Vol.3, No.5, 669-673 (2012) Agricultural Sciences
http://dx.doi.org/10.4236/as.2012.35081
Assessment of cadmium, mercury and lead contents
of frozen Eurorean sea bass (Dicentrarchus labrax L.,
1758) and gilthead sea bream (Sparus aurata L.,
1758) fillets from Turkey
Murat Yabanli*, Yunus Alparslan, Tacnur Baygar
Muğla Sıtkı Koçman University, Faculty of Fisheries, Mugla, Turkey; *Corresponding Author:
Received 16 June 2012; revised 17 July 2012; accepted 30 July 2012
ABSTRACT
In this study, trace metals [cadmium (Cd), mer-
cury (Hg) and lead (Pb)] consentration of 76
pieces of frozen European sea bass (Dicen-
trarchus labrax Linnaeus-1758) and gilthead sea
bream (Sparus aurata Linnaeus-1758) fillets,
produced and marketed in Turkey, were deter-
mined using Inductively Coupled Plasma Mass
Spectrometry (ICP-MS) after microwave damp
burning process, and results obtained were as-
sessed in terms of public health. This study was
conducted from June 2010 to July 2011. At the
end of study, maximum heavy metal levels for
sea bass and sea bream fillets were determined
as 256.50, 216.22 µg/kg for Cd; 414.79, 338.46
µg/kg for Hg ve 1047.61, 147.14 µg/kg for Pb,
respectively. At the end of the study, the levels
of cadmium (for 3 samples) and lead (for 1 sam-
ples) were higher than the recommended legal
limits of the European Union for human con-
sumption. It was detected that the fillets which
were analyzed was good quality from the point
of cadmium, mercury and lead contents.
Keywords: Europ ean Sea Bass Fillet; Gilthead Sea
Bream Fillet; Cadmium; Mercury; Lead; Turkey
1. INTRODUCTION
The effects of heavy metals on human health and the
environment is of great interest today, especially for
aquatic products [1]. Toxic elements can be very harmful
even at low concentration when ingested over a long
time period. The essential metals can also produce toxic
effects when their intake is excessive [2]. Levels of trace
elements including cadmium, mercury and lead in fish
and fishery products from many areas in Turkey have
been reported [2,3]. In many countries, significant al-
terations in industrial development lead to an increased
discharge of chemical effluents into the ecosystem, lead-
ing to damage of marine habitats. Heavy metal dis-
charged into the marine environment can damage both
marine species diversity and ecosystems, due to their
toxicity and accumulative behaviour [4]. Heavy metals
are present in the aquatic environment where they bio
accumulate along the food chain. Accumulation occurs in
the tissues of aquatic animals and may become toxic for
fish and also for people when it reaches a substantially
high level [5].
Fish has been the main supply of cheap and healthy
protein to a large percentage of the world’s population
[6]. The proper human diet should satisfy the require-
ments for energy and nutritive components including:
essential polyunsaturated fatty acids, exogenous amino
acids being the component of standart proteins, mineral
components, fat and water-soluble vitamins [7]. In addi-
tion to the key nutrients mentioned, fish can accumulate
substantial concentrations of heavy metals in their tissues.
Fish is therefore a product for which suitable measures
should be taken to provide chemical monitoring of the
risks derived from its consumption [8]. High metal con-
centrations in food can provoke serious health hazards in
humans (Table 1).
Turkey is surrounded by four different seas with 8333
km long coastal line and fishing is one of the biggest
income sources for the country. The four seas around
Turkey each reflect a different ecological characters, for
instance salinity is 18 per thousand in the Black Sea, 23
per thousand in the Marmara Sea, 32 per thousand in the
Aegean Sea and 38 per thousand in the Mediterranean
Sea. The aim of this study was to determine ranges of
toxic trace metals (Cd, Hg and Pb) in the fisheries pro-
ducts (frozen European sea bass and gilthead sea bream
illets) produced and marketed in Turkey. f

M. Yabanli et al. / Agricultural Sciences 3 (2012) 669-673
670
Table 1. Potantial health hazards of cadmium, mercury and lead.
Element Potential health hazards References
Cd Kidney damage, testicular tumors, renal dysfunction, hypertension, arteriosclerosis, growth inhibition,
chronic diseases of old age, and cancer [9,10]
Hg
Minamata disease, cardiovascular disease, sensorimotor symptoms, memory loss in adult, late talking and late
walking in children/infants, decreases rate of fertility in both males and females, birth of abnormal offsprings,
decreases overall immunity of the body, cancer
[11-13]
Pb Delays in physical or mental development in infants, slight deficits in attention span and learning abilities in
children, kidney problems, high blood pressure, anemia, muscle paralysis [9,14]
2. MATERIALS AND METHODS
2.1. Samples Collection
Total seventy six composed European sea bass and
gilthead sea bream fillet samples were collected ram-
domly from İzmir which is a port city in Turkey to assess
the levels of cadmium, mercury and lead. This study was
conducted from June 2010 to July 2011.
