The soil quality of rice fields in Egypt has been increasingly studied; however little
attention has been paid to metal pollution. The current work aimed at investigating
the distribution of total and DTPA-extractable Cd, Co, Cu, Pb, Ni and Zn in Kafr El-
Sheikh Governorate, one of the greatest rice-producing regions in Egypt. The studied
area covers 88709 ha between 31◦ 01′ 30′′ to 31◦ 25′ 05′′ N and 30◦ 25′ 34′′ to 30◦ 54′
64′′ E. Twenty-five soil profiles were dug and 75 samples were collected at 0-30, 30-60
and 60-100 cm. The total and DTPA-extractable fractions of the studied metals showed
decreases with depth. Total Co was within the safe limit, while Cd, Cu, Pb, Ni, and Zn
showed potential risks in the three layers. The DTPA-extractable forms of Cd, Co, Pb,
and Ni were within the safe limits, while Cu and Zn surpassed these limits. The single
pollution index and enrichment factor followed the sequence: Cd > Pb > Cu > Zn > Ni
> Co. The pollution load index indicated high to extreme pollution levels in the topsoil,
while moderate levels in the subsurface and deep layers. Metal availability ratios were
less than 3% and closely related to pH, organic matter and Fe and Mn. Effective measures
should be implemented to alleviate metals accumulation (mainly Cu and Zn) in rice soils
to reduce their translocation from soil to edible parts of crops. |
