This chapter provides an overview of geochemical indicators for nitrogen (N), acidity, and metals in soil and water (soil solution, ground water and surface water) in view of their impacts on different endpoints (tree growth/health, human health, soil biodiversity etc.). Relevant indicators for N are the soil C/N ratio, nitrate (NO3) concentration in ground water and total N concentration in soil and surface water. For acidity the most relevant endpoint indicators are the exchangeable base cation pool or base saturation in the soil, the ratio of aluminium (Al) to base cation (Bc) in soil solution, the total Al concentration in ground water and the acid neutralizing capacity (ANC) in surface water. Relevant indicators for metals are the total or reactive metal concentration in the soil and the free or total metal ion concentration in water. Using critical limits for those endpoint indicators, it is possible to assess critical loads for both terrestrial and aquatic ecosystems based on geochemical modelling. An overview is given of the derivation of those limits, mostly under laboratory circumstances, and a critical evaluation of their relevance in the field situation.
|Title of host publication||Critical Loads and Dynamic Risk Assessments: Nitrogen, Acidity and Metals in Terrestrial and Aquatic Ecosystems|
|Editors||W. de Vries, J.P. Hettelingh, M. Posch|
|Publication status||Published - 2015|