Assessment of Marine Coastal Water Pollution from Karachi Harbour Pakistan

In Pakistan, marine pollution is a major problem that is caused by the waste from industrial, municipal, agronomy, and oil leak sources. The pollutant loads along with the coastline areas near Karachi is received from terrestrial contaminants including discharges from Karachi Harbour located on the estuary of the Lyari river. Karachi generates 472 Million Gallon per Day (MGD) of wastewater out of which only 55 MGD is treated and the rest is discharged in the sea. The prevailing sewage treatment plants are functioning at reduced capacity due to the insufficient transmission capacity of interceptors. Water sampling was carried out from the Lyari River and five different selected coastal point around Karachi harbour for physicochemical parameters and selected heavy metals. Results show that the Karachi Harbour area is noticeably polluted, whereas; the coastal environment in the vicinity of Karachi is also under the stress of pollution. High COD and BOD5 values were noticed at the Lyari river samples and the sampling locations close to the Lyari river outfall area. The Pb, Cd, Ni, and Hg heavy metals that pollute marine water are found. This situation is due to the discharge of mixed effluents of industrial and domestic wastes as well as dredging, cargo handling, dumping of ship waste and other coastal activities. The highest value of pollution observed at Karachi Harbour which is near Lyari river mouth, where the domestic and industrial effluents with organic and inorganic wastes have a greater influence on the water quality and the marine environment. At present, there is no effective controlling mechanism for industries to treat their waste, nor has any investigation to assess increasing marine pollution been carried out. As a result, there is an adverse impact on fish habitat and mangroves, corrosion of cargo ships, naval vessels and the residents living in the coastal area. Therefore, the government agencies and industrial sectors should work together to avert marine pollution and attain total environmental sustainability.