Figure 5.26 - Trends in the nitrate concentration of European rivers

Sources: Eight English rivers from José, 1989; River Rhine from van der Weijden and Middelburg, 1989; six Czech rivers from Czechoslovakia, 1992; six Northern Irish rivers from Smith et al, 1982; five Hungarian rivers from Hock and Somlyódy, 1989; three Danish rivers from Kristensen et al, 1990