http://www.wwfpak.org/sgp/pdf/toxics/1_study_%20of_%20heavy_metal_pollution.pdf ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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FINAL PROJECT REPORT
1. Project No. #: 50022801
2. Project Title: Study of Heavy Metal Pollution Level and Impact on the Fauna
and Flora Of the Karachi and Gwadar Coast.
3. Project Start Date: October 2001
4. Project End Date: September 2002
5. Report Prepared by: Monawwar Saleem
7. Introduction:
Karachi is located on the northern border of the Arabian Sea and its population is over
thirteen million. Karachi coastal area receives 472,000m3 domestic and industrial
wastewater primarily through Lyari and Malir River and from streams and drainages
(KDA master plan
1
, 1990-2000). This water reaches Karachi coastal area via Karachi
Harbour and Gizri creek. Industrial waste discharge originating form the industries located
at SITE (Sindh Industrial Trading Estate), LITE (Landhi Industrial Trading Estate), KIA
(Korangi Industrial Area) that also add their effluent to Karachi coastal area. The two
existing treatment plants located at Malir and Lyari Rivers treat approximately 20-25% of
the total waste. Karachi coastal area is badly affected by industrial and untreated sewage
of Karachi Harbour and Gizri and Korangi creek. According to Beg
2
(1975) Karachi
Harbour receives a variety of chemicals such as calcium carbonate (115.74 metric
tons/day) total dissolved solids (317 metric tons/day) iron oxide (5.14 metric tons/day).
Due to the tidal flushing of wastes in the Karachi Harbour and Gizri and Korangi creek
the highly toxic wastes make their way in to the coastal waters of Karachi resulting the
increasing levels of pollution. Preliminary survey of Karachi Harbour seawater reveals
that it contains high concentration of nutrients downstream of Lyari River Monawwar
3
(1995). The tides of the Karachi Harbour are semi diurnal type Quraishee
4
(1975). The ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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effluents received by the Karachi Harbour through Lyari River and the adjoining areas are
not completely flushed out in to the open sea during tidal cycle. Therefore poor circulation
condition creates production of hydrogen sulfide that produces a stress on the marine life.
Tidal flats of the Sandspit and Channa creek in the Karachi Harbour area have flourishing
vegetation of mangrove. The most part of the central area of Karachi Harbour and some
area of Korangi creek are devoid of any benthic life in the sediments. The bottom
sediments are black in colour with presence of hydrogen sulfide. The fauna and flora of
this area are severe stress from the industrial and domestic pollution (Ahmed
5
, 1979).
The city of Gwadar is located at the extreme northern border of the Arabian Sea, some
~450 km west of Karachi. The population of Gwadar is over 120,000. More than 50% of
the population is engaged in fishing activity. The fishermen’s boats occupy a very large
stretch of the East Bay where fish landing and boat building and repairs take place. About
400 boats (mostly small) are busy in fishing in the territorial waters. According to
Rabbani
6
(1989) the area is highly productive and red tide blooms have been observed in
the winter monsoon period. Gwadar city has no proper drainage system; the liquid waste
is dumped septic tank (underground). According to Memon
7
(1995), heavy minerals are
found in the range of 1-.15%. High concentrations of heavy metal in water and sediment
have also been observed in Karachi Harbour and in the sediment of Gwadar East Bay
(Monawwar
8
, 1999). Continued disposal of the industrial and domestic waste in to
Arabian Sea will cause fish kill and reduction in the valuable export of shrimps as well as
the reduction of marine life in the coastal waters. Some work has been done regarding the
heavy metal concentration in the fish and shellfish of the Karachi offshore, Korangi creek,
and Karachi Harbour (Ashraf
9
, 1988; Monawwar
10,
,1999)
8. Objectives:
- Estimate the level of heavy metals (Cd, Pb, Ni, Cu, and Hg) in the seawater at hot
spot sites of Karachi and Gwadar coast. ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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- Determine the heavy metal in the marine sediments and biota of Karachi and
Gwadar coastal area.
- To determine any heavy metal indicator species of Karachi and Gwadar coastal
areas.
- To establish the relationship of heavy metal pollution in marine biota with the
environment.
9.Project Achievements (Short and long term):
Result and discussion provide the following useful information: -
- From this project, the data information on heavy metal distribution patterns at
selected sites in the seawater, sediments, fauna and flora of Karachi and Gwadar
coastal areas has been recorded.
- The project provides a comprehensive baseline data for heavy metals that would
be useful for pollution monitoring of the study area in future.
- Data of bioaccumulation obtained from this study will help in determining possible
health risks by consumption of seafood from the area.
