Increases in dissolved organic carbon accelerate loss of toxic Al in Adirondack lakes recovering from acidification

Environmental Science & Technology
New York State Energy Research and Development Authority; USGS
By: , and 

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Abstract

Increasing pH and decreasing Al in surface waters recovering from acidification have been accompanied by increasing concentrations of dissolved organic carbon (DOC) and associated organic acids that partially offset pH increases and complicate assessments of recovery from acidification. To better understand the processes of recovery, monthly chemistry from 42 lakes in the Adirondack region, NY, collected from 1994 to 2011, were used to (1) evaluate long-term changes in DOC and associated strongly acidic organic acids and (2) use the base-cation surplus (BCS) as a chemical index to assess the effects of increasing DOC concentrations on the Al chemistry of these lakes. Over the study period, the BCS increased (p < 0.01) and concentrations of toxic inorganic monomeric Al (IMAl) decreased (p < 0.01). The decreases in IMAl were greater than expected from the increases in the BCS. Higher DOC concentrations that increased organic complexation of Al resulted in a decrease in the IMAl fraction of total monomeric Al from 57% in 1994 to 23% in 2011. Increasing DOC concentrations have accelerated recovery in terms of decreasing toxic Al beyond that directly accomplished by reducing atmospheric deposition of strong mineral acids.

Publication type Article
Publication Subtype Journal Article
Title Increases in dissolved organic carbon accelerate loss of toxic Al in Adirondack lakes recovering from acidification
Series title Environmental Science & Technology
DOI 10.1021/es4004763
Volume 47
Issue 13
Year Published 2013
Language English
Publisher American Chemical Society
Publisher location Washington, D.C.
Contributing office(s) New York Water Science Center
Description 6 p.
First page 7095
Last page 7100
Online Only (Y/N) N
Additional Online Files (Y/N) N
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