Purpose

The availability of potentially toxic elements in the soil is important to evaluate the risk they pose for humans and the broader environment. Implementation of environmental laws, especially in developing countries, makes it necessary to establish background concentrations for contaminants in soil.

Methods

Soil samples from Aridisols, Entisols, and Vertisols in the northern Nile Delta, Egypt, were taken at three depths and extracted with Mehlich III (M3) reagent to evaluate the availability and potential ecological risk of some emerging contaminants (Ba, Cd, Co, Cr, Li, and Se).

Results

Concentrations of the studied elements in the 60–90 cm depth soil layer, which were used as background values, showed that Li concentration was highest in Aridisols and Entisols, while Ba had the highest concentration in Vertisols. The contamination status of the soils was addressed by calculating a variety of pollution indices. Vertisols were enriched in the studied elements, while the Aridisols and Entisols were not enriched to moderately enriched (relative to background values).

Conclusions

This study provides an effective reference for the local background ‘available’ concentrations of the above-mentioned elements in different soil orders in the Nile Delta. Although many countries in the world built their environmental legislation on (pseudo)total element concentrations, these are not representative of the actual risk, and we recommend the use of M3 extraction and pollution indices to set up guidelines for trace element limits in the soils of Egypt.