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Mercury, cadmium and lead content of canned Tuna fish



Mercury levels in canned tuna fish were determined by cold vapour atomic absorption spectrophotometry while cadmium and lead levels were determined by flame atomic absorption spectrophotometry. The metal contents in the samples, expressed in μg g−1 wet weight, varied from 0.20 to 0.66 with an average value of 0.29 for mercury, from 0.09 to 0.32 with an average value of 0.18 for cadmium and from 0.18 to 0.40 with an average value of 0.28 for lead. The results of this study indicate that tuna fish from the Mediterranean coast of Libya have concentrations well below the permissible levels for these toxic metals. Their contribution to the body burden can therefore be considered negligible.
Mercury, cadmium and lead content of canned tuna ®sh
R.B. Voegborlo*, A.M. El-Methnani, M.Z. Abedin
Environmental Science Department, Faculty of Engineering and Technology, P.O. Box 68, Brack-Alshati, Libya
Received 26 March 1996; received in revised form 19 November 1997; accepted 19 November 1997
Mercury levels in canned tuna ®sh were determined by cold vapour atomic absorption spectrophotometry while cadmium and
lead levels were determined by ¯ame atomic absorption spectrophotometry. The metal contents in the samples, expressed in mgg
wet weight, varied from 0.20 to 0.66 with an average value of 0.29 for mercury, from 0.09 to 0.32 with an average value of 0.18 for
cadmium and from 0.18 to 0.40 with an average value of 0.28 for lead. The results of this study indicate that tuna ®sh from the
Mediterranean coast of Libya have concentrations well below the permissible levels for these toxic metals. Their contribution to the
body burden can therefore be considered negligible. #1999 Published by Elsevier Science Ltd. All rights reserved.
1. Introduction
Toxicological and environmental studies have
prompted interest in the determination of toxic elements
in food. While mercury, cadmium and lead can be tol-
erated only at extremely low levels, at certain con-
centrations they are exceptionally toxic to humans.
Fish accumulate substantial concentrations of mer-
cury in their tissues and thus can represent a major
dietary source of this element to humans. With the
exception of occupational exposure, ®sh are acknowl-
edged to be the single largest source of mercury for
man. In some instances ®sh catches were banned for
human consumption because their total mercury con-
tent exceeded the maximum limits recommended by the
Food and Agriculture/World Health Organisation
(FAO/WHO, 1972). Takizawa (1979) cited the case
where several major incidents of human poisoning in
Japan (at Minamata) were implicated in the ingestion of
methylmercury-contaminated ®sh in large quantities.
The likelihood of mercury toxicity from ®sh consump-
tion has been identi®ed in Peru and some coastal
regions of the Mediterranean (Inskip & Piotrowski,
1985; Piotrowski & Inskip, 1981).
Tuna was recognised as a predator able to con-
centrate large amounts of heavy metals. For example,
Enomoto and Uchida (1973) reported mercury con-
centrations ranging from 50 to 120 mgg
in internal
organs of Japanese tuna. The ingestion of food is an
obvious means of exposure to metals, not only because
many metals are natural components of foodstus, but
also because of environmental contamination and con-
tamination during processing. Solder used in the manu-
facture of cans is a recognised source of contamination
of food by lead during canning. The presence of heavy
metals, and particularly mercury, in the environment
has been a matter of concern since their toxicity has
been clearly documented (Uchida, Hirakawa & Inoue,
1961). The presence of mercury in the environment was
reviewed (Holden, 1973; Krenkel, 1973). Extensive sur-
veys have been carried out, in a number of countries, to
evaluate the presence of heavy metals in the aquatic
biota, including ®sh, which can often be considered as
indicators of marine pollution. Levels of heavy metals
including mercury, lead and cadmium, in ®sh, have been
widely reported (Hellou, Warren, Payne, Belkhode &
Lobel, 1992; Joseph & Srivastava, 1993; Kowalewska &
Korzeniewski, 1991; Sharif, Mustafa, Mirza & Sa®ul-
lah, 1991; Sharif, Mustafa, Hossain, Amin & Sa®ullah,
1993; Winchester, 1988). The toxic nature of certain
metals and the major contribution made to the total
body burden of these metals by food consumption are
well documented (Bonner & Bridges, 1983; Browning,
1969; Department of Health and Social Security, DHSS,
1980). Hence the levels of these metals in foodstus are
under frequent review.
Canned tuna ®sh are frequently and largely eaten in
Libya, so their toxic metal content should be of some
concern to human health. The present study was, there-
fore, carried out in view of the scarcity of information
Food Chemistry 67 (1999) 341±345
0308-8146/99/$ - see front matter #1999 Published by Elsevier Science Ltd. All rights reserved.
