Wiener, J. G., Anderson, R. V., and McConville, D. R., 1984, Introduction - Contaminants in the upper Mississippi River, Wiener, J. G., Anderson, R. V., and McConville, D. R., eds., Contaminants in the upper Mississippi River: Boston, Butterworth Publishers, p. 1-4. Abstract: For the purpose of this book an aquatic contaminant is defined as any foreign substance in water that causes undesirable change in the chemical, physical, or biological characteristics of the aquatic environment. Given the physicochemical environment of the Upper Mississippi River, this pertains to sediments and excess nutrients as well as to toxic organic and inorganic pollutants. Keywords: sedimentation, nutrients-mineral, pollutants, organic-compounds, inorganic-compounds, nutrients, pollutant-dispersion, USA, Upper-Mississippi-R.