2.2. Reagents
Double deionized water (ELGA water purification
system, 18.0 MΩ cm resistivity) was used for all dilu-
ons. All reagents used were of analytical grade (nitric
acid, 65% Suprapur Merck; hydrochloric acid, 30% Su-
apur Merck). Multi-element calibration solutions of all
investigated elements were prepared daily by dilution of
10 mg/L mix element standard stock solution (AccuTrace
MES-21-1) and 10 mg/L mercury standard stock solution
(AccuTrace MES-21-HG-1).
2.3. Sample Preparation (Microwave
Digestion)
European sea bass and gilthead sea bream fillets were
homogenized throughly in a laboratory blender (Waring
trade marker) with stainless steel cutters. For each ho-
mogenized samples, 0.5 g homogenate (wet weight) was
weighed and placed in polytetrafluorethylene (PTFE)
vessel with 5 mL of 65% nitric acid. Material was then
subjected to a microwave program (Ta ble 2 ). The tem-
perature of each vessel was rised to 190˚C in approxi-
mately 10 minutes and remained at 190˚C for 15 minutes.
Digest was finally made up with 2% nitric acid, 0.5%
hydrochloric acid solution to 50 mL in acid washed
standard flasks and then placed in 50 mL polypropylene
centrifuge tubes.
2.4. App aratus
Bergh of speed wave MWS-3 microwave digestion sys-
tem with DAP 60+ vessels was used to digest European
sea bass and gilthead sea bream fillet samples prior to
toxic element analysis. Inductively coupled plasma-mass
spectroscopy (Agilent 7700×) with auto sampler (Agilent
ASX-500) was used to analyze digested samples for total
metals. The operating conditions for ICP-MS are shown
in Table 3.
2.5. Determination of Recovery
Ten homogenized fish muscle tissues were spiked with
1000 µg/kg each metal (cadmium, mercury and lead) for
the recovery repeatability test. Ten spiked samples and
ten blanks were taken through the microwave digestion
procedure. And then, digested spiked samples were ana-
lyzed using ICP-MS. Obtained values were given in Ta-
ble 4. The mean recoveries for cadmium, mercury and
lead 100.22, 107.11 and 92.82 respectively. Acceptable
recovery of >90% - <110% were obtained for studied
metals, an indication of good analytical protocol.
2.6. Statistical Analysis
To determine the correlations between the metal con-
centrations in fish and fish products was performed with
Mann-Whitney U Test by using Statistica software pro-
gram. Any statistical significant difference was not de-
tected for cadmium, mercury and lead between European
sea bass and Gilthead sea bream samples (p = 0.599; p >
Table 2. Microwave burning process.
Process 1 2 3
T (˚C) 160 190 100
Ta (transition time, minute) 5 1 1
Waiting time (minute) 5 15 10
Table 3. ICP-MS operating conditions.
Radio frequency power 1550 W
RF matching 2.1 V
Sample depth 8 mm
Carrier gas 1.05 L/min
S/C temperature 2˚C
Nebulizer type MicroMist

M. Yabanli et al. / Agricultural Sciences 3 (2012) 669-673 671
Table 4. Recoveries of cadmium, mercury and lead from fish muscle tissue.
µg/kg Sample concentration Concentration of lead added Concentration of recovered % Recovery
Cd 1.08 1000 1003.28 100.22
Hg 7.60 1000 1079.25 107.11
Pb 65.41 1000 988.95 92.82
0.05 for cadmium, p = 0.277; p >0.05 for mercury and p
= 0.590; p > 0.05 for lead).
3. RESULT AND DISSCUSSION
In this study, seventy six samples of fillet were ana-
lysed for cadmium, mercury and lead. Good recovery
was obtained for studied elements (Ta ble 4). The mean
levels obtained in our study are listed in Table 5. Box
Whisker plot of measured toxic metal concentrations in
fillets are given Figure 1. The evaluation of the levels of
the cadmium, mercury and lead in the European sea bass
and gilthead sea bream fillets was performed based on
the maximum levels set forth in Commission Regulation
EC 1881/2006 [15]. Public health concerns have focused
on the fish fillets the levels of cadmium in only three
samples analyzed (one sample European sea bass fillet,
two samples gilthead sea bream fillet) was found that
might have exceeded the regulatory limits. The concen-
tration of lead in one European sea bass fillet investi-
gated was higher than the recommended legal limits (Ta-
ble 6). In European sea bass and gilthead sea bream fil-
lets analyzed, the mean concentrations of toxic elements
decreased as mercury > lead > cadmium.
