Comparative reductions of hepatitis A virus, enteroviruses and coliphage MS2 in miniature soil columns

Abstract

The reduction of viruses in wastewater and other contaminated waters in the subsurface or soil environment is an important public health consideration for land disposal of wastes and the use of ground sources as water supplies. Because of the lack of information on the comparative reductions of different viruses in soils receiving wastes, we determined the reductions of hepatitis A virus (HAV), poliovirus 1, echovirus 1 and the indicator virus MS2 in 10-cm deep, miniature soil columns dosed twice weekly with 2.5 cm of water or wastewater and incubated at 5 or 25°C for 16 weeks. The soils studied were coarse sand, loamy sand, clay loam and organic muck. By examination of column effluents, few or no viruses were detected in clay loam column effluents, with >99.98% virus reductions under all conditions tested. In organic muck columns virus reductions ranged from 30-98%, with greater reductions at 25°C than at 5°C and greater reductions of enteroviruses than either HAV or MS2. In the sandy soil columns viruses were retained generally better in loamy sand than in coarse sand. Overall, poliovirus was reduced the most and echovirus the least. In coarse sand, mean virus reductions ranged from a low of about 50% for echovirus at 5° to a high of about 99.4% for poliovirus at 25°. In loamy sand, mean virus reductions ranged from a low of about 60% for echovirus at 5° to a high of 99.997% for poliovirus at 25°. Virus reductions were greater in sandy soil columns dosed with groundwater than with wastewater. The appreciable breakthroughs of viruses in column effluents of organic muck and coarse sand soils indicate that these soil types may be unsuitable for land application of wastewater under some hydrogeological conditions.