Md. Atikul Islam

Trace metals accumulation in soil irrigated with polluted water and assessment of human health risk from vegetable consumption in Bangladesh

Trace metals accumulation in soil irrigated with polluted water and human health risk from vegetable consumption was assessed based on the data available in the literature on metals pollution of water, soil, sediment and vegetables from the cites of Bangladesh. The quantitative data on metal concentrations, their contamination levels and their pollution sources have not been systematically gathered and studied so far. The data on metal concentrations, sources, contamination levels, sample collection and analytical tools used were collected, compared and discussed. The USEPA-recommended method for health risk assessment was used to estimate human risk from vegetable consumption. Concentrations of metals in water were highly variable, and the mean concentrations of Cd, Cr, Cu and As in water were found to be higher than the FAO irrigation water quality standard. In most cases, mean concentrations of metals in soil were higher than the Bangladesh background value. Based on geoaccumulation index (Igeo) values, soils of Dhaka city are considered as highly contaminated. The Igeo shows Cd, As, Cu, Ni, Pb and Cr contamination of agricultural soils and sediments of the cities all over the Bangladesh. Polluted water irrigation and agrochemicals are identified as dominant sources of metals in agricultural soils. Vegetable contamination by metals poses both non-carcinogenic and carcinogenic risks to the public. Based on the results of the pollution and health risk assessments, Cd, As, Cr, Cu, Pb and Ni are identified as the priority control metals and the Dhaka city is recommended as the priority control city. This study provides quantitative evidence demonstrating the critical need for strengthened wastewater discharge regulations in order to protect residents from heavy metal discharges into the environment.

Effectiveness of solar disinfection (SODIS) in rural coastal Bangladesh

Scarcity of drinking water in the coastal area of Bangladesh compels the inhabitants to be highly dependent on alternative water supply options like rainwater harvesting system (RWHS), pond sand filter (PSF), and rain-feed ponds. Susceptibility of these alternative water supply options to microbial contamination demands a low-cost water treatment technology. This study evaluates the effectiveness of solar disinfection (SODIS) to treat drinking water from available sources in the southwest coastal area of Bangladesh. A total of 50 households from Dacope upazila in Khulna district were selected to investigate the performance of SODIS. Data were collected in two rounds to examine fecal coliform (FC) and Escherichia coli (E. coli) contamination of drinking water at the household water storage containers and SODIS bottles, and thereby determined the effectiveness of SODIS in reducing fecal contamination. All water samples were analyzed for pH, electrical conductivity, turbidity and salinity. SODIS significantly reduced FC and E. coli contamination under household conditions. The median health risk reduction by SODIS was more than 96 and 90% for pond and RWHS, respectively. Besides, turbidity of the treated water was found to be less than 5 NTU, except pond water. Only 34% of the participating households routinely adopted SODIS during the study.

Bis[benzyl N′-(3-phenylprop-2-enylidene)hydrazinecarbodithioato-κ2N′,S]copper(II)

The CuII atom of the title complex, [Cu(C17H15N2S2)2], lies on a twofold rotation axis, and is in a distorted tetrahedral geometry with the two bidentate N2S2 Schiff bases. In the crystal structure, the molecules are interconnected into chains along the c axis by weak C—H⋯S intermolecular interactions. The crystal packing is further stabilized by C—H⋯π interactions.

The Impact of Environmental Variables on Faecal Indicator Bacteria in the Betna River Basin, Bangladesh

Environmental variables influence Faecal Indicator Bacteria (FIB) in surface water. Understanding that influence is important, because presence of FIB, which are an indication of faecal contamination, means that harmful pathogens could be present that could also be influenced by environmental variables. Although some recent studies have focused on this topic, most of this work has been conducted in developed countries. Similar studies in developing countries and in a (sub)tropical climate are lacking. In this study we assess the influence of environmental variables on fluctuations in FIB concentrations of the Betna River in southwest Bangladesh that floods almost every year. Monthly water samples from five locations along Betna River were tested for FIB (E. coli and enterococci) in 2014–2015. A linear regression model was developed to assess the effect of the environmental variables on FIB concentrations. The study revealed increased FIB concentrations during wet weather conditions. Precipitation and water temperature were positively correlated with FIB concentrations. Water temperature was positively correlated, because the warm May to September period coincides with frequent precipitation. Precipitation increases manure release from land to surface water. The regression model explains nearly half of the variability in FIB concentrations (R2 of 0.46 for E. coli and 0.48 for enterococci). This study indicates that increased precipitation combined with higher water temperature, as is expected in this region with climate change, likely increases FIB concentrations. Waterborne pathogens are expected to respond similarly to these environmental changes, indicating that disease outbreaks could well become more frequent and severe.

