Coliphage prevalence in high school septic effluent and associated ground water

At the present time, somatic and male-specific coliphage and human enterovi rus groups are being considered as indicators of possible pathogenic human enteric virus contamination from fecal contamination. A primary attribute f or any indicator of fecal contamination is its prevalence at the source and in associated ground water. It must be consistently found in the source ma terial at concentrations that are measurable with available techniques. Ove r a period of ten months, male-specific and somatic coliphage ranged from s imilar to 7000 to similar to 4,000,000 PFU/L in the effluent from a multi-u ser septic-tank. Unlike the values determined for septic-tank effluent, col iphage concentrations measured in ground water over this same period only v aried by five-fold. Coliphage concentration in ground water under the down- gradient edge of the drainfield contained similar to 1000 PFU/L. This conce ntration decreased at -1 log(10)/5 m during 17.4 m of ground-water transpor t. From these data, coliphage concentrations in septic-tank effluent seem s ufficient to allow their use as indicators of fecal contamination in ground water. (C) 1998 Elsevier Science Ltd. All rights reserved.