Nonionic detergents as tracers of ground water pollution caused by municipal sewage

This study aimed at determining the extent of which Israel's ground waters, in the vicinities of streams polluted by municipal sewage, have been contaminated by synthetic detergents, particularly, the locally used, nonbiodegradable, alkylphenol-based nonionic type. Streams polluted by sewage (domestic and/or industrial) and six adjacent water wells were sampled simultaneously, and their nonionic detergent concentration determined. It was found that ground waters are being contaminated by nonionic synthetic detergents (0.1–0.8 mg/L), the origins of which are the adjacent surface water bodies polluted by sewage. The data collected indicate an inverse relationship between the distance of a given well from the polluted stream and the concentration of the nonionic detergent in the well. No obvious simple pattern appears to emerge concerning the detergent concentration-hydraulic head relationship. However, the data appear to suggest that the deeper the well, the higher the concentration of the nonionic detergents in the well's water, assuming all other involved factors are similar. The mean velocity of movement of the detergent pollutant front in the soil was found to be about 0.4 m/d. Clearly, neither naturally occuring biodegradation nor physical soil adsorption processes in the subsurface water/soil systems is capable of avoiding the infiltration of nonbiodegradable, nonionic detergents into Israel's ground water.