This study aimed to identify the effect of different factors such as seasonal variation, site of sampling and system of housing on the levels of some heavy metals in poultry environment (feed and water) .The concentrations of Cd, Pb, Cu, Fe, Mn, Cr, Zn and Ni were determined in 144 samples of feed and water comprising of broiler and layers during summer and winter seasons using flame atomic absorption spectrophotometry. The mean concentrations of detected metals in feed samples for layers and broiler during summer are 0.82 ± 0.061 and 1.023 ± 0.0653 for Pb, 0.47 ± 0.047 and 0.617 ± 0.058 for Cd, 2.04 ± 0.089 and 2.533 ± 0.159 for Cu, 13.407 ± 0.68 and 15.39 ± 0.47 for Fe, 18.527 ± 0.398 and 20.513 ± 0.69 for Mn, 0.88 ± 0.074 and 1.137 ± 0.08 for Cr, 20.887 ± 0.692 and 26.277 ± 1.208 for Zn, 1.847 ± 0.0636 and 1.353 ± 0.054 for Ni, respectively. While, during winter season the mean concentration of metals were lower than those during summer season. The mean concentrations of detected metals in water samples for layers and broilers during summer were 0.563 ± 0.048 and 0.957 ± 0.26 for Pb, 0.307 ± 0.042 and 0.417 ± 0.04 for Cd, 0.83 ± 0.064 and 1.323 ± 0.148 for Cu, 10.513 ± 0.62 and 13.62 ± 0.904 for Fe, 0.66 ± 0.064 and 1.09 ± 0.129 for Mn, 0.123 ± 0.012 and 0.163 ± 0.01 for Cr, 0.51 ± 0.065 and 0.577 ± 0.027 for Zn, 0.177 ± 0.021 and 0.197 ± 0.013 for Ni, respectively. While, during winter season the mean concentration of metals were lower than those during summer season. The results of this study showed that the concentrations of detected heavy metals were higher during summer season, feed samples and from broiler than winter, water samples and layers, respectively. |