- The results of this study will also provide a baseline for the assessment of the
impact of disposal of industrial and municipal wastes in the entire area of the
environment.
10.Constraints & Obstacles encountered:
Time required for the sampling collection and analysis was constraints. This was
overcome by extending the report period.
11. Action taken to overcome constraints & Obstacles
The WWF-P Scientific Committee was requested to extend the time period, which
was granted to me. ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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12.Target/ Objective not achieved and why?
The target/ Objectives set out in the initial proposal have been achieved.
13. Described the methods developed for the project:
The following protocols were adopted for the collection of samples and data
analysis.
13.1 Collection of surface sediment
Seabed sediment samples were collected using Peterson Grab at eight
stations in Gwadar East Bay, four stations at Karachi Harbour, three station
in Korangi creek area and one each in Gizri Creek, Buleji, Manora (open
sea side), (Fig.1-3). A part of the sample from middle of the grab was
retained for analysis. Soon after the collection of samples, the sediment
samples were kept in polyethylene wide neck bottles (Pre-washed with
10% HC1 acid) and stored in iceboxes and refrigerator until analysis. The
sediment samples were collected from Karachi coast in January 2002 to
July 2002. The sampling from Gwadar was done in the middle of July
2002.
13.2 Collection of seawater Samples
Seawater samples for dissolved heavy metals were collected using Niskin ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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bottles / plastic Bucket (pre-washed with distilled water). These seawater
samples were collected at above station along with the stations.
Immediately after the collection of seawater it was filtered through micro
glass fiber filter (0.8 µ) paper followed by membrane filter (0.45 µ) under
300 mm Hg pressure acidified with hydrochloric acid to pH-2 and kept in
cool place in polyethylene (Nelgin) bottles until analysis. All equipments
and filter were of non-metallic materials, carefully acid washed with 10 %
hydrochloric acid and rinsed with double distilled water.
13.3 Collection of fish and mussel samples
The fish and shellfish were collected by a trawl net at high tide from the
Manora Channel (Karachi Harbour) and in Korangi creek (Fig.1-3). These
samples were taken between January and July 2002. Fifteen fishes (Pelagic
and benthic) were also collected from Gwadar East Bay during the mid of
July 2002. Soon after the collection, the samples were rinsed with distilled
water. These samples were identified to the species level and stored in deep
freezers until analysis.
Mussels (Perna viridis) were collected random by hand picking from each
site of Manora channel (Karachi Harbour), Korangi creek and Gwadar East
Bay (Near fish harbour) during low tide in January & July 2002. (Fig.1-3).
In the laboratory, the samples were cleansed to remove the mud or any
attachment and then washed with double distilled water. Tissues (edible
portion) from the shells were removed with a plastic knife and kept in precleaned Petri dish. Finally the edible portion samples were dried in the
oven at 65°C. ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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13.4 Collection of seaweeds and mangrove plant leaves
Seaweeds were collected by hand picking from two different sites of
Karachi coast, Manora Island (Sea-side) and Buleji during low tide in
January 2002; Mangrove leaves were collected at four different sites
(Sandpit back water, Karachi Harbour, Kemari back water, Korangi Fish
Harbour and Rehri Goth) of the Karachi coast in January 2002. These
samples were cleaned and rinsed with double distilled water, and finally
dried at room temperature.
13.5 Digestion and analysis of sediment samples
One to four gram of dried sediment sample were added to 3 ml
concentrated nitric acid and 9 ml of hydrochloric acid (Aqua regia) in prewashed beaker and digested at room temperature. The sediment samples
were then evaporated almost to dryness at moderate temperature 65-70 C°
on the hot plate under the clean air-fuming hood. Finally, the samples were
diluted up to 25 ml with 2% nitric acid (FAO, 1975)
11
,Heavy metals (Cu .
Cr, Ni, & Zn, in the sediment samples were analyzed on Flame Atomic
Absorption Spectrophotometer (FAAS) using PERKIN-ELMER Model
3300, Cadmium samples were analyzed on Graphite Furnace Atomic
Absorption Spectrophotometer (HGA-600 Perkin-Elmer).
