Assessing the Transport of Heavy Metals from Al-Faria Main Stream into Soil and Groundwater

Faria catchment is one of the most important region in the West Bank, Palestine, due to the intensive agricultural activities and it contains a lot of groundwater wells and springs which used in irrigation and domestic consumption. Therefore, the quality of this water resource is an important issue. Heavy metals are one of the most toxic pollutants that must be taken in consideation, so the aim of this research is to assess the concentrations of Nickel, Cadmium, Copper and Chromium in wadi AlFaria stream, soil and groundwater in six selected Faria locations. Then comparing them with permissible limits of heavy metals in irrigation water and soil. A second objective of this research is modeling the transport of heavy metals in soil using column study. In this experiment the columns used were defined as follow: two columns represent the concentration of heavy metals for 5years, the other two columns for 10years and the last two columns for 20 years.Thereafter, to know the fate of selected heavy metals in soil and if there is possibility to reach and pollute groundwater in Faria catchment. Results show that Ni, Cd, Cu and Cr are found in wadi AlFaria stream, soil and groundwater wells in the six selected locations at very low concentrations which are under the permissible limits. Also the concentrations in dry season are larger than it in wet season. The concentrations of Ni, Cd, Cu and Cr in stream, soil and groundwater wells at dry and wet seasons for the six selected locations were subjected to analysis of variance (ANOVA). A probability ≤ 0.05 was considered as significant. ANOVA showed that there is no significant variation in the concentrations of Ni, Cd, Cu and Cr with sampling location in dry and wet season. According to column leaching experiment, the results showed that the concentrations in the effluents were too small and decreased with time through the experiment period which was 24 hours. And at the long term of time as appeared in the columns of 20yr-concentration the relation tends to be linear. Most of Ni, Cu, Cd and Cr are accumulated in the top and middle layers of the columns. According to R2 values the concentration-depth relation is linear, when depth increases, the concentration decreases. That means the soil is homogeneous and heavy metals adsorption occurs. The average depth in soil at which the concentrations of selected heavy metals becomes zero in the columns of 5yr-concentartion, 10yr-concentration and 20yr-concentrations are 32.97cm, 48.10cm and 38.50cm respectively. In general, Faria soil has a high adsorption capacity for the selected heavy metals at different high inflow concentrations. But the presence of heavy metals in groundwater samples means they were transported from the stream, adsorbed by soil and reach the groundwater even at low concentrations, which indicates a potential risk for pollution at the long term of time.