Content uploaded by Hussein Kaoud
Author content
All content in this area was uploaded by Hussein Kaoud on Jan 15, 2015
Content may be subject to copyright.
Nature and Science 2010;8(4)
http://www.sciencepub.net/nature naturesciencej@gmail.com
147
Bioaccumulation and histopathological alterations of the heavy
metals in Oreochromis niloticus fish
H.A. Kaoud* and A.R. El-Dahshan
Department of Veterinary Hygiene and Environmental Pollution, Faculty of VeterinaryMedicine, Cairo University,
Egypt.
e-mail:ka-oud@link.net
Abstract: Copper, lead, cadmium and mercury concentrations were recorded in water and tissues of Oreochromis
niloticus from Egyptian fish farms in 2007-2009. Histopathological alterations in fish tissues were also studied.
Bioconcentration factors of copper, lead, mercury and cadmium in liver and muscle tissue were (3.93 & 3.87), (8.10
& 7.60), (0.79 & 50.0) & (38.25 & 30.25), respectively. Mercury was the most bioaccumulated and biomagnified
metal in the muscles, while Cu was the least. The concentration of cadmium,lead and copper were highest in liver
and lowest in kidney tissue, while mercury (Hg) concentrations were highest in muscles, lowest in kidney tissue.
Several histopathological changes were noted in muscles, liver, gills, kidney and intestine tissue attributable to
heavy metals exposure. [Nature and Science. 2010;8(4):1 47-156]. (ISSN: 1545-0740).
Key words: Bioconcentration, copper, lead, cadmium, mercury, Tilapia, Pollution, histopathology.
1.Introduction
Metal contamination of aquatic ecosystems has
long been recognized as a serious pollution problem.
When fish are exposed to elevated levels of metals in a
polluted aquatic ecosystem, they tend to take these
metals up from their direct environment (Seymore
1994). Heavy metal contamination may have
devastating effects on the ecological balance of the
recipient environment and a diversity of aquatic
organisms (Farombi et al. 2007).
Transport of metals in fish occurs through the blood
where the ions are usually bound to proteins. The metals
are brought into contact with the organs and tissues of
the fish and consequently accumulated to a different
extent in different organs and tissues of the fish. Most
heavy metals released into the environment find their
way into the aquatic environment as a result of direct
input, atmospheric deposition and erosion due to
rainwater, therefore aquatic animals may be exposed to
elevated levels of heavy metals due to their wide use for
anthropogenic purposes (Kalay and Canli, 2000). Heavy
metals are non-biodegradable and once they enter the
environment, bioconcentration occurs in the fish tissue
in the case of aquatic environment, by means of
metabolic and biosorption processes (Wicklund-Glynn
1991).
Heavy metals such as cadmium, lead, cupper and
more specifically mercury are potentially harmful to
most organisms even in very low concentrations and
have been reported as hazardous environmental
Pollutants able to accumulate along the aquatic food
chain with severe risk for animal and human health.
Toxic heavy metal contamination mostly occurred in
aquaculture farms and frequently occurs in groundwater,
rivers, estuaries, wetland and coastal areas. Of particular
concern are the highly toxic non-nutrient elements such
as mercury (Hg), lead (Pb), and cadmium (Cd).
The presence of pollutants have been associated
with decreased fertility and other reproductive
abnormalities in birds, fish, shellfish and mammals and
also altered immune function. Heavy metals like
mercury and cadmium are known to accumulate in
marine organisms and cause rapid genetic changes
(Nimmo et al. 1978, Nevo et al. 1986).
The toxicity of these elements is due to their ability
to cause, oxidative damage to living tissues. Damage
includes enhanced lipid peroxidation, DNA damage,
enzyme inactivation and the oxidation of protein
sulfydryl groups (Taiz and Zeiger 1998). Toxic heavy
metal can cause dermatological diseases, skin cancer
and internal cancers (liver, kidney, lung and bladder),
cardiovascular disease, diabetes, and anaemia, as well as
reproductive, developmental, immunological and
neurological affects in the human body. Metal
contamination sources are typically derived from natural
sources: mining, industrial waste discharges, sewage
effluent, harbor activities and agrochemicals etc.
It is also possible that environmental toxicants may
increase the susceptibility of aquatic animals to various
diseases by interfering with the normal functioning of
their immune, reproductive and developmental
processes (Couch and John,1978).
Prolonged exposure to water pollutants even in very
low concentrations have been reported to induce
morphological, histological and biochemical alterations
in the tissues which may critically influence fish quality.
According to EPA guidelines, "the BCF
Nature and Science 2010;8(4)
http://www.sciencepub.net/nature naturesciencej@gmail.com
148
(Bioconcentration Factors) is defined as the ratio of
chemical concentration in the organism to that in the
surrounding water. Bioconcentration occurs through
uptake and retention of a substance from water only,
through gill membranes or other external body surfaces.
In the context of setting exposure criteria it is generally
understood that the terms "BCF" and "steady-state BCF"'
are synonymous. A steady-state condition occurs when
the organism is exposed for a sufficient length of time
t h a t t h e r a t i o d o e s n o t c h a n g e .
The present study was carried out to investigate the
bioaccumulation of heavy metals (lead, copper,
cadmium and mercury) in the tissues of Oreochromis
niloticus and to determine the histopathological changes
caused by the residues of these metals in their organs.
