Survey of trace metals in drinking water supply options in coastal areas of Bangladesh

To ascertain the water quality for human consumption, chemical parameters such as pH, conductivity and the concentrations of calcium, magnesium, iron, manganese, copper, zinc, lead, chromium, cadmium, nickel and arsenic were evaluated in the drinking water supply options employed in the southwest coastal areas of Bangladesh. The mean iron and manganese concentrations for pond and pond sand filter (PSF) water were much higher than harvested rainwater. The iron concentrations for 41% of the pond water samples were higher than the Bangladesh guideline value. However, iron and manganese removal by PSFs were found 74% and 51%, respectively. Furthermore, scarcity of calcium and magnesium were found in harvested rainwater. One pond water sample showed arsenic concentration above the 10 μg/l WHO drinking water guideline. The presence of an elevated iron and manganese and low calcium and magnesium concentrations in the drinking water could be a matter of public health concern

Hydrogeochemical quality and suitability studies of groundwater in northern Bangladesh

Agriculture, rapid urbanization and geochemical processes have direct or indirect effects on the chemical composition of groundwater and aquifer geochemistry. Hydro-chemical investigations, which are significant for assessment of water quality, were carried out to study the sources of dissolved ions in groundwater of Dinajpur district, northern Bangladesh. The groundwater samplish were analyzed for physico-chemical properties like pH, electrical conductance, hardness, alkalinity, total dissolved solids and Ca2+, Mg2+, Na+, K+, C032', HC03", SO,2 and CI" ions, respectively. Based on the analyses, certain parameters like sodium adsorption ratio, soluble sodium percentage, potential salinity, residual sodium carbonate, Kelly's ratio, permeability index and Gibbs ratio were also calculated. The results showed that the groundwater of study area was fresh, slightly acidic (pH 5.3-6.4) and low in TDS (35-275 mg I"1). Ground water of the study area was found suitable for irrigation, drinking and domestic purposes, since most of the parameters analyzed were within the WHO recommended values for drinking water. High concentration of N03" and CI' was reported in areas with extensive agriculture and rapid urbanization. Ion-exchange, weathering, oxidation and dissolution of minerals were major geochemical processes governing the groundwater evolution in study area. Gibb's diagram showed that all the samples fell in the rock dominance field. Based on evaluation, it is clear that groundwater quality of the study area was suitable for both domestic and irrigation purposes

Comparative Analysis of Pre-Trained Models and Interpolation for Facial Expression Recognition

This study presents a comprehensive examination of facial emotion detection using the FER 2013 dataset. In numerous disciplines, including psychology, human-computer interface, and marketing research, efficient facial expression recognition is a crucial problem to resolve. This study experimented with four different convolutional neural network architectures: ResNet50, VGG16, EfficientNetV2L, and NasNetLarge, in order to categorize seven different emotions: anger, disgust, fear, happiness, sadness, surprise, and neutral. Before passing the images to the classification layers, this study feeds the images to ResNet50, VGG16, EfficientNetV2L, and NasNetLarge to extract features from them. Model and interpolation methods are validated and assessed using the Public Text in two different sizes (128,128) and (256,256). The Adam optimizer is used to train models, with a batch size of 32 and a learning rate 0.001. The accuracy of the models is assessed during the evaluation process. In order to determine whether interpolation produces better results or not, this study will conduct an experimental analysis of the interpolation used to upscale a lower-resolution image. Additionally, the most recent state-of-the-art models need images with higher resolution, so using interpolation to upscale images could enable the use of models like NasNetLarge and others. For all considered models this study could get at most 69% validation accuracy using interpolation to resize the images from 48x48 to 128x128 and 256x256. This study provides insightful viewpoints of the effectiveness of different pre-trained and publicly accessible CNN architectures for feature extraction and interpolation methods in facial emotion detection. The findings can direct the selection of appropriate models with appropriate interpolation sizes for emotion detection applications and stimulate additional study in this area

Willingness to pay for improved drinking water in southwest coastal Bangladesh

Households in the rural areas of Southwest coastal Bangladesh mainly depend on unreliable sources of drinking water. This study assessed the willingness to pay (WTP) for improved drinking water in a rural area of the Southwest coastal Bangladesh, using contingent valuation survey data of 215 households. The samples for the face-to-face interview were selected by purposive random sampling from Chila union of Mongla sub-district under Bagerhat district. The mean WTP for improved drinking water was estimated to be BDT 193 (US$ 2.47) per month (3% of the monthly income of the households). Results also indicate that educated respondents and households with higher income are willing to pay more for improved water supply. Moreover, the expenditure of the households for buying water and for medicine for waterborne diseases has a significant positive impact on the WTP. The results of this study can be useful for decision-makers to promote improved drinking water supply in Southwest coastal Bangladesh

