Processes and Causes of Lake Acidification during Spring Snowmelt in the West-Central Adirondack Mountains, New York

Abstract

The surface and outlets of two headwater lakes acidified during the 1978, 1979, and 1980 spring snowmelt periods. The decrease in pH was accompanied by an increase in nitrate whereas the other strong acid anion, SO42−, remained relatively constant. Chemical mass-balance calculations, using data from the Integrated Lake–Watershed Acidification Study, indicate that the peak in acidification observed in the Adirondack Mountains in the spring is caused by (1) a dilution of base cations (Ca2+, Mg2+, Na+, and K+) and associated alkalinity by snowmelt, (2) an increase in NO3− concentration in the acidified portion of the lakes, and (3) the constant elevated concentration of SO42−. At Woods Lake, the NO3− that accumulated in the snowpack plus that deposited from the atmosphere during snowmelt was sufficient to account for the increased NO3− in and transported from the lake. At Panther Lake, an additional source of NO3− was needed and was believed to be contributed by nitrification in the upper soil horizons. If atmospheric deposition of sulfur is reduced, low-alkalinity systems like Woods and moderate-alkalinity systems like Panther will be less likely to develop strong acidity during spring acidification.

Prediction of episodic acidification in North-eastern USA: an empirical/mechanistic approach

“…Intensive sampling programmes to characterise acidic episodes are very costly and challenging (Galloway et al, 1987;McAvoy, 1989;Kahl et al, 1992;Wigington et al, 1996b;Evans et al, in review). Water quality monitoring/survey programmes generally are of coarse temporal ( from days to months) and spatial resolution, and therefore, the potential of proxy indicators to estimate the most extreme episodic acidi®cation has been explored, often based on one or a few samples per year during base¯ows.…”

“…This approach has generated some interest and controversy (Schaefer et al, 1990;Schaefer and Driscoll, 1992;Davies and Tranter, 1996). Gerritsen et al (1996) used a similar approach, but also incorporated precipitation and antecedent precipitation to estimate regional-scale distributions of minimum episodic pH. Van Sickle et al (1997) generated monthly samples from a more intensive sampling programme [the Episodic Response Project (ERP) of the US Environmental Protection Agency; Wigington et al (1996b)], choosing the sample closest to an arbitrarily selected time during each month as the monthly index sample.…”

Geoscience of Climate and Energy 12. Water Quality Issues in the Oil Sands Region of the Lower Athabasca River, Alberta

“…Melting snow is known to be low in conductivity because of low base cation concentrations, but, industrial emissions can contaminate it with high concentrations of strong acids and toxins (Schindler et al 1981). The combination of dilution (which probably varies considerably, based on snowpack and speed of melting) and high hydrogen ion input leads to significant acid pulses (Galloway et al 1987). While data for the oil sands region are few, significant pH depressions of up to two units were recorded already in 1990.…”

Comment on “The episodic acidification of Adirondack Lakes during snowmelt” by Douglas A. Schaefer et al.

“…York [Galloway et al, 1980[Galloway et al, , 1987. Based on studies of three lakes in the Adirondacks in the late 1970s and early 1980s, Galloway et al [1987] concluded that the acidification at lake outlets during snowmelt could be largely explained as a result of (1) dilution of base cation concentrations and (2) increases in NO•-concentrations.…”

“…Based on studies of three lakes in the Adirondacks in the late 1970s and early 1980s, Galloway et al [1987] concluded that the acidification at lake outlets during snowmelt could be largely explained as a result of (1) dilution of base cation concentrations and (2) increases in NO•-concentrations. Galloway et al [1987] further noted that both of these effects could be ascribed to changes in dominant hydrological flow paths during snowmelt: an increase in the proportional contribution of dilute meltwater and a decrease in the proportional contribution of alkaline groundwater.…”