Global Gray Water Footprint and Water Pollution Levels Related to Anthropogenic Nitrogen Loads to Fresh Water

Mesfin M. Mekonnen*, Arjen Y. Hoekstra

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

327 Citations (Scopus)
244 Downloads (Pure)

Abstract

This is the first global assessment of nitrogen-related water pollution in river basins with a specification of the pollution by economic sector, and by crop for the agricultural sector. At a spatial resolution of 5 by 5 arc minute, we estimate anthropogenic nitrogen (N) loads to freshwater, calculate the resultant gray water footprints (GWFs), and relate the GWFs per river basin to runoff to calculate the N-related water pollution level (WPL) per catchment. The accumulated global GWF related to anthropogenic N loads in the period 2002–2010 was 13 × 1012 m3/y. China contributed about 45% to the global total. Three quarters of the GWF related to N loads came from diffuse sources (agriculture), 23% from domestic point sources and 2% from industrial point sources. Among the crops, production of cereals had the largest contribution to the N-related GWF (18%), followed by vegetables (15%) and oil crops (11%). The river basins with WPL > 1 (where the N load exceeds the basin’s assimilation capacity), cover about 17% of the global land area, contribute about 9% of the global river discharge, and provide residence to 48% of the global population.
Original languageEnglish
Pages (from-to)12860-12868
Number of pages9
JournalEnvironmental science & technology
Volume49
Issue number21
Early online date22 Oct 2015
DOIs
Publication statusPublished - 3 Nov 2015

Keywords

  • IR-99195
  • METIS-312414
  • Crops
  • Natural resources
  • Plant derived food
  • Water pollution
  • Water treatment
  • UT-Hybrid-D

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