International Journal of Marine Science 2015, Vol.5, No.58: 1-6
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Table 1 Mean concentrations of trace metal (mg/L) in water of Qua Iboe estuary during the study period compared with Standards
Trace
Station 1
Station 2
Station 3
WHO (2011)
NIS (2007)
Metals
Permissible level
permissible level
Fe
0.20±0.13
a
0.12±0.06
b
0.18±0.04
c
0.3
(0.05-0.56)
(0.04-0.27)
(0.12-0.23)
Zn
0.09±0.09
a
0.06±0.05
a
0.09±0.03
a
15.0
3.0
(ND-0.3)
(ND-0.15)
(0.02-0.15)
Pb
0.02±0.01
a
0.01±0.01
b
0.01±0.01
c
0.01
0.01
(ND-0.03)
(ND-0.02)
(0-0.02)
Cd
0.01±0.01
a
0.003±0.00
a
0.01±0.00
a
0.003
0.003
(ND-0.02)
(ND-0.01)
(ND-0.01)
abc= mean values in the same row with different superscript are significantly different at α= 0.05. NIS (Nigerian Industrial Standard);
ND - not detected
Table 2 Trace metal concentrations in sediment of Qua Iboe estuary during the study
Metals
Station 1
Station 2
Station 3
DPR (2002)
CEQC
Fe
0.47±0.54
a
0.739±1.21
b
0.553±0.70
c
20
-
(0.09-1.67)
(0.1-3.6)
(0.1-2.13)
Zn
0.27±0.31
a
0.35±0.42
a
0.37±0.41
a
50 - 300
60
(0.06-0.99)
(0.07-1.27)
(0.01-1.27)
Pb
0.02±0.01
a
0.04±0.05
a
0.05±0.05
a
2 - 20
25
(0.01-0.03)
(0.01-0.17)
(0.01-0.17)
Cd
0.015±0.019
a
0.019±0.02
a
0.020±0.03
a
0.03 - 0.3
0.5
(0.001-0.06)
(0.003-0.075)
(0.002-0.08)
abc= mean values in the same row with different superscript are significantly different at α = 0.05. CEQC - Canadian environment
quality criteria 1991
Table 3 Correlation matrix of trace metals in Qua Iboe estuary
Fe
Zn
Pb
Cd
Fe(sed)
Zn(sed)
Pb(sed)
Cd(sed)
Fe
1
Zn
0.67*
1
Pb
0.68*
0.56*
1
Cd
0.71*
0.61*
0.59*
1
Fe(sed)
-0.10
- 0.15
-0.06
-0.05
1
Zn(sed)
-0.13
- 0.12
-0.09
-0.07
0.94*
1
Pb(sed)
-0.16
- 0.18
-0.09
-0.10
0.86*
0.843*
1
Cd(sed)
-0.15
- 0.15
-0.11
-0.097
0.94*
0.981*
0.841 *
1
*Significantly correlated at P=0.05
wet season. This study has shown that the concentrations
of trace metals like Fe, Zn, Pb, and Cd in both water
and sediment of Qua Iboe estuary were below or
slightly higher than the permissible standard limits
recommended for polluted water. Bader et al (2015)
explained why the concentrations of metals measured
in water do not reflect the relative contributions of
pollution from the activities in the estuary. This they
said may be caused by the action of some
physicochemical process such as precipitation,
trapping, settling and storage of pollutants in
sediments and bioaccumulation in aquatic organisms.
Qua Iboe estuary is tidal with continuous ebb and
flood flows which ensure proper flushing of the
estuary.
Matrices of correlation coefficient between the metal
levels in the water and sediments for the six (6) month
variation show high significance (p<0.05) which is the
direct correlation between some of the metals. Fe in
water showed a significant positive relationship with
other metals.
Significant correlation among the variables
indicates that there are linear relationships between
the parameters. The relationship between Fe and other