2. Material and Methods
SAMPLING
The water samples were obtained from different
farms derived their water supply from some River Nile
ramifications. Forty eight water samples and one
hundred adult freshwater tilapia (Oreochromis niloticus )
ranged between 100- 150 g in weight were collected
from 12 Tilapia farms located in 6 Governorates (Kafer
Al-Sheikh, Ismailia, Kaliobea, Damiatta, Al-Fayum and
Behera) during 2007-2009. At laboratory, the fish
samples were washed with deionized water and wrapped
separately in acid washed polyethylene bag and stored
frozen at -20°C until analysis was carried out.
PROCEDURES:
PREPARATION AND ANALYSIS OF WATER
SAMPLES:
The analysis of water samples was carried out ac-
cording to A.P.H.A. (1992). The water samples were
preserved by the addition of one ml of concentrated
nitric acid per liter until the time of analysis. The water
samples were filtered through 0.45µl membrane filter.
The required volume (100 ml) of the filtrate was
collected to measure lead, cadmium, mercury and
copper levels in water samples by using Air/Acetylene
Flame Atomic Absorption Spectrophotometer
(UNICAM 696 AA Spectrometer). Flameless Atomic
Absorption Spectrophotometer equipped with (MHS)
mercury hydride system "Cold Vapour Technique" was
used for determination of mercury levels in examined
water samples.
PREPARATION AND ANALYSIS OF FISH
SAMPLES:
Procedure (A): Each sample was represented by one
gram of tissues dissected from the gills, liver, kidney
and muscles, then placed in a clean screw-capped tube
and digested according to the method described by
Finerty et al. (1990). The obtained solutions were then
analyzed by using Air/ Acetylene Flame Atomic
Absorption Spectrophotometer (UNICAM 696 AA
Spectrometer) for determination of copper (Cu), lead
(Pb), cadmium (Cd) and mercury (Hg) levels in
examined samples.
Procedure (B): The measurement of the mercury
concentration in examined fish samples was carried out
at minimal temperature for all fish samples where 0.5
gram macerated fish tissues was digested according to
the technique described by Diaz-Ravina et al. (1994).
About 5 ml stannous chloride solution were added to the
obtained solutions to reduce mercury to elemental form
and then analyzed by using Flameless Atomic
Absorption Spectrophotometer equipped with "MHS"
mercury hydride system "Cold Vapour Technique".
HISTOPATHOLOGICALEXAMINATION
Tissue specimens from fresh Nile Tilapia were
taken (gills, muscles, livers, intestine and kidney) and
fixed in 15 % buffered neutral formalin. They were
processed to obtain five micron thick paraffin sections
then stained with Hematoxylin and Eosin (Bancroft et
al., 1996) and examined under light microscope.
STATISTICALANALYSIS
Data were analyzed using Analysis of Variance
(ANOVA) and means were separated by Duncan at a
probability level of < 0.05 (SASInstitute 2000).
3. Result
Results are shown in Table 1 (Heavy metal
concentrations in water of Nile Tilapia farms) and Table
2 (Concentration of heavy metals in fresh Nile tilapia
tissues). Figure A-1-12 (The histopathological
alterations in Tilapia tissues) , Figure (B)-2(Mean
concentrations of Cu, Pb, Cd and Hg in water of fish
farms in different Governorates and the permissible
limits according to WHO,1984) and Figure (C)-3 (Mean
residual accumulations of Cu, Pb, Cd and Hg in tissues
of Oreochromis niloticus and the permissible limits
according to WHO,1984).
Table 1, showed that the mean concentration of
copper in water of Tilapia farms was 0.65 ± 0.01 ppm,
while Table 2 showed the mean concentrations of
copper in gills, liver, kidney and muscles of Tilapia
(were 4.8 ± 0.05 , 2.56 ± 0.21, 1.52 ± 0.06 and 2.54 ±
0.05 ppm, respectively). The BCF of copper in liver and
muscles was 3.93 and 3.87, respectively. The mean
concentration of lead in water of Tilapia cultures was
0.20 ± 0.07 ppm, whiles the mean concentrations of lead
in gills liver, kidney and muscles, were 0.483 ± 0.05,
1.523 ± 0.02, 0.155 ± 0.02 and 1.521± 0.02 ppm,
Nature and Science 2010;8(4)
http://www.sciencepub.net/nature naturesciencej@gmail.com
149
respectively. The BCF of lead in liver and muscles was
8.10 and 7.60 ppm, respectively. The mean
concentration of cadmium in water of Tilapia farms was
0.04 ± 0.009 ppm, while the mean concentrations of
cadmium in gills liver, kidney and muscles were 0.891 ±
0.05 , 1.523 ± 0.02, 0.212 ± 0.02 and 1.21 ± 0.05
ppm, respectively. The BCF of cadmium in liver and
muscles was 38.25 and 30.25 ppm, respectively.
The mean concentration of mercury in water of Tilapia
farms was 0.07 ± 0.009 ppm, while the mean
concentrations of mercury in gills liver, kidney and
muscles were 0.04 ± 0.002, 0.055 ± 0.003, 0.020 ±
0.005 and 3.50 ± 0.22 ppm, respectively. The BCF of
mercury in liver and muscles was 0.79 and 50 ppm,
respectively. The histopathology of different Tilapia
tissues revealed that there are several histopathological
changes in different Tilapia organs (muscles, liver, gills,
kidney and intestine) as shown in Figure (A1).
