1. World Applied Sciences Journal 15 (12): 1645-1650, 2011
ISSN 1818-4952
© IDOSI Publications, 2011
Corresponding Author: Amani, M. Salem, Department of Meat Hygiene, Faculty of Veterinary Medicine,
Benha Branch, Benha University, Benha, Egypt.
1645
Depletion of Polychlorinated Biphenyl (PCBs) Congeners in Fresh Mugil cephelus
and Sardine Fish after Its Exposure to Different Cooking Treatments
Amani M. Salem and Amal M. Eid1 2
Department of Food Control, Faculty of Veterinary Medecine, Benha Univeristy, Benha, Egypt1
Department of Food Control, Animal Health Research Institute, Tanta, Egypt2
Abstract: Fresh Mugil cephelus and Sardine fish samples (15 of each) were randomly collected from different
markets at Gharbia governorate. Samples were used for evaluation of percentage of polychlorinated biphenyl's
congener's depletion by the ordinary cooking methods used in grillrooms and houses on the existed PCBs 52,
44, 70, 101 and 180 were 5.5, 80.1±6.46, 4.8±0.58, 2.3±0.11 and 86.4±13.39 ng gG , respectively, in examined fish1
samples. Results revealed that the decrease in the estimated congeners were 100, 100, 61.6, 100 and 87.2 % for
examined Mugil cephelus fish samples after cooking by frying and were 100, 81.1, 71.3, 20.4 and 41.3 % for
samples cooked by grilling, whereas for Sardine the mean value of the same existed contaminants were 8.6±0.30,
17.8±1.51, 6.8±0.48, 6.6±0.51 and 116.9±68.7 ng gG , respectively and the reduction % were 100, 71.7, 13.6, 1001
and 87.4 for fried samples while for grilled one the percentage were 37.1,100, 46.5, 100 and 86.5%. Fresh and
cooked fish were analyzed to detect 10 PCBs congeners with a mean value using Gas Chromatography and the
most abundant percentage of PCBs congeners' residue in the analyzed fresh fish samples followed the following
descending order 70 and 180 > 101> 44 > 52.It was concluded that cooking has potential significant decrease
PCBs concentration in fish tissues. The decrease was observed to be ranged from 13.6 to 100%.
Key words: PCBs % Fish % Tissue % Frying % Grilling
INTRODUCTION good heat conduction and dielectric properties; they were
It is well established that proper balance of micro- electrical engineering and electronic applications [ 6, 7].
and macro- nutrient intake and avoidance of its excess or As a result of many years' production and broad
deficiency, are essential to keep good health and thus not application and due to their lipophilic nature they are
to induce risks leading to lifestyle - related diseases [1, 2]. characterized by high accumulation coefficients in living
In contrast to the health benefits of a potentially organisms and consequently in food item, especially fish
equilibrated diet, an issue of concern related with the tissues(from diet), which is the main source of their
regular / frequent consumption of certain food is the risk assimilation for most populations [8].
derived from exposure to chemical pollutants contained in PCBs contaminants in fish act as indicators of
those foodstuffs [3, 4]. Fish is one of the most evident pollution of aquatic ecosystem [9]. The potentially high
examples. In addition to the well known health benefits content of these compounds in seafood, may constitute
associated with fish consumption (i.e. intake of omega-3 a threat for the health of consumer, whereas they are
polyunsaturated fatty acids), a number of recent studies believed to be possible carcinogens or mutagens as well
have shown that fish may also be a potential source of as endocrine disruptors, type II diabetes, acute infections
human exposure to toxic contaminants [5]. of the upper and lower respiratory tract, middle ear
Polychlorinated biphenyls belong to a group of (otitis media) and gastrointestinal tract [10, 11].
synthetic chlorine-containing compounds. They are a The stability and high bioaccumulation coefficients
mixture of congeners built of biphenyl rings, saturated by of PCB in aqueous organisms, may constitute a threat for
different number of chlorine atoms, ranging from 1 to 10. the health of consumers [12]. Thus, an important issue is
These compounds are characterized by low vapor to understand the effect of ordinary cooking procedures
pressure and co-distil easily with water vapor. Due to their on concentration changes of PCB .
widely used in many industrial applications, mainly in
S

2. World Appl. Sci. J., 15 (12): 1645-1650, 2011
1646
The effects of cooking on PCBs levels have been n-hexane contained PCBs congeners. The fraction was
studied by several researchers, with special attention for transferred to rotary vacuum evaporator adjusted at 35°C
fish species. Some scientists did not find significant and evaporated until the volume reached 2-3 ml. then
changes in PCBs concentrations, while others reported evaporated to dryness by concentrated tube. The residue
both decrease and/or increases in PCBs levels following was dissolved in 2 ml of n-hexane and transferred into
cooking of fish [13, 14]. auto sampler vial for GC.
