Investigation of heavy metal contents in Cow milk samples from area of Dhaka, Bangladesh

Background: Cow milk is considered as one of the responsible food sources contaminated with heavy metals. The objectives of the study were to assess the content of selected metals in cow milk and its associated human health risks in the food chain of Bangladesh. A total of 90 cow milk samples of Branded, Dairy and Domestically produced milk were collected randomly from different sources of Savar Upazila in Dhaka area. Cadmium (Cd), chromium (Cr), lead (Pb), manganese (Mn), copper (Cu) and iron (Fe) contents in collected milk samples were determined using Flame Atomic Absorption Spectrometry (FAAS). To ensure quality control, one of the best quality control parameters i.e. recovery test; from eight various sample digestion methods were used. The Hazard Quotient (HQ) and Carcinogenic Risk (CR) values were also calculated. Results: From the results, it was found that, the orders of heavy metal content in brand, dairy and domestic cow milk were Cr > Fe > Cu>Mn > Cd > Pb, Cr > Fe > Mn > Cu > Cd > Pb and Fe > Cr > Mn > Cu > Cd > Pb, respectively. Among the six metals, only Cr showed to exceed the highest Estimated Daily Intake (EDI) rate (for brand cow milk: 0.413 mg/day, dairy farm cow milk: 0.243 mg/day, domestic cow milk: 0. 352 mg/day),and the comparison percentages of calculated values per permeable values were as follows; 206.5 % for brand cow milk,121.5 % for dairy farm cow milk and 176.0 % for domestic cow milk. Hazard Quotients (HQ) values and Carcinogenic Risk (CR) values were found within the acceptable level. Conclusion: Although, the metal content in sampled cow milks were within the safe limit, the potential human health risks cannot be neglected for the regular/long time consumption of heavy metal contained cow milk

Spatio-temporal patterns of pre-eclampsia and eclampsia in relation to drinking water salinity at the district level in Bangladesh from 2016 to 2018

This analysis examines whether salinity in drinking water is associated with pre-eclampsia and eclampsia (PE/E), a leading cause of maternal morbidity and mortality. Bangladesh’s national health information system data were extracted at the district level (n = 64) to assess PE/E rates, and these were overlaid with three environmental measures approximating drinking water salinity, remotely sensed low-elevation coastal zone (LECZ), monthly rainfall data, and electrical conductivity of groundwater (i.e., water salinity). Results from a negative binomial fixed effects model suggest PE/E rates are higher with less rainfall (dry season), lower population density, and that district level rates of PE/E increase with higher groundwater salinity and in the high risk LECZ category closest to the coast. Results suggest that drinking water salinity may be associated with PE/E and that using national health surveillance data can improve understanding of this association. This approach can potentially be leveraged in the future to inform targeted interventions to high risk regions and times

Assessment of the Status of Groundwater Arsenic at Singair Upazila, Manikganj Bangladesh : Exploring the Correlation with Other Metals and Ions

Comparative study was conducted to correlate Arsenic (As), Iron (Fe), Copper (Cu), Manganese (Mn), Calcium (Ca2+), Magnesium (Mg2+), Potassium (K+), Nitrate (NO3¯), Phosphate (PO43¯), and Ammonia (NH3) by determining their concentration at different depth of the tube-wells in the selected study area at Singair, Manikganj Bangladesh. Total 99 tube-well water samples were collected from the study area. In most of the sampling points the present concentrations of As were less than the previous concentrations. The correlation between As and Fe was positively significant. It can be suggested possible adsorption/coprecipication of As with Fe in shallow aquifer. However, the relationship between As and Mn was not significantly observed. On the other hand, relationship between Cu and As showed a positive significant correlation. The correlation between As and PO43¯ was also significant, although the correlation between As and NO3¯ was not significant. PO43¯ may be comes from phosphate fertilizers application and can be a contributer of As in the shallow aquifer. The PCA biplot also indicated the significant relationship between As, Cu, Fe and PO43-. Excessive withdrawal of tubewell water along with aquifer dynamics along with ionic interference might be responsible for the mobilization of As in the study area

Impacts of Salinity Intrusion in Community Health: A Review of Experiences on Drinking Water Sodium from Coastal Areas of Bangladesh

