Use of stable isotopes of carbon, nitrogen, and sulfur to identify sources of nitrogen in surface waters in the lower Susquehanna River basin, Pennsylvania

With the exception of sewage and septic effluents, most nitrogen sources and soils contain larger proportions of organic and reduced forms of carbon, nitrogen, and sulfur than inorganic, oxidized forms. In contrast, most surface water and ground water contains larger proportions of dissolved inorganic carbon, nitrogen, and sulfur forms than organic forms. Data indicate that carbon, nitrogen, and sulfur are extensively processed in soils and streams.