Since Mugil cephelus and Sardine fish are in great
demand in Egypt, the goal of this study was to determine Preparation of Blank Solution: The same volume of the
changes in total PCBs content in fresh fish purchased solvents and anhydrous sodium sulphate, which used in
from Gharbia governorate markets after cooking by frying extraction of PCBs from fish samples, was subjected to the
and grilling. same procedures as the examined samples to detect any
MATERIALS AND METHODS subtracted from the results.
Fish Sampling: A total of 30 fresh samples of Mugil Quantitative Determination of PCBs: The extracts were
cephalus and Sardine of a similar size (15 of each) were concentrated and injected into GC (Aglient 6890)
collected from different fish markets at Gharbia equipped with a Ni ECD, a split/split less injection inlet,
governorate, Egypt. Samples were transported without capillary column capability and a 7683A autosampler. All
sexing to the laboratory in ice tank. Each sample was PCBs reference standards were obtained from Central of
divided into three parts, the first was kept raw and Agricultural Pesticides Lab. (CAPL), Agriculture Research
chemically analysed while the other two parts were Center (ARC), Ministry of Agriculture.
cooked as following: Method of sensitivity and recovery were determined
by using spicked samples with the tested congeners.
Frying: The fish (both types) with skin were pan-fried in Before analysis; relevant standards were run to check
oil at 190°C for 3-5 min till golden brown color on each column performance, peak height, resolution and
side were obtained. limits of detection. Peak was identified by comparison of
Grilling: The fish (both types) with skin were packed in corresponding of pure standard compounds. With each
wheat bran and grilled without oil with electrically set of samples to be analyzed, a solvent blank, a standard
operated grill at 180°C for 3-5 min till black color obtained. mixture and a procedural blank were run sequence to
Chemical Analysis: Sample Extraction and clean up was quantification.
prformed following the well established techniques The average recovery percentages of PCBs for
[15, 16]. fortified samples at different levels were determined and
A 10 g tissue sample was placed in ceramic mortar, calculated for all tested compounds.
anhydrous sodium sulphate (30g) was added and the
mixture was well homogenized. The mixture was RESULTS AND DISCUSSION
transferred to a pre-cleaned extraction thimble and the
dehydrated tissue was extracted with 200 ml of 50% The global demand for aquatic food products is
methylene chloride in n-hexane for 8 hours in a Soxhlet increasing and the aquaculture industry is expanding as
apparatus cycling 5-6 times per hour. The extracted it strives to meet this increasing demand. There are
solvents were concentrated with rotary evaporator to concerns about the environmental impact of aquaculture
about 1 ml. to the seabed close to fish farm cages, including potential
Clean Up: Fish extracts were cleaned and fractionating come from the feed or anti-foulants on the cages [19].
using 20 g of 0.5 % deactivated florisil topped with 1 g Chemical contaminants in fish were considered as an
anhydrous sodium sulphate in order to avoid important source of human exposure to chemicals.
resuspention of the top layer when pouring solvents into Assessments of the fish consumption pathway need to
the column then the column washed with 50 ml n-hexane, adjust the concentrations of the chemical to account for
before the sample loaded. The fraction eluted by 70 ml of reduction in PCBs that can occur during cooking.
