to ensure safe drinking water for the coastal population of southwest Bangladesh.