Challenges in the Era of Globalization - iaabd

Proceedings of the 12th Annual Conference © 2011 IAABD
Fish spp Mn Pb Zn Fe
Pseudolithus
senegalaenis
0.58 ± 0.53
4.52
1.09
±
0.57 ± 0.31 8.33± 4.72
Atlantic
bumper
NA 2.1 0.071 8.48
Cynoglosus
senegalensis
Drapane
africana
Pentatenus
quanius
Disscussion
1.095 ±
1.48
0.36 ± 0.00
NA
4.48 ±
0.57
4.3 ±
0.71
2.75 ±
0.35
0.5118 ±
0.31 5.5625 ± 4.96
0.7785 ±
0.63 9.39 ± 7.18
0.3765 ±
0.31 4.135 ± 4.21
In the cause of sampling, it was observed that heavy metal concentration in the different fish species
varied at the different sampling points. It is worthy to note that the concentration of iron Fe was relatively
higher when compared to the other heavy metals tested. Lead (Pb) concentrations where relatively higher
as compared to manganese (Mn) and Zinc (Zn) but lower than Iron (Fe). The significance of heavy metals
in our environment and concentration in commercially important fish species cannot be overemphasized.
Bioaccumulation, in this context is the process through which an organism concentrates metals in its body
from the aquatic environment either by absorption or ingestion. Based on research and reported by Al-
Kahtani (2009), fish can regulate metal concentration to a point, after which bioaccumulation occurs
(Heath 1991). It is important to note that heavy metal concentration varies in an organism and from
different organs (Al-Kahtani, 2009).
The interaction between chemical, physiological and environmental factors results in the bioaccumulation
of heavy metals in an organism (Casas et al 2006). This study revealed concentrations of Zinc (Zn) is
important in many enzymatic processes but are still regarded as highly toxic according to Hellawell
(1986) and as shown from the study, bioaccumulate in aquatic organisms. High concentrations of Zinc
lead to reproductive impairement in fish species. This is evident in a study carried out by Al-Kahtani
(2009), where it was implied that high zinc concentrations result in reproductive impairement in Tilapia
nilotica. It is suggested that zinc results in adverse toxicological effects especially in high concentrations
in water (Pelgrom et al 1995).
As observed by studies carried out, at low concentrations, heavy metals result in health effects which
include damage to the nervous system as evident by the Minamata incident, cancer, damage to vital
organs and in some extreme cases death. It is worrisome that a few fish species namely; Cynoglosus
senegalensis, Drapane Africana and Pseudolithus senegalesis recorded relatively high levels of lead
concentrations in their tissues. The most common toxic heavy metals include cadmium, mercury, arsenic
and lead. They are of environmental and health importance due to the fact that they readily accumulate in
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