The contamination of riverbed sediments by heavy metals has assumedserious problems due to their toxicity and accumulative behavior. The present studyinvestigated the concentrations of heavy metals from the bottom sediments of ShitalakhyaRiver to understand the level of contamination and their distribution. The averageconcentrations of heavy metals Al, K, Ca, Mg, Fe, As, Cu, Co, Cr, and Zn are 30432.41,10929.21, 391139.13, 23148.14, 38697.37, 14.02, 143.69, 13.37, 74.82, and 200.59mg/kg respectively in river sediments, and their abundance decreased in the followingorder: Ca (79.05%)>Fe (7.82%)>Al (6.15%)>Mg (4.68%)>K (2.21%)>Zn (0.04%)>Cu(0.03%)>Cr (0.015%)>As (0.0028%)>Co (0.0027%). In most cases, the meanconcentrations of the heavy metals exceed the permissible limit. Significantly higherconcentrations of Ca, Mg, Zn, and Cu were found in sediment samples. The heavy metalscontaminations in the sediments were also evaluated by applying index of geoaccumulation(Igeo), contamination factor (Cf), degree of contamination (Cd), and pollutionload index (PLI) etc. These indices indicated that most of the samples were moderate tostrongly pollute by heavy metals and the spatial distribution showed that the northern andsouthern parts of the study area are more contaminant than middle portion.

There are many potential risks to human health from heavy metal contamination of vegetables resulting from wastewater irrigated sites. This study was carried out to assess the concentration of chromium (Cr) and the risk to human health by chromium through the intake of locally grown vegetables collected from wastewater irrigated agricultural fields. Twenty-seven samples of 9 (nine) different types of vegetables were analyzed by an Atomic Absorption Spectrometer (AAS) (Varian AAS 240 F S). The range of chromium concentration in wastewater irrigated vegetables was ND (Not detected) -4.14mg/kg. The highest mean concentration of chromium (4.14 mg/kg) was detected in radish. The mean concentration of chromium in all the vegetables was within the safe limits of WHO/FAO except radish which was much higher than the standard. Health risk index for chromium contamination in all vegetables was less than 1 for both adults and children which cause no risk to the local population. Among all vegetables tested, the highest intake value of chromium was from consumption of radish for both adults and children. The lower values of health risk index indicated chromium contamination in the wastewater irrigated vegetables that cause less negative impact on human health.

More than 35 million people in coastal Bangladesh are vulnerable to increasing freshwater salinization. This will continue to affect more people and to a greater extent as climate change projections are realised in this area in the future. However the evidence for health effects of consuming high salinity water is limited. This research examined the association between drinking water salinity and blood pressure in young adults in coastal Bangladesh. We conducted a cross-sectional study during May-June 2014 in a rural coastal sub-district of Bangladesh. Data on blood pressure (BP) and salinity of potable water sources was collected from 253 participants aged 19–25 years. A linear regression method was used to examine the association between water salinity exposure categories and systolic BP (SBP) and diastolic BP (DBP) level. Sixty five percent of the study population were exposed to highly saline drinking water above the Bangladesh standard (600 mg/L and above). Multivariable linear regression analyses identified that compared to the low water salinity exposure category (<600 mg/L), those in the high water salinity category (>600 mg/L), had statistically significantly higher SBP (B 3.46, 95% CI 0.75, 6.17; p = 0.01) and DBP (B 2.77, 95% CI 0.31, 5.24; p = 0.03). Our research shows that elevated salinity in drinking water is associated with higher BP in young coastal populations. Blood pressure is an important risk factor of hypertension and cardiovascular diseases. Given the extent of salinization of freshwater in many low-lying countries including in Bangladesh, and the likely exacerbation related to climate change-induced sea level rise, implementation of preventative strategies through dietary interventions along with promotion of low saline drinking water must be a priority in these settings.

Using artificial mussels (AMs), this study reports and compares time-integrated level of eleven trace metals (Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, U, Zn) in Karnafuli River estuary and coastal area of the Bay of Bengal, Bangladesh.Through this study, “hot spots” of metal pollution were identified. The results may demonstrate that the Karnafuli Estuary, and adjacent coastal area of Chittagong, Bangladesh are highly polluted by high risk metals (cadmium, chromium, copper, mercury, nickel, lead, uranium). Agricultural, domestic and industrial wastes directly discharged into the waterways have been identified as the main causes of metal pollution in Chittagong, Bangladesh. The high level of metal pollution identified may impact on local water quality, and seafood catch, livelihoods of people and public health resulting from seafood consumption. There is a need for regular monitoring to ascertain that local water quality with respect to metal levels are within acceptable levels to safeguards both environmental health and public health.

