In the present study, the tube well water quality and the associated health risks, emphasizing on arsenic contamination, were investigated in rural and urban samples from Tehsil Mailsi located in Punjab, Pakistan. Arsenic concentrations (μg/L) were ranged from 12 to 448.5 and which exceeded the WHO recommended limit (10 μg/L) in all cases. The calculated average daily dose (3.3 × 10 to 1.2 × 10 mg/kg day) and hazard quotient (1.1-40) reflected the potential health risk to local population due to tube well water consumption as drinking purpose. Sodium percent (Na%), sodium absorption ratio, residual sodium carbonate, Kelly's index and magnesium absorption ratio were also determined to assess the suitability of tube well water for irrigation purpose. The resulting piper plot revealed the Na-Ca-HCO type water chemistry of the area and generally alkaline environment. The spatial distribution of arsenic in the tube well waters pinpoints the significant contribution of anthropogenic activities to arsenic pollution. Nevertheless, different statistical tools, including principal component analysis, hierarchical cluster analysis and correlation matrices, revealed the contribution of both natural and anthropogenic activities and alkaline type of aquifers toward the high level of arsenic contamination.
The present study have used space observations of NO emission (OMI) and aerosol optical depth (AOD) (MODIS) from the last couple of years (2015)(2016)(2017)(2018)(2019) to investigate the changes in air pollution in response to COVID-19 pandemic during the lockdown period (Mar-May, 2020) over the Indo-Pak region. Result of this study reveals a huge drop in air pollution that accounted for 40-50% reduction in NO emissions and 45% in AOD over the whole Indo-Pak region. The major metropolitan areas (cities) of the region showed a remarkable decrease in NO emissions, whereas the calculated rate of reduction was found highest for the city of Lahore (Pak) ranges between 29-52% followed by Ahmadabad (Chennai) as 27-52% (32-42%) respectively. The geospatial analysis revealed the existence of positive correlation (range from 0.23-0.50) between AOD and NO emissions, which further implies that a decrease in AOD may be attributed to reduction in NO to some extents.
Glacier changes are driven by glacier melt, which in turn affects streamflow. This paper describes an accounting scheme for glacier area change distribution across elevation profiles for application in the glacier module of the Soil and Water Assessment Tool (SWAT) model. In addition to volume-area scaling relationship in the module, the paper introduced volume-length scaling relations to estimate changing glacier terminus and update glacier area changes between equilibrium line altitude (ELA) and the terminus. The improved scheme was used in the nested Urumqi Glacier No. 1 catchment and Urumqi River Basin in Tienshan Mountains, China. Comparison of the simulated and observed data suggested that the new scheme accurately reproduced the length and area changes of Glacier No. 1. The contributions of glacier melt and ice melt to runoff were estimated at 71% and 38% for Glacier No. 1 Hydrological Station and 11.1% and 5.8% for Yingxiongqiao Hydrological Station, respectively. This helped to better interpret long-term monitored glacio-hydrological processes of Glacier No. 1 and the variation of glacier melt contribution to streamflow at the catchment scale.
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