13.6 Extraction of heavy metals and analysis from the seawater samples
300ml to 1000ml samples of seawater was transferred to a pre-washed ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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separating funnel and 1.0 ml of citrate buffer was added. The pH of the
samples was adjusted to 4.0 with concentrated hydrochloric acid or purified
ammonia. After adjusting the pH, 2 ml of 1.0 % chelating reagent APDC
(Ammonium Pyrolline Dithocarbamate) solution was added followed by 20
ml MIBK (Metyl Isobutyl Ketone) The mixture was kept for 2 to 3 minutes
and they were allowed 15-16 minutes for the separation of phase,
subsequent the lower organic layer was drained in 100 ml separating
funnel. The procedure was repeated by adding an additional aliquot of 10
ml MIBK to the funnel shaken after 2 to 3 minutes the two extracts were
combined and 0.5 ml of nitric acid was added by micropipette mixed for
one minute and left for 15 minutes. Subsequently 9.5 ml of double distilled
water was added for back extraction (Kremling
12
, 1983). After phase
separation, the aqueous phase was collected in pre-cleaned Nelgin
polyethylene bottle for analysis.
Measurement of heavy metal in seawater was made with Flame AAS /
Graphite furnace. Standard operating conditions of the instrument were set
during the analysis for Cadmium, nickel, copper and chromium in
seawater.
13.7 Digestion and analysis of heavy metal in fish, shellfish, seaweeds, and
mangrove leaves
Approximately 1 to 3 gram dry weight of marine organisms (For Fishes
edible portion and whole soft tissue of Mussels), seaweed and mangrove
plant leaves were mixed separately and to each digestion vessel were added
3 ml of Nitric acid, 9 ml of Hydrochloric acid (Aqua regia) and 5 to 15 ml
of Hydrogen peroxide according to the FAO
11
(1975) Manual and were
digested at 70-100°C to dryness. After removal from hot plate, the samples
were cooled at room temperature, and then added with 25 ml of 2% of ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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nitric acid and kept for two hours. The samples were then filtered by
Whatman No.42 filter paper.
For calibration purpose known concentration of each element was added to
digest the samples and recoveries were >92% for the known amount of
each element. All samples and blanks were analyzed using double beam
Atomic Absorption Spectrometer (Perkin-Elmer model 3300). Zinc, copper
and chromium were analyzed on flame, while cadmium and nickel on
Graphite Furnace (Model HGA-600)
14. Lessons learnt from the project:
The presence of heavy metal pollution in the coastal waters of Karachi is
significant as shown in the results and discussion. The heavy metal concentration
at Gwadar was however lower. But we must not be complacent. Awareness and
the efforts for the containment of heavy metal must continue to be monitored at
regular intervals and brought to the notice of the concerned authorities.
14. Result and discussion
14.1 Concentrations and distribution of heavy metals in sea water
The observation of heavy metal concentration levels recorded at four different sites
of Karachi coastal area (Karachi harbour, Buleji, Korangi and Gizri creek) and
Gwadar East Bay and off-Gwadar East Bay five heavy metals (zinc, copper;
cadmium, chromium and nickel) were studied their levels are given in fig.4-fig 6).
Generally the concentrations of these metals were found highest in following
order; Karachi Harbour> Korangi creek > Gizri creek> Buleji in Karachi coast and
in Gwadar East Bay. The high concentration of the heavy metals in seawater in the
Karachi Harbour, Korangi and Gizri creek indicates that the area continuously ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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receives industrial and domestic waste of Karachi city, while Buleji is relatively
less polluted.
14.1.1 Nickel
The concentration of nickel in the Karachi Coast ranges from 0.27 to 0.72 µg/l
(Fig.4). Highest concentration of nickel was found in the Karachi Harbour (Mean
0.72µg/l) and lowest in Buleji and Gwadar East Bay 0.27 and 0.42µg/l
respectively. High concentration of nickel in Karachi Harbour is due to the waste
originating from the electroplating industries at S.I.T.E. Similar trend of nickel
distribution was observed by L.Brugman
13
(1998) in northern part of the Baltic
near Skagerrak area. Seng
14
(1987) also noticed high concentration of nickel (1.6-
1.8 µg/l) in the Juru Estuary due to the industrial activity along the coast (Table-I).
At least 40 times lower concentration of nickel was found in our coastal area in
comparison with the recommended marine water quality standard for UK for the
protection of marine life (Mance, 1984)
15
.
14.1.2 Copper
The concentration levels of copper in the water samples of Karachi Harbour are
found to be highest. Mean value obtained was 2.13µg/l, and low values were found
at Buleji and Gwadar East Bay 0.85 0.98µg/l respectively (Fig.4). High
concentration in Karachi Harbour can be attributed to the release of copper from
the industries and other coastal installations. Comparatively higher concentration
of copper in the seawater are reported by Patel
16
(1985) in Bombay harbour,
Mart
17
(1985) in Elbe Estuary, Harper
18
(1991) in Severn Estuary, Sengupta
19
(1978) in Goa and Zingde
20
(1987) in Perna River Estuary .On the other hand
lower copper concentrations were recorded by Seng
14
(1987) in Juru Estuary,
Fowler in Oman coastal water and Valanta
21
(1983) in Wester Shedlt Estuary ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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(Table-1).
