Arsenic and heavy metal concentrations in surface soils and vegetables of Feni district in Bangladesh

An investigation of various heavy metals including the arsenic (As) poisoning in soils and vegetables in five upazillas under Feni district of Bangladesh was performed by neutron activation technique using the neutron irradiation facilities of TRIGA MARK II research reactor at Bangladesh Atomic Energy Research Establishment (BAERE), Savar, Dhaka. A total of 30 samples (15 surface soils and 15 foodstuffs) were studied in five Upazillas namely as, Sonagazi, Dagan Bhuiya, Feni Sadar, Fulgazi and Parsuram of Feni district taking three samples of each kind from each upazilla. Samples of each kind together with the standard reference material (SRM) were irradiated in the same neutron flux and the gamma-rays of nuclides from the irradiated samples were assessed and screened for As, Br, U, Th, Cr, Sc, Fe, Zn and Co in soils and As, Br, Na, K, Cr, Sc, Fe, Zn and Co in vegetables (i.e; eddoe, taro, green papaya, plantain, potato, callaloo, bottle ground and carambola). The measurement of gamma-rays was carried out by means of a calibrated high resolution HPGe detector. The concentration of product nuclides containing in the irradiated samples was determined from the peak count-rates of prominent gamma-lines for the corresponding nuclides. Among all contaminants, only As, Zn and Cr for both samples were focused because of their higher values compared with the local as well as the world typical values. The present results revealed that the mean levels of As in Parsuram, Feni Sadar and Pulgazi upazillas are higher than the world typical value of 2 mg/kg. The mean values of Zn and Cr for all upazillas are higher than the world typical values 32 and 27.9 mg/kg, respectively. For the case of vegetables, the mean concentration of As is found only in Eddoe (5.33 ppm) and Taro (1.46 ppm) collected from Sonagazi and Feni Sadar upazilla; which are higher than the values in Samta (0.1 ppm for eddoe and 0.44 ppm for taro) under Jessore district of Bangladesh. The mean concentrations of Zn and Cr in all kinds of vegetables are higher compared with the existing local values as well as the world typical values. The mean estimated daily dietary intake of As, Zn and Cr from vegetables are found to be 0.105, 12.47 and 3.53 mg respectively, which are higher than the recommended values of some countries. The consumption of toxic metals in vegetables is a risk for public health in the studied area.     

Deterioration of water quality of Surma river

Surma River is polluted day by day by human activities, poor structured sewerage and drainage system, discharging industrial and household wastes. The charas (natural channels) are responsible for surface runoff conveyance from its urban catchments to the receiving Surma River. Water samples have been collected from a part of Surma River along different points and analyzed for various water quality parameters during dry and monsoon periods. Effects of industrial wastes, municipal sewage, and agricultural runoff on river water quality have been investigated. The study was conducted within the Chattak to Sunamganj portion of Surma River, which is significant due to the presence of two major industries – a paper mill and a cement factory. The other significant feature is the conveyors that travel from India to Chattak. The river was found to be highly turbid in the monsoon season. But BOD and fecal coliform concentration was found higher in the dry season. The water was found slightly acidic. The mean values of parameters were Conductivity 84–805 μs; DO: dry-5.52 mg/l, monsoon-5.72 mg/l; BOD: dry-1mg/l, monsoon-0.878 mg/l; Total Solid: dry-149.4 mg/l, monsoon-145.7 mg/l. In this study, an effort has been taken to investigate the status of concentration of phosphate (PO⁻⁴) and ammonia–nitrogen (NH₄–N) at four entrance points of Malnichara to the city, Guali chara, Gaviar khal and Bolramer khal. Data has been collected from March–April and September–October of 2004. Concentrations have been measured using UV Spectrophotometer. Although the phosphate concentration has been found within the limit set by DOE for fishing, irrigation and recreational purposes, however ammonia–nitrogen has been found to exceed the limit.     

Influence of pyrolysis temperature on production and nutrient properties of wastewater sludge biochar

The important challenge for effective management of wastewater sludge materials in an environmentally and economically acceptable way can be addressed through pyrolytic conversion of the sludge to biochar and agricultural applications of the biochar. The aim of this work is to investigate the influence of pyrolysis temperature on production of wastewater sludge biochar and evaluate the properties required for agronomic applications. Wastewater sludge collected from an urban wastewater treatment plant was pyrolysed in a laboratory scale reactor. It was found that by increasing the pyrolysis temperature (over the range from 300 °C to 700 °C) the yield of biochar decreased. Biochar produced at low temperature was acidic whereas at high temperature it was alkaline in nature. The concentration of nitrogen was found to decrease while micronutrients increased with increasing temperature. Concentrations of trace metals present in wastewater sludge varied with temperature and were found to primarily enriched in the biochar.     