The present paper reviewed the average concentrations of trace elements in soils near coal mine areas from various cities/countries to provide a current global summary of this issue. The contamination of soils was assessed by using global reference materials and various contamination indices. The results show that the average concentrations of trace elements varied widely: As (0.5–38.3 mg/kg), Mn (86–3,700 mg/kg), Zn (1.5–296 mg/kg), Cu (0.5–110 mg/kg), Cr (17.5–954 mg/kg), Ni (4.3–390 mg/kg), Pb (0.5–433 mg/kg), Cd (0.02–4.48 mg/kg), and Hg (0.02–0.69 mg/kg). Most of these values are higher than the average world background soils and upper continental crust (UCC). The geo-accumulation (I gₑₒ) and contamination factor (CF) indices show that the contamination levels of Ni and Pb are higher than other elements. The potential ecological risk index (E ᵢ) suggests a high risk from Cd, especially in the Tabagi River watershed in Brazil and Ledo coal mines in India, and Hg, especially in Oltu (Turkey). The degree of contamination index (C d) reveals that the soils from Barapukuria (Bangladesh), Ledo (India), Ptolemais-Amynteon (Greece), and the Tibagi River (Brazil) have a higher degree of contamination than other sites. To control soil contamination, effective monitoring and legislative measures must be taken immediately. For the long term, various physical, chemical, and biological methods should be implemented. Although the selection of suitable methods is site-specific based on the extent and nature of contamination, in general, phytoremediation seems to be more beneficial and cost-effective than physical/chemical techniques.

Trace metals contamination in commercial fish and crustaceans have become a great problem in Bangladesh. This study was conducted to determine seven trace metals concentration (Cr, Ni, Cu, Zn, As, Cd, and Pb) in some commercial fishes and crustaceans collected from coastal areas of Bangladesh. Trace metals in fish samples were in the range of Cr (0.15 − 2.2), Ni (0.1 − 0.56), Cu (1.3 − 1.4), Zn (31 − 138), As (0.76 − 13), Cd (0.033 − 0.075), and Pb (0.07 − 0.63 mg/kg wet weight (ww)), respectively. Arsenic (13 mg/kg ww) and Zn (138 mg/kg ww) concentrations were remarkably high in fish of Cox’s Bazar due to the interference of uncontrolled huge hatcheries and industrial activities. The elevated concentrations of Cu (400), Zn (1480), and As (53 mg/kg ww) were also observed in crabs of Cox’s Bazar which was considered as an absolutely discrepant aquatic species with totally different bioaccumulation pattern. Some metals in fish and crustaceans exceeded the international quality guidelines. Estimated daily intake (EDI) and target cancer risk (TR) revealed high dietary intake of As and Pb, which was obviously a matter of severe public health issue of Bangladeshi coastal people which should not be ignored and concentrate our views to solve this problem with an integrated approaches. Thus, continuous monitoring of these toxic trace elements in seafood and immediate control measure is recommended.

The cleansing efficiencies of laundry detergents depend on composition and variation of ingredients such as surfactants, phosphate, and co-builders. Among these ingredients, surfactants and phosphate are considered as hazardous materials. Knowledge on compositions and micellar behavior is very useful for understanding their cleansing efficiencies and environmental impact. With this view, composition, critical micelle concentration, and dissolved oxygen level in aqueous solution of some laundry detergents available in Bangladesh such as keya, Wheel Power White, Tibet, Surf Excel, and Chaka were determined. Surfactant and phosphate were found to be maximum in Surf Excel and Wheel Power White, respectively, while both of the ingredients were found to be minimum in Tibet. The critical micelle concentration decreased with increasing surfactant content. The amount of laundry detergents required for efficient cleansing was found to be minimum for Surf Excel and maximum for Chaka; however, cleansing cost was the highest for Surf Excel and the lowest for Tibet. The maximum amount of surfactants and phosphate was discharged by Surf Excel and Wheel Power White, respectively, while discharges of both of the ingredients were minimum for Tibet. The maximum decrease of dissolved oxygen level was caused by Surf Excel and the minimum by Tibet. Therefore, it can be concluded that Tibet is cost-effective and environment friendly, whereas Surf Excel and Wheel Power White are expensive and pose a threat to water environment.