possible traces of the studied PCBs and its value was
63
sample retention time value with those of the
check for contamination, peak identification and
effects from persistent organic pollutants, which may

3. World Appl. Sci. J., 15 (12): 1645-1650, 2011
1647
Fig. 1: Depletation % of PCBs in the examined samples of both Mugil cephelus and Sardine after cooking
(frying and grilling)
Table 1: Statistical analysis of polychlorinated bipheny (PCBs) in the examined Mugil cephelus samples ng gG (n=15)1
+ve sample +VE s. exceed TL @
------------------------------ ----------------------------
PCBs No. % No % Min- Max. Mean +SD
52 1 6.66 0 0 5.55 0
44 2 13.33 0 0 34.42 -125.9 80.1±6.46*
70 10 66.66 0 0 0.77-18.92 4.8 ±0.58
101 3 20.00 0 0 1.18 - 2.96 2.3±0.11*
152 0 0.00 0 0 0 0
118 0 0.00 0 0 0 0
105 0 0.00 0 0 0 0
138 0 0.00 0 0 0 0
180 10 66.66 0 0 4.47 - 434.7 86.4±13.39*
192 0 0.00 0 0
* significe at P<0.05
@TL: Tolerance limit set by US Food and Drug Administration (FDA) for total PCBs in fish and shellfish is 2000 ng gG wet weight [17, 18]1
Table 2: Statistical analysis of polychlorinated biphenyls (PCBs) in the examined Sardine samples ng gG w w (n= 15)1
+ve sample +ve S. exceed TL
------------------------------ ----------------------------
PCBs No. % No. % Min - Max. Mean +SD
52 1 6.66 0 0 0-8.64 8.6±0.30
44 3 20.00 0 0 3.68- 33.86 17.8±1.51*
70 10 66.66 0 0 1.11-13.16 6.8±0.48
101 4 26.66 0 0 1.37-13.55 6.6 ±0.51
152 0 0.00 0 0 0 0
118 0 0.00 0 0 0 0
105 0 0.00 0 0 0 0
138 0 0.00 0 0 0 0
180 10 66.66 0 0 24.86 ±199.3 116.9±68.7*
192 0 0.00 0 0 0 0
* at Significance P<0.05
Examination of Mugil cephelus and Sardine fish on fresh weight basis 52, 44, 70, 101, 152, 118, 105, 138, 180
samples that were taken for studying represent the and 192 are depicted in Tables (1 & 2). PCBs were defined
dominating fish species in Egypt among rich and poor as the sum of 10 PCB congeners. Because PCBs
populations, the minimum, maximum, average component have different structures, each component has
concentrations of PCBs residues in fish samples in ng gG its own physical and chemical properties, resulting in1

4. World Appl. Sci. J., 15 (12): 1645-1650, 2011
1648
differences in marine environment processes. The data in
Table (1) show that the most abundant PCBs residues
determined (52, 44, 70, 101 and 180) in fish muscles of
examined Mugil cephelus samples were found to be
5.5±0.0, 80.1±64.6, 4.5±5.8, 2.3±1.01 and 86.4±133.9 in a* *
percentage of 6.66, 13.33, 66.66, 20 and 66.66%,
respectivelly.
For sardine samples Table (2) illustrates the presence
of the same congeners of PCBs with an averages of
8.6±0.03, 17.8±15.1, 6.8±4.8, 6.6±5.1 and 116.9±68.7,
respectively, in a percentages of 6.66, 20.0, 66.66, 26.66
and 66.66%. These results were in agreement with those
of Nasr et al. [20] who found similar congeners (70, 101,
118, 44, 52 and 180) in fish samples collected from different
locations in Monofia governorate, Egypt. Also they
observed the elevated PCBs concentrations in muscle
tissue of Sphyraena and Sardina pilchardus from EL-Max
Bay and two Tilipia sp. From Maryut Lake and the PCBs
congeners 101, 138 and 153 were the most dominants one
[21]. Also similar results were previously obtained [22-24]
whereas significant positive correlation between the lipid
content and the levels of detected PCBs due to their
lipophilicity were recorded. Since PCBs residues pose a
potential health hazard, the maximum permissible limits
recommended for fish consumers protection by the
National Academy of Sciences and National Academy of
Engineering is 500 ng gG as weight concentration in1
whole body tissue. The tolerance limit set by US Food
and Drug Administration (FDA) for total PCBs in fish and
shellfish is 2000 ng gG wet weight [17, 18]. The residue1
levels of PCBs in all analyzed fish in this investigation
were considerably lower than these tolerance levels and
the accumulation pattern between both fish species were
significant. In the present study, the decline of PCB levels
were clearly evident in Mugil cephelus and Sardine fish
after frying and grilling as shown in Tables (3&4).
Regarding the Mugil cephelus samples the depletion % in
PCBs congeners (52, 44, 70, 101 and 180) were 100, 100,
61.6, 100 and 87.2%, respectively by traditionally frying
method in oil, while in grilling method the depletion
percentages were 100, 81.1, 71.3, 20.4 and 41.3% for the
same congeners, respectively. The obtained results
showed complete destruction of some congeners,
significant reduction to others and no significant
depletion to another. The different levels of success in
elimination of the contaminants were found depending
upon the studied compound, the levels of contamination
and the tissue from which the extraction was
accomplished [25].
