| Autor: |
Haider, Syed Wasi, Kazmi, Syed Jamil Hasan, Alamgir, Aamir, Khan, Adnan, Arsalan, Muhammad |
| Předmět: |
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| Zdroj: |
Arabian Journal of Geosciences; Oct2023, Vol. 16 Issue 10, p1-22, 22p |
| Abstrakt: |
The groundwater quality in upper (MLB) and lower riparians (MRB) of Malir River (MR) system is not fully understood. In the present study, geospatial technique has been used to determine groundwater quality along both banks of MR. The groundwater sampling and quality characteristics are measured in semiarid environments of MR basin in Karachi city having shallow and deeper wells to estimate the type of water composition in urban sprawl and elevated areas. Approximately 28 and 43 samples were collected from MLB and MRB, respectively and found that both banks were heavily polluted at lower elevated levels, while upper elevated areas show a decrease in non-potability of groundwater with agricultural lands and recharging streams. The comparative study suggests that toxic elements like arsenic, fluoride and nitrate were concentrated in urban spots and places far from industrial and commercial units. The total dissolved salts (TDS) content at upper riparian of Malir left bank (MLB = 3039 mg/L) and lower riparian of Malir right bank (MRB = 6451 mg/L) shows that pollution levels is greater at MRB than MLB with average well depth of MLB (76.66 m) > MRB (44.57 m). The occurrence of groundwater variables from spatial patterns is more intense in estuary vicinities and MR meandering curves, causing natural recharge of shallow and deeper wells from the west to south. From correlation (CM) and principal component analysis (PCA), organic matter from manmade activities, evaporation caused by climate change, untreated sewage and industrial effluents (more anthropogenic activities than natural influence) raise concentration levels of physical as well as chemical variables of groundwater with presence of microbial activity reducing nitrate to some extent in groundwater, while higher elevated areas show signs of potable conditions and less anthropogenic occurrence. The Piper diagram depicts samples from both sides showing majority of samples were NaCl type. The study with spatial distribution patterns concludes that groundwater at lower elevated areas of MLB and MRB are unfit for human consumption due to urban sprawl and downstream. This study will help delineating the polluted movement of water zones in comparative research and targeting the safe water aquifers for the public use. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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