Inorganic Nitrogen Compounds in Water Mains in Northern Poland and Their Implication for Health Risk

Abstract

AbstractThe presence of nitrogen compounds significantly affects the quality of water intended for human consumption. The maximum contaminant level (MCL) of nitrogen in potable water in Poland was set up as follows: NO2−–0.5 and NO3––50 mg/L, NH4+–0.50 mg/L. For this reason, the objective of the study was to monitor the chemical composition of water as a priority basis for the water quality information system to provide consumers with water that meets the appropriate health and quality standards. The results of a multiyear study (1992–2003) carried out in four regions and at 12 monitoring sites in northern Poland showed NO2− and NO3− levels significantly below MCL limits. Low nitrate concentrations in water drawn from Quaternary water-bearing horizons indicate the absence of point sources of pollution. Ammonia levels exceeded MCL values at every monitoring site. Supernormal ammonia concentrations in raw water are indicative of the natural origin of ammonia ions. They are correlated with the depth of the...