Increasing salt intake has substantial negative impacts on human health and well-being. This article focused on the construction of Driver-Pressure-State-Impact-Response (DPSIR) framework for drinking water sodium (DWS) followed by a review on the published studies regarding salinity intrusion, DWS, and their effects on health perspectives in Bangladesh. Saline water is an important factor for hypertension or high blood pressure in the coastal areas. DWS can also lead women, especially pregnant women, to an increased risk of (pre)eclampsia, hypertension, as well as infant mortality. Several interventions, such as rainwater harvesting, pond sand filter (PSF) system, managed aquifer recharge (MAR), and pilot scale solar-powered desalination plants, such as reverse osmosis (RO), were reviewed on the context of their effectiveness in controlling drinking water sodium. Although rainwater consumption has the positive impact of low or no sodium intake, it still possesses negative impacts from not having vital minerals. A steady increment in sodium concentration through the span of the dry season was observed in MAR. It is, subsequently, important to increase awareness on DWS intake by providing and adopting correct technological interventions and training communities on the maintenance of the adaptive measures

Hydrobiology of Saline Agriculture Ecosystem: A Review of Scenario Change in South-West Region of Bangladesh

The aim of this review paper is to identify the production trends of shrimp and rice farming systems and associated hydrobiological parameters such as salinity in the coastal districts of Bangladesh. An intensive literature review has been conducted to explore salt stress-driven land use change, crop production, and changing ecosystem hydrobiology to adapt climate change impact from 2012–2022. The results indicate that a gradual extension of salt-driven land use and land cover (LULC) change has stressed agricultural production to a greater extent from 1973 to 2022 due to the high level of salinity. The unplanned expansion of shrimp culture is creating adverse consequences for the coastal ecosystem. Some suggestions have been proposed by analysing the mechanisms of crops’ response to salt stress, including several physiological, biochemical, and molecular bases to mitigate the adverse effects of salinity on agricultural production. Alternatively, prawn, shrimp, and crab have similar or slightly higher economic outputs, except for the crop-based agricultural system, which is highly affected by salinity rise. However, due to low input costs, low maintenance, and less environmental impact, farmers are shifting towards crab fattening and thus changing the hydrobiology of coastal land use and land cover

Photo-flocculation of microbial mat extracellular polymeric substances and their transformation into transparent exopolymer particles: Chemical and spectroscopic evidences

Upon exposure to sunlight extracellular polymeric substances (EPS) were partially transformed into transparent exopolymer particles (TEP) and unstable flocs of different sizes without the addition of any precursors. Parallel factor (PARAFAC) modelling of the sample fluorescence spectra identified humic-like and protein-like or tyrosine-like components in both untreated and irradiated EPS samples. After 58 hours of solar irradiation, humic-like substances were entirely decomposed, while the regenerated protein-like substance from EPS was the key component in the irradiated samples. Degradation and reformation of EPS occurred which was confirmed by the results of size exclusion chromatography, dissolved organic carbon, total protein and total polysaccharide analyses. Irradiated EPS was composed of -COOH or C = O (amide I band) and -NH and -CN (amide II band), while Fourier transform infrared spectroscopy (FTIR) of TEP revealed more acidic -COOH and -C-O groups, indicating typical acidic protein-like TEP. The regenerated protein-like substances could form complexes with free metals originating from degraded EPS in irradiated samples, which could be responsible for the formation of TEP/floc in the aqueous media. These results suggest that TEP/floc formation from EPS could occur by a complexation mechanism between dissolved organic matter and metals, thereby causing ionic charge neutralisation upon sunlight exposure

Potential Allelopathic Candidates for Land Use and Possible Sustainable Weed Management in South Asian Ecosystem

Weed management is one of the significant challenges of field crops since weeds pose a remarkable threat to crop productivity in South Asian countries, including Bangladesh. Allelopathy, a phenomenon whereby secondary metabolites produced and released by one plant species influence the growth and development of other species can be exploited in sustainable management. The focus of this study was to evaluate potential allelopathic plant species which can be further explored as alternatives to synthetic herbicides or incorporated as part of integrated weed management in sustainable agriculture. Two hundred fifty-two plant samples from 70 families were collected from Bangladesh and evaluated with the sandwich bioassay. Thirty-one percent of the samples showed significant allelopathic potential on lettuce radicle elongation. Among the species that showed substantial inhibition, more than 7% of the samples showed higher inhibition (HI) and 25% showed moderate inhibition (MI) on lettuce radicle. Fruit pulps of Couroupita guianensis (95.4%), fruits of Phyllanthus emblica (95.4%), and Acacia concinna (95.4%) showed the highest inhibition on lettuce radicle elongation. In contrast, the leaf of Bombax insigne had growth promoting activity by stimulating radicle (23%) and hypocotyl (80%) elongation of lettuce seedlings. This result suggested that the species with significant plant growth inhibitory potential may play a vital role as an alternative to the increasing use of synthetic herbicides for sustainable weed management in agricultural land

