Table 5.17 - Examples of European lakes in which phosphorus concentration has decreased during the last 10 to 20 years

Country* Lake(s) Period Reduction in in-lake
phosphorus level (%)
Europe1,2 9 deep lakes Mid-1970s to late 80s 51
Europe1,2 9 shallow lakes Mid-1970s to late 80s 63
DK3 46 lakes 1972­79 to 1985­89 33
SE4 Vättern 1962 to 86 57
CH5 richsee 1979 to 88 31
CH5 Walensee 1979 to 88 92
AT, CH, DE5,6 Bodensee 1979 to 89 45
CH, FR7 Lac Léman 1976 to 89 36
CH, IT8 Lago di Lugano 1984 to 90 32
IT9 Lago Maggiore 1977 to 88 46
AT10 Mondsee 1979 to 89 70
NO11 Mjøsa Early 1970s to 1991 39

  1. Sas, 1989;
  2. Seip et al, 1990;
  3. Kronvang et al, 1993;
  4. Persson et al, 1989;
  5. Stabel, 1991;
  6. Tilzer et al, 1991;
  7. Lang, 1991;
  8. Barbieri and Mosello, 1992;
  9. Mosello, 1989;
  10. Dokulil and Jagsch, 1992;
  11. NIVA, 1992

* See Table 5.9 for country codes.