Abstract:
The study assessed the effect of smoking and grilling on the levels of As, Cd, Hg, Pb
and 18 PAH congeners in 48 composite fillet samples of O. niloticus from 2 aquatic
environments on the Afram Arm of the Volta Lake. The PAH congeners were analysed
by GC-MS using Agilent bond Elut QuEChERS dSPE sample preparation and a Highefficiency
DB-5ms Ultra Inert GC column. For HM analysis, fillets samples were
digested in HNO3 and H2O2 and analysed for As, Pb, Hg and Cd using ICP-MS with
helium as the carrier gas. The mean levels of HMs in fresh fillets from both
environments was As > Pb > Cd with no significant difference in the levels of Cd and
Pb, but a higher mean of As in fillets of cultured O. niloticus. Ant, Pyr, Pyl and Ind
were detected in fresh fillets of cultured O. niloticus, whiles only Pyr was detected in
wild O. niloticus. Sixteen (16) and fourteen (14) PAHs were detected in smoked wild
and cultured O. niloticus, respectively. Grilled cultured and wild O. niloticus fillets
contained PAHs in the order Ant > Pyr > FL = B[a]A > Ind and Ant > Pyr > FL >
B[a]A > Pyl = Ind respectively. Smoking and grilling increased the total PAHs in all
fillets but decreased the level of Ind in fillets of cultured O. niloticus. Smoking and
grilling had a greater effect on the mean level of detected PAHs in wild and cultured O.
niloticus, respectively. The effect of smoking was, however, more significant than
grilling. Smoking increased levels of Pb, Hg and As; however, its effect on As in
cultured O. niloticus and Hg in wild O. niloticus was significantly high. Grilling
increased the mean level of Pb in cultured O. niloticus and As in all fillets and
decreased the level of Pb in fillets of wild O. niloticus. Smoking and grilling did not
affect the mean levels of DBA, BP, and Cd in all fillets. The mean levels of HMs
detected in the study were below the Maximum Permissible Limits, whiles the mean
Description:
A thesis in the Department of Chemistry Education, Faculty of Science Education,
submitted to the School of Graduate Studies in partial fulfilment
of the requirements for the award of the degree of
Master of Philosophy
(Chemistry Education)
in the University of Education, Winneba
NOVEMBER, 2021