ABSTRACT
Pakistan, among the top five most water-stressed nations globally, grapples with water scarcity owing to inadequate treatment infrastructure and groundwater overextraction. We demonstrate a successful nature-based closed-loop system to treat wastewater from urban vehicle-washing facilities, previously reliant on groundwater. An eco-friendly integrated system containing floating treatment wetlands (FTWs), subsurface flow constructed wetlands (SSF-CWs), and sand filtration (SF) was designed and installed at three vehicle-washing facilities for wastewater treatment and reuse in a loop. While the system is still operational after years, a consistent and significant reduction in water quality indicators is recorded, successfully meeting the national environmental quality standards of Pakistan. By reducing per unit water treatment costs to as low as $0.0163/m³ and achieving payback periods under a year, the embrace of these closed-loop strategies vividly underscores the imperative of transitioning to a circular economy in the domains of wastewater treatment and resource conservation.
ABSTRACT
The Hindukush-Karakoram-Himalaya (HKH) mountain ranges are the sources of Asia's most important river systems, which provide fresh water to 1.4 billion inhabitants in the region. Environmental and socioeconomic conditions are affected in many ways by climate change. Globally, climate change has received widespread attention, especially regarding seasonal and annual temperatures. Snow cover is vulnerable to climate warming, particularly temperature variations. By employing Moderate Resolution Imaging Spectroradiometer (MODIS) datasets and observed data, this study investigated the seasonal and interannual variability using snow cover, vegetation and land surface temperature (LST), and their spatial and temporal trend on different elevations from 2001 to 2020 in these variables in Gilgit Baltistan (GB), northern Pakistan. The study region was categorized into five elevation zones extending from < 2000 to > 7000 masl. Non-parametric Mann-Kendall trend tests and Sen's slope estimates indicate snow cover increases throughout the winter, but decreases significantly between June and July. In contrast, GB has an overall increasing annual LST trend. Pearson correlation coefficient (PCC) reveals a significant positive relationship between vegetation and LST (PCC = 0.73) and a significant negative relationship between LST and snow cover (PCC = - 0.74), and vegetation and snow cover (PCC = - 0.78). Observed temperature data and MODIS LST have a coefficient of determination greater than 0.59. Snow cover decreases at 3000-2000 masl elevations while increases at higher 5000 masl elevations.The vegetation in low and mid-elevation < 4000 masl zones decreases significantly annually. The temperature shows a sharply increasing trend at lower 2000-3000 masl elevations in the autumn, indicating the shifting of the winter seasons at this elevation zone. These findings better explain the spatiotemporal variations in snow cover, vegetation, and LST at various elevation zones and the interactions between these parameters at various elevations across the HKH region.
Subject(s)
Satellite Imagery , Snow , Climate Change , Seasons , TemperatureABSTRACT
A modified, efficient, and sensitive acetate-buffered QuEChERS extraction method was developed for the quantitative study of 16 commonly applied multiclass pesticides on date palm fruit. The date palm fruit samples were rehydrated by adding water during comminution. Samples were extracted with acidified acetonitrile, buffered with acetate salt. To minimize the matrix interferences, clean-up of the rehydrated samples was optimized by comparison with different sorbents (alumina, silica gel, florisil, primary secondary amine (PSA), and chitosan). The method validation parameters were evaluated as per European Union (EU) guidelines (SANTE/12682/2019). For 16 pesticides, % recovery of 69 to 121.8% with an associated precision (RSD ≤ 20%) was achieved at the fortification levels that were 0.5 to 2 times of European Union maximum residue limits (EU-MRLs). The validated method was successfully employed for the analysis of date palm fruit samples (n = 20) collected from various markets. Forty percent (40%) of samples (n = 8) were found to be contaminated with various pesticides. The most frequently detected residues were carbofuran, carbaryl, metalaxyl, tebuconazole, triazophos, and pyriproxyfen. The concentration of all the detected pesticides in real samples was below the EU-MRLs.