SPATIOTEMPORAL MODELLING OF HEAVY METAL POLLUTION AND WATER QUALITY DEGRADATION IN KARACHI’S COASTAL WATERS: THREAT TO MARITIME SUSTAINABILITY

Abstract

The industrialization, maritime operations, and urban expansion adjacent to major port cities around the world are becoming a threat to coastal ecosystems. The research presents a decade review on spatiotemporal analysis of water quality along a Karachi coastal zone, one of Pakistan's most active maritime and economic sectors. Physico-Chemical parameters and Heavy metals were evaluated to quantify the Water Quality Index (WQI), correlation analysis, Heavy Metal Pollution Index (HPI), and statistical analysis. The major parameters were pH, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Dissolved Oxygen (DO), Chromium (Cr), Nickel (Ni), Cadmium (Cd), Arsenic (As) and Lead (Pb) were gathered for six different locations i.e. Sandspit, Hawksbay, Seaview, Manora, Gizri Creek and mouth of Lyari River. The modeling trend revealed a severe degradation in water quality at Seaview and Gizri Creek due to untreated sewage, industrial effluent, shipping operation discharges, and port activities. The research summarizes a strong correlation between metallic and organic pollutants due to maritime transport, the absence of wastewater treatment, and unsustainable ship-breaking practices. The Manora Beach water quality is comparatively stable due to isolation from the direct influence of pollutants. The sustainability of the coastal zone was also measured to predict the future risk by projecting the WQI for 2030. The forecast shows that maximum deterioration at Sea view exceeds the critical threshold and greatly influences the coastal tourism, marine biodiversity and aquatic life. The integrated analysis provides a comprehensive dataset and establishes a baseline for environmental monitoring for coastal zone management. The results highlight the vulnerable zone to adopt the mitigation plans and sustainable development strategies for Pakistan's coastal and maritime economic corridors.