During the present study, a decrease in the concentration of copper was noted from
Karachi Harbour towards the open sea. Kremling and Peterson
22
(1984) made
similar observation in the Bothnian Bay.
14.1.3 Zinc
The concentration level of zinc at the Karachi Coast ranges from 3-24.3µg/l, while
in the Gwadar East Bay the concentration ranges between 12-13µg/l (fig.5). The
results obtained for zinc in Karachi Harbour are similar to the observations made
by Bryan
23
(1976) in Corpus Crusty Harbour in Texas, during the summer when
the harbour water stagnates and concentration of zinc was 480µg/l. Wong
24
(1980)
also observed high concentration of zinc i.e.38 to 94µg/l in the Tolo Harbour,
Hong Kong (Table-1). Accumulation of zinc in seawater in present study shows
discharge from the Karachi Harbour and Korangi Creek.
14.1.4 Cadmium
Highest mean concentration level of cadmium has been recorded in Karachi
Harbour to be 0.485µg/l about half of its concentration is reported in the Korangi
creek, while lowest was recorded in Buleji (0.063µg/l) table-5. According to a
published report Industrial and domestic waste is considered to be the main source
of cadmium in the marine environment. The concentration of cadmium in our
study is comparable to that in the Severn Estuary where cadmium ranged between
0.11-0.4 µg/l as reported by Harper
18
(1991), Wong
24
(1980) and Ouseph
25
(1992)
in Tolo Harbour and Cochin Estuary where higher concentrations (Table-1).
Lower concentration of cadmium was found in Gwadar and Bulleji seawater ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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respectively. This concentration is 40 times lower according to USA-EPA
26
(1998)
or marine water quality criteria for chronic and acute level (Table-1).
14.1.5 Chromium
The highest mean chromium concentration in seawater was found in the Karachi
Harbour and Gizri creek where the concentration ranges from 2.61 and 2.13µg/l
(Fig.6). High concentration of chromium is mainly due to untreated tannery waste
which is being dumped in the Karachi Harbour and Gizri creek via Lyari and Malir
River respectively.
14.2 Concentration and distribution of heavy metals in sediments
The results of heavy metals (Cu, Zn, Cd, Ni and Cr) in sediments that were
collected from Buleji, Karachi Harbour, Korangi and Gizri and Creek Gwadar fish
Harbour and off-Gwadar fish Harbour (Gwadar East Bay) are shown in Fig.7-9.
Concentration of all five heavy metals in surface sediments decrease in the
following order Karachi Harbour > Korangi creek > Gizri creek > Buleji in
Karachi Coastal > Gwadar East Bay >off-Gwadar East Bay.
14.2.1 Nickel
Nickel concentration was observed to be highest at Karachi Harbour where as its
concentration was 46 ppm, and lowest at Buleji (5 ppm). About half the
concentration (22 ppm) of nickel of Karachi Harbour was recorded in Gwadar East
Bay sediment, the source of which may be natural of rocks (Fig.7).
This data is comparable to other parts of the world (Table-2).such as. Bombay
Harbour (Patel
16
,1985) Kaohsiung Harbour (Chen
27
,1977) reported higher ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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concentration of nickel in sediment compared to the Karachi coastal and Gwadar
coastal areas. In contrast, lower concentrations were recorded by Soulsby
28
(1978),
Salamanca
29
(1978), and Seng
14
(1978).
14.2.2. Zinc
The highest mean concentration of zinc in sediment was found in the surface
sediments of the Karachi Harbour i.e. (192.7 ppm) while about 22 times lower
concentration was found in Buleji Coast (Fig.7). In the previous studies
(Monawwar
3
1995), in Karachi Harbour, concentrations were found to be almost
half of recent studies. Monawwar
8
,(1999) reported mean concentration levels of
zinc in sediment as 35.2 ppm in Gwadar East Bay.
Comparatively the relative concentration of zinc in the Karachi Harbour was
found to be higher than Bombay Harbour, Portsmouth Harbour, Conception Bay,
Juru Estuary and Upper Gulf of Thailand (Table-2).
14.2.3 Copper
The highest concentration of copper in sediment was observed in the Karachi
Harbour (89 ppm) while the lowest was recorded in Buleji (1.6 ppm) The
concentration was (7.8 ppm) off Gwadar East Bay (Fig.8). Untreated waste of
SITE, KITE and LITE area can be attributed to high concentration in the sediment
of Karachi Harbour, Korangi and Gizri creek respectively.
