• Water quality and bottom sediment in Rillito Creek and selected tributaries in Tucson, Arizona

      Hawkins, Richard H.; Tadayon, Saeid, 1957- (The University of Arizona., 1993)
      In 1986, a monitoring plan was developed to collect baseline data on the physical and chemistry of surface water, ground water, and bottom sediment in Rillito Creek and selected tributaries. Several total trace elements exceeded the U.S. Environmental Protection Agency's primary and secondary maximum contaminant levels for drinking-water standards. When the sediment is removed, none of the constituents in surface water exceed the drinking-water standards; therefore, adsorption by sediment particles plays a vital role in increasing the concentrations of constituents. The presence of the priority pollutants and pesticides in surface water and bottom sediment is probably due to a higher intensity of urbanization and the type of land use within the Alamo Wash and Rillito Creek watersheds. Maximum concentrations of 25 milligrams per liter for total nitrite plus nitrate as nitrogen at well (D-13-14)26bbb exceeded the USEPA's primary maximum contaminant levels of ten milligrams per liter. Lower concentrations of constituents in the ground water indicate that the vadose zone generally attenuates the majority of the contaminants and the level of constituents.