• James E. Bollinger,

  • Laura J. Steinberg,

  • Andrew J. Englande,

  • James P. Crews,

  • Janet M. Hughes,

  • Cruz Velasco,

  • Karen H. Watanabe,

  • William R. Hartley,

  • Christopher M. Swalm,

  • Jeffrey M. Mendler,

  • LuAnn E. White,

  • William J. George

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    • 2

      Respectively, Bollinger, Crews, Mendler, George: Division of Toxicology, Department of Pharmacology Tulane University Medical Center, 1430 Tulane Ave., New Orleans, Louisiana 70112; Steinberg: Department of Civil and Environmental Engineering, Tulane University, New Orleans, Louisiana 70118; Englande, Watanabe, Hartley, White: Department of Environmental Health Sciences, Tulane University, New Orleans, Louisiana 70112; Hughes, Velasco: Department of Biostatistics, Tulane University, New Orleans, Louisiana 70112; and Swalm: Entergy Spatial Analysis Laboratory, Tulane University, New Orleans, Louisiana 70112 (E-Mail/George:

  • 1

    Paper No. 99006 of the Journal of the American Water Resources Association.Discussions are open until August 1, 2001.


ABSTRACT: Nutrient data from all available sources for the lower Mississippi River were examined for potential differences among sampling agencies and geographic locations for the period between 1960 and 1998. Monthly means grouped by parameter, sampling location and agency, were calculated and compared as paired sets, excluding those months where data were not available for both sets. Some significant differences were found between various agencies collecting nutrient data on the river, as well as between various stretches of river, especially in the case of phosphorus nutrient data. Results were used to synthesize data sets from which a history of nutrient loading in the Mississippi River was determined. General trends in nitrate+nitrite, total Kjeldahl nitrogen, orthophosphate, total phosphorus and silica loads, as well as changes in nutrient proportions and the specific limiting nutrient (by month) are reported. This study provides a useful summary of contemporary and historical nutrient data that may assist in the evaluation of Mississippi River water quality and its potential effect on the Gulf of Mexico.