Copper concentration in the sediments Karachi Harbour was found to be lower
than that found in Bombay Harbour, Higher concentrations were reported in
Portsmouth Harbour (Soulsby
28
1978), Juru Estuary (Seng
14
1987), Singapore
Estuary (Sin
30
1991), Koasiung Harbour (Chen
27
1977), Conception Bay ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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Salimanica
29
(1988) Menasveta
31
(1981) in Gulf of Thailand (Table-2).
14.2.4 Cadmium
Highest concentration of cadmium in surface sediment was found at Karachi
Harbour and Korangi creek 1.12 and 0.99 ppm respectively whereas lower values
were recorded at Buleji and Gwadar East Bay 0.31 and 0.42 ppm respectively
(Fig.8). Previous record (Monawwar
3
1995) shows that concentration of cadmium
in Karachi Harbour has increased up to three times in the past 8 years The
concentration of cadmium in the surfacial sediments is although lower than the
other geographical areas as reported by Portsmouth Harbour (Soulsby), Juru
Estuary (Seng), Singapore Estuary (Sin), Conception Bay (Salamanca) and
(Menasveta) in Gulf of Thailand except Koasiung Harbour (Chen). (Table-2)
14.2.5 Chromium
The concentration and distribution of chromium in sediments was observed to be
similar pattern as Cu, Ni and Zn for this study. The mean concentration of
chromium was 94.25, 27.67, 20 and 14.3 ppm recorded from the Karachi Harbour
Korangi creek, Gizri Creek and Gwadar East Bay respectively (Fig.9). High
concentration of Chromium can be attributed probably to large amounts of
chromium being utilised (waste of tannery industries) in the Lyari River, thst
ultimately enters in the Karachi coastal area via Karachi Harbour. Similar
observations were noted by Papakostidis
32
1974, who reported high chromium
concentration near sewage outfall in Saronikos Gulf, Greece. The results of
chromium concentration in surface sediment were comparable with the Bombay
Harbour and Koasiung Harbour (Table-2).
14.3 Heavy metals in marine organisms ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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Heavy metals observed in the bodies of the marine organisms were mainly as a
resultant of the processes of uptake and losses due to metabolic control, although the
body metal concentration is also affected by changes in body weight due to growth,
and reproduction, storage or depletion of energy reserves, etc. Bryan
33
(1980)
Enrichment of heavy metals in the marine organisms depends on available food that
is probably the major pathway of the uptake of the heavy metal and accumulation in
the tissue of marine organisms. Marine organisms also have the capability to
detoxify the excess of heavy metals through the formation of metal binding protein
(Metallothioneins).
14.3.1 Heavy metals concentration in mussel (Perna viridis)
Mussels are widely distributed in the aquatic world. Mussels are rich in protein and
are nutritious food. Due to its nutritious value, it becomes important commercial
fisheries product of the coasts, estuaries and bays. According to Farrington
34
(1987)
mussels have the capability to accumulate the excess of heavy metals from seawater
up to 100,000 times higher than the seawater.
Perna viridis are generally known as green mussels and are usually, found in
Arabian sea and adjacent seas. Perna viridis are marine bivalve with their green
shells and are found in coastal waters attached to rocks and other substrate. Various
species of mussels have been widely used in pollution monitoring programs such as
mussels watch program. Perna viridis has been used as heavy metal pollution
indicator species by Phillips in Hongkong, Hungspreugs
35
(1984) in Gulf of
Thailand, Chidambram
36-37
(1992) in Indian coast.
Since mussels are the best accumulator of the heavy metals, therefore green mussels
Perna viridis have been used for the assessment of the heavy metal pollution at ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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Karachi and Gwadar coast. The results of heavy metal concentration distribution in
mussels (Perna viridis) have been shown in the fig.10-11.
14.3.2 Copper
Concentration of copper in the mussel tissues were found in the following order
Karachi Harbour > Korangi Creek > Gwadar East Bay 10.32, 7.3, 6.44 (ppm dry
weight) respectively (Fig.10). The copper accumulation in the mussel tissues from
the current study were compared with report from different geographical areas
(Table-3). It is found that the results were comparable to the mussels found in the
Thailand and Oman areas however higher concentration of copper were reported
from England, Wales and Scotland mussels.
16.3.3 Cadmium
Concentration of cadmium in mussel was found highest in following order Karachi
Harbour>Korangi Creek>Gwadar East Bay 0.45, 0.34 & 0.21 ppm dry weight
respectively (Fig.10). High concentration of cadmium in mussels of Karachi Harbour
is due to the untreated waste from the industries and sewage that enhances the
accumulation of cadmium in the mussel tissues. Similarly Phillips
38
(1992) observed
high concentration of cadmium in the mussels (Perna viridis) in the industrially
contaminated Port Phillips Bay (18 ppm dry weight).