3.1. Cadmium (Cd)
Cadmium is a non-essential metal, but competes with
other essential metallic ions when accumulated in orga-
nisms and produces unpredictable changes [16]. Mean
cadmium concentrations of the studied fillets were 7.92
µg/kg for European sea bass, 9.88 µg/kg for gilthead sea
bream. The highest cadmium content was found in the
European sea bass fillet (256.50 µg/kg). 2.63% of sam-
ples of gilthead sea bream fillet, 5.26% of samples of
European sea bass fillet exceeded the limits of EC
1881/2006 [15]. Mean cadmium concentrations of Euro-
pean sea bass and gilthead sea bream muscle tissues was
found as 92 µg/kg and 120 µg/kg, respectively, by Dural
et al. [17]. In another study, mean cadmium concentra-
tions in the flesh of cultured European sea bass were
found 270 µg/kg [18]. Our obtained values were found as
lower than these values.
3.2. Mercury (Hg)
Mercury is a known toxicant which is present in the
environment as a result of natural processes and anthro-
pogenic activities [19]. Fish accumulate substantial con-
centrations of mercury in their tissues and thus, can rep-
resent a major dietary source of this element to humans
[20]. The highest mercury value was detected in the
European sea bass fillet (353.36 µg/kg). All examined
samples had a mercury content below the permissible
level of 500 µg/kg (wet weight of fish) for human con-
sumption recommended by EC 1881/2006 [15]. The
highest mercury concentrations measured in our study is
lower then that reported by Abreu et al. [21], 1700 µg/kg,
in European sea bass muscle tissues in Portugal. In a
similar way, mean mercury levels (120 µg/kg) were
found higher than current study (74.90 µg/kg) in gilthead
sea bream muscle tissues in Ligurian Sea, Italy [22].
3.3. Lead (Pb)
Lead is a widely distributed environmental poison and,
solder used in the manufacture of cans is a source of
contamination of food by Pb. Therefore, the monitoring
of lead concentration became essential [23]. Lead is a
ubiquitous environmental and industrial pollutant that
has been detected in almost all phases of environmental
and biological systems [24]. The general population is
exposed to lead from air and food in roughly equal pro-
portions [25]. Mean cadmium concentrations of the
European sea bass and gilthead sea bream fillets were
57.69 and 27.89 µg/kg, respectively. Generally, lead lev-
els of analyzed European sea bass fillet samples (97.37%)
were found to be lower than legal limits of EC 1881/
2006. Any sea bream fillet samples analyzed did not ex-
ceeded EC 1881/2006 limits [15]. The mean lead levels
of analyzed European sea bass and gilthead sea bream
fillet samples are lower than those reported in the litera-
ture (1030 µg/kg for European sea bass, Alasalvar et al.
[18]; 480 µg/kg for European sea bass, Türkmen et al.
[26]; 620 µg/kg for gilthead sea bream, Uluozlu et al. [1];
7330 µg/kg for gilthead sea bream, Yılmaz [27].
4. CONCLUSION
The concentration of trace metals in samples is de-
pended on fish species. Some species is accumulated
trace metals at high ratio [28]. The consequence of heavy
metal pollution can be hazardous to man and it often
becomes mandatory to check chemical contaminants in

M. Yabanli et al. / Agricultural Sciences 3 (2012) 669-673
672
Table 5. Cadmium, mercury and lead concentrations (µg/kg on a wet weight basis) in frozen European sea bass and gilthead sea
bream fillet, number of products investigated (n), arithmetic mean (Mean), standard error (SD).
Mean ± SE
Product n
Cd Hg Pb
European sea bass fillet 38 7.92 ± 6.73 97.65 ± 17.26 57.69 ± 28.46
Gilthead sea bream fillet 38 9.88 ± 6.68 74.90 ± 13.43 27.89 ± 7.08
Table 6. The percentage of samples exceeding limits of EC and EC limits.
Sample rate (%) that exceeded of EC 1881/2006 limits
Element
European sea bass fillet Gilthead sea bream fillet
Maximum residue limits (µg/kg)
according to EC 1881/2006
Cd 2.63 5.26 50
Hg * * 500
Pb 2.63 * 300
*Any samples analyzed did not exceed limits.
(a) (b)
Figure 1. Box whisker plot of concentrations of measured toxic elements in European sea bass filets (a) and gilthead sea bream filets
(b) (▫: median, □: 25% - 75%, −: min-max).
foods from the aquatic environment to understand their
hazard levels [4]. According to current study results
amount of toxic elements in studied muscle tissues (fil-
lets) may vary depending on species. The cadmium,
mercury and lead concentrations in the majority of the
European sea bass and gilthead sea bream fillets ana-
lyzed were convenient within the recommended legal
limits for human consumption, except in a few cases.
Monitoring of fisheries products in terms of heavy met-
als is of great importance for public health.
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