Table 3.

Non-parametric Kruskal–Wallis One-Way Analysis of Variance Test on mean values of Cd, Hg and Pb for the gills of eleven fish species from Aiba Reservoir, Iwo, Nigeria.

Fish species	Cd (ppm) Mean ± SE	Hg (ppm) Mean ± SE	Pb (ppm) Mean ± SE
Marcusenius senegalensis	0.006 ± 0.001	0.004 ± 0.001	0.004 ± 0.001
Labeo senegalensis	0.002 ± 0.001	0.001 ± 0.001	0.002 ± 0.001
Hepsetus odoe	0.003 ± 0.000	0.002 ± 0.000	0.004 ± 0.000
Chrysichthys auratus	0.004 ± 0.001	0.003 ± 0.001	0.003 ± 0.001
Chrysichthys nigrodigitatus	0.004 ± 0.000	0.003 ± 0.000	0.004 ± 0.000
Clarias ebriensis	0.007 ± 0.001	0.005 ± 0.001	0.005 ± 0.001
Clarias macromystax	0.024 ± 0.004	0.017 ± 0.004	0.024 ± 0.004
Channa obscura	0.010 ± 0.003	0.007 ± 0.002	0.010 ± 0.003
Tilapia zillii	0.002 ± 0.000	0.001 ± 0.000	0.002 ± 0.000
Sarotherodon galilaeus	0.003 ± 0.001	0.002 ± 0.001	0.003 ± 0.000
Oreochromis niloticus	0.002 ± 0.000	0.001 ± 0.000	0.002 ± 0.000
(df = 10) P-value	30.78 0.001	28.21 0.002	27.67 0.002