Comparison of heavy metal contents in the mussels tissue from different regions of
the world have been presented in table-3.
14.3.4 Chromium
Highest concentration of chromium in the mussels (Perna viridis) was found in ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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Karachi Harbour 3.77 ppm dry weight, while lowest concentration was recorded in
1.12 ppm dry weight in the Gwadar East Bay (Fig.10). Gault
39
(1983) found high
concentration of chromium in the mussels of Northern Ireland near the sewage
outfall and effluents of local tannery waste discharge point. High concentration in
mussels are also reported by Satmadjis
40
(1983) in Sorinikos Gulf (Table-3).
14.3.5 Zinc
Zinc is one of the essential metals for the marine organisms, and it increases the
enzymatic activity (Vallee
41
1978). The concentration of zinc was found between
36-64 ppm dry weight in the study area. Highest concentration as expected was
found in the Karachi harbour (Fig.11). Similar observations were recorded by
Anderlin
42
(1991) near the sewage outfall at the entrance of Wellington Harbor,
New Zealand.
The comparison of zinc contents in the Mussels in different coastal areas is shown
in table-3. Higher contents of zinc were reported in Scotland (Devies
43
1981),
Salalah (Fowler
44
1983), and Saronikos (Satsmadjis
41
1983) and England & Wales
(Murray
45
1982) than the studied area except in Gulf of Thailand (Manuwadi
46
1984) and Pitani Bay of Thailand (Evraartsts
47
1987).
14.3.6 Nickel
Concentration of nickel in the mussel of Karachi harbour was found to be double of
that found in the Korangi Creek and Gwadar East Bay (Fig.11). Fowler
44
(1983)
observed similar concentration of nickel in the mussels of Omani waters, while
higher concentration were reported by Satmadjis
40
(1983) in Sorinikos Gulf (Table-
3).
14.4 Heavy metals concentration in fishes ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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The result of five heavy metals reported in fishes of Karachi harbour Korangi
creek and Gwadar East Bay are shown in Fig.12-20. The species used during this
study were juvenile of twelve species of fish from Karachi Harbour, eleven species
of Korangi creek and fifteen species of Gwadar East Bay.
14.4.1 Zinc
The highest mean concentration of zinc in fishes were recorded in Acanthopagrust,
Gerres filamentosus, Terapon jerbua of Karachi harbour, Korangi creek and
Gwadar East Bay fishes respectively (Fig.13, 16 &19).
High concentration of zinc has been documented in the sediments as well as water
that reflected condition of fishes of Karachi harbour and Korangi creek. Similar
observations were made by Stenner and Nickless
48(
1974) in the marine biota of
Hardenger Fjord Norway due to high concentration background in the water and
sediments. The comparison of heavy metal contents in fishes in different coastal
areas is shown in Table-4 .The concentration of zinc recorded by Eustace
49
(1974),
Huseyin
50
(1982) Singball
51
1982) in the fishes of Derwent Estuary, Izmir Bay and
Aguda Bay respectively were found lower than that in the Karachi Harbour.
14.4.2 Cadmium
________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
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Cadmium is the most toxic element after mercury for marine life as well as for
human life. It is accumulated in the body of the marine organisms due to its poor
regulatory ability, as recorded by Pentrath
52
(1976), Olafson
53
(1977).
The mean concentration of cadmium in the fishes was found to be 0.06, 0.04, 0.06
ppm fresh weight in the fishes of Karachi harbour, Korangi creek and Gwadar East
Bay respectively. The highest concentration of cadmium was recorded both in
Sillago shiama of Karachi harbour and Gwadar East Bay and Carangoides
oblongus obtain from Korangi creek fish. Cadmium contents in the present study
were found to be lower compared with the maximum permissible daily intake
(Table-5). The concentration of cadmium in the fishes is also compared with the
published results. High values were observed by Huseyin
50
(1982) Singball
51
(1982) and Kureishy
54
(1993) in Izmir Bay, Aguda Bay and Qatari coast
respectively. Stenner and Nickless
55
(1992) found high concentration of cadmium
in the body muscles of Solea solea and Raja clavata (2.1, 2.45 ppm fresh weight)
respectively in the coastal areas of Spain and southern Portugal due to the river
inflow near the industrialized inland region. Wright
56
(1976) also found high
concentration of cadmium ranging between 3.4-5.4 ppm fresh weight in the fish
Patichthyes flestus in the Severn Estuary while Hardisty
57
(1974) found cadmium
that ranged between (1.1-1.7 ppm fresh weight) in the same species in the
Barnstable Bay.
