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Bulletin of the National Research Centre

Table 4 Seasonal variations of heavy metals concentrations (μg/g dry weight) in liver tissue of Oreochromis niloticus

From: Seasonal assessment of some heavy metal pollution and Metallothionein gene expression in cultured Oreochromis niloticus

Heavy metal

Winter

Spring

Autumn

Summer

Cadmium

5.6 ± 0.23a

< 0.05

< 0.05

< 0.05

Copper

36.3 ± 1.3b

68.8 ± 1.9a

28.6 ± 0.17b

15.8 ± 2.6c

Lead

1.6 ± 0.01b

1.2 ± 0.05c

2.1 ± 0.006a

< 0.05

Zinc

3.8 ± 0.01c

18.8 ± 0. 3b

60.1 ± 1.5a

14.8 ± 1.7c

  1. Data shown as mean ± SEM (n = 6), mean values with unlike superscript letters were significantly different (p ≤ 0.05)
  2. FAO (1983) limits in fresh muscle (mg/Kg): Cd (0.5), Cu (30), Pb (0.5) and Zn (30)
  3. EOS (1993) MPL limits in fish (mg/Kg): Cd (0.5), Cu (20), Pb (2) and Zn (40)
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