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Seasonal variations in the concentrations of heavy metals (μg g−1 d_w_) in fish (O_ niloticus) muscles collected from Lake Burullus
| Metal | Site | Autumn | Winter | Spring | Summer | Means | permissible limits | References |
|---|---|---|---|---|---|---|---|---|
| Fe | East | 129.37 | 79.72 | 26.13 | 67.64 | 35.35 | …… | …… |
| Middle | 140.13 | 56.35 | 31.37 | 71.06 | 56.40 | |||
| West | 178.10 | 29.38 | 28.16 | 73.75 | 59.35 | |||
| Mn | East | 5.75 | 15.65 | 4.00 | 3.85 | 7.31 | …… | …… |
| Middle | 4.68 | 13.13 | 4.12 | 3.85 | 6.44 | |||
| West | 8.28 | 16.55 | 11.98 | 4.80 | 10.40 | |||
| Zn | East | 37.50 | 56.95 | 41.35 | 38.75 | 43.64 | 40 | Marks et al. 1980; Mohamed 2008 |
| Middle | 39.95 | 51.83 | 33.38 | 30.03 | 38.79 | |||
| West | 38.55 | 70.25 | 51.60 | 33.08 | 48.37 | |||
| Cu | East | 1.05 | 1.15 | 1.10 | 0.88 | 1.04 | 30 | Marks et al. 1980; Mohamed 2008 |
| Middle | 1.33 | 1.60 | 1.23 | 0.83 | 1.24 | |||
| West | 1.93 | 1.95 | 1.13 | 0.58 | 1.39 | |||
| Pb | East | 0.12 | 0.13 | 0.13 | 0.10 | 0.12 | 2 | Adeyeye 1993; Mohamed 2008 |
| Middle | 0.13 | 0.14 | 0.13 | 0.05 | 0.11 | |||
| West | 0.20 | 0.28 | 0.23 | 0.11 | 0.20 | |||
| Cd | East | 0.04 | 0.08 | 0.05 | 0.03 | 0.05 | 2 | FAO 1992 |
| Middle | 0.05 | 0.05 | 0.05 | 0.03 | 0.04 | |||
| West | 0.05 | 0.03 | 0.05 | 0.05 | 0.04 |
Longitude and latitude of the selected sites of Lake Burullus
| Sector | Site | Longitude | Latitude |
|---|---|---|---|
| Eastern | I | 31°3.853ʹE | 31°33.199ʹN |
| II | 31°0.484ʹE | 31°32.057’N | |
| Middle | III | 30°56.914ʹE | 31°30.286ʹN |
| IV | 30°56.772ʹE | 31°27.574ʹN | |
| Western | V | 30°45.836ʹE | 31°25.832ʹN |
| VI | 30°44.351ʹE | 31°24.604ʹN |
Ranges and mean values of physicochemical parameters in Lake Burullus
| Parameter | Autumn | Winter | Spring | Summer |
|---|---|---|---|---|
| Temp. (°C) | 21–21.6 (21.1) | 17.4–18.9 (18.2) | 25–26.6 (25.8) | 31.4–33.1 (32.4) |
| Trans. (cm) | 45–70 (59.2) | 30–65 (39.7) | 27–40 (33.1) | 28–36 (29.8) |
| EC (mS cm−1) | 4.5–10 (7.3) | 5.3–10.8 (7.9) | 4.5–9.9 (6.5) | 4.8–8.5 (6.1) |
| pH | 8.1–8.4 (8.2) | 8–8.7 (8.5) | 8.2–8.9 (8.4) | 8.2–8.7 (8.4) |
| DO (mg l−1) | 5.8–8.8 (7.01) | 4.8–9.3 (7.7) | 5.6–9.2 (7.4) | 3.5–6.8 (5.6) |