Present pollution profile of Karachi coastal waters

Abstract

Natural and human interventions have posed serious threats to the sustainability and development of the coastal environment. This problem is more apparent in Karachi, a metropolitan city of Pakistan, which has a coastline extending up to about 30 km. The city, with more than 18 million people, generates around 472 million gallons per day of municipal and industrial wastewater. Out of which, about 80% is being discharged untreated into the Arabian Sea. The problem is more aggravated by oil spills from cargo ships, and oil tankers in the Harbor Area. This research study was focused to assess the level of pollution and its impact on the coastal environment. During the study, surface seawater samples were collected from six different locations in Manora Channel, the main pollution prone area. Significantly high volatile matter (42–65%) coupled with the measurable depletion of Dissolved Oxygen (DO) and a decrease in pH level was observed. Moreover, the distribution pattern of heavy metal pollution at the Karachi coast was found in the following descending order: Zn > Mn > Fe > Cu > Ni > Pb. Its concentration at several locations was not very critical. However, the trend indicated the likely increase in metal pollution. At Fish Harbor, the metal concentration was higher when compared with the sea water quality standard. Overall, the study suggested that the concerned authorities and industrialists should jointly take measures to reduce pollution and to achieve coastal ecosystem sustainability.

Full text

Present pollution profile of Karachi coastal waters
Seema Jilani
1
Received: 26 July 2016 /Revised: 25 April 2017 / Accepted: 1 November 2017 /Published online: 16 November 2017
#Springer Science+Business Media B.V., part of Springer Nature 2017
Abstract Natural and human interventions have posed serious
threats to the sustainability and development of the coastal envi-
ronment. This problem is more apparent in Karachi, a metropol-
itan city of Pakistan, which has a coastline extending up to about
30 km. The city, with more than 18 million people, generates
around 472 million gallons per day of municipal and industrial
wastewater. Out of which, about 80% is being discharged un-
treated into the Arabian Sea. The problem is more aggravated by
oil spills from cargo ships, and oil tankers in the Harbor Area.
This research study was focused to assess the level of pollution
and its impact on the coastal environment. During the study,
surface seawater samples were collected from six different loca-
tions in Manora Channel, the main pollution prone area.
Significantly high volatile matter (42–65%) coupled with the
measurable depletion of Dissolved Oxygen (DO) and a decrease
in pH level was observed. Moreover, the distribution pattern of
heavy metal pollution at the Karachi coast was found in the
following descending order: Zn > Mn > Fe > Cu > Ni > Pb.
Its concentration at several locations was not very critical.
However, the trend indicated the likely increase in metal pollu-
tion. At Fish Harbor, the metal concentration was higher when
compared with the sea water quality standard. Overall, the study
suggested that the concerned authorities and industrialists should
jointly take measures to reduce pollution and to achieve coastal
ecosystem sustainability.
Keywords Coastal environment .Karachi .Waste w ate r .
Pollution .Volatile matter .Sustainability
Introduction
Worldwide anthropogenic activities causing marine pollution
have now become a major environmental concern. Several
researchers have reported that toxic pollutants from cities
and fields, discharge of untreated municipal and industrial
wastewater, extreme input of nutrients and oil spills, signifi-
cantly affect the rivers, coastal and marine environments
(Luger and Brown 1999; Tyrrel 1999; Rabalais and Nixon
2002; Danulat et al. 2002;WHO2003). Hence, monitoring
of the coastal environment is essential in order to understand
the origin, distribution, fate and behavior of pollutants and to
formulate a viable management strategy for the conservation
of aquatic resources (De Wolf et al. 2005).
Like other populated and industrialized coastal regions in the
world, the Karachi Coast, especially Manora Channel has been
receiving a large volume of untreated municipal and industrial
effluent. About 20% of the annual wastewater produced in the
city is treated and the rest is discharged without treatment into
Karachi Harbor and adjoining coastal waters through Lyari and
Malir Rivers (JICA report 2007). The industrial processing units
are contributing relatively high quantity of problematic com-
pounds, since most of them have either no treatment facilities
or have grossly inadequate arrangements. Contaminants of the
major concerns from industrial sources include persistent organ-
ic pollutants, nutrients, oils, radionuclides, heavy metals, patho-
gens, sediments, litters and debris etc., (Williams 1996). These
compounds may be toxic, mutagenic and carcinogenic and may
be bio-accumulated or bio-magnified by the biota (Hayes 1984;
Wagner 1993; Groten and Vanbladeren 1994;Khan2006).
During the last few decades, coastal pollution by chemicals
and heavy metals such as Lead, Cadmium, Copper, Nickel,
Zinc, etc., have increased alarmingly (Mashiatullah et al.
2009; Qadri et al. 2011;Nergisetal.2012). Previous investi-
gations reported that the point and non-point sources of
*Seema Jilani
seemajilani@hotmail.com
1
Institute of Environmental Studies, University of Karachi,
Karachi 75270, Pakistan
J Coast Conserv (2018) 22:325–332
https://doi.org/10.1007/s11852-017-0581-x
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