Spatio-temporal assessment and trend analysis of surface water salinity in the coastal region of Bangladesh

The study was designed to collect water samples over two seasons-wet-monsoon season (n = 96) (March-April) and dry-monsoon season (n = 44) (September October)-to understand the seasonal variation in anion and cation hydrochemistry of the coastal rivers and estuaries contributing in the spatial trend in salinity. Hydrochemical examination of wet-monsoon season primarily revealed Ca-MgHCO3 type (66%) and followed by Na-Cl type (17.70%) water. In the dry-monsoon season, the scenario reversed with primary water being Na-Cl type (52.27%) followed by Ca-Mg-HCO3 type (31.81%). Analysis of Cl/Br molar ratio vs. Cl (mg/L) depicted sampling area affected by seawater intrusion (SWI). Spatial analysis by ordinary kriging method confirmed approximately 77% sample in the dry-monsoon, and 34% of the wet-monsoon season had shown SWI. The most saline-intruded areas in the wet-monsoon seasons were extreme south-west coastal zone of Bangladesh, lower Meghna River floodplain and Meghna estuarine floodplain and southeastern part of Chittagong coastal plains containing the districts of Chittagong and Cox's Bazar adjacent to Bay of Bengal. In addition, mid-south zone is also affected slightly in the dry-monsoon season. From the analyses of data, this study could further help to comprehend seasonal trends in the hydrochemistry and water quality of the coastal and estuarine rivers. In addition, it can help policy makers to obligate some important implications for the future initiatives taken for the management of land, water, fishery, agriculture and environment of coastal rivers and estuaries of Bangladesh

Removal of Pollutants from Water by Using Single-Walled Carbon Nanotubes (SWCNTs) and Multi-walled Carbon Nanotubes (MWCNTs)

Water crisis is one of the supreme challenges worldwide as clean water is the ultimate need for human civilization and all other life on earth. In the present study, continuous adsorption experiments were carried out in an adsorption column to survey the efficiency of the carbon nanotubes (CNTs) for removal of pollutants from water/wastewater in terms of physicochemical parameters, such as electrical conductivity, total dissolved solids (TDS), pH, chemical oxygen demand (COD) and total organic carbon (TOC), by using both single-walled carbon nanotubes and multi-walled carbon nanotubes. Sample solutions were allowed to flow in down-flow mode through the fixed-bed of CNTs. The CNTs column showed a reduction efficiency of electrical conductivity 80 % from effluent treatment plant (ETP) treated water sample, 69.23 % from raw effluent sample, and 53.33 % from the synthetic salt water sample. Similarly, the efficiency of TDS reduction was 78.61 % from raw effluent sample, 66.86 % from ETP treated water sample, and 62.02 % from the synthetic salt water sample. COD also reduced 84.71 % from raw effluent sample and 39.58 % from the ETP treated water sample. In case of TOC, the column showed a reduction efficiency of 85.88 % from the ETP treated water sample and 70.79 % from the raw effluent sample. These findings suggested that CNTs present a great potential in removal of pollutants in terms of physicochemical parameters from water/wastewater

Occurrence and health risks assessment of polycyclic aromatic hydrocarbons (PAHs) in road dust and soil samples at Dhaka city, Bangladesh

The status of PAH in the urban areas of Bangladesh is not known. For the first time, this study investigated concentration, spatial distributions, likely sources and potential toxicities of PAHs. 13 PAH compounds were analyzed in RDS (dust) and NS (soils) by gas chromatography-mass spectrometry (GC-MS). PAHs were enriched in relatively high molecular weight compounds (>3 rings), and Dibenzo(a,h)anthracene was the most abundant, indicating pyrogenic sources. Both in NS and RDS the concentrations of all PAHs were significantly associated to one another except high molecular weight PAHs (6 rings). There is no carcinogenic and health hazard for children and adults