PII: S0308-8146(98)00008-9
* Corresponding author.
about heavy metals in marine organisms from this
region. In this paper, the levels of mercury, cadmium
and lead in samples of canned tuna ®sh are reported.
It is hoped that the results of this study will help in
generating data needed for the assessment of toxic metal
intake from this source.
2. Materials and methods
2.1. Apparatus
All glassware was soaked overnight in 10% (v/v)
nitric acid. Glassware, for the analyses of lead and cad-
mium was rinsed thoroughly with deionised distilled
water and dried before use, and that for mercury ana-
lyses was rinsed with distilled water. This was to control
the possible mercury contamination of water from the
resins used in deionisers.
A Perkin-Elmer Model 2380 atomic absorption spec-
trophotometer equipped with a deuterium background
corrector was used for the determination and the mer-
cury/hydride generator was a Perkin±Elmer Model
MES-10 with an open quartz tube. The signals were
obtained on a Perkin-Elmer PRS-10 Printer Sequencer.
2.2. Reagents
All reagents used were of analytical reagent grade
(BDH Chemicals Ltd, Poole, England). Standard stock
solutions of lead, cadmium and mercury were prepared
by diluting concentrated solutions to obtain solutions of
1000 mg l
(E. Merck).
The working solutions were freshly prepared by
diluting an appropriate aliquot of the stock solutions
through intermediate solutions using 5% HNO
diluting lead and cadmium solutions, and 1 MHCl for
diluting mercury solution. Stannous chloride was pre-
pared fresh by dissolving 10 g in 100 ml of 6 MHCl. The
solution was boiled for about 5 min, cooled, and
nitrogen bubbled through it to expel any mercury
impurities. Diluting solution for mercury determination
was prepared by diluting 100 ml of conc HNO
25 ml of conc H
to 1000 ml with distilled water.
2.3. Sample preparation and digestion
Tuna ®sh caught by commercial vessels from the
Mediterranean coast of Libya are canned as chunks at
a commercial factory on land. Fifty cans of tuna
(5 kg each) obtained from the Tuna Canning Factory in
Misurata, Libya were used for this study. After opening
each can, oil was drained o and the meat was
homogenized thoroughly in a food blender with stain-
less steel cutters. Samples were then taken and digested
The homogenised sample (10.01 g) was weighed
into a 100 ml Erlenmeyer ¯ask and 1 ml of conc HCl
was added. After about 10 min, 5 ml of conc HNO
added slowly. After swirling gently, 2 ml of (1+1)
was added. It was then covered with a watch
glass and left at room temperature until most of the
sample had dissolved. The ¯ask was then placed on top
of a steam bath until complete dissolution. It was then
removed from the steam bath, cooled and the solution
transferred carefully into a 20 ml volumetric ¯ask and
diluted to the mark with distilled water. For each run, a
duplicate sample, spiked samples, and two blanks were
carried through the whole procedure.
For the determination of lead and cadmium, about
100.01 g was weighed into a 150 ml beaker and 10ml of
freshly prepared 1:1(v/v), H
(conc) was
added per gram of sample, slowly, in portions. The bea-
ker was covered with a watch glass and, after most of the
sample had dissolved, heated on a hot plate until the
solution was clear. Heating was continued until the
volume was reduced to about 5 ml. The solution was
allowed to cool, transferred into a 20 ml volumetric ¯ask
and diluted to the mark with deionised distilled water.
For each run, a duplicate sample, spiked samples and
two blanks were carried through the whole procedure.
2.4. Determination of recovery
The recoveries of the metals were determined by add-
ing increasing amounts of mercury, cadmium and lead to
samples which were then taken through the digestion
procedure. The resulting solutions were analysed for the
metal concentrations. The results are reported in
Tables 1±3. The mean recoveries for lead, cadmium and
mercury were 99.8, 99.3 and 97.2, respectively, with
coecients of variation 8.7, 3.8 and 3%, respectively.
2.5. Chemical analysis
Lead and cadmium were determined by direct
aspiration of the sample solutions into the air/acetylene
¯ame. The blanks and calibration standard solutions
were also analysed as the sample solutions and calibra-
tion curves constructed. Mercury was determined by the
MES-10 Mercury/Hydride system with a modi®cation
in the operation. The manufacturer's operating proce-
dure involves continuous addition of sodium borohy-
dride solution from a reluctant reservoir with the aid of
argon gas until maximum absorbance is produced. This
procedure was, however, found to give poor reproduci-
bility because the volume of sodium borohydride added
each time varies. In this study, the reluctant reservoir
was left empty. An aliquot of the sample solution (5 ml)
was diluted to 30 ml in the reaction ¯ask with the dilut-
ing acid solution and 2 ml of the stannous chloride
solution was added. The reaction ¯ask was immediately
342 R.B. Voegborlo et al. / Food Chemistry 67 (1999) 341±345
connected to the system and the plunger actuated
immediately, allowing argon to bubble through the
solution after ¯owing through the empty reservoir.
