الفهرس 
ACKNOWLEDGMENT
Heavy Metals Pollution in Aquatic SystemsOnly 14 pages are availabe for public view
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Abstract
Five tilapia fish aquacultures in both Assiut and Al-minia Governorates were involved in this study for studying the hygienic quality of their water, fish and fish feed. The five fish farms included three aquacultures and their water source (Bahr Yousef canal) in Al-minia Governorate, while two aquacultures were studied in Assiut Governorate Lead, cadmium, manganese and copper were the estimated heavy metals in each of water, fish and fish feed samples, while water samples subjected to an estimation of some water quality parameters included (water temperature, pH, total hardness, chloride, total dissolved solids, calcium ions concentration and electrical conductivity). Seasonal fluctuation between winter and summer values of the estimated metals and water quality parameters were also of the studied. A of The results estimated metals in water, fish, feed samples revealed the following:
1) Water samples
One hundred and twenty (120) water samples were examined for their heavy metals loads in the five examined aquacultures and Bahr-Yousef canal in winter and summer seasons, the mean concentrations of the estimated metals were as following:
Lead (0.392 ± 0.046; 0.291 ± 0.070; 0.457 ± 0.073; 0.338 ± 0.053; 0.271 ± 0.050 and 0.072 ± 0.018 ppm) and (0.432 ± 0.058; 0.152 ± 0.034; 0.262 ± 0.060; 0.158 ± 0.055; 0.210 ± 0.009 and 0.296 ± 0.033 ppm). Cadmium (0.011 ± 0.003; 0.005 ± 0.004; 0.010 ± 0.004; 0.004 ± 0.002; 0.011 ± 0.003 and 0.007 ± 0.002 ppm) and (0.007 ± 0.003; 0.007 ± 0.001; 0.005 ± 0.001; 0.002 ± 0.001; 0.006 ± 0.002 and 0.007 ± 0.007 ppm). Manganese (1.405 ± 0.174; 2.937 ± 0.355; 2.169 ± 0.092; 0.989 ± 0.149; 1.124 ± 0.078 and 1.041 ± 0.289) and (0.389 ± 0.028; 0.424 ± 0.051; 0.635 ± 0.140; 0.977 ± 0.485; 0.432 ± 0.057 and 1.244 ± 0.333 ppm). Copper concentrations were (0.141 ± 0.072; 0.161 ± 0.084; 0.327 ± 0.100; 0.372 ± 0.046; 0.300 ± 0.031 and 0.363 ± 0.020 ppm) and (0.531 ± 0.185; 1.085 ± 0.723; 0.494 ± 0.217; 1.502 ± 0.417; 0.032 ± 0.014 and 0.028 ± 0.015 ppm), respectively.
2) Feed samples:
Forty feed samples were examined for their heavy metals loads in the four closed system aquacultures (three in Al-Minia and one in Assiut) that used fish feed, the mean concentrations of the evaluated metals in both winter and summer seasons, were as following:
Lead (120.332 ± 10.384; 79.320 ± 9.070; 150.440 ± 6.523; 52.236 ± 9.703) and (74.427 ± 9.040; 101.388 ± 11.046; 90.044 ± 5.603 and 96.226 ± 4.239). Cadmium (1.145 ± 0.705; 7.276 ± 2.715; 2.370 ± 0.473 and 1.723 ± 0.400) and (6.394 ± 0.204; 5.764 ± 0.299; 6.536 ± 0.011 and 2.847 ± 0.188). Manganese (136.000 ± 12.160; 78.880 ± 8.992; 151.800 ± 16.967 and 100.580 ± 19.097) and (73.320 ± 0.365; 74.030 ± 1.088; 72.280 ± 1.498 and 68.910 ± 2.576). Copper (1.377 ± 0.272; 1.217 ± 0.183; 0.670 ± 0.232 and 0.814 ± 0.430) and (4.017 ± 2.151; 3.634 ± 1.328; 3.930 ± 2.844 and 6.100 ± 3.654), respectively.
