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Table 3 Seasonal variations of heavy metals concentrations (μg/g dry weight) in muscle 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 < 0.05 < 0.05 < 0.05 < 0.05
Copper 1 ± 0.02b 0.97 ± 0.05b 2.2 ± 0.1a < 0.05
Lead 1.2 ± 0.08b 1.15 ± 0.8b 1.80.05a < 0.05
Zinc 17.9 ± 0.6bc 21.4 ± 0.9b 50 ± 2a 10.7 ± 0.32c
  1. Data are shown as mean ± SEM; (n=5); 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)