During this period, any mercury vapour generated is
swept into the absorption quartz cell aligned in the light
path of the mercury hollow cathode lamp where the
absorption is measured. Aliquots of the calibration
standard solutions and blanks were analysed in the same
way as the samples.
3. Results and discussion
Fifty samples of canned tuna ®sh from Misurata
canning factory were analysed for lead, cadmium and
mercury. Good recoveries of spiked samples demon-
strate the accuracy of the methods used (Tables 1±3).
Of the 50 samples analysed, mercury was detected in
20 samples, while lead and cadmium were detected in
only 12 samples. The concentrations of lead, cadmium
and mercury are presented in Table 4 as means with
standard deviation and coecient of variation. The
results of the analysis indicate that the concentration of
cadmium varied from 0.09 to 0.32 with a mean of
0.18 mgg
1; for lead it ranged from 0.18 to 0.40 with a
mean of 0.28 mgg
. Good agreements were observed
when our results were compared with those reported by
other authors (Committee for Inland Fisheries of Africa
CIFA, 1992). The cadmium concentrations were low
compared to ®sh from the coast of Philippines and the
Northern Indian Ocean (CIFA, 1992). Woidich and
Pfanhauser (1974) reported a concentration range of
cadmium in tuna ®sh (0.050±0.970 mgg
) within which
our values fell. Muller and Forstner (1973), however,
reported higher levels of cadmium (10±40 mgg
®shes from Necker and Ems. Teherani, Stehlik, Tehrani
and Schada (1979) reported 0.1±0.13 mgg
cadmium in
several ®sh types caught in upper Austrian waters,
Table 4
Mean contents of mercury, cadmium and lead (g g
) in canned tuna samples
Metal No. of samples Range Mean Standard deviation Coecient of
variation (%)
Mercury 20 0.20±0.66 0.29 0.12 40.7
Lead 12 0.18±0.40 0.28 0.07 24.3
Cadmium 12 0.09±0.32 0.18 0.08 42.2
Table 1
Recovery of lead from canned tuna samples
Sample no. Sample
weight (g)
of lead (mgg
) added
of lead (mgg
) recovered
% Recovery
9 10 0.20 0.18 90
9 10 0.40 0.41 103
9 10 1.00 0.96 96
9 10 2.00 2.20 110
Table 2
Recovery of cadmium from canned tuna samples
Sample no. Sample
weight (g)
Concentration of
cadmium (mgg
) added
Concentration of
cadmium (mgg
) recovered
% Recovery
9 10 0.10 0.10 100
9 10 0.20 0.19 95
9 10 0.50 0.52 104
9 10 1.00 0.98 98
Table 3
Recovery of mercury from canned tuna samples
Sample no. Sample
weight (g)
Concentration of
mercury (mgg
) added
Concentration of
mercury (mgg
) recovered
% Recovery
10 1 0.02 0.0202 101
10 1 0.05 0.0490 98
10 1 0.10 0.0980 98
10 1 0.20 0.1920 96
R.B. Voegborlo et al. / Food Chemistry 67 (1999) 341±345 343
which are lower than values reported here. The con-
centration of lead was found to be less than 0.35 mgg
in most of the samples, which agrees well with values
reported by other authors (CIFA, 1992; Woidich and
Pfanhauser, 1974).
The concentration of mercury in the tuna ®sh samples
analysed varied from 0.2 to 0.66 mgg
. Apart from two
samples which have concentrations of 0.55 and
0.66 mgg
mercury, all the samples have concentrations
below the 0.5 mgg
limit recommended by the FAO/
WHO (1972) and adopted by many countries (CIFA,
1992). The levels of the toxic metals in the tuna samples
are not high when compared to some other areas of the
world. The mercury content of tuna ®sh has variously
been reported as ranging from 0.8 to 1.20 mgg
with an
average content that is between 0.3 and 0.4 mgg
(Holden, 1973), below which our values fall. Mean
mercury levels reported here are lower by an order of
magnitude compared to values reported for mullets in
the Tyrrhenian Sea, an area close to naturally occurring
mercury deposits (CIFA, 1992). However, they were
similar to levels in other tropical, less industrialised
areas like Indonesia, Thailand and Papua New Guinea
(CIFA, 1992). A similar trend was observed when our
values were compared with values (0.04±0.44 mgg
reported for canned salmon and tuna and values (0.009±
0.73 mgg
) reported for canned sea food (Fricke, Rob-
bins & Caruso, 1979; Kaiser & Tolg, 1980).