Gills showed mild congestion and edema of the
primary lamellae (Figure A1-8). Severe edema,
hyperplasia, fusion and focal desquamation of the
epithelial lining of the secondary lamellae as seen in
Figure (A1)-9. The gill arch, especially at the bases of
the gill filaments, showed numerous mononuclear
leukocytic infiltration, edema and congestion. The
apex of gill filaments showed congestion, hyper
activation of the mucous and chloride cells with
epithelial vacuolation of the secondary lamellae.
Liver showed degeneration of the hepatocytes and
intravascular haemolysis in blood vessels as shown in
Figure (A1 -2), congestion of central vein, hemorrhages
(Figure A1-3), nuclear pyknosis in the majority of
hepatic cells (FigureA1-4) and the metal-binding
proteins were accumulated in the nuclei of hepatocytes
42% of the examined adult freshwater tilapia
(Oreochromis niloticus) were showed histopathological
alterations.
Kidney The kidney is composed normally of
numerous renal corpuscles with well developed
glomeruli and a system of tubules. The proximal
segment is covered by tall columnar epithelial cells with
basal nuclei and brush border located along the cell
apices. The distal segment was lined with large,
relatively clear columnar epithelial cells with central
nuclei and the brush border was reduced or not present.
The glomerulus is larger in diameter than the distal
segment, containing columnar epithelial cells with basal
nuclei and no brush border (Figure A1-10). In our study,
the kidney showed hydropic swelling of tubules,
sometimes with pyknotic nuclei and many necrotic areas
as well as swollen proximal epithelial cells with necrotic
nuclei as noticed in Figure A1- 11.
Muscular tissues Several histopathological
alterations were seen in the muscles of Tilapia which
included degeneration in muscle bundles with
aggregations of inflammatory cells between them and
focal areas of necrosis. Also, atrophy and edema of
muscle bundles as well as splitting of muscle fibers
were seen as in Figure A1-6.
The pathological findings in the intestine
included atrophy in the muscularis, degenerative and
necrotic changes in the intestinal mucosa and
submucosa with necrotized cells aggregated in the
intestinal lumen, edema and atrophy in the submucosa
as shown in Figure A1-12.
Table 1. Heavy metal concentrations in water of Nile
Tilapia farms.
In water samples (mg/L)
Metal Min. Max. Mean ± SE Occurren
-ce
%
Copper
Lead
Cadmium
Mercury
0.044
0.04
0.001
0.01
0.887
0.29
0.082
0.11
0.65 ± 0.01
0.20± 0.07
0.04± 0.009
0.07 ± 0.009
35%
82%
72%
12%
Nature and Science 2010;8(4)
http://www.sciencepub.net/nature naturesciencej@gmail.com
150
Table 2. Concentration of heavy metals (ppm ) in fresh Nile Tilapia tissues.
Figure A-1 (1-12).1: Liver of Tilapia nilotica fish showing the normal structure (X400). 2: Liver of Tilapia
nilotica fish showed degeneration of the hepatocytes and intravascular haemolysis in blood vessels. 3: Liver of
Tilapia nilotica fish showing haemorrhage (X400). 4: The liver showed congestion and central vein, nuclear
pyknosis in the majority of hepatic cells. (X400). 5: Muscle bundles of Tilapia nilotica fish showing the normal
structure (X400). 6: Degeneration in muscle bundles with focal area of necrosis (X400). 7: Gills: Gills of Tilapia
nilotica fish showing the normal structure (X100). 8: Degenerative and necrotic changes in the epithelium of gill
filaments and secondary lamellae (X400). 9: Edema in secondary lamellae and gill filaments (X400). 10: Kidney
showing the normal structure (X400). 11: Severe degenerative and necrotic changes in the renal tubules with
focal areas of necrosis(X400) and aggregations of inflammatory cells. 12: Degeneration, haemorrhage in the
submucosa and aggregations of inflammatory cells in the mucosa and submucosa (X400).
Metal Copper Lead Cadmium Mercury
Tissue
Gills
Mean 4.8±0.05 0.483±0.05 0.891±0.05 0.04±0.002
Min 1.32 0.02 0.11 0.002
Max 6.22 1.21 1.82 0.24
Liver
Mean 2.56 ± 0.21 1.523 ±0.02 1.523 ± 0.02 0.055 ± 0.003
Min 1.22 0.01 0.20 0.001
Max 3.55 3.20 2.43 0.72
Kidney
Mean 1.52±0.06 0.155±0.02 0.212±0.02 0.02±0.05
Min 0.21 0.11 0.09 0.002
Max 2.42 2.02 0.89 0.12
Muscles
Mean 2.54±0.05 1.52±0.02 1.21±0.05 3.50±0.33
Min 0.21 0.892 0.55 1.32
Max 2.8 1.00 1.780 5.240
Nature and Science 2010;8(4)
http://www.sciencepub.net/nature naturesciencej@gmail.com
151
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
ppm
K
AlSheikh Ismailia Sharkia Kaliobea Damiatta Behera WHO
LocationsofTilapiacultures
MeanofCupper,Lead,CadmiumandMercuryinwatercultureof
TilapianiloticaandthePermisipleLimitsof WHOof culturewater
Cu
Pb
Cd
Hg
Figure (B)-2: Mean concentrations of Cu, Pb, Cd and Hg in water of fish farms in different Governorates and the
permissible limits according to WHO (1984) .
