Study of spatial distribution of heavy metals in agricultural soils of El Tarf area (Northeast Algerian)

The present study was conducted in both the surface horizons and during two seasons (for the wet season and the dry season) in 2014 and nine (09) sites were selected across the plain of El Tarf area (North-East Algeria). The average contents of heavy metals namely cadmium, zinc, cobalt and iron in the soil were determined using a chemical digestion process and analysis by ICP-MS to evaluate the mobility and availability to plants, also ecological characterization of the same samples: Granulometry, organic matter, pH and electrical conductivity. Analytical results show that the samples analyzed soils are characterized by an abundance of certain heavy metals especially for iron and zinc and following a seasonal pattern and are distributed according to a seasonal cycle, showing an increase taking place in the wet season, meaning dry season. Other elements cobalt and cadmium present no harm to the environment. Also the results indicate that our soils are low in organic matter, have low electrical conductivity and not salty. Soil pH has an alkaline character very alkaline, while pH_KCl have a neutral character. After all, the results indicate a deterioration of the environment as a result of agricultural activity intense, urban and industrial discharges. The results of the statistical analysis confirm those obtained in the laboratory and reveal variability between intra-period sites and a potential variability between the two periods.