[1] Lancaster Environm Ctr, NERC Ctr Ecol & Hydrol, Lancaster LA1 4AP, England
[2] CEN Cadarache, SERIS, Inst Radioprotect & Sikete Nucl, F-13115 St Paul Les Durance, France
[3] Univ Stirling, Sch Nat Sci, Stirling FK9 4LA, Scotland
[4] Soc Magelis, Cadenet, France
[5] Univ Copenhagen, Dept Basic Sci & Environm, Fac Life Sci, DK-1168 Copenhagen, Denmark