Table 3. Permissible limits of various heavy metals
Country and referencePermissibleMetal WHO (1984)
South Africa (Foodstuffs, cosmetics and disinfectants Act. No. 54 of 1972)
Spain: Boletin Official del Estado (1991)
1.00 ppm
20.0 ppm
20.0 g/g
Copper
WHO (1984)
Egypt "E.O.S.Q.C. (1993)
FAO/WHO (1992)
Spain: Boletin Official del Estado (1991)
0.05 ppm
0.1 mg/kg
0.5 ppm
5.0 g/g
Lead
WHO (1984)
FAO/WHO (1992)
Egypt "E.O.S.Q.C. (1993)
Spain: Boletin Official del Estado (1991)
0.005 ppm
0.05 ppm
0.1 mg/kg
1.0 pg/g
Cadmium
WHO (1984)
Egypt "E.O.S.Q.C. (1993)
FAO/WHO (1992)
Spain: Boletin Official del Estado (1991), Schuhmacher and Domingo (1996)
0.001 ppm
0.5 mg/kg
0.5 ppm
1.0 g/g
Mercury
Mean residual accumulationof Cu,Pb,Cd and Hg
intissuesofTilapianiloticaandWHOpermisiple
limits
0
1
2
3
4
5
6
Gills Liver kidney Muscles WHO
Microg/g(ppm)
Cu
Pb
Cd
Hg
Figure (C)-3: Mean residual accumulations of Cu, Pb, Cd and Hg in tissues of Oreochromis niloticus and the
permissible limits according toWHO (1984).
Nature and Science 2010;8(4)
http://www.sciencepub.net/nature naturesciencej@gmail.com
152
4.Discussion
Mean copper concentration in water of Tilapia
farms was 0.65 ± 0.01 ppm and the maximum permis-
sible limits recommended by WHO (1984) is 0.05
ppm, while in flesh was 2.54 ± 0.05 ppm. The recorded
results of copper concentrations in fish were lower
than the permissible limits intended by Foodstuffs,
Cosmetics and Disinfectants (1972) [20.0 ppm] and
Boletin Official del Estado (1991) in Spain [20.0 µg g–
1] and Schumacher and Domingo (1996). The BCF
were; 3.93 and 3.87ppm in liver and muscles,
respectively.
It is shown from Table.1 that the lead
concentration in Tilapia tissues was exceed the
permissible limit recommended by E.Q.S.Q.C. (1993).
This result was nearly higher than those reported by
Seddek et al. (1996) and Marouf and Dawoud (2006),
they recorded levels ranged from 0.42 to 0.74 ppm.
This result was much higher than those recorded by
Suppin et al., (2005) and Celik and Oehlenschlager
(2007), they recorded levels varied from 0.04 ppm to
76.1 ppb.
High levels of lead may be attributed to presence
of industrial and agricultural discharges, motor boat
traffics and also from mine and smelting operations.
Lead is non-essential element and higher
concentrations can occur in aquatic organisms close to
anthropogenic sources. It is toxic even at low
concentrations and has no known function in
biochemical processes (Burden et al., 1998). It is
known to inhibit active transport mechanisms,
involving ATP, to depress cellular oxidation reduction
reactions and to inhibit protein synthesis (Waldorn and
Stofen 1974). Lead was found to inhibit the impulse
conductivity by inhibiting the activities of monoamine
oxidase and acetylcholine esterase to cause
pathological changes in tissue and organs (Rubio et al.,
1991) and to impair the embryonic and larval
development of fish species (Dave and Xiu, 1991).
Mean cadmium concentration in water of Tilapia
farms was 0.04 ± 0.009 ppm and the maximum permis-
sible limits recommended by WHO (1984) is 0.005
ppm, while in flesh was 1.21 ± 0.05 ppm. The recorded
results of cadmium concentrations in fish were higher
than the permissible limits intended by Boletin Official
del Estado (1991) in Spain [l.0 µg g–1], FAO/WHO
(1992) [0.05 ppm] and Egyptian Organization for
Standardization and Quality Control "E.O.S.Q.C".[0.1
mg kg–1]. The BCF were; 38.25 and 30.25ppm in liver
and muscles, respectively. This result agree with that
obtained by Daoud (1999) who reported that the
cadmium concentrations in water and fish were higher
than the maximum permissible limits recommended by
WHO (1984). The presence of cadmium in fish in
Egypt was detected by Seddek (1996) with mean levels
of 0.62 ppm in Oreochromis fish and 0.39 ppm in
Bagrus Byad fish. Our result was nearly parallel to
those reported by Celik and Oehlenschlager (2007)
who recorded Cd concentration with levels varied from
0.1 to 0.8 ppm. Cadmium is highly toxic non-essential
heavy metal and it does not have a role in biological
processes in living organisms. Thus even in low
concentration, cadmium could be harmful to living
organisms (Burden et al., 1998). The value of cadmium
accumulation in liver of Tilapia was (1.523 ± 0.02) μg
g–1 dry weight. High accumulation of cadmium in liver
may be due to its strong binding with cystine residues
of metallothionein.
The high levels of Cd may be attributed to industrial
and mining operations as well as the phosphate
fertilizer which is considered the main source of Cd in
the environment (Dimari et al. 2008).
