Evaluation of the role of sea salt inputs in the long-term acidification of coastal new england lakes

Input of neutral salt (NaCl) from sea spray, followed by Na⁺-H⁺ exchange within the soil exchange complex, has been proposed as an important factor in surface water acidification of coastal areas. This hypothesis was tested on a regional basis by comparing the Na:Cl ratio of lake water with that of precipitation for the coastal lakes included in the U.S. Environmental Protection Agency Eastern Lake Survey-I in New England. The precipitation Na:Cl ratio closely approximated that of seawater at monitoring stations located within approximately 20 km of the coast. Few lakes in this coastal region exhibited a Na:Cl ratio less than that observed in precipitation. Those lakes that Were acidic (ANC ≤ 0) showed no tendency toward a lowered Na:Cl ratio. Sodium contribution from, rather than retention by, watershed soils was suggested by the data from these lakes. Although episodic acidification of runoff due to NaCl deposition may occur, there is little support for the neutral salt effect being an important long-term acidifying process in Northeastern lakes.