. Effects of acid rain on soil and water. Acid rain; Soil pollution; Water. Effects of Acid Rain on Soil and Water Table 1. Northeast Podzol Soil Profile Data. Site Horizon Depth (cm) pH(H20) CEC (me/100g) Organic Matter (%) Base Saturation (%) Adirondacks, NY Hubbard Brook, NH o2 o2 * Adirondacks, NY Hubbard Brook, NH A2 A2 Adirondacks, NY Hubbard Brook, NH B2h B2h Adirondacks, NY Hubbard Brook, NH B2ir B2ir Adirondacks, NY Hubbard Brook, NH c„
. Effects of acid rain on soil and water. Acid rain; Soil pollution; Water. Effects of Acid Rain on Soil and Water Table 1. Northeast Podzol Soil Profile Data. Site Horizon Depth (cm) pH(H20) CEC (me/100g) Organic Matter (%) Base Saturation (%) Adirondacks, NY Hubbard Brook, NH o2 o2 * Adirondacks, NY Hubbard Brook, NH A2 A2 Adirondacks, NY Hubbard Brook, NH B2h B2h Adirondacks, NY Hubbard Brook, NH B2ir B2ir Adirondacks, NY Hubbard Brook, NH c„ cx — Both soils are Beckett pedons, well developed podzol soils. Adirondack soil data is pre-acid rain data from Lutz and Chandler (1946, p. 398). Hubbard Brook soil data is from Wood (1980, pp. 16 and 92) and Whittaker et al. (1979). Hubbard Brook % organic matter is % weight loss on ignition and B2ir CEC (cation exchange capacity) is grand average of 3 B2ir subhorizons. Hubbard Brook O, % base saturation = S(Ca + 2 + Mg + 2 + K+ + Na + ) Percent base saturation CEC * Depth of O, + 02 horizons since the increased acidity decreases the solubility of hu- mic acids. This is because most soil humic materials are in a solid or gel state. Electrostatic repulsion between like charges of dissociated groups is required for dissoci- ation of any humic fraction. Therefore, polar functional groups and charged sites with counter-ions will be strongly solvated in water. Replacement of readily disso- ciated counter-ions by H+ causes contraction and pre- cipitation of humic substances by reduction of charge repulsion between weakly dissociated carboxyl groups, enhanced hydrogen bonding, and expulsion of water from within the macromolecular humate structure (Hayes and Swift, 1978, p. 281: Ghosh and Schnitzer, 1980; and Ritchie and Posner, 1982). A common misconception is that acid humus accumu- lates because of greatly decreased rates of decomposition
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