Mean mercury concentration in water of Tilapia
cultures was 0.07 ± 0.009 ppm and the maximum permis-
sible limits recommended by WHO (1984) is 0.001 ppm,
while in flesh was 3.50 ± 0.22ppm. The recorded results
of mercury concentrations in Tilapia tissues were higher
than the permissible limits intended by Boletin Official
del Estado (1991) in Spain [1.0 µg g–1], FAO/WHO
(1992) [0.5 p.p.m] and Egyptian Organization for
Standardization and Quality Control (E.O.S.Q.C) (1993)
[0.5 mg kg–1]. The BCF were; 0.79 and 50.0 in liver and
muscles respectively. These findings coincide with those
reported by Daoud et al. (1999) and Tantawy (1997).
Conama (2005) recommend a maximum
concentration of 0.0002 mg Hg l–1 in water supplies
used for rearing fish species destined for human
consumption in Brazil. This value is very similar to
those recommended by Malaysia National Water
Quality Standards (Doe-Um, 1986). Meanwhile, the
most notorious mercury compounds in the
environment are monomethyl and dimethyl salt of
mercury which are soluble. They are produced from
inorganic mercury in sediment by anaerobic bacteria
through the action of methyl-cobalamine and
intermediate in the synthesis of methane and get into
natural water (Manahan, 1989). The average (88.9%)
of total mercury in fish musculature was in the form of
methyl mercury (Bishop and Neary, 1974) which is
lipid soluble and easily absorbed and distributed
through biological system.
This element is one of the most toxic metals,
which are introduced into the natural environment by
human interferences (Buhl, 1997). Some papers have
reported situations where high mercury levels were
detected in water, mainly nearby gold extraction
locations (Maurice-Bourgoin et al. 2000; Dolbec et al.
2001) and industrial zones (Kime 1998, Sunderland
and Chmura 2000). According to Allen (1994), the
exposure of Orechromis aureus to 0.5 mg Hg l –1 caused
Nature and Science 2010;8(4)
http://www.sciencepub.net/nature naturesciencej@gmail.com
153
a raise in the number of leukocyte and erythrocyte
within 24 hours. Gill and Pant (1985) also reported
hematological anomalies in Barbus conchonius
exposed to 0.18 mg Hg l–1 in acute test.
It can be noticed that the highest bioaccumulation
were observed in the organs mainly implicated in
metals metabolism. The concentration of cadmium
(Cd),lead and copper in tissues was high in the
following order; liver> muscles > gills > kidney, while
mercury (Hg) concentrations were high in the muscles
> liver > gills > kidney. Oladimeji and Offem (1989)
noticed that the gills of Oreochromis niloticus
consistently accumulated higher amount of lead as lead
nitrate.
BCF obtained for Pb, Cu, Cd and Hg in the
muscles of Tilapia were all greater than 1.00ppm which
indicated that the metals were highly bioaccumulated
and biomagnified (according to Falusi and Olanipekun
2007). Mercury was the most bioaccumulated and
biomagnified of all metals studied in the muscles of the
O. niloticus, while Cu was the least one.
From the results of this study, the concentrations
of different metals investigated in the tissues of Tilapia
(gills, liver, kidney and muscle) except copper exceed
the acceptable levels proposed for human consumption
(USEPA 1995).
The histopathological alterations attributed to the
prolonged exposure to heavy metals resulted in
respiratory, osmoregulatory and circulatory impairment.
These findings were demonstrated by Fernandes et al.,
(2008). Moreover, Alvarado et al. (2006) reported that,
the dramatic increase of chloride cells in the gills that
produces epithelial thickening of the filament
epithelium enhances migration of chloride cells up to
the edge of the secondary lamellae and provokes the
hypertrophy and fusion of secondary lamellae. These
could be considered as unspecific biomarker responses
of heavy metals exposure and disturbed health of fish.
Gills showed edema of the primary lamellae;
severe edema, hyperplasia, fusion and focal
desquamation of the epithelial lining of the secondary
lamellae were observed. According to Mallatt (1985),
the edema of the gill epithelium is one of the main
structural changes caused by the exposure to heavy
metals. Our results confirm this lesion of heavy metals
exposure. These alterations have been reported for
other species exposed to heavy metals particularly Cd
(Gardner and Yevich 1970; Karlsson-Norrgren et al.
1985; Pratap and Wendelaar Bonga 1993; Thophon et
al. 2003) and sometimes referred as a first sign of
pathology (Thophon et al. 2003). Cellular proliferation
in the gill epithelium is also observed in fish exposed
to different pollutants as described by Gardner and
Yevich 1970 and Thophon et al. 2003. Lifting,
swelling, and hyperplasia of the gill epithelium could
serve as a defense function, as these alterations
increase the distance across which waterborne irritants
must diffuse to reach the bloodstream. Lamellar fusion
could be protective once it reduces the amount of
vulnerable gill surface area (Mallatt 1985). However,
branchial responses that serve to slow entry of
toxicants have the undesirable side effect of impairing
gas exchange. This was described by Benson et al.,
(1987) who observed a fall in respiratory function of
Notemigonus crysoleucas exposed to Cd.
The liver showed degeneration of the hepatocytes,
congestion of central vein and nuclear pyknosis in the
majority of hepatic cells. These findings were apparent
as the liver considered the organ of detoxification,
excretion and binding proteins such as metallothionein
(MTs). The metal-binding proteins were present in the
nuclei of hepatocytes suggested that the increase in the
cell damages (De Smet and Blust 2001). Similar results
were observed by Van Dyk (2003) and Mela et al.
(2007). Liver of fish is sensitive to environmental
contaminants because many contaminants tend to
accumulate in the liver and exposing it to a much
higher levels than in the environment, or in other
organs (Heath 1995).
