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Tap water is the sole source of water in urban cities but gradually being polluted by potentially toxic elements due to unplanned urbanization. The south Asian megacity, Dhaka (capital of Bangladesh) encounters drastic water pollution resulting mainly from anthropogenic differential factors. Consumption of such polluted water distributed to residents by pipelines can trigger health risks. Therefore, this study investigated the public health vulnerability associated with dissolved metal(oid)s in tap water collected across Dhaka city. The concentrations of Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, Hg and Pb in measured tap water ranged from 8-156, 7–73, 400-20100, 12–110, 7-101, 12–136, 12–908, 0.03–9.75, 1–5, 0.22–1.30, and 8-118 µg/L, respectively. Among the observed elements, Pb, Cr, and Fe concentrations in 18%, 26%, and 75% of sampling sites, respectively, exceeded the standard guideline criteria of Bangladesh. Entropy-based water quality index demonstrated that ~ 12% of sampling sites possessed water unsuitable for drinking and other household works. The dominant sources of water pollution in this region are industrial effluents and domestic sewage. Both non-carcinogenic and carcinogenic health risks are invoked mostly from ingestion of Co and Pb. Regular consumption of this tap water without further pretreatment may result in detrimental health consequences to both children and adults due to the physiological accumulation of toxic elements over time. This study highlighted a comprehensive scenario of the potentially toxic elements in the tap water of Dhaka city, which will allow policymakers to take adequate measures for sustainable water quality management.

To understand the mechanistic pathway of arsenic (As) enrichment and mobilization in groundwater (southeastern Bangladesh) and to evaluate the water quality as well as associated health risks, a suite of systematically collected groundwater samples (depth: 17-61 m) were analyzed. Arsenic concentrations (μg L

The monthly weighted mean stable isotopic composition of rainfall in eight GNIP (Global Network of Isotopes in Precipitation) stations of Bangladesh vary in a short range i.e. δ18O = −6.998‰ to −5.58‰. The weighted δp value shows the order as HT > XB > SR > CN > DN > KH > BN > BS although modification of trend occurs when considered differently for monsoon and non-monsoon periods. Pre or post-monsoonal rain shows relatively enriched signature compared to the monsoon period. The local meteoric water lines (LMWLs) are much similar to Craig’s GMWL (Global Meteoric Water Line) except DN. The way of the effects from meteorological control vary according to seasons and locations. The spatiotemporal distribution of humidity accounts for ≈34% of isotopic variation. Temperature effect is most prominent in CN (41%, non-monsoon) and BS (19%, monsoon). Around 50% dependency on precipitation amount has been observed in coastal stations and DN during January to May, while monsoon precipitation is mostly characterized by reduced amount effect and “anti-amount effect”. Moreover, wide range of d-excess during non-monsoon precipitation bears the evidence of mixture of vapour from different sources and recycling events. However, monsoonal vapour source is rather consistent since d-excess value varies within a little margin.

To observe the current hydro-geo-chemical condition of shallow aquifers and the response from anthropogenic activities as well as to study the arsenic contents and affiliated health risks, groundwater samples from different parts of north-central Bangladesh (Tangail) were studied. In doing so, analytical parameters, including pH, total dissolved solids, electrical conductivity, dissolved oxygen, NO3−, HCO3−, Cl−, SO42-, Na, K, Ca, Mg, Fe, Cr, Mn, Ni, As, Cu, Cd, Zn, and Pb abundances were utilized. Aquifer hydrochemistry presents mainly Ca-Mg-HCO3 type water, while in some cases appreciable amount of Na+ and Cl− proclaim their presences in the formation of groundwater mineralogy. Therefore, there was significant impact from irrigation return flow to affect the groundwater hydrochemistry of this region. Source rock-water interactions in the form of dolomite and calcite weathering is the chief natural agent to provide minerals in the groundwater. The waters in the aquifer seem to be comparatively young with mostly being unsaturated in terms of carbonate minerals and having the scope of reverse ion exchange. Among the trace elements of this study average values of As, Mn, Fe, and Cd were above the guideline values, where As is the dominant contaminant in deteriorating the water quality. In terms of irrigation water indices, groundwater of the studied site is mostly suitable for agricultural usages. Although, magnesium hazard ratio and total hardness values can exert potential threats. However, As level in the studied groundwater possesses potential health hazardous for both non-carcinogenic and carcinogenic risks where children are more vulnerable than adults. The outcome this study invokes regular monitoring of groundwater quality, especially for As contamination to save the public-health.