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The study area is a part of the Salt Range, where water quality is being deteriorated by natural and anthropogenic sources. This research integrates water quality assessment, arsenic enrichment, hydrogeochemical processes, groundwater recharge and carbon sources in aquifer. Total dissolved solid (TDS) contents in springs water, lake water and groundwater are in range of 681-847 mg/L, 2460-5051 mg/L and 513-7491 mg/L, respectively. The higher concentrations of magnesium and calcium in water bodies next to sodium are because of carbonates, sulfates, halite and silicates dissolution. The average concentrations of ions in groundwater are in order of HCO 3 -  > SO 4 2-  > Cl -  > Na +   > Mg 2+  > Ca 2+ , virtually analogous to springs water, but different from lake water, categorized as poor quality and unfit for drinking purposes. Based on major ions hydrochemistry, NaCl and mixed Ca-Mg-Cl type hydrochemical facies are associated with concentration of arsenic (4.2-39.5 µg/L) in groundwater. Groundwater samples (70%) having arsenic concentration (11 ≤ As ≤ 39.5 µg/L) exceeded from World Health Organization (WHO) guideline (As ≤ 10 µg/L) in near neutral to slightly alkaline (6.7 ≤ pH ≤ 8.3), positive Eh(6 ≤ Eh ≤ 204 mV), signifying its oxic condition. Eh-pH diagrams for arsenic and iron indicate that 80% of groundwater for arsenic and iron were in compartments of HAsO +  > NO 3 , unveil oxic environment. Arsenic is moderately positive correlated with TDS, sodium, chloride, bicarbonate, nitrate, sulfate and weak negative with δ - , virtually analogous to springs water, but different from lake water, categorized as poor quality and unfit for drinking purposes. Based on major ions hydrochemistry, NaCl and mixed Ca-Mg-Cl type hydrochemical facies are associated with concentration of arsenic (4.2-39.5 µg/L) in groundwater. Groundwater samples (70%) having arsenic concentration (11 ≤ As ≤ 39.5 µg/L) exceeded from World Health Organization (WHO) guideline (As ≤ 10 µg/L) in near neutral to slightly alkaline (6.7 ≤ pH ≤ 8.3), positive Eh(6 ≤ Eh ≤ 204 mV), signifying its oxic condition. Eh-pH diagrams for arsenic and iron indicate that 80% of groundwater for arsenic and iron were in compartments of HAsO 4 in surface and groundwater, forecasting multiple sources of arsenic to aquifer. Stable isotopes of waters show recharge of groundwater from local rain and lake water. The lower δ 2- and Fe(OH) 3 , unveil oxic environment. Arsenic is moderately positive correlated with TDS, sodium, chloride, bicarbonate, nitrate, sulfate and weak negative with δ 13 C DIC in surface and groundwater, forecasting multiple sources of arsenic to aquifer. Stable isotopes of waters show recharge of groundwater from local rain and lake water. The lower δ 13 C DIC values of groundwater are modified by influx of CO 2 produced during biological oxidation of soil natural organic matter., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

The exposure variation of arsenic from different ground and surface water sources has remained unpredictable which may cause severe human health problems. The current study is, therefore, designed to analyze the spatial variability of arsenic contamination in shallow aquifer and assess the potential human health risks. For this purpose, a total of 55 groundwater, 10 drain water, 4 river water, and 6 sediment samples were collected along zero to 5 km stretch of the River Ravi, Lahore. All water samples were tested for As, pH, and total dissolved solids (TDS), whereas sediments were only tested for As. Health risk models were used to predict cancer and non-cancer risk in adults and children. Among water samples, highest median (minimum-maximum) concentrations (µg/L) of As were recorded 53.32 (1.98-1555) in groundwater, followed by 53.04 (1.58-351.5) in drain water, and 4.80 (2.13-8.67) in river water, respectively, whereas As concentration (mg/kg) in river sediments was 6.03 (5.56-13.92). Variation of As in groundwater was non-significant (P > 0.05) among every 1-km stretch from the Ravi River. However, maximum median concentrations (µg/L) of 60.18 and 60.08 were recorded between 2-3 and 0-1 km from River Ravi, respectively, reflecting possible mixing of river water with shallow aquifers. A very high cancer and non-cancer risk (HI > 1.0 × 10 -4 ) through groundwater As exposure was predicted for both children and adults. The current study concluded that prevalence of As above WHO prescribed limits in shallow aquifer along the urban stretch of the River Ravi is posing serious health risk to the exposed population., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In this study, exposure to arsenic (As), lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn) was investigated in the blood, pectoral muscles and tail feathers of two terrestrial (spotted owlet; Athena brama and bank myna; Acridotheres ginginianus) and two aquatic (cattle egret; Bubulcus ibis and pond heron; Ardeola grayii) bird species inhabiting Pakistan. Food chain specimens, as well as the dietary proxies δ 15 N and δ 13 C, were also analyzed to validate potential trophic and dietary transfers of metals and As in birds. Zn was found to be the most prevalent metal in the tissues of birds followed by Pb, As, Cu, and Cd. The bioaccumulation of metals and As was higher in tail feathers reflecting the combined effect of both endogenous and exogenous contamination. Pectoral muscle and blood harbored lower levels of As and metals, indicating less recent exposure through diet. Aquatic birds feeding at higher trophic levels accumulated significantly higher concentrations of metals and As in their tissues (P < 0.05) and, therefore, may be at a greater risk of metal and As toxicity than terrestrial birds. Linear regression model depicts δ 15 N as a strong predictor of metals and As levels in the tissues of both aquatic and terrestrial birds, followed by the δ 13 C dietary proxy. All metals in aquatic species, except for Cd, as well as terrestrial species, except for Cu, exhibit bioaccumulative potential through the food chain (Trophic transfer factor: TTFs > 1) indicating potential harmful consequences for birds. Elevated concentrations of metals and As in tissues may cause harmful effects in birds potentially leading to declines in their populations., Competing Interests: Declaration of competing interest The authors declare no conflict of interest at personal and/or organizational level., (Copyright © 2020 Elsevier Inc. All rights reserved.)