With respect to the heavy metal content of marine
organisms taken from other Mediterranean coastal
areas, very little comparison data appear to be avail-
able. However, our results compare well with values
reported for ®sh from the Mediterranean coast of Israel
(Hornung & Kress, 1989; Roth & Hornung, 1977) and
that of Morocco (El-Hraiki, Kessabi, Sabhi, Benard &
Buhler, 1992).
Because of the bioaccumulation of mercury by ®sh
and shell®sh, these food items can be a rich source
of metal (Buzina, Suboticanec, Vukusi'c, Sapunar,
Anton'ic & Zorica, 1989; Piotrowski & Inskip, 1981).
As a consequence of its known toxicity, as well as that
of lead and cadmium and of the serious contamination
of foods that occurs from time to time during commer-
cial handling and processing, most countries monitor
the levels of toxic elements in foods. The Joint Food
and Agriculture Organisation/World Health Organisa-
tion (FAO/WHO) Expert Committee on Food Addi-
tives has suggested a provisional tolerable intake of
400±500 mg cadmium per week for man; the quantity of
mercury to be tolerated in human food is 0.3 mg per
week and, for lead, a weekly intake of 3 mg (FAO/
WHO, 1972). The maximum concentration of lead
which is permitted in prepared foods speci®cally intended
for babies or young children is 200mgkg
Although, marine food does not signi®cantly con-
tribute to the chronic lead body burden, the monitoring
of lead concentration in the diet is essential since ®sh of
various types were found to be contaminated with lead
in addition to cadmium and mercury. Lead concentrations
could be high in marine animals that live on sediment.
Though estimates of the amount of toxic metals con-
sumed in the diet are dicult to obtain and a discussion
of metal tolerances in the diet is beyond the scope of this
paper, it can be concluded from the results so far
obtained that mercury, lead and cadmium content of
the canned tuna ®sh is unlikely to constitute a sig-
ni®cant health hazard.
Bonner, F. W., & Bridges, J. W. (1983). Toxicological properties of
trace elements. In J. Rose, Trace elements in health (pp. 1±20).
London: Butterworth.
Browning, E. M. (1969). Toxicity of Industrial Metals (2nd ed.) London:
Buzina, R., Suboticanec, K., Vukusi'c, T., Sapunar, J., Anton'ic, K.,
& Zorica, M. (1989). Eect of industrial pollution on seafood
content and dietary intake of total and methylmercury. Science of
the Total Environment, 78, 45±57.
CIFA (Committee for Inland Fisheries of Africa) (1992). Report of the
Third Session of the Working Party on Pollution and Fisheries,
FAO Fisheries Report No 471, Food and Agriculture Organisation
of the United Nations, Rome.
DHSS (Department of Health and Social Security) (1980). Lead and
health: the report of a DHSS working party on lead in the environ-
ment. London: HMSO.
El-Hraiki, A., Kessabi, M., Sabhi, Y., Benard, P., & Buhler, D. R.
(1992). Contamination of seafood products by cadmium, chro-
mium, mercury and lead in Morocco. Rev. Med. Vet., 143, 49±56.
Enomoto, N., & Uchida, Y. (1973). Cadmium and other heavy metal
contents in marine products from the Ariake Sea and in canned
goods on the market. Saga Daigaku Nogaku Iho,35, 1973, 69±75
[Cited in Chem. Abstr. 18 (1974) 2506].
Food and Agriculture/World Health Organisation (FAO/WHO)
(1972). Evaluation of certain food additives and the contaminants
mercury, cadmium and lead. WHO Technical Report Series No.
505. Geneva: WHO.
Fricke, F. L., Robbins, W. B., & Caruso, J. A. (1979). Trace element
analysis of food and beverages by atomic absorption spectrometry.
Progress in Analytical Atomic Spectroscopy, 2, 185±286.
Hellou, J., Warren, W. G., Payne, J. F., Belkhode, S., & Lobel, P.
(1992). Heavy metals and other elements in three tissues of cod,
Gadus morhua from the Northwest Atlantic. Marine Pollution Bul-
letin, 24, 452±458.
Holden, A. V. (1973). Mercury in ®sh and shell®sh, a review. Journal
of Food Technology, 8, 1±25.
Hornung, H., & Kress, N. (1989). Trace elements in oshore and
inshore ®sh from the Mediterranean coast of Israel. 5th International
Congress on Environmental Pollution and its impact on life in the
Mediterranean Region, Blanes (Spain), 2±6 October 1989.
Inskip, M. J., & Piotrowski, J. K. (1985). Review of the health eects
of methylmercury. Journal of Applied Toxicology, 5, 113±133.
