Effects of an Intensive Hog Farming Operation on Groundwater in East Mediterranean (II): A Study on K+, Na+, Cl−, PO43−-P, Ca2+, Mg2+, Fe3+/Fe2+, Mn2+, Cu2+, Zn2+ and Ni2+

The application of treated animal wastewater generated in concentrated animal feeding operations on surface soil (within farm borders) leads to degradation of groundwater. Effects of an intensive hog farming operation, located at a Mediterranean limestone soil coastal area, on groundwater were investigated. Treated animal wastewater was discharged on a small plot (~10.8 ha) with a geologic fault. Samples were taken from seven groundwater monitoring wells close to the farm. A significant increase of K+, Na+, Cl−, PO43−-P, Ca2+ and Mg2+ concentrations was found in monitoring wells which are affected by the subsurface flow of groundwater. Concentrations of Fe3+/Fe2+, Mn2+, Cu2+, Zn2+ and Ni2+ in all groundwater monitoring wells were extremely low. During the winter, significant increases in concentrations of K+ and PO43−-P were noted and attributed to high precipitation, which assisted in the leaching of K and P to groundwater.