The hepatopancreas contained the highest levels of Cr and Cd. It is the key site of metals
storage and detoxification in crustacean and particularly crabs (Bejaoui et al., 2021).
Although the muscles receive the major portion of hemolymph, metal accumulation was
found to be relatively low. The zinc was the most abundant metal in the different tissues
followed by iron and copper with the highest concentrations in the exoskeleton. Same
results were observed with Portunus pelagicus from the Persian Gulf but with highest
levels in the hepatopancreas (Haidarieh et al., 2013). However, Annabi et al. (2018) found
that Cu contents in P. segnis from the gulf of Gabès were higher than Zn which was
accumulated especially in muscles.
Some of trace metals such as Zn, Fe, Cu, Co, Ni and Mn play a vital role in the metabolic
activity of living organisms (a component of hormones and enzymes) and can be toxic
only at relatively high concentrations. In fact, Zn and Mn are important components of
several enzymes and play an essential role in a number of biological processes involved
in growth and development. Iron is one of the very important essential trace elements
since it serves as a carrier of oxygen to the tissues from blood. Besides, copper serves as
an essential co-factor for several oxidative stress-related enzymes and Cr is required for
carbohydrates metabolism (Barath Kumar et al., 2019).
Results have shown that all trace metals concentrations were within the permissible limits
of FAO/WHO (1984),
except for exoskeleton which exceeds those limits in the case
of Mn, Cu, Cd and Pb. In addition, the hepatopancreas also resulted in high contents
of Cd, which exceeded the permitted threshold, highlighting the need of monitoring these
metals . This is in line with the European Food Safety Authority (EFSA) which advises
to limit crab hepatopancreas consumption because it accumulates high amounts of Cd.
This bioaccumulation may be due to the site of collection, in fact, Tunis lagoon borders
a strongly urbanized area in continuous expansion. It has long served as a receiving
environment for domestic and industrial discharges from the city of Tunis and
neighboring agglomerations. Therefore, sediments of the southern lagoon may contain
high concentrations of trace metals (Pb, Cd and Cu) (Derouiche, 2016) .
Indeed, the most consumed tissues (muscles) are the least affected and targeted by toxic
metals (Pb, Cd). More controls are strongly needed to guarantee human health safety.
Biomonitoring must cover all fishing sites, especially polluted areas, and must take into
account seasonal variations, sex and crab physiology.
Bibliography
ANNABI A., BARDELLI R., VIZZINI S., MANCINELL, G. (2018) - Baseline assessment of
heavy metals content and trophic position of the invasive blue swimming crab Portunus segnis
(Forskål, 1775) in the Gulf of Gabès. Marine Pollution Bulletin, 136 : 454– 463.
AZZURRO E., SBRAGAGLIA V., CERRI J., BARICHE M., BOLOGNINI L. et al., (2019) -
Climate change and biological invasions are rapidly reshuffling species distribution,
restructuring the biological communities of many ecosystems of Mediterranean fishes: A
large-scale survey based on local ecological knowledge. Global Change Biology, 25(8), 27792792.
BARATH KUMAR S., PADHI R.K., SATPATHY K.K. (2019) - Trace metal distribution in crab
organs and human health risk assessment on consumption of crabs collected from coastal water
of South East coast of India, Mar. Pol. Bul. 141: 273–282
BEJAOUI S., TRABELSI W., CHETOUI I., GHRIBI F., FOUZAI C., SOLTANI A., EL CAFSI
M., SOUDANI N. (2021) - Assessment of trace elements uptake on the invasive crab Portunus
segnis hepatopancreas using a multivariate biochemical approach.Isagoge – J Hum Soci
Sci(1):131–151
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
66
storage and detoxification in crustacean and particularly crabs (Bejaoui et al., 2021).
Although the muscles receive the major portion of hemolymph, metal accumulation was
found to be relatively low. The zinc was the most abundant metal in the different tissues
followed by iron and copper with the highest concentrations in the exoskeleton. Same
results were observed with Portunus pelagicus from the Persian Gulf but with highest
levels in the hepatopancreas (Haidarieh et al., 2013). However, Annabi et al. (2018) found
that Cu contents in P. segnis from the gulf of Gabès were higher than Zn which was
accumulated especially in muscles.
Some of trace metals such as Zn, Fe, Cu, Co, Ni and Mn play a vital role in the metabolic
activity of living organisms (a component of hormones and enzymes) and can be toxic
only at relatively high concentrations. In fact, Zn and Mn are important components of
several enzymes and play an essential role in a number of biological processes involved
in growth and development. Iron is one of the very important essential trace elements
since it serves as a carrier of oxygen to the tissues from blood. Besides, copper serves as
an essential co-factor for several oxidative stress-related enzymes and Cr is required for
carbohydrates metabolism (Barath Kumar et al., 2019).
Results have shown that all trace metals concentrations were within the permissible limits
of FAO/WHO (1984),
except for exoskeleton which exceeds those limits in the case
of Mn, Cu, Cd and Pb. In addition, the hepatopancreas also resulted in high contents
of Cd, which exceeded the permitted threshold, highlighting the need of monitoring these
metals . This is in line with the European Food Safety Authority (EFSA) which advises
to limit crab hepatopancreas consumption because it accumulates high amounts of Cd.
This bioaccumulation may be due to the site of collection, in fact, Tunis lagoon borders
a strongly urbanized area in continuous expansion. It has long served as a receiving
environment for domestic and industrial discharges from the city of Tunis and
neighboring agglomerations. Therefore, sediments of the southern lagoon may contain
high concentrations of trace metals (Pb, Cd and Cu) (Derouiche, 2016) .
Indeed, the most consumed tissues (muscles) are the least affected and targeted by toxic
metals (Pb, Cd). More controls are strongly needed to guarantee human health safety.
Biomonitoring must cover all fishing sites, especially polluted areas, and must take into
account seasonal variations, sex and crab physiology.
Bibliography
ANNABI A., BARDELLI R., VIZZINI S., MANCINELL, G. (2018) - Baseline assessment of
heavy metals content and trophic position of the invasive blue swimming crab Portunus segnis
(Forskål, 1775) in the Gulf of Gabès. Marine Pollution Bulletin, 136 : 454– 463.
AZZURRO E., SBRAGAGLIA V., CERRI J., BARICHE M., BOLOGNINI L. et al., (2019) -
Climate change and biological invasions are rapidly reshuffling species distribution,
restructuring the biological communities of many ecosystems of Mediterranean fishes: A
large-scale survey based on local ecological knowledge. Global Change Biology, 25(8), 27792792.
BARATH KUMAR S., PADHI R.K., SATPATHY K.K. (2019) - Trace metal distribution in crab
organs and human health risk assessment on consumption of crabs collected from coastal water
of South East coast of India, Mar. Pol. Bul. 141: 273–282
BEJAOUI S., TRABELSI W., CHETOUI I., GHRIBI F., FOUZAI C., SOLTANI A., EL CAFSI
M., SOUDANI N. (2021) - Assessment of trace elements uptake on the invasive crab Portunus
segnis hepatopancreas using a multivariate biochemical approach.Isagoge – J Hum Soci
Sci(1):131–151
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
66