Pandey et al., (1994) described the alterations in
liver and intestine of Liza parsia exposed to Hg Cl2
(0.2 mg Hg l–1) for 15 days. Similarly, Oliveira Ribeiro
et al. (2002) reported serious injuries in gills and
olfactory epithelium of Salvelinus alpinus exposed to
0.15 mg Hg l–1.
Similar alterations in muscles and kidney of
Tilapia were observed in several species of fish
exposed to heavy metals and these alterations were
described by Oliveira Ribeiro et al. (2002),
Jiraungkoorskul et al. (2003), Thophon et al. (2003)
and Gupta and Srivastava (2006).
The result indicates that the heavy metal
contamination definitely affects the aquatic life of the
fresh water fish. Hence, a scientific method of
detoxification is essential to improve the health of
these economic fish in any stressed environmental
conditions. However, the high concentrations of the
analyzed metals in the whole body tissues investigated
could be due to the storage role played bythese tissues.
Fish contaminated by heavy metals suffers
pathological alterations, with consequent inhibition of
metabolic processes, hematological changes, and
decline in fertility and survival.
It can be conclusively deduced from this study
that fish has the tendency to bioaccumulate heavy
metals in a polluted environment. Since virtually all
metals investigated were found in higher concentration,
so government should intact laws that will ensure that
industries make use of standard waste treatment plants
for the treatment of their wastes before they are being
discharged into water bodies.
Nature and Science 2010;8(4)
http://www.sciencepub.net/nature naturesciencej@gmail.com
154
Acknowledgements
This research was sponsored by Department of
Animal Hygiene and Environmental Sanitation (Faculty
of Veterinary Medicine, Cairo University). We thank
Dr. Kawkb A. Ahmed, Dept. of Pathology, Faculty of
Veterinary Medicine, Cairo University for technique
assistance.
References
1. Allen P. 1994.Changes in the haematological
profile of the cichlid Oreochromis aureaus
(Steindachner) during acute inorganic mercury
intoxication. Comparative Biochemistry and
Physiology 108 C : 117-121.
2. Alvarado NE, Quesada K, Hylland I,
Marigómez, L, Soto M. 2006. Quantitative
changes in metallothionein expression in target
cell-types in the gills of turbot (Scophthalmus
maximus) exposed to Cd, Cu, Zn and after a
depuration treatment. Aquatatic Toxicology 77:
64-77.
3. American Public Health Association (APHA)
(1992). Standard methods for the examination of
water and wastewater. 18th ed. American Public
Health Association, Washington, DC.
4. Bancroft D, Stevens A, Turner R. 1996. Theory
and practice of histological techniques. Fourth
edn., Churchill Livingstone, Edinburgh, London,
Melbourne.
5. Benson WH, Baer KN, Stackhouse RA, Watson
CF 1987. Influence of cadmium exposure on
selected hematological parameters in freshwater
teleost, Notemigonus crysoleucas. Ecotoxicology
and Environmental Safety 13: 92–96.
6. Bishop JN , Neary BP. 1974. The form of
mercury in fresh water fish. Proc. Int. Conf.
Transp. Persist. Chem. Aquatic Ecocyst, Ottawa,
III-25-III-29.
7. Boletin Oficial Del Estado (1991). Separates del
Boletin Oficial del Estado Espanol No. 195.
Gaceta de Madrid, P: 27154. In: Schuhmacher, M.
and Domingo, J. L. (1996).
8. Buhl KJ. 1997. Relative sensitivity of three
endangered fishes, Colorado Squaw fish,
Bonytail, and Razorback Sucker, to selected metal
pollutants. Ecotoxicology and Environmental
Safety 37: 186-192.
9. Burden VM, Sandheinrich CA, Caldwell A. 1998.
Effects of lead on the growth and alpha amino
levulinic acid dehydrates activity of juvenile
rainbow trout, Oncorhynchus mykiss.
Environmental Pollution 101: 285-289.
10. Celik U, Oehlenschlager D. 2007. High contents
of Cd, Pb, Zn and Cu in popular fishery products
sold in Turkish Supermarkets. Food Control 18:
258-261.
11. Conama 2005 Resolução no 357, de 17 de março
de 2005. Brasília: Ministério do Meio Ambiente.
Conselho Nacional do Meio Ambiente.
Publicação D.O.U. 18/03/2005. Disponível em:
http://www.mma.gov.br/port/conama/res/res05/
res35705.pdf Acesso em: 18/abril/2006.
12. Couch C, John A. 1978. Diseases, parasites, and
toxic responses of commercial penaeid shrimps of
the Gulf of Mexico and South Atlantic soasts of
North America. EPA-600/J-78-072. U.S. Fish and
Wildlife Service. Fishery Bulletin 76: 1-44. (ERL,
GB 283).
13. Daoud JR, Amin AM, Abd El-Khalek MM. 1999.
Residual analysis of some heavy metals in water
and Oreochromis niloticus fish from polluted
areas. Veterinary Medical Journal 47: 351-365.
14. Dave G, Xiu R. 1991. Toxicityof mercury, copper,
nickel, lead and cobalt to embryos and larval of
Zebra fish Brachydanio rerio. Archive of
Environmental Contamination and Toxicology 21:
126-134.
15. De Castro E, Ferreira H, Cunha M, Bulcao C,
Sarmento C, De Oliveira I , Fregoneze JB. 1996.
Effect of central acute administration of cadmium
on drinking behavior. Pharmacology
Biochemistry and Behaviour 53: 687-693.
