Search Results       Your search for [subject]Nitrogen - Environmental aspects - Oregon - Tualatin River returned 1 record.           Sources and transport of phosphorous and nitrogen during low-flow conditions in the Tualatin River, Oregon, 1991-93. by Kelly, Valerie J.; Reston, Virginia: U.S. Geological Survey, 1999. Subject: Nitrogen - Environmental aspects - Oregon - Tualatin River; Phosphorous - Environmental aspects - Oregon - Tualatin River; Water quality - Oregon - Tualatin River.          Add to Book Cart Relevance: 51.44%