Metal concentrations in irrigation canals and the Nile River in an intensively exploited agricultural area.

Concentrations of major and trace elements (Al, Fe, Mn, B, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sr, V, and Zn) were determined in water and sediments from irrigation canals and the Nile River in an agricultural area of 120 km(2) to evaluate the impact of agricultural practices and the spatial distribution and mobility of these elements. The enrichment factors of cadmium indicate contamination in this area. Metal pollution indices are higher at locations downstream of the irrigation canals, possibly a consequence of waste discharges and phosphate fertilizing. Comparisons with consensus-based sediment quality guidelines revealed that ∼92 % (Cr), ∼85 % (Cu), ∼46 % (Ni), and ∼23 % (Zn) of the samples exceeded the threshold effect concentrations, with 7.7 % for Cr and Ni being above the probable effect concentration. Contamination with many metals in water was found in the secondary irrigation canals. The partition coefficients of all determined metals were evaluated. The major elements Al, Fe, and Mn were found to be very mobile while V was the least mobile.