16. De Smet H, Blust R. 2001. Stress responses and
changes in protein metabolism in carp (Cyprinus
carpio L.) during cadmium exposure.
Ecotoxicology and Environmental Safety 48: 255-
62.
17. Diaz-Ravina M, Baath E, Frostegard A. 1994.
Multiple heavy metal tolerance of soil bacterial
communities and its measurement by a thymidine
incorporation technique. Applied Environmental
Microbiology 60: 2238–2247.
18. Dimari GA, Abdulrahman JC, Garba ST. 2008.
Metals concentrations in tissues of Tilapia galli,
Clarias lazera and Osteoglossidae caught from
Alau Dam, Maiduguri, Borno State, Nigeria.
American Journal of Environmental Sciences 4:
373-379.
19. Doe-um M. 1986. Water quality criteria and
standards for Malaysia. Executive Summary.
Final Report. Department of Environment,
Ministry of Science, Technology and
Environment, Malaysia/ Consultant group of
water quality, Institute of Advanced Studies, Univ.
of Malaya, Kuala Lumpur, Malaysia, 1, V-Xll.
20. Dolbec J, Mergler D, Larribe F, Roulet M, Lebel
J, Lucotte M. 2001. Sequential analysis of
mercury levels in relation to fish diet of an
Nature and Science 2010;8(4)
http://www.sciencepub.net/nature naturesciencej@gmail.com
155
Amazonian population, Brazil. Science of the
Total Environment 271: 87-97.
21. Egyptian Organization for Standardization and
Quality Control (EOSQC). 1993. Maximum
residue limits for heavy metals in food. Ministry
of Industry. No. 2360/1993. PP. 5.
22. Falusi BA, Olanipekun EO. 2007.
Bioconcentrations factors of heavy metals in
tropical crab (Carcinus sp.) from River Aponwe,
Ado-Ekiti, Nigeria. Journal of Applied Science
and Environmental Management 11: 51-45.
23. FAO/WHO (1992) Food Monitoring and
Assessment Programme, WHO, Geneva 5,
UNEP, Nairobi. 52. Report of the Third
Meeting of the GEMS/Food
24. Farombi EO, Adelowo OA, Ajimoko YR.
2007. Biomarkers of oxidative stress and
heavy metal levels as indicator of
environmental pollution in African Catfish
(Clarias gariepinus) from Nigeria Ogun
River. International Journal of Environmental
Research and Public Health 4: 158-165.
25. Fernandes C, Fernandes AF, Ferreira M,
Salgado M. 2008. Oxidative stress response
in gill and liver of Liza saliens, from the
Esmoriz-Paramos coastal lagoon, Portugal.
Archives of Environmental Contamination
and Toxicology 55: 691-700.
26. Finerty MW, Madden JD, Feagly SE,
Grodner RM. 1990. Effect of environs and
seasonality on metal residues in tissues of
wild and pond-raised Crayfish in southern
Louisiana. Archives of Environmental
Contamination and Toxicology 19: 49-55.
27. Foodstuffs,Cosmetics,Disinfectants (1972)
Regulation No. R 2064. Marine Food Gov-
ernment Gazette. Government Printer,
Pretoria. Act. No. 54 of 1972.
28. Gardner GR, Yevich PP. 1970. Histological
and hematological responses of an estuarine
teleost to cadmium.Canadian Journal of Fish
Research 27:2185-2196.
29. Gill TS, Pant JC. 1985. Mercury-induced
blood anomalies in the freshwater teleost
(Anguilla rostrata. Water, Air and Soil
Pollution: 165-171.
30. Gupta P, Srivastava N. 2006. Effects of
sublethal concentrations of zinc on
histological changes and bioaccumulation of
zinc by kidney of fish Channa punctatus
(Bloch). Journal of Environmental Biology
27:211-215.
31. Heath AC. 1995. Water pollution and fish
physiology. 2nd edn., Lewis Publishers, Boca
Raton. pp. 125-140.
32. Jiraungkoorskul W, Uptham ES, Kruatrachue M,
Sahaphong S, Vichasri-Grams S, Pokethitiyook P.
2003. Biochemical and histopathological effects
of glyphosate herbicide on Nile tilapia
(Oreochromis niloticus).Environmental
Toxicology18:260-267.
33. Kalay M, Canli M. 2000. Elimination of essential
(Cu and Zn) and non essential (Cd and Pb)
metals from tissues of a fresh water fish, Tilapia
zillii.Tropical Journal of Zoology 24:429-436.
34. Karlsson-Norrgren L, Runn P, Haux C, Förlin L.
1985. Cadmium-induced changes in gill
morphology of zebra fish Brachydanio rerio
(Hamilton-Buchanan) and rainbow trout Salmo
gairdneri Richardson. Journal of Fish Biology
27: 81–95.
35. Kime J. 1998. Endocrine Disruption in Fish.
Kluwer, Dordrecht
36. Manahan SE. 1989. Toxicological Chemistry; a
guide to toxic substances in chemistry. pp. 256-
257. Brooks/Cole Publishing Co, C.A.
37. Mallatt J. 1985. Fish gill structural changes
induced by toxicants and other irritants: a
statistical review. Canadian Journal of Aquatic
Science 42:630-648.
38. Marouf HA, Dawoud AS. 2006. Evaluation of
heavy metals content in freshwater Crayfish in
Damietta. Journal of Veterinary Medical
Association,Egypt 66:217-225.