Joseph, K. O., & Srivastava, J. P. (1993). Mercury in the Ennore
estuary and in ®sh from Madras coastal waters. Journal of Environ-
mental Biology, 14, 55±62.
Kaiser, G., & Tolg, G. (1980). Mercury. In O. Hutzinger, The handbook
of environmental chemistry (pp. 1±58). New York: Springer Verlag.
Kowalewska, M., & Korzeniewski, K. (1991). Trace metals in Gaster-
osteus aculeatus L. from the Gdansk Bay. Pol. Arch. Hydrobiology,
38, 475±484.
Krenkel, P. A. (1973). Mercury, environmental considerations, Part 1.
CRC Crit. Rev. In Environmental Control Saf. Manage. May, 303±73.
344 R.B. Voegborlo et al. / Food Chemistry 67 (1999) 341±345
Muller, G., & Forstner, U. (1973). Naturwissenschaften 60, 258±265.
Piotrowski, J. K., & Inskip, M. J. (1981). Health eects of methyl-
mercury. AMRC Technical Report 24, MARC.
Roth, I., & Hornung, H. (1977). Heavy metal concentrations in water,
sediments and ®sh from Mediterranean coastal area, Israel. Environ-
mental Science and Technology, 11, 265±269.
Sharif, A. K. M., Mustafa, A. L., Hossain, M. A., Amin, M. N., &
Sa®ullah, S. (1993). Lead and cadmium contents in ten species of
tropical marine ®sh from the Bay of Bengal. Science of the Total
Environment, 113, 193±199.
Sharif, A. K. M., Mustafa, A. L., Mirza, A. H., & Sa®ullah, S. (1991).
Trace metals in tropical marine ®sh from the Bay of Bengal. Science
of the Total Environment, 107, 135±142.
Takizawa, Y. (1979). Epidemiology of mercury poisoning. In J. O.
Nriagu, The biogeochemistry of mercury in the environment (pp. 325±
365). Amsterdam: Elsevier.
Teherani, D. K., Stehlik, G., Tehrani, N., & Schada, H. (1979).
Environmental Pollution,18, 241±249.
Uchida, M., Hirakawa, Y., & Inoue, T. (1961). Biochemical studies on
Minamata disease IV. Isolation and chemical identi®cation of the
mercury compound in the toxic shell®sh with special reference to the
causal agent of the disease. Kumamoto Medical Journal, 14, 181±184.
Winchester, R. V. (1988). Trace metal levels in ®sh from the Manukau
Harbour, Auckland, New Zealand, related to a water pollution
incident. New Zealand Journal of Marine Freshwater Research, 22,
Woidich, H., & Pfanhauser, W. (1974). Z. Lebensm Unters Forsch 155,
R.B. Voegborlo et al. / Food Chemistry 67 (1999) 341±345 345
... Atendiendo a la salud pública, se hace necesario mantener el contenido de estos contaminantes dentro de unos niveles aceptables desde el punto de vista toxicológico. En este sentido, hay que hacer una clara diferenciación entre los elementos que poseen funciones esenciales para la vida, como es el caso del cobre y el zinc (6), frente a aquéllos cuya ingestión a bajas dosis desencadena ya efectos tóxicos, como el plomo y el cadmio (7). En el primer caso, estos elementos desarrollan acciones fisiológicas de primer orden, como por ejemplo la estabilización de membranas, y fundamentalmente la regulación de la actividad de numerosas enzimas corporales (8). ...
... En cuanto a las repercusiones en la alimentación de los dos elementos tóxicos analizados, y siguiendo siempre las recomendaciones de la JECFA (12), está establecido que el nivel de ingesta semanal provisionalmente tolerable es de 7 µg/kg de peso corporal para el Cd, de tal manera que en una persona media se estima que es de 400-500 µg por semana (7). En el caso hipotético de que se consumiera una lata diaria de mejillón durante una semana, el contenido de cadmio llegaría a 0,163 mg. ...
... Computed averages were compared for transactions using (Dunkin) Multipliers and the probability level (P ≤ 0.05) according to the Minitab-Ver-17 statistical program . (1.91ppm), respectively according to the technique of digestion, which is slightly higher than what researchers found [9] and [11] while the concentration in other techniques (0.87-0.66 ppm) for the sample (F) and (0.83-0.64 ppm) for sample (A) using techniques Ultra-Sonic and Ashing respectively, while the Cadmium concentrations in the other samples within the Iraqi standards and compatible with the findings of [10] , [12] and [13] . ) and (B) of Lead, whose concentration is below the detection limit (nd) of the device, which is ˂ ) 0.01ppm) ppm This finding is consistent with that found [12] . The highest concentration of lead was found was in the form of (C) which was (2.9 ppm) in digestion technique was and this agrees with the finding of [9] while disagree with [10]. ...
