Deposition of NOx, SOx and NHx will affect the chemical composition of soil and groundwater. Deposition effects are strongest under natural and extensively managed vegetations on acid sandy soils with aluminium hydroxyde being the main acid buffering soil constituent. At 155 sites with forest and heathland, differing in size from 0.1 to 25 ha, about 10 groundwater samples were taken from the uppermost meter of groundwater and analyzed for NH4+, NO3-, SO4-2-, Na+, K+, Mg2+, Ca2+, Al3+, pH, EC and DOC. Relations are derived for individual and site mean aluminium concentrations with the other chemical variables and with variables on a local scale hundreds of m2 and a regional scale (some km2).