HEAVY METALS SAFETY ASSESSMENT OF TRACHURUS TRACHURUS, SCOMBER SCOMBRUSAND TRACHURUS MURPHYIIMPORTED FROZEN FISH SOLD IN ZARIA METROPOLIS, NIGERIA
HEAVY METALS SAFETY ASSESSMENT OF TRACHURUS TRACHURUS, SCOMBER SCOMBRUSAND TRACHURUS MURPHYIIMPORTED FROZEN FISH SOLD IN ZARIA METROPOLIS, NIGERIA
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Date
2015-12
Authors
ABUBAKAR, Abdullahi
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Abstract
This study aimed at assessment of safety levels of cadmium, lead, mercury, iron and nickel in frozen fishTrachurus trachurus, Scomber scombrus and Trachurus murphyi imported into Nigeria and sold in Zaria metropolis. The assessment involves variation of heavy metals levels in fishthat are supplied from Russia (RS) and Europe (EU) fishing origins (zones). The concentrations ofCd, Pb, Hg, Fe and Niwith respects to each species were assessed on the bases of fish import batches and variation of metals localization in different fish organs/tissues (skin, muscles, gills, liver, intestine, kidneys, brain and bone). Accumulation levels of metals concentrations in different fish tissues were determined with flame Atomic Absorption Spectrophotometer (FAAS). The highest concentration of the metals determined across RS and EU fishing origins were given as follows: for Trachurus trachurus species, the cadmium concentrations are 5.142mgkg-1 (RS) and 6.517mgkg-1 (EU), lead concentrations are 15.742mgkg-1 (RS) and 18.058mgkg-1 (EU), mercury concentrations are 78.208mgkg-1 (RS) and 72.592mgkg-1 (EU), Iron concentrations are 230.14mgkg-1 (RS) and 836.26mgkg-1 (EU), and nickel concentrations are 10.308mgkg-1 (RS) and 18.383mgkg-1 (EU). For Scomber scombrus fish species, the cadmium concentrations are 19.758mgkg-1(RS) and 10.658mgkg-1(EU), lead concentrations are 17.558mgkg-1 (RS) and 8.725mgkg-1 (EU), mercury concentrations are 76.000mgkg-1 (RS) and 80.358mgkg-1 (EU), iron concentrations are 375.93mgkg-1 (RS) and 225.25mgkg-1 (EU) and nickel concentrations are 7.017mgkg-1 (RS) and 9.067mgkg-1 (EU). For Trachurus murphyi fish species, cadmium concentrations are 36.650mgkg-1 RS and 37.867mgkg-1 (EU), lead concentrations are 10.825mgkg-1 (RS) and 20.225mgkg-1 (EU), mercury concentrations are 115.21mgkg-1 RS and 86.483mgkg-1 (EU), iron concentrations are 818.05mgkg-1 (RS) and 431.84mgkg-1 (EU) and nickel concentrations are 3.775mgkg-1 (RS) and 4.208mgkg-1 (EU). The trend in metals accumulation across the entire tissues were found to show similarities for Trachurus trachurus and Scomber scombrus which were in this other: Fe > Hg > Pb > Ni > Cd. While, the species Trachurus murphyi was found to showed accumulations in the order: Fe > Hg > Pb > Cd > Ni. The entire tissues showed significant variation (at p<0.05) in the accumulation levels of the studied heavy metals across the entire batches; majorly liver, intestine and kidneys accumulates highly than the corresponding skin, muscles, gills, brain and bones.The concentrations of heavy metals obtained in all the tissues of Trachurus trachurusScomber scombrus and Trachurus murphyi fish wereabove the safety limits recommended by FAO/WHO. The risk of human health for heavy metals with the entire fish tissues are considerably high and individuals consuming fish livers, intestine and kidneys might be at higher risk from ingestion of toxic metals at unacceptable concentrations. The results of the research work shows that the studied imported fish species are unfit for human consumption.
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DISSERTATIONSUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF MASTER OF SCIENCE DEGREE IN ANALYTICAL CHEMISTRY DEPARTMENT OF CHEMISTRY, FACULTY OF SCIENCE, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA
Keywords
HEAVY METALS,, SAFETY ASSESSMENT,, TRACHURUS,, SCOMBER SCOMBRUS,, TRACHURUS MURPHYIIMPORTED,, FROZEN FISH,, ZARIA METROPOLIS,, NIGERIA.