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.</p

Potential ecological risk of metal pollution in lead smelter-contaminated agricultural soils in Khulna, Bangladesh

Lead smelters are important source of metal pollution. This study assessed ecological risks of three heavy metals (Pb, As, and Zn) in agricultural soils surrounding five Pb smelters from Khulna district in Bangladesh. A total of 81 surface soil samples collected within 500-m radius of the smelters were analyzed using an atomic absorption spectrophotometer (AAS). Concentrations of Pb, As, and Zn ranged within 6–3902, 1.8–9.6, and 45.4–563\ua0mg/kg, respectively. About half of the Pb samples (~ 51%) exceeded soil quality standard target value (85\ua0mg/kg), and the concentrations gradually decreased with horizontal distance from the smelter. The value of pollution index (PI) measured for Pb, As, and Zn varied respectively in the range of 0–195, 0.6–3.2, and 0.67–8.28, with mean values of 11.7, 1.9, and 3.92. The value of integrated pollution index (IPI) calculated for these metals remained between 0.58 and 66.2 with a mean of 5.7, and that designates ~ 96% of the sampled soils as moderately or highly contaminated. Potential ecological risk (PER) calculated for the metals indicate that all the samples were within low to moderate risk, and the descending order of PER of the metals was Pb > As > Zn

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

Southwest 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

An analogical method for evaluating ring performance based on quality and production parameters

This study was carried out to determine the best ring size for a certain yarn count. In a ring frame with three separate rings of varying sizes, 20s/1 kW yarn was created. The spinning method used the same ring speed, twist, ring traveller, and spacer but three distinct rings with diameters of 38 mm (Ring- A), 40 mm (Ring- B), and 42 mm (Ring- C). Then, under the same testing conditions, ten samples of each yarn were examined by Uster Evenness Tester (UT-6) and compared to determine the best one. The “Ring- C″ production yield was 0.22% and 1.34% greater than the “Ring- B″ and “Ring- A″ yields, respectively. Yarn breakage for “Ring- C″ was 47.78% and 200% greater than for “Ring- B″ and “Ring- A,” respectively. Yarn unevenness for “Ring- C″ was found to be 4.15% and 4.14% higher than “Ring- B″ and “Ring- A,” imperfection of yarn produced by “Ring- B″ was 18.54% and 3.47% lower than “Ring- C″ and “Ring- A,” and tenacity of yarn produced by “Ring- B″ was 3.35% and 0.64% higher than “Ring- C″ and “Ring- A.” “Ring- C″ yarn hairiness was 10.63% and 12.31% higher than “Ring- B″ and “Ring- A″ yarn hairiness, respectively. According to the study of the tested report, yarn generated from “Ring- B″ delivered optimized results in terms of both quality and output. Ring “Ring- B″ had a lower production loss than Ring “A'' but a higher loss than Ring “C.” Also, the hairiness of yarn made from “Ring- B″ was remarkably similar to yarn made from “Ring- A.'

Trace elements in rice grain and agricultural soils: assessment of health risk of inhabitants near a former secondary lead smelter in Khulna, Bangladesh

Ingestion of food grain grown in metal-contaminated soils may cause serious effects on human health. This study assessed the concentrations of Pb, As, Cd and Zn in agricultural soils and in rice grains near a former secondary lead smelter in Khulna, Bangladesh. It analyzed 29 samples of surface soil and rice grain collected around 500 m of the smelter. Contamination factor (Cf), pollution load index and total hazard quotient (THQ) were calculated to determine ecological and human health risks. Cd was not detected in any of the samples. For the soil samples, medians of the concentrations of Pb, As and Zn were 109, 6.2 and 514 mg/kg, respectively. For the rice grain samples, medians of the concentrations of Pb, As and Zn were 4, 1.4 and 25 mg/kg fw, respectively. Medians of the concentrations of Pb and As in rice grain were higher compared to their maximum allowable limit (0.2 mg/kg), which indicate potential health risks to inhabitants near the Pb smelter. The mean values of Cf for Pb, As, and Zn were, respectively, 11.6, 2.1 and 7.4. For Pb, around 41% of the samples had Cf > 6 indicating very strong contamination. THQ values for Pb and As were greater than 1.0, which evinces the health hazards of these trace elements. Measures should be taken to prevent trace elements exposure from Pb smelter in the study area