3) Fish samples:
One hundred and eighty fish muscles samples were examined for their heavy metals loads in the five examined aquacultures and Bahr-Yousef canal. The mean concentrations of the estimated metals in both winter and summer seasons revealed the following:
Lead (0.454 ± 0.042; 0.439 ± 0.057; 0.484 ± 0.055; 0.461 ± 0.075; 0.190 ± 0.032 and 0.186 ± 0.050) and (0.242 ± 0.023; 0.277 ± 0.014; 0.324 ± 0.023; 0.321 ± 0.025; 0.254 ± 0.045 and 0.322 ± 0.016). Cadmium (0.009 ± 0.004;0.015 ± 0.001; 0.014 ± 0.002; 0.000 ± 0.000; 0.002 ± 0.001 and 0.003 ± 0.001) and (0.014 ± 0.001; 0.038 ± 0.005; 0.035 ± 0.009; 0.010 ± 0.001; 0.014 ± 0.002 and 0.018 ± 0.002). Manganese (69.533±8.846; 65.912±8.323; 80.236 ± 7.178; 74.524 ± 14.351; 38.849 ± 6.702 and 22.549 ± 4.860) and (1.756 ± 0.486; 1.844 ± 0.203; 1.887 ± 0.256; 0.977 ± 0.210; 1.454 ± 0.439 and 1.250 ± 0.242). Copper (0.298 ± 0.040; 0.381 ± 0.061; 0.877 ± 0.182; 0.528 ± 0.176; 1.080 ± 0.386 and 0.497 ± 0.163) and (2.548 ± 0.570; 4.848 ± 0.831; 0.515 ± 0.180; 0.963 ±0.562; 3.101±0.620 and 3.052±0.573) in winter and summer seasons, respectively.
• Water, fish and fish feed were fluctuated in their heavy metals concentrations. The highest concentrations were recorded in fish feed followed by fish muscles and water.
• Season had different effects on metals concentrations of the examined substrates, where cases of significance between the seasonal differences were clearer in case of fish than water.
• Fish weight and length showed different correlations with heavy metals concentrations where, both lead and manganese showed significant positive correlation with fish weight, and negative significant correlation with fish age. Cadmium and copper recorded positive correlation with both fish weight and length which was only not significant in case of cadmium and fish length.
(B) Mean values of the estimated water quality parameters in the five aquacultures and Bahr-Yousef canal in winter and summer seasons were as following:
Water temperature values were (19.0±0.4, 18.3±0.3; 18.2±0.2; 17.8±0.1; 19.6±0.3 and 18.8±0.2˚C) and (28.5±0.1; 27.5±0.2; 28.8±0.3 29.0±0.3; 28.0±0.2and 29.2±0.5˚C). pH values were (8.8±0.1; 8.7±0.1; 7.4±0.0; 8.0±0.1; 7.6±0.1 and 7.7±0.1) and (9.2±0.0; 9.0±0.1; 8.0±0.1; 8.0±0.0; 7.9±0.1 and 8.0±0.0). Total hardness values were (488.0±14.4; 680.0±14.0; 204.0±6.9; 124.0±5.4; 118.0±7.7 and 114.0±13.6 mg/l) and (508.0±45.7; 484.0±40.7; 216.0±43.6; 78.0±8.5; 104.0±7.8 and 82.4±13.2 mg/l). Chloride values were (404.0±2.7; 522.0±3.3; 25.0±2.1; 16.0±0.6; 16.8±0.6 and 20.6±2.6 mg/l) and (371.2±75.5; 364.0±47.5; 114.0±57.7; 12.0±1.7; 19.0±2.2 and 13.0±1.3 mg/l). Total dissolved solids were (1525.6±22.0; 2083.2±8.9; 414.4±10.6; 237.0±2.4; 217.2±11.8 and 181.6±5.4 mg/l) and (1527.6±158.7; 1375.0±122.1; 537.6±178.4; 158.0±24.3; 208.6±2.9 and 191.4±5.3 mg/l). Calcium concentrations were (448.0±13.1; 629.8±13.7; 175.2±9.0; 95.6±3.3; 99.4±6.0 and 97.0±13.0) and (457.6±42.2; 429.8±38.8; 175.4±38.4; 59.6±7.5; 84.2±6.7 and 66.0±11.0). Electrical conductivity values were (2.38±0.04; 3.25±0.01; 0.65±0.02; 0.37±0.00; 0.34±0.02 and 0.28±0.01 µs/cm) and (2.38±0.25; 2.14±0.19; 0.84±0.28; 0.25±0.04; 0.30±0.00 and 0.30±0.01 µS/cm) in winter and summer seasons, respectively.
- Correlations between water quality parameters and heavy metals concentrations in fish muscles revealed the following:
• Temperature showed negative significant correlation with both lead and manganese concentration in fish muscles, while it showed positive not significant correlation with both cadmium and copper.
• Water pH values revealed positive significant correlation with copper concentration in fish muscles, while it recorded negative significant correlation with manganese concentration in fish muscles, while its correlations were not significant with both lead and cadmium.
• Total water hardness, chloride, total dissolved solids, calcium concentration and electrical conductivity, showed no significance with any of the estimated metals, where they showed negative correlation with both lead and cadmium and positive correlation with manganese and copper.
Water quality parameters showed significant positive correlations with each other except for temperature which showed no significance with any of the estimated parameters.