Effects of an Intensive Hog Farming Operation on Groundwater in East Mediterranean (I): A Study on Electrical Conductivity, as well as Nitrogen and Sulfur Nutrients

Abstract

The discharge of treated animal wastewater produced in concentrated animal feeding operations (CAFOs) on surface soil (within CAFOs borders) leads to groundwater degradation. In this research, groundwater degradation effects of an intensive hog farming operation, located in a Mediterranean area, were investigated. Treated animal wastewater was discharged on a small plot (~10.8 ha) with a geologic fault. Groundwater samples were taken from seven groundwater monitoring wells close to the farm. These wells were affected by the subsurface flow of waters, due to the presence of the geologic fault. In the summer, a significant increase of electrical conductivity values was noted in and attributed to falling water table levels. During the winter, significant increases in concentrations of ammonium nitrogen, nitrate nitrogen, and sulfate were noted and attributed to high precipitation, which assisted in the leaching of nitrogen and sulfur to groundwater.

Assessing the relationship between groundwater nitrate and animal feeding operations in Iowa (USA)

“…Monitoring wells 2 – 8 km downgradient of a cattle AFO in Nebraska had an average nitrate concentration of 11.3 mg/L, and N isotope analyses indicated both fertilizer and animal sources (Exner and Spalding, 1994). Land application of treated wastewater from a hog AFO in Crete contributed to nitrate-nitrogen concentrations up to 29 mg/L in monitoring wells downgradient 0.3 – 1.5 km (Michalopoulos et al, 2014). Nitrate concentrations in the winter were significantly greater than in the spring due to increased precipitation and leaching of nitrate to groundwater.…”