... (1.91ppm), respectively according to the technique of digestion, which is slightly higher than what researchers found [9] and [11] while the concentration in other techniques (0.87-0.66 ppm) for the sample (F) and (0.83-0.64 ppm) for sample (A) using techniques Ultra-Sonic and Ashing respectively, while the Cadmium concentrations in the other samples within the Iraqi standards and compatible with the findings of [10] , [12] and [13] . ) and (B) of Lead, whose concentration is below the detection limit (nd) of the device, which is ˂ ) 0.01ppm) ppm This finding is consistent with that found [12] . The highest concentration of lead was found was in the form of (C) which was (2.9 ppm) in digestion technique was and this agrees with the finding of [9] while disagree with [10]. This difference could be attributed to the type of packaging or extraction technique used for preparation. ...
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... The minimum and maximum Cd concentration in both kind of canned fish analysed in this study resulted higher than the EU limits. The Nigerian canned fish samples here analysed had a higher concentration of Cd than Libya (0.09-0.32 mg/kg), USA (0.00 mg/kg), Turkey (0.08 mg/kg) and Iran (0.003-0.03 mg/kg) [57][58][59][60] . Kowalska et al. [52] reported that Cd mean level in canned meat was 0.005 mg/kg, which was below the level detected in this study. ...
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The purpose of the study was to determine the concentrations of potential toxic metals (PTMs) and polycyclic aromatic hydrocarbons (PAHs) in 20 canned food samples (fish, meat, vegetable, non-alcoholic drink and beverage) sold in markets of Port Harcourt city (Nigeria) and to assess their potential human health risks (non-carcinogenic and carcinogenic). The methodology comprised the Graphite Furnace Atomic Absorption Spectrometry (GFAAS) analysis of metals and Gas Chromatography-Mass Spectrometry (GC-MS) analysis of PAHs, and then the calculation of the estimated daily intake (EDI), target hazard quotient (THQ) and cancer risk (CR) in adults and children. Results showed that the EDI values for As, Cd, Cu, and Pb from consumption of canned foods were below the provisional tolerable daily/provisional tolerable weekly intakes (PTDI/PTWI), and for Fe and Zn below the recommended daily intake (RDI), in both adults and children. The EDI value for B[a]P from consumption of canned foods was less than the PTWI value in both adults and children. Whilst the individual THQ values of metals were less than 1, the ∑THQ values were higher than 1 thus indicating a potential health risk arising from consumption of canned foods containing a mixture of metals. Moreover, the CR values by individual carcinogenic metals indicated a priority risk in both adults and children for As (mean, 2.43E-02 and 9.73E-03) and Cd (mean, 6.03E-03 and 1.95E-03), while the risk was acceptable for PAHs exposure (2.13E-09). In addition, the total CR (TCR), which was used to assess the effects of multiple carcinogenic metals, ranged from 1.24E-02 to 6.237E-02 indicating a carcinogenic risk for adults and children. In conclusion, the consumption of canned foods by Nigerian community can bring about worst health risks due to the residual concentration of PTMs in these products and the health hazard associated with them.
... Pollution of fresh water due to a wide range of pollutants has become an issue of serious concern since the industrialization (MPCB, 2018;Canli et al., 1998;Dighavkar, 2016;Dirilgen, 2001;Vutukuru, 2005;Voegborlo et al., 1999). Surface water and ground water of natural aquatic systems may be contaminated with heavy metals released from domestic, industrial and other human activities (MPCB, 2018;Dighavkar, 2016;Conacher et al., 1993;Velez and Montoro, 1998). ...
In the present study, an attempt has been made to compare the bioaccumulation of some heavy metals in the different tissues of the most common fish Oreochromis mossambicus collected from two sites of Ujani backwaters during three seasons of the year. The backwater of Ujani dam is a major resource of freshwater fishes to local population, where fishery is practiced on large scale. It is essential to conduct a survey of the bioaccumulation pattern of toxic heavy metals such as Hg, Pb, Cu, and Zn in the fish species commonly consumed by people in this region. The survey was carried out during three seasons of the year. The accumulated toxic heavy metals were found in the order Zn>Cu>Pb> Hg. The seasonal order was Monsoon > Pre-monsoon > Post-monsoon. The seasonal variation might be the effect of monsoonal runoff from the highly urbanized and industrial city of Pune that convey huge quantum of effluents in the water of tributaries of Bhima. Such study has immense importance as fishes are consumed by a large percentage of the people in the area of backwaters. This study would also provide a roadmap for researchers and policymakers to identify and implement effective and sustainable measures to counteract the increasing trends of pollution levels in natural ecosystems.