39. Mela MR, Ventura F, Carvalho DF, Pelletier CE,
Ribeiro CA. 2007. Effects of dietary
methylmercury on liver and kidney histology in
the neotropical fish Hoplias malabaricus.
Ecotoxicology and Environmental Safety 68:
426 - 35.
40. Maurice-Bourgoin L, Quiroga I, Chincheros J,
Courau P. 2000. Mercury distribution in waters of
the upper Madeira Rivers and mercury exposure
in Riparian Amazonian populations. Science of
the Total Environment 260: 73-86.
41. Nevo E, Noy R, Lavie B, Beiles A, Muchtar S.
1986. Genetic diversity and resistance to marine
pollution. Biological Journal of the Linnean
Society 29: 139-144.
42. Nimmo DR, Rigby RA, Bahner LH, Sheppard
JM. 1978. The acute and chronic effects of
cadmium on the estuarine mysid Mysidopsis
bahia. Bulletin of Environmental Contamination
and Toxicology 19: 80–85.
43. Oladimeji AA, Offem BO. 1989. Toxicity of lead
to Clarias lazera, O. niloticus, Chironomus
tantans and Benacus sp. Water, Air and Soil
Pollution 44: 191-201.
44. Oliveira-Ribeiro CA, Belger L, Pelletiter E,
Rouleau C. 2002. Histopathological evidence of
inorganic mercury and methylmercury toxicity in
the arctic charr (Salvelinus alpinus).
Nature and Science 2010;8(4)
http://www.sciencepub.net/nature naturesciencej@gmail.com
156
Environmental Research 90: 217-225.
45. Pandey AK, Mohamed MP, George KC. 1994.
Histopathological alterations in liver and intestine
of Liza parsia (Hamilton-Buchanan) in response
to mercury toxicity. Journal of Advanced Zoology
15: 18-24.
46. Pratap HB, Wendelaar Bonga SE. 1993. Effect of
ambient and dietary cadmium on pavement cells,
chloride cells, and sodium, potassium -ATPase
activity in the gills of the freshwater teleost
Oreochromis mossambicus at normal and high
calcium levels in the ambient water. Aquatic
Toxicology 26: 133–150.
47. Rubio R, Tineo P, Torreblance A, Del-Romo J,
Mayans JD. 1991. Histological and electron
microscopical observations on the effects of lead
on gills and midget gland of Procamarus clarkii.
Toxicology and Environmental Chemistry 31:
347-352.
48. SAS Institute. 2000. SAS User’s Guide: statistics,
SAS Institute, Cary, NC.
49. Schumacher M, Domingo JL. 1996. Concentra-
tions of selected elements in oysters (Crassostrea
angulata) from the Spanish coast. Bulletin of
Environmetal Contamination and Toxicology 56:
106-113.
50. Seddek AS, Salem DA, El-Sawi NM, Zaky ZM.
1996. Cadmium, lead, nickel, copper, manganese
and flourine levels in River Nile fish. Assiut
Veterinary Medical Journal,Egypt 35: 95-102.
51. Seymore T. 1994. Bioaccumulation of metals in
Barbus marequensis from the Olifants River,
Kruger National Park, and lethal levels of Mn to
juvenile Oreochromis mossambicus. MSc thesis,
Rand Afrikaans University, South Africa.
52. Sunderland EM, Chmura GL. 2000. An inventory
of historical mercury emissions in maritime
Canada: implications for present and future
contamination. Science of the Total
Environment 256: 39-57.
53. Suppin D, Zahlbruckner R, Krapfenbauer CC,
Hassan I, Hauser C, Smulders F. 2005. Mercury,
lead and cadmium content of fresh and canned
fish collected from Austrian retail operations.
Ernahrung Nutrition 29: 456-460.
54. Taiz L, Zeiger E. 1998. Plant defenses: surface
protectants and secondary metabolites. In: Taiz L
and Zeiger E (eds.). Plant physiology. Sinauer
Associates, Massachusetts. pp. 347-377.
55. Tantawy EA. 1997. Safety and quality of fishes
infested with parasites. PhD thesis (Meat
Hygiene), Faculty of Veterinary Medicine, Cairo
University, Egypt.
56. Thophon S, Kruatrachue M, Upatham ES,
Pokethitiyook P, Sahaphong S, Jaritkhuan, S.
2003. Histopathological alterations of white
seabass, Lates calcarifer, in acute and subchronic
cadmium exposure. Environmental Pollution 121:
307–320.
57. U.S. Environmental Protection Agency (USEPA).
1995. National Water Quality Inventory: 1994
Report to Congress. EPA 841-R-95-005. U.S.
Environmental Protection Agency, Office of
Water, Washington, DC.
58. Van Dyk JC. 2003. Histological changes in the
liver of Oreochromis mossambicus (Cichlidae)
after exposure to cadmium and zinc.MSc thesis,
Rand Afrikaans University, South Africa.
59. Waldorn HA, Stofen S. 1974. Sub-clinical lead
poisoning. Academic Press, New York, pp: 1-224.
60. World Health Organisation (WHO). 1984.
Guidelines for drinking water quality. WHO,
Geneva, No.111.
61. Wicklund-Glynn A. 1991. Cd and Zn kinetics fish:
studies on water-borne Cd and Zn turnover and
intracellular distribution in minnows, Phoxinus
phoxinus. Pharmacology and Toxicology 69:
485-491.
2/9/2010
