Spatio-temporal analysis of pollutants in Karachi coastal water

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.