... 18,19 In developed countries, various studies and warnings have long been conducted on the risk of Hg exposure through excessive tuna intake. [20][21][22] In a study conducted in Europe, the species that contributed the most to the risk of MeHg were tuna, sea bream and bass; cod, pollack, shrimp and octopus also contributed in some countries. 23 The annual consumption of per capita fishery product in the ROK shows an increasing trend from 49.5 kg in 2005 to 69.9 kg in 2019, and the per capita tuna supply per day has also increased from 2.76 g in 2005 to 5.32 g in 2019. ...
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Background: Studies on the risk of mercury (Hg) in Korean fishery products focus primarily on total Hg levels as opposed to methylmercury (MeHg) levels. None of the few studies on MeHg in tuna investigated tuna from Japanese restaurants. Few have evaluated lead (Pb), cadmium (Cd) and arsenic (As) in tuna. Thus, this study aimed to conduct a risk assessment by evaluating heavy metal concentrations in tuna from Japanese restaurants. Methods: Thirty-one tuna samples were collected from Japanese restaurants in the Republic of Korea. They were classified according to region and species. The concentration of heavy metals in the samples was analyzed using the Ministry of Food and Drug Safety Food Code method. The rate of exceedance of maximum residue levels (MRLs) and the risk compared to the provisional tolerable weekly intake (PTWI) set by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (%PTWI) were evaluated for risk assessment. Results: The mean of MeHg, Pb, Cd and As concentrations were 0.56 ± 1.47 mg/kg, 33.95 ± 3.74 μg/kg, 14.25 ± 2.19 μg/kg and 1.46 ± 1.89 mg/kg, respectively. No sample exceeded the MRLs of Pb and Cd, but 9.7% of the samples exceeded the MRL of MeHg. The %PTWIs of MeHg, Pb, Cd and As were 4.2037, 0.0162, 0.0244 and 1.1627, respectively. The %PTWI of MeHg by age group and sex was highest among men aged 19-29 years (10.6494), followed by men aged 30-49 years (7.2458) and women aged 19-29 years (4.8307). Conclusions: We found that 3 out of 31 samples exceeded the MRL of MeHg. The %PTWI of MeHg showed significant differences based on age and sex, and the value was likely to exceed a safe level depending on individuals' eating behaviors. Therefore, improved risk management for MeHg is required.
... For example, Russo et al. [62] found that Pb was the most abundant heavy metal, followed by Hg and Cd. This trend seems to be a general pattern for most canned tuna commercialized in different countries such as Saudi Arabia, Libya, and the United States [63][64][65]. One explanation may be that canned tuna from both Pappalardo et al. [61] and our study were from the same or similar capture zones, while canned tuna from the other studies were from a different area. ...
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The incorrect labeling, as well as the bioaccumulation of heavy metals in seafood, represent a recurring problem worldwide, not only for natural resources but also for the consumers’ health. Heavy metals can be accumulated through the food chain and transferred to the final human consumer. Despite its toxicology, arsenic does not have a concentration limit on food, unlike other heavy metals like cadmium, mercury, and lead. Tuna species, with a worldwide distribution and high per capita consumption, represent a well-known toxicological issue caused by heavy metals. In this context, 80 samples of canned tuna were analyzed to check if the information contained in the label was correct and complete. Genetic identification was made by sequencing a fragment of 16S rDNA from 80 samples. For the heavy metal quantification, only those samples with the complete FAO fishing area information on the label were analyzed. Only 29 out of 80 samples presented enough information on the labels for the analysis. Some of the canned tuna commercialized in Spanish markets surpassed the safety standard levels established by the Joint FAO/WHO Expert Committee on Food Activities (JECFA) under the consumption rates of 300 g and 482 g per week. However, the carcinogenic risk (CRlim) for arsenic in all cans and all scenarios was higher than the safety levels.
... The rate of entry into aquatic systems of heavy metals is alarming. The accumulation of heavy metals above natural loads in aquatic ecosystems has become a major problem over the past decades and a topic of concern (Voegborlo et al., 1999;Canli et al., 1998;Dirilgen 2001;Vutukuru, 2005) [11,13] . Effluents are released into water systems directly or through rivers, leaching or drainage (Ezemonye and Kadiri, 2000) [18] by the means of human activities such as industrialisation, urbanization and farming. ...