Rural Water Consumption Behavior: A Case Study in Southwest Coastal Area, Bangladesh

In the coastal areas of Bangladesh, scarcity of drinking water is acute as the fresh water aquifers at reasonable depths are not available and surface water is highly saline. Peoples are mainly dependent on alternative water supply options. In this paper, water supply scarcity and water consumption behavior in two southwestern coastal districts of Bangladesh have been investigated. The data for this study were collected from a survey of 750 rural households in 39 villages of southwest coastal areas of Bangladesh, using a simple random sampling technique. Results of the study revealed that coastal populations are mainly dependent on natural sources such as rain water and pond water for drinking purposes. In this study, per capita daily drinking water consumption for all ages and sexes was found to be 3.35l/d. Distance and time required for water collection were found important determinants for safe water consumption. The findings of the study can be used by stakeholders for addressing the key planning questions.

Evaluation of risk communication for rural water supply management: a case study of a coastal area of Bangladesh

Consumption of safe drinking water is an important public health issue. In this study, we considered the risk communication topic of human health concerns related to unsafe water consumption in rural coastal areas of Bangladesh, where potable water is scarce. Our objective was to investigate the level of knowledge that rural residents had concerning safe water consumption and to evaluate the effects of risk communication on knowledge and behavior changes. We considered four rural villages of southwest coastal areas of Bangladesh as sample. This study was based on the results of a questionnaire survey administered before and after risk communication. The pre- and post-survey were conducted during August 2009 and March 2010, respectively. Data were collected from 120 women aged 18–60 years. Two format presentations, with and without water quality information, were used to convey the risk messages. In the present study, indicator bacterial (Escherichia coli) contamination levels in drinking water sources were considered as water quality information since absence of E. coli is the safety margin for the detection of disease-causing organisms. Analysis of the survey data revealed that risk communication can be vital to changes in water consumption knowledge and behavior. Overall general knowledge scores were almost same in the pre-survey for without- (mean score 3.16) and with-information (mean score 3.10) villages. However, after risk communication, there were detectable increases in the mean scores (mean scores, 3.54 and 3.64, respectively, on a 4 point scale) for both groups. Furthermore, risk communication with water quality information appears to be a more effective method of risk communication. Dissemination of risk messages was also higher in with-information villages. Seventy four percent of the participants from with-information villages reported that they had discussed the risk messages with family members and neighbors, compared to 59% of those from without-information villages. The results of this study revealed that age, education, and distance of water sources influence changes in consumption and maintenance behavior. These findings suggest that, in addition to installation of water supply facilities, there is a need to address the low levels of knowledge about safe water consumption in rural coastal communities of Bangladesh. Location specific water quality information may be more useful to convey health risk messages concerning unsafe drinking water consumption.

Climate change adaptations of shrimp farmers: a case study from southwest coastal Bangladesh

Sustainability of brackishwater shrimp farming is of paramount importance for socio-economic development of southwest coastal Bangladesh. Here, shrimp farming is predominantly traditional, which is more vulnerable to climate change. Lack of understanding exists regarding the adaptation measures of local shrimp farmers in response to emerging impacts of changing climatic variables. This study provides the perceptions and adaptations of shrimp farmers in changing climatic context. A systematic random sampling method was employed to conduct a total of 240 questionnaire surveys and 60 key informant interviews from six sub-districts (Upazila) of southwest coastal Bangladesh to collect primary data. Changes in climate variables largely affect the shrimp yield by increasing frequency of shrimp disease, causing physical damage to farm structure and deteriorating quality of water. Shrimp farmers try to adapt to those changes in various ways, including increasing pond depth, exchanging tidal water, providing shade using aquatic plants, strengthening earthen dike and netting and fencing around the dike. Shrimp mixed cultivation is the most popular form of shrimp farming in the study area. More emphasis on implementing polyculture shrimp farming is necessary to improve climate change adaptation and to promote sustainability of this aquaculture practice in southwest coastal Bangladesh.