Dhaka and its neighboring areas suffer from severe air pollution, especially during dry season (November–April). We investigated temporal and directional variations in particulate matter (PM) concentrations in Dhaka, Gazipur, and Narayanganj from October 2012 to March 2015 to understand different aspects of PM concentrations and possible sources of high pollution in this region. Ninety-six-hour backward trajectories for the whole dry season were also computed to investigate incursion of long-range pollution into this area. We found yearly PM₁₀ concentrations in this area about three times and yearly PM₂.₅ concentrations about six times greater than the national standards of Bangladesh. Dhaka and its vicinity experienced several air pollution episodes in dry season when PM₂.₅ concentrations were 8–13 times greater than the World Health Organization (WHO) guideline value. Higher pollution and great contribution of PM₂.₅ most of the time were associated with the north-westerly wind. Winter (November to January) was found as the most polluted season in this area, when average PM₁₀ concentrations in Dhaka, Gazipur, and Narayanganj were 257.1, 240.3, and 327.4 μg m⁻³, respectively. Pollution levels during wet season (May–October) were, although found legitimate as per the national standards of Bangladesh, exceeded WHO guideline value in 50 % of the days of that season. Trans-boundary source identifications using concentration-weighted trajectory method revealed that the sources in the eastern Indian region bordering Bangladesh, in the north-eastern Indian region bordering Nepal and in Nepal and its neighboring areas had high probability of contributing to the PM pollutions at Gazipur station.

Although the tobacco production and consumption rate in Bangladesh is very high and a substantial portion of premature deaths is caused by tobacco smoking, the status of heavy metals in tobacco plants has not yet determined. This study, therefore, investigated the concentrations of Cu, Ni, Cd, Pb, Cr, and Zn in tobacco plants and their surrounding agricultural soils in Kushtia District, Bangladesh. The geochemical maps showed a similar spatial distribution pattern of the analyzed metals and identified Shempur, Kharara, Taragunia, and Shantidanga as metal hot spots. Geoanalytical indexes were applied to assess the extent of soil contamination, and the results depicted that the soils of Shempur, Kharara, Taragunia, and Shantidanga were moderately contaminated where Cd contributed the most to contamination degree (C d) in spite of its relative low content. However, other five areas in Kushtia District were suggested as uncontaminated according to both C d and pollution load index (PLI). The hazard quotient (HQ) and hazard index (HI) showed no possible indication of human health risks via ingestion of agricultural soils. This study also determined that human activities such as excess application of commercial fertilizers, animal manures, and metal-based pesticides were the sources of Cu, Ni, Cd, and Cr enrichment in soils and that the metals into tobacco plants were transported from the soils. The present study conclusively suggested that regulation of improper use of agrochemicals and continuous monitoring of heavy metals in tobacco plants are needed to reduce the tobacco-related detrimental health problems in Bangladesh.

Chronic exposure to inorganic arsenic (iAs) in the human population is associated with various internal cancers and other adverse outcomes. The purpose of this study was to estimate a population-scale exposure risk attributable to iAs consumptions by linking a stochastic physiological-based pharmacokinetic (PBPK) model and biomonitoring data of iAs in urine. The urinary As concentrations were obtained from a total of 1,043 subjects living in an industrial area of Taiwan. The results showed that the study subjects had an iAs exposure risk of 27 % (the daily iAs intake for 27 % study subjects exceeded the WHO-recommended value, 2.1 μg iAs day⁻¹ kg⁻¹ body weight). Moreover, drinking water and cooked rice contributed to the iAs exposure risk by 10 and 41 %, respectively. The predicted risks in the current study were 4.82, 27.21, 34.69, and 64.17 %, respectively, among the mid-range of Mexico, Taiwan (this study), Korea, and Bangladesh reported in the literature. In conclusion, we developed a population-scale-based risk model that covered the broad range of iAS exposure by integrating stochastic PBPK modeling and reverse dosimetry to generate probabilistic distribution of As intake corresponding to urinary As measured from the cohort study. The model can also be updated as new urinary As information becomes available.