Water quality is a big concern for the humankind as it is the most important natural resource. Water is polluted by increasing activities of population and the necessity to provide them with goods and services that use water as a vital resource. In this study, surface water samples were collected in the summer and the winter season from Rupsa river, Bangladesh, and pH, electrical conductivity (EC), Cr, Ni, Cu, As, Cd and Pb concentrations were analyzed to assess the metal toxicity, identify the possible sources and determine health risk from metals in water. During the the summer season, the mean concentrations of Cr, Pb, As, Cu, Ni and Cd were measured as 7.20 ± 0.613, 7.09 ± 0.904, 5.45 ± 0.441, 5.36 ± 0.471, 3.85 ± 0.694 and 0.975 ± 0.106 µg/L, respectively, whereas the concentrations were measured as 8.87 ± 0.756, 7.32 ± 0.93, 6.05 ± 0.490, 6.02 ± 0.529, 5.48 ± 0.986 and 1.38 ± 0.151 µg/L, respectively, during the the winter season. Source identification like correlation analysis, Principal component analysis (PCA) and cluster analysis (CA) were applied to identify the source of toxic metals in water. Total heavy metal toxicity load and heavy metal evaluation index values were found to be higher than permissible value except for Cu. According to the ecological risk index classification, 85% of the total samples were found to pose moderate ecological risks, while the rest 15% were found to pose low ecological risks during both seasons. As showed high non-carcinogenic risk on the basis of single element via oral exposure. The hazard index value for oral exposure by male, female and children was found to be 4.17E + 00, 3.67E + 00 and 8.64E + 00, respectively; indicating that non-carcinogenic effects are obvious to occur. The carcinogenic risks of Ni and As due to regular exposure via oral and dermal contact pathways were higher than the standard value (>1.0E-04) which anticipated possible cancer risks to male, female and children in the study area.

Heavy metals contamination is a serious threat for the toxicity and bioaccumulation in food chain. Aquatic environment contamination has become a global concern because they have toxic effects on fishes. The concentration of heavy metals like arsenic (As), chromium (Cr), cadmium (Cd) and lead (Pb) in commercially fishes (Tenualosa ilisha, Gudusia chapra, Otolithoides pama, Setipinna phasa, Harpadon nehereus, Polynemus paradiseus, Sillaginopsis panijus and Pampus chinensis) collected from Karnaphuli River in Bangladesh were (fish muscles) assessed with health risk during summer and winter season. These heavy metals are toxic in nature and can come to human food chain through fish consumption. The mean concentration of As, Cr, Cd and Pb was found 1.59, 0.73, 0.41 and 1.13 mg/kg in summer and 1.81, 0.92, 0.52 and 1.45 mg/kg in winter, respectively. Cr and Pb concentration of all fish species were found to be higher than Food and Agriculture Organization (FAO)/(WHO) tolerable concentration assuming these metal pose risk to human. The hazard quotients value of heavy metals in Harpadon nehereus was found higher than one resulting non-carcinogenic risk for consumption of this fishes. Carcinogenic risk value for As and Pb were remaining 10⁻⁶ to 10⁻⁴ indicating continuously consumption of studied fish samples may cause cancer risk.

Pharmaceutical wastewater (PWW) is rapidly growing into one of the world’s most serious environmental and public health issues. Existing wastewater treatment systems carry numerous loopholes in supplying the ever-increasing need for potable water resulting from rises in population, urbanization, and industrial growth, and the volume of wastewater produced is growing each day. At present, conventional treatment methods, such as coagulation, sedimentation, oxidation, membrane filtration, flocculation, etc., are used to treat PWW. In contrast to these, the application of microbial fuel cells (MFCs) for decontaminating PWW can be a promising technology to replace these methods. MFC technologies have become a trending research topic in recent times. MFCs have also garnered the interest of researchers worldwide as a promising environmental remediation technique. This review extensively discusses the flaws in standalone conventional processes and the integration of MFCs to enhance electricity production and contaminant removal rates, especially with respect to PWW. This article also summarizes the studies reported on various antibiotics and wastes from pharmaceutical industries treated by MFCs, and their efficiencies. Furthermore, the review explains why further research is needed to establish the actual efficiency of MFCs to achieve sustainable, environmentally friendly, and cost-effective wastewater treatment. A brief on technoeconomic impacts has also been made to provide a glimpse of the way these technologies might replace present-day conventional methods.

Rice is the staple food of Bangladeshi people and is consumed at least twice a day. Thus, the presence of toxic metals in rice grains has become a major public health concern in Bangladesh. The present research was conducted to investigate the concentrations of toxic metals in rice grains and their possible human health risks in the Tangail district of Bangladesh. Toxic metals were measured by using an inductively coupled plasma mass spectrometer (ICP-MS), and the mean concentrations of toxic metals in rice samples were found in order of Cr > Pb > Ni > As > Cu > Cd. The concentrations of Cr, Pb, As, and Cd in the studied rice grain samples exceeded the FAO/WHO standard values for food samples by 100%, whereas the Ni concentrations by 10%. The principal component analysis (PCA) revealed significant anthropogenic contributions of Cr, Ni, As, and Pb concentrations in rice grains. The metal concentrations in rice grain samples showed strong significant correlations by forming primary clusters with each other. The estimated daily intake (EDI) values of Cr, Ni, As, Cd, and Pb from all samples were higher than the maximum tolerable daily intake (MTDI) allowed. The total targeted hazard quotient (TTHQ) values of Cu, Ni, As, Cd, and Pb also exceeded the threshold value of 1.00, indicating a potential non-carcinogenic risk. The estimated target carcinogenic risk of As was higher than the USEPA threshold level 10⁻⁴ (0.0001) indicating increased risk of cancer for adults and children in the study area.