Changes in the chemistry of acidified Adirondack streams from the early 1980s to 2008

► Acidity of Adirondack streams has remained unchanged or shown small decreases since the early 1980s. ► The base cation surplus in stream water did not change from 1998 to 2008. ► Increased DOC concentrations led to increased leaching of soil calcium. ► Sulfate concentrations decreased in Buck Creek tributaries from 1998 to 2008, but rates varied with soil carbon content. ► Increases in ANC in the North Tributary of Buck Creek were linked to calcium leaching by strong organic acids.