In this study, we investigated metal- and metalloid-induced oxidative stress response in two aquatic (cattle egret (Bubulcus ibis) (n = 10), pond heron (Ardeola grayii) (n = 10)), as well as two terrestrial (spotted owlet (Athene brama) (n = 6) and bank myna (Acridotheres ginginianus) (n = 16)) bird species collected from the outskirts of Lahore city, Pakistan. For this purpose, glutathione (tGSH) and lipid peroxidation (thiobarbituric acid-reactive substances (TBARS)) levels and activities of antioxidant enzymes (superoxide dismutase (SOD); catalase (CAT)) were analyzed as biomarkers of oxidative stress against metal (Pb, Cd, Cu, Zn) and metalloid (As) concentrations in kidney liver and blood of birds. Our results depicted significant correlation for Pb, Cd, and As with oxidative stress biomarkers in birds. The levels of heavy metals and As and their corresponding effects on oxidative stress biomarkers were comparably higher in aquatic species (p ≤ 0.01) except for Pb and Zn. In comparison of species, SOD and tGSH activities were higher in bank myna and cattle egret, while CAT activity and TBARS concentrations were higher in pond heron and cattle egret, respectively. We deduced that tissues with higher accumulation of metal(loid)s such as liver and kidney were under a great risk to oxidative damage. The overall order of metal accumulation and subsequent oxidative damage among families followed the pattern as Strigidae ≥Ardieda ≥ Sturnidae with their respective trophic levels. Globally, metal- and As-induced oxidative stress is least emphasized in multiple tissues of birds that is needed to be addressed with focus on case-control studies using dose-response approach. Graphical abstract .

The study area is a part of the Salt Range, where water quality is being deteriorated by natural and anthropogenic sources. This research integrates water quality assessment, arsenic enrichment, hydrogeochemical processes, groundwater recharge and carbon sources in aquifer. Total dissolved solid (TDS) contents in springs water, lake water and groundwater are in range of 681–847 mg/L, 2460–5051 mg/L and 513–7491 mg/L, respectively. The higher concentrations of magnesium and calcium in water bodies next to sodium are because of carbonates, sulfates, halite and silicates dissolution. The average concentrations of ions in groundwater are in order of HCO3− > SO42− > Cl− > Na+ > Mg2+ > Ca2+ > K+ > NO3−, virtually analogous to springs water, but different from lake water, categorized as poor quality and unfit for drinking purposes. Based on major ions hydrochemistry, NaCl and mixed Ca–Mg–Cl type hydrochemical facies are associated with concentration of arsenic (4.2–39.5 µg/L) in groundwater. Groundwater samples (70%) having arsenic concentration (11 ≤ As ≤ 39.5 µg/L) exceeded from World Health Organization (WHO) guideline (As ≤ 10 µg/L) in near neutral to slightly alkaline (6.7 ≤ pH ≤ 8.3), positive Eh(6 ≤ Eh ≤ 204 mV), signifying its oxic condition. Eh–pH diagrams for arsenic and iron indicate that 80% of groundwater for arsenic and iron were in compartments of HAsO42− and Fe(OH)3, unveil oxic environment. Arsenic is moderately positive correlated with TDS, sodium, chloride, bicarbonate, nitrate, sulfate and weak negative with δ13CDIC in surface and groundwater, forecasting multiple sources of arsenic to aquifer. Stable isotopes of waters show recharge of groundwater from local rain and lake water. The lower δ13CDIC values of groundwater are modified by influx of CO2 produced during biological oxidation of soil natural organic matter. [ABSTRACT FROM AUTHOR]

This study investigated physico-chemical drinking water quality of 115 water supply schemes of of District Mianwali along with estimating the health risks associated with the intake of arsenic and flouride in drinking water. One sample was collected from the source end while two samples were collected from consumer ends of each scheme. Overall results showed that 81% of the water samples were safe while 19% were unsafe for drinking purposes. Results showed that TDS (30%), chloride (15%), sulphate (40%), calcium (40%), sodium (14.2%), hardness (24%), nitrate (13%), flouride (30%), and arsenic (7%) exceeded World Health Organization (WHO) standards. Pearson correlation matrix also showed statistically significant relationships (p<0.01) between various physico-chemical parameters and statistically strong significant positive relationships (r = 0.68-1.00, p<0.01) between TDS, Ca, SO4 2-, and hardness.There was no variation in the source and consumer end water quality. Risk assessment revealed a low potential health risk to the population of Mianwali for arsenic at source 0.4309<1 (mean) and consumer ends 0.70438<1 (mean), and F- 0.4339<1 at source (mean) and 0.4068<1 (mean) at consumer ends. Hence, this study is in time for the authorities to act immediately, as Mianwali groundwater quality is deteriorating. [ABSTRACT FROM AUTHOR]