published by EQA - International Journal of Environmental Quality ISSN 2281-4485 - Vol. 42 (2021): 6-21 Journal homepage: https://eqa.unibo.it/ Spatio-temporal analysis of pollutants in Karachi coastal water Rabia Majeed*, Syeda Urooj Fatima, Muhammad Azher Khan, Moazzam Ali Khan, Syed Shahid Shaukat Institute of Environmental Studies, University of Karachi, Karachi, Pakistan Corresponding author e-mail:
[email protected] ARTICLE INFO Received 24/6/2020; received in revised form 9/9/2020; accepted 17/12/2020. DOI: 10.6092/issn.2281-4485/11099 © 2020 The Authors. Abstract Karachi coast is heavily polluted due to the regular discharge of domestic and industrial effluents. The present study discloses the occurrence and distribution of anthropogenic pollutants in samples collected from ten different places along the coastline of Karachi. The extent of pollution load for three consecutive years was estimated through the GIS technique. The results of the analysis revealed that physical parameters (pH, DO, salinity) were within the permissible limits whereas the level of chemical pollutants (except cyanide, As, Cr, and Cd) were exceptionally higher as compared to National Environmental Quality Standards (NEQS). On average, the study site Creek Avenue showed a higher pollution load of BOD, COD cyanide, TKN, and oil and grease. The average concentration of all heavy metals for three consecutive years (2015-2017) was found to be in an order of As<Cr<Cd<Pb<Ni. The study concluded that Karachi coastal area is overwhelmed with heavy loads of chemical and metallic pollution that requires strict regulations to secure the aquatic ecosystem. Keywords pollutant, heavy metals, toxicity, Karachi, seawater, GIS Introduction Rapid urbanization and unsustainable industrialization coastal areas particularly in developing countries, where across the world is responsible for alarming the limited facilities available are likely to cause lethal environmental pollutions level that poses continuing effects to the marine eco-systems (Huang et al.