Md. Ali Akber

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.

Land use change and its effect on biodiversity in Chiang Rai province of Thailand

Abstract The Chiang Rai province of Thailand has experienced rapid deforestation and consequent land use change in recent years. This research carried out in Chiang Rai province simulated future land uses under three management scenarios and assessed their effect on biodiversity. The Dyna-CLUE model was used to simulate land uses of 2029 according to the management scenarios, and their effect on biodiversity was analyzed by the GLOBIO3 model. About 4% of total area of the province was deforested within 2002–2009 and has a possibility to lose more, that is, 7% by 2029. If this rate of deforestation continues, then biodiversity will be affected as shown by reduced ‘mean species abundance’ of 0.45 at present to 0.38 by 2029, whereby highly threatened area can be increased up to 15% of the total land area. Hence, protecting locations with higher biodiversity value can be efficient in conserving biodiversity.

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.