Table 3: Statistical analytical results of reduction % of PCBs in the
examined samples of Mugil cephalus after cooking (frying and
grilling)
PCBs Depletion% Min - Max Mean +SD
Control 52 5.55 0
44 34.42-125.9 80.1±6.46
70 1.55-18.92 4.8±0.58
101 1.18-2.96 2.3±0.11
180 4.47 - 434.7 86.4±13.39
Total 175.31±156.4
Fried 52 100.0 0 0
44 100.0 0 0
70 61.6 1.61-4.46 3.03±2.01
101 100.0 0 0
180 87.2 9.74-10.33 9.95±0.32
Total 12.98±2.33
Grilled 52 100.0 0 0
44 81.1 3.46-21.13 12.20±12.4
70 71.3 0.84-5.96 3.4±3.6
101 20.4 0-2.35 2.35±0
180 41.3 6.2-114 45.9±59.2
Total 63.85±75.2
* Significance at P<0.05
Table 4: Statistical analytical results of depletion % of PCBs in the
examined samples of Sardine after cooking (frying & grilling)
PCBs Depletion% Min - Max. Mean +SD
Control 52 0-8.64 8.64±0
44 15.94-33.86 24.9±12.6
70 1.81-12.05 8.8±6.1
101 1.37-4.76 2.04±2.39
180 24.86-169.04 113.1±77.3
Total 157.48±98.39
Fried 52 100.0 0 0
44 71.7 0-14.08 14.08±0
70 13.6 0.79-12.05 7.63±6.1
101 100.0 0 0
180 87.4 12.23-16.26 14.2±2.01
Total 34.91±8.11
Grilled 52 37.1 0-5.43 5.43±0
44 100.0 0 0
70 46.5 1.87-10.12 4.76±4.64
101 100.0 0 0
180 86.5 4.67-31.18 15.2±14.1
Total 25.39±18.74
* Significance at P<0.05
For Sardine samples the reduction % was 100, 71.7,
13.6100 and 87.4% by frying and 37.1, 100, 46.5, 100 and
86.5% by grilling for the same congeners, respectively.
Thus, cooking reduced PCBs concentration in sardine
very especially in the grilled samples. These results were
in agreement with those of Perello et al. [26]. During the
cooking process, more extensive losses in total PCBs
were observed in Sardine when compared to the

5. World Appl. Sci. J., 15 (12): 1645-1650, 2011
1649
Mugill cephilus. This result is mostly likely from 2. Satio, M., 2007. Role of FOSHU(food for specified
differences in the structure and consistency of the muscle
tissue and lipid content of these fish species [12, 17]. Both
for the frying and grilling in Mugill cephalus and Sardine
fish, significant of differences between changes in
residues levels were obtained.
The relatively high reductions percentages in frying
might be explained by the evaporation of water and PCBS
from the fish resulting from the high temperature of the
cooking oil. Another possible influence of different
methods of cooking on changes in the levels of toxic
compounds in final products is of great importance and
may be helpful for appropriate processing [12]. Moreover,
a significant factor in estimating human intake of PCBS
from fish consumption was the loss of PCB duringS
cooking. The total amount of PCB actually consumed inS
the cooked fish might be significantly lower than the
PCBs level present before cooking, because lipids and
lipophilic compounds like PCB tend to be removed fromS
the fish during cooking. PCBs cooking losses also
depended mainly on changes in the initial lipid
concentration in the fish, heat processing temperature and
duration [28].
As the fish are mostly eaten in the form of processed
products, the influence of different methods of cooking
on changes in the levels of toxic compounds in final
products is of great importance and may be helpful for
appropriate processing [12].
On the basis of these obtained results, it has been
reported that cooking has potential significant decrease
PCBs concentration in fish tissues. The decrease was
observed to be ranged from 13.6 to 100%.
On the basis of these variable and limited results, it
was concluded that additional studies are needed to guide
consumers in cooking techniques which can reduce
dietary PCBs exposure from fish consumption and to
provide toxicologists with more accurate PCBs exposure
estimates. Much attention was devoted to explore
residues level in the two studied species, because they
are commonly favored by Egyptians for (salted raw fish)
as well as being widely distributed throughout Egypt so
we need to increase awareness of consumers about these
chemical pollutants that might specific adverse human
health effects.
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