Stephen A. Norton

The role of stream substrates in aluminium mobility and acid neutralization

Abstract Acidification experiments were conducted on two streams to determine the mobilization of Al and the size of the pool of exchangeable Al associated with streambed materials during acid episodes. The first experiment demonstrated a buffering capacity of the stream 20-fold higher than that associated with the water and resulted in releases of massive amounts of Al (to 2500 μg 1 −1 ) at pH + was dominated by release of Al.

Red Herring lakes and streams in the acid-rain literature

Abstract Examples of naturally acidic lakes and streams that occur in areas not receiving acid rain are frequently cited in the literature on acidic precipitation. Both organic acidity and the effect of salt have been postulated as explanations for naturally occurring acidity. The example lakes have been presented as being representative of the processes responsible for regionally acidified lakes in Scandinavia and eastern North America. We have analyzed the published water chemistry data for the examples cited and conclude that the interpretations are incorrect because of faulty or incomplete chemical analysis, and errors in data compilation, summary, and analysis. Furthermore, the use of analogy is incorrect in some cases because the examples are not representative of lake types in regions where there are large numbers of recently acidified lakes. Organic acidity and the sea-salt effect may contribute to the acid-bas status of a lake or stream, but there is no evidence that either one is responsible for the regional and recent chronic acidification observed in lakes and streams in areas of North America and Scandinavia receiving acidic precipitation.