14.4.3 Nickel
The highest concentration of nickel was found in both Sillago shiama of Karachi
harbour and Gwadar East Bay, and in Pomadasys argyreus of Korangi creek fish.
High concentration of nickel was due to their feeding habits and both species feed
on invertebrate, crustaceans and small fishes. Most of invertebrate such as ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
19
crustaceans are less mobile than the fishes. They can therefore accumulate higher
concentration of heavy metal from the Karachi coastal environment.
14.4.4 Copper
Copper is an essential metal required by the marine organisms for their enzymatic
activity to meet metabolic needs. Marine organisms have the capability to regulate
copper concentration according to their body requirement. Maximum
concentration of copper was found in both Sillago shiama of Karachi harbour and
Gwadar East Bay and Carangoides oblongus of Korangi Creek.
The concentration of copper reported in fish from different world coastal areas are
given in Table-4. This comparison shows that the average concentration of copper
in fish from Oman coast, Qatari coast, Derwent Estuary, Aguda Bay and Izmir Bay
were higher than the values found in the present study. The average daily intake of
heavy metals is given in Table-5.
14.4.5 Chromium
The concentration of chromium in fish found in the fish of Karachi Harbour was
0.42 ppm fresh weight, whereas maximum concentrations were recorded both in
Sillago shiama of Karachi harbour and Gwadar East Bay. These fishes have
chromium under the limit of normal daily intake as recommended in United
Kingdom in the foodstuff (Mance
15
1984)
Concentration of heavy metal contents in our coastal fishes have been compared
with the maximum permissible daily intake limit (Mc-Graw Hill Encyclopedia
58
(1982), Burch
59
1975 and GESAMP
60
, 1985). These Concentrations of heavy
metals are generally found within safe limit for human consumption Table-5. ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
20
14.5 Heavy metals concentration in mangrove leaves
Mangrove forest plays an important role in the productivity of the coastal estuarine
environment. They serve as a breeding ground and provide shelter for the fish and
shellfish of the coastal area. Rapid increase in population and industrial activities
effect the ecology of mangrove ecosystem of the creek area, particularly in the
vicinity of the Karachi coast. A numbers of studies have been reported with regards
to the metal contamination of mangrove Leela
61
(1979), George
62
(1997),
Chakarabarti
63
(1993), and Chiu
64
(1991). There is no published information
available about the metal contamination of mangroves in our coastal area.
This present study provides information on the heavy metal levels in the mangrove
leaves of Karachi coast. The results of the five metals in the mangrove leaves of four
different sites are given in figures 21-22. There is no variation in the concentration
of copper & zinc contents in the mangrove leaves of Karachi coast. Highest
concentration of heavy metals was recorded in the Kemari mangrove leaves, an
mean concentration of zinc and copper observed was 5.25 and 23.34 ppm dry weight
respectively.
According to Elderfield
65
(1979) heavy metals precipitated with iron forms
polysulfide mineral particularly with copper and zinc. Similar formation can be
observed in the Karachi Sandspit backwater mangrove which receives considerable
amount of untreated domestic wastes containing high concentration of heavy metals.
Concentration of copper and zinc concentration in Karachi mangrove leaves was
found to be lower than reported by Chakarabarti in Sundarbun, George in Kerala
India, Leela in Ganapatipule India (Table-6).
Highest concentration of cadmium was recorded in the Karachi Harbour (Sandspit
back water) 0.305 ppm dry weight and Korangi Creek area (Rehri Goth) ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
21
concentration was 0.249 ppm dry weight. Concentration of cadmium was three times
lower than the Sunderbun mangrove leaves. Low concentration in mangrove leaves
suggested that cadmium is mostly unavailable for the uptake by plants and that
uptake is inhibited by the presence of large amount of other metal ions especially
zinc presence in the sediment (Thornton
66
, 1981).
Concentration of Chromium and nickel was found highest in Sandspit backwater of
Karachi Harbour and its concentration was recorded 6.15, 2.91and 3.04, 3.83 ppm
dry weight respectively. High concentration of chromium reflected water and
sediment concentration in Karachi Harbour.
14.6. Heavy metals concentration in seaweeds
Seaweeds and algae are best indicators of metal in the coastal waters due to their
ability to reflect the concentration of metals present in the environment, (Sanchiz
67
,1999, Eide
68
1983, Phillips
69
1977 and Munda
70
1991). Only one study on heavy
metals in Sindh coast has been reported in seaweeds by Jaleel
71
(1983) .
In the present investigation five metals were determined in the eleven species at
two different sites of Manora (Open sea side) and Buleji. The results of heavy
metal contents in the seaweeds are shown in fig.23-27.