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The earth has only 3% of freshwater out of all the water available on the earth and only 1.2% water can be utilized as drinking water. It is thus quiet clear that freshwater ecosystem consists only 3% of all ecosystems on earth. Aquatic toxicity is the measure of contamination in aquatic ecosystem and its impacts on inhabiting organisms. The toxics generally found in aquatic ecosystem are metals, fertilizers, micropollutants and macropollutants. The sources of these pollutants are mostly due to industrial discharge, run off or anthropogenic activities. The toxic effects are lethal and sub lethal both, which may change development, growth rate, reproduction, biochemistry, physiology and behaviour. The toxics are added to water body as a result of runoff residue which is extremely hazardous and harmful to fish. There are emerging concerns about these toxics and its hazardous impacts but comparable research is not reported in freshwater environments. Present study aims to investigate the occurrence and impact of toxics on aquatic species. The importance of such fishes are food web management, regulation of carbon flows, sediment strength and ecosystem links. Hence, freshwater fish populations should be protected and preserved in natural habitat. The purpose of the paper is to highlight the contaminants in freshwater and their impact on adjoining species; responding with different behavioural changes as we are closely associated with it.
(FR)Grace à des avantages des propriétés physico-chimiques, les PCB testés ont été largement utilisée dans plusieurs domaines dans le monde, mais ils sont toxiques pour les organismes, et la production a été arrêtée dans les années 1980s. L’écosystème aquatique est considère comme le premier compartiment pour recevoir ces polluants. Ils sont insoluble dans l’eau et facile a sédimenter. Cette étude a pour l’objectif de l’analyser la biodisponibilité des PCB testés dans les sédiments par un élevage ex-situ des carpes commune (Cyprinus carpio), une espèce largement élevée dans les étangs dans la région Lorraine, afin de déterminer la capacité des sédiments sur la rétention des PCB. L’expérience s’est faite par une contamination orale avec les aliments contaminés, deux matrices d’aliment sont préparée soit avec les sédiments soit avec l’huile contaminée, afin d’avoir un rapport entre les résultats des deux matrice pour déterminer la biodisponibilité relative. Une ANOVA est utilisée pour l’analyse statistique afin de réaliser la comparaison des moyennes entre les rapports et déterminer la BR (EN)The PCB tested had been widely used in many areas in the world, due to the advantage of their physic-chemical properties, however, they are toxic to organisms, and the production was stopped in the 1980s. The aquatic ecosystem is considered as the first compartment to receive these pollutants. They are insoluble in water and easy to settle down in the sediment. This study has the objective to analyze the bioavailability PCB tested in the sediment by using an ex-situ breeding of common carp (Cyprinus carpio), a specie widely raised in ponds in Lorraine, to determine the ability of sediment to retain the PCB tested. The experiment was done by oral contamination with contaminated food; two matrices foods are prepared either with sediments or contaminated oil, in order to have a report between the results of both matrix to determine the relative bioavailability. The ANOVA was used for statistical analysis in order to perform the comparison of means between the reports and determine the RB.
A photometric method based on the dithizone and AAS method is described for the determination of cadmium in food, especially in fish and mussel preserves. Wet oxidation was found to be suitable for digestion. Examination of samples in Austria showed relatively higher contents of cadmium in mussels than in fish. Also observed was the low cadmium contents in tuna fish, which are known to be a mercury burdened species.
Studies carried out during 1984-85 on bottom sediments, water and biota revealed that the contamination of mercury was higher in the vicinity of discharge zones, towards the uppor reaches of the estuary. The levels decreased gradually downstream towards the mouth of the estuary. The bioaccumulation of mercury in relation to water was 3 orders higher in magnitude as observed in Mystus gulio, a fish that has detritus (dead phyto-zooplankton) - invertebrate food chain pathway. A positive correlation observed between organic carbon and mercury content in the sediment suggests a possible role of estuarine sediments in mitigation of mercury loading in biological systems. Total mercury in 29 species of marine fish and 3 shellfish varieties sampled from commercial landings varied in the range of 0.01 to 0.48 ug. g-l dry tissue.
Mercury, copper, manganese, zinc and iron contents were assayed in three-spined stickleback. Owing to its specific biology, stickleback meets all requirements imposed on a bioindicator for trace metals. -from Authors
The cadmium content of fish and shellfish collected from the Ariake Sea and of dried lavers and canned goods made in various districts were determined; heavy metal contents were also determined. Cadmium content in fish and shellfish was lower in flesh than in internal organs and cadmium content of fish flesh was generally negligible. The internal organs of Tengunishi (Hemifusus ternatanus) and Bai (Babylonia japonica) contained an exceedingly large amount of cadmium, while the amount was very small in their flesh. An appreciable amount of cadmium was found in canned oysters produced at Hiroshima Prefecture. Dried lavers collected from various districts contained lower cadmium levels than those previously found in the Ariake Sea. Plankton (zoo- and phytoplankton) from the offing of Omuta City contained 7.50 ppm of cadmium in dry matter. Oysters contained a considerable amount of zinc.