Northern GIG - Organisation Sweden (Swedish EPA coordinator), Finland, Norway, + UK, Ireland joined from 2004 Work started in 2002, funded by EPAs and supported by Nordic Council of Ministers Collaboration between national EPAs and national research institutes (SLU Sweden, SYKE Finland, NIVA and NINA Norway, CEH UK) Only rivers and lakes (coastal waters will IC with North- East Atlantic region or Baltic region)

Northern GIG – IC Options Option 1 not realistic since the member states do not have the same classification system Option 2 will be attempted for IC, using a combination of common metrics and national metrics. Test intercalibration in autumn 2004 for three lake types and three river types and some common metrics, and range of sites from high to poor/bad status. Option 3 can also be used if the common metric approach fails.

Northern GIG – Lake types to be used for test IC (2004) Type name Pressure Element L-N1 Lowland, shallow, siliceous moderate alk. (0.2-1 meq/L) Eutrophica-tion Phyto-plankton L-N3 Lowland, shallow, humic (> 30 mg Pt/L), low alk. (<0.2meq/L) L-N5 Boreal, shallow, siliceous low alk. (<0.2 meq/L) Acidification Macroinvertebrates, fish

Northern GIG – River types to be used for test IC (2004) Type name Pressure Element R-N3 Lowland, small, siliceous low alk. (<0.2 meq/L), humic (>30 mg Pt/L) Organic pollution (eutrophica-tion) Macroinvertebrates R-N4 Lowland, medium, siliceous moderate alk. (<0.2meq/L), clear R-N5 Boreal, small siliceous low alk. (<0.2 meq/L), clear Acidification

Northern GIG – Common metrics Pressure Element Metric Eutrophication (lakes) Phytoplankton Chlf.a, Biovolume, %blue-greens, Total P Eutrophication /Organic loading (rivers) Macroinvertebrates ASPT, DSFI, STAR/AQEM-metrics, BOD (?) Acidification (rivers and lakes) Raddum index, Medins index, STAR/AQEM? pH, alk, ANC Acidification (lakes) Fish CPUE-index, % acid-sensitive species, pH, alk.,ANC