Highest concentration of copper was found in the Calpomonia sp. At both the sites
of Manora and Buleji, concentrations were 8.66 and 7.11 ppm dry weight
respectively. Higher concentration was also observed by Munda and Shiber
72
(1980) in the same species in the Adriadic sea (22 ppm dry weight) and Ras
Beirut, Lebanon (11-41 ppm dry weight).
The small variation was observed for Chromium in all seaweeds (except
Calpamonia sp. and Botrocladia laptopodia) with the minimum and maximum ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
22
values ranging from 2 to 3 times. Comparable concentration was observed by
Shiber in the Ras Beirut Lebanon (2-11 ppm dry weight).
Highest mean concentration of cadmium was found in Coelarthrum muelleri,
Padina povina and Calpamonia sp. from the seaweeds samples collected from of
Manora and its concentrations were 3.41, 3.11 and 3.06 ppm dry weight
respectively.
Zinc is essential element for the cell metabolism of seaweeds. In the present study
highest concentration were observed in the Calpamonia sp. and Ulva lactuca (41,
38 ppm dry weight) respectively. Concentration of zinc was almost three times
higher in Manora seaweed than in the seaweeds of Buleji (38 and 14 ppm dry
weight). The results indicate that Ulva lactuca has a higher capacity for zinc
accumulation from the surrounding environment. Similar observation was
observed by Y.B.Ho
73
(1990) in the Hong Kong rural and urban sites where the
concentration was 27 and 66 ppm dry weight respectively.
Chromium was found in similar distribution pattern in both Calpamonia sp. and
Botrocladia laptopodia observed and their concentration were 13.3, 9.92 ppm dry
weight (fig.27). Shiber reported higher values in Calpamonia sp. of Ras Beirut
Labanon (28.7 ppm dry weight)
Comparing the results of metal accumulation with those from the other areas as
discussed above, the seaweeds of Manora were found to have accumulated metal,
partially due to untreated industrial and domestic waste entering in marine coastal
environment through the Lyari River from the city.
15.Conclusion & Recommendations: ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
23
Conclusions
- Highest Concentration of metals in water and sediments was observed in Karachi
Harbour area followed by; Korangi creeks> Gizri creeks> Gwadar fish Harbour>
Off Gwadar East Bay>Buleji.
- Heavy metals accumulation was observed to be twice in concentration two times
more of Heavy metals in green mussels of Karachi Harbour as compared to that of
Gwadar East Bay.
- Within Karachi Harbour, highest accumulation was observed for Zn, Cd, and Cu in
shellfish (Sepia sp.) and Ni & Cr in fish (Sillago sihama).
- In Gwadar East Bay highest accumulation was recorded in Sillago sihama for Ni,
Cu, Zn, Cd and Cr, while in Korangi creek Carangoides oblongus higher
accumulation was observed for Cd and Cu.
-
- At present the heavy metal concentrations studding undertaken in the respective
fishes etc. were within the safe limits.
- For Mangrove higher accumulation of Cd, Cr and Ni was observed in mangrove
leaves of Sandpit back water (Karachi Harbour), while highest concentration of Cu
& Zn was recorded in Kemari backwater and Rehri Goth (Korangi Creek).
- Amongst seaweeds higher accumulation of Cd was found in Red seaweed
(Botrocladia laptopodia). Highest accumulation of Zn, Cu, and Ni & Cr was
recorded in Brown seaweed (Colpamonia Sp.) Cu & Zn were found in Green
seaweed (Ulva faciata). ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
24
- Generally the concentration of heavy metals found in fish and shellfish are found
to be lower when compared with the results published for tropical region.
Recommendations
1. Continued monitoring of heavy metals of Karachi Harbour and Korangi creek
should be undertaken commercial important fish and shellfish.
2. National environmental quality standards for water quality and toxic metal content
in fish and shellfish should be formulated and implementation.
3. A programme should be prepared for the monitoring of organic and inorganic
pollutant along the coast of Pakistan.
4. Upgrade the existing sewage treatment capacity of treatment plant at Karachi and
other coastal areas to treat the sewage and industrial wastes water.
16.Output: List of reports, media articles slides, photographs etc.
The results will be published in scientific journal and author of this report will
write popular science article.
17. Equipments status report:
The instruments that were used in the present study were the property of the
National Institute of Oceanography. However, the funds provided by WWFProject were utilized for collection of samples and the purchase of the consumable
for Atomic Absorption spectrometer. ________________________________________________________________________
Study of Heavy metals pollution Karachi and Gwadar coast National Institute of Oceanography
25
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