Fate of Potential Contaminants Due to Disposal of Olive Mill Wastewaters in Unprotected Evaporation Ponds

The disposal of olive mill wastewaters (OMW) in shallow and unprotected evaporation pondsis a common, low-cost management practice, followed in Mediterranean countries. So far, the fate of potential soil pollutants in areas located near evaporation pondsis not adequately documented. This study investigates the extent in which the long-term disposal of OMW in evaporation pondscan affect the soil properties of the area located outside the evaporation pondand assesses the fate of the pollution loads of OMW. Four soil profiles situated outside and around the down slope side of the disposal area were excavated. The results showed considerable changes in concentration of soil phenols at the down-site soil profiles, due to the subsurface transport of the OMW. In addition, excessive concentrations of NH4 +, PO4 3− and phenols were recorded in liquid samples taken from inside at the bottom of the soil profiles. It is concluded that unprotected evaporation pondslocated in light texture soils pose a serious threat to favour soil and water pollution.