Disaster coordination preparedness of soft-target organisations

This paper introduces a network‐enabled model to examine the disaster coordination preparedness of soft‐target organisations (STOs). Little attention is devoted to this matter in recent research. This study places emphasis on such organisations and the proposed model tests hypotheses related to network relation and coordination preparedness. It analyses the data set entitled ‘Preparedness of large retail malls to prevent and respond to terrorist attack, 2004′, which contains 120 completed surveys of security directors of retail malls in the United States. ¹ 1 See http://www.icpsr.umich.edu/icpsrweb/TPDRC/studies/21140 .
The following questions form the basis of this study: ‘What do STOs need to be better prepared to respond to a disaster?’; ‘How does network relationship between STOs and emergency agencies affect the coordination preparedness of STOs for disaster recovery?’; and ‘Which centrality measure needs to be followed to measure network variables in order to analyse coordination preparedness?’ The results show that STOs with a high level of connectedness and strong ties to other emergency agencies are better prepared for disaster response.     

Stagnant surface water bodies (SSWBs) as an alternative water resource for the Chittagong metropolitan area of Bangladesh: physicochemical characterization in terms of water quality indices

The concern over ensuing freshwater scarcity has forced the developing countries to delve for alternative water resources. In this study, we examined the potential of stagnant surface water bodies (SSWBs) as alternative freshwater resources in the densely populated Chittagong metropolitan area (CMPA) of Bangladesh??where there is an acute shortage of urban freshwater supply. Water samples were collected at 1-month intervals for a period of 1 year from 12 stations distributed over the whole metropolis. Samples were analyzed for pH, water temperature (WTemp), turbidity, electrical conductivity (EC), total dissolved solids, total solids, total hardness, dissolved oxygen (DO), chloride, orthophosphates, ammonia, total coliforms (TC), and trace metal (Cd, Cr, Cu, Pb, As, and Fe) concentrations. Based on these parameters, different types of water quality indices (WQIs) were deduced. WQIs showed most of CMPA-SSWBs as good or medium quality water bodies, while none were categorized as bad. Moreover, it was observed that the minimal water quality index (WQI_m), computed using five parameters: WTemp, pH, DO, EC, and turbidity, gave a reliable estimate of water quality. The WQI_m gave similar results in 72% of the cases compared with other WQIs that were based on larger set of parameters. Based on our finding, we suggest the wider use WQI_m in developing countries for assessing health of SSWBs, as it will minimize the analytical cost to overcome the budget constraints involved in this kind of evaluations. It was observed that except turbidity and TC content, all other quality parameters fluctuated within the limit of the World Health Organization suggested standards for drinking water. From our findings, we concluded that if the turbidity and TC content of water from SSWBs in CMPA are taken care of, they will become good candidates as alternative water resources all round the year.     

A systematic review of the utilization of waste materials as aggregate replacement in stone matrix asphalt mixes

Environmental Science and Pollution Research - The daily utilization of a large amount of raw materials is causing a rapid depletion of natural resources. The growth of the human population is...     

Multivariate statistics and entropy theory for irrigation water quality and entropy-weighted index development in a subtropical urban river,Bangladesh

Environmental Science and Pollution Research - Currently, a well-developed combination of irrigation water quality index (IWQIs) and entropy water quality index (EWQIs) for surface water appraisal...     

Mobilization of arsenic from subsurface sediments by effect of bicarbonate ions in groundwater

Arsenic leaching by bicarbonate ions has been investigated in this study. Subsurface sediment samples from Bangladesh were treated with different carbonate and bicarbonate ions and the results demonstrate that the arsenic leaching efficiency of the carbonate solutions decreased in the order of Na2CO3>NaHCO3>BaCO3>MnCO3. Sodium carbonate and bicarbonate ions extracted arsenic most efficiently; Na2CO3 leached maximum 118.12 microg/l of arsenic, and NaHCO3, 94.56 microg/l of arsenic from the Ganges delta sediments after six days of incubation. The arsenic concentrations extracted in the batch experiments correlated very well with the bicarbonate concentrations. The kinetics study of arsenic release indicates that arsenic-leaching rate increased with reaction time in bicarbonate solutions. Bicarbonate ions can extract arsenic from sediment samples in both oxic and anoxic conditions. A linear relationship found between arsenic contents in core samples and those in leachates suggests that dissolved arsenic concentration in groundwater is related to the amount of arsenic in aquifer sediments. In batch experiment, bicarbonate solutions effectively extracted arsenic from arsenic adsorbed iron oxyhydroxide, reflecting that bicarbonate solutions may mobilize arsenic from iron and manganese oxyhydroxide in sediments that are ubiquitous in subsurface core samples. Carbonate ion may form complexes on the surface sites of iron hydroxide and substitute arsenic from the surface of minerals and sediments resulting in release of arsenic to groundwater. Like in the batch experiment, arsenic and bicarbonate concentrations in groundwater of Bangladesh correlated very well. Therefore, bicarbonate leaching is presumed to be one important mechanism to mobilize arsenic in bicarbonate dominated reducing aquifer of Bangladesh and other parts of the world as well.