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Soil cation leaching by acid rain with varying nitrate-to-sulfate ratios

Journal Article · · J. Environ. Qual.; (United States)
OSTI ID:5315537

The influence of the anion composition of simulated acid rain on cation leaching of three soils with different surface-charge properties was examined. Four acid mixtures of H/sub 2/SO/sub 4/ and HNO/sub 3/, all with pH 3.5, but with varying NO/sub 3//sup -//SO/sub 4//sup 2 -/ mole ratios of 1.00:0.00, 0.75:0.25, 0.55:0.45, and 0.00:1.00, were used to leach an Ultic-Alfisol, an Oxisol, and an Entisol. The Alfisol had a high SO/sub 4//sup 2 -/ adsorption capacity because of its high Fe/sub 2/:O/sub 3/ content of 12 g kg/sup -1/ and high point-of-zero charge (PZC) of 6.0. The Oxisol, although strongly weathered, had a lower Fe/sub 2/O/sub 3/ of 5 g kg/sup -1/ and PZC of 4.5. The Entisol was relatively unweathered soil derived from silicaceous alluvium, with even less Fe/sub 2/O/sub 3/ of 3 g kg/sup -1/ and a lower PZC of 3.5, and represented a soil of fixed charge. Cation leaching of the Alfisol varied directly with the NO/sub 3//sup -/ content of the leaching input due to the higher mobility of NO/sub 3/..sqrt.. compared with SO/sub 4//sup 2 -/ that was adsorbed. The relative NO/sub 3//sup -//SO/sub 4//sup 2 -/ contents of inputs had no effects on cation leaching of the Entisol. Effects on leaching of the Oxisol were intermediate between those of the Alfisol and Entisol. It was clearly demonstrated that the anion composition of acid rain plays a significant role in the cation leaching of soils with amphoteric-charge properties, which are able to adsorb SO/sub 4//sup 2 -/. 44 references, 4 figures, 4 tables.

Research Organization:
Univ. of California, Berkeley
OSTI ID:
5315537
Journal Information:
J. Environ. Qual.; (United States), Journal Name: J. Environ. Qual.; (United States) Vol. 13:3; ISSN JEVQA
Country of Publication:
United States
Language:
English