Metals and micronutrients in some edible crops and their cultivation soils in eastern-central region of Tunisia: A comparison between organic and conventional farming.

In the present study, we evaluated the concentrations of several micronutrients and heavy metals (Fe, Mg, Mn, K, Ca, Na, Zn, Cu, Ni and Cd) in soils and in edible parts of two vegetables (Solanum lycopersicum cv. Amal) and (Lactuca sativa L. cv Augusta) and a fruit (Fragaria x ananassa cv. Sabrina) from conventional and organic farming in the eastern-central region of Tunisia. A principal component analysis (PCA) was conducted to investigate correlations between metals in the edible part of the crops and metals in soil. The bio-concentration factors (BCF) were calculated to evaluate the ability of plants to absorb nutrients from the soil. Our data indicated a significant decrease in micronutrients in the edible part of crops from organic farming. However, toxic metals loads significantly increased in crops from conventional agriculture. Our data should be carefully considered in view of the potential health risk assessment for Tunisian consumers.