Freshwaters acidification

Because of decreased SO2 emissions, the importance of nitrogen for freshwater acidification becomes more and more determinant. Therefore, uncertainties in the evolution of nitrogen emissions make it difficult to predict future trends in freshwater recovery. On the other hand, climate warming may increase the number of alkaline rain episodes (containing Saharan dust) and enhance weathering reactions, which buffer better acid precipitation, increasing alkalinity and pH. 

Galloway J. N., Norton S. A., and Church M. R. (1983) Freshwater acidification from atmospheric deposition of sulfuric acid a conceptual model. Environ. Sci. Technol. 17, 541-545. 

A. Henriksen/ Changes in Base Cation Concentrations due to Freshwater Acidification Norwegian Institute for Water Research/ Report 1/1982. 

Acidified waters are now a widespread phenomenon throughout areas of hard, slow-weathering rocks in the UK (Table 2.). Trends in acidity have been difficult to identify from past records of surface waters, but studies conducted over the last decade in Scotland, Wales and to a lesser extent England have now shown acid deposition to be the major cause of freshwater acidification and declines in fish populations. Additional scavenging of acidity from the atmosphere by conifers has also exacerbated the problem in many upland areas. 

Stoner, J.H. Harriman, R. (1988) Forests and freshwater acidification. In Acid Rain and British Forests. Royal Society, London. 

Kamari, J., Hettelingh, J.-P., Posch, M., and Holmberg, M. (1990). Regional Freshwater Acidification Sensitivity and Long-Term Dynamics. In Alcamo, J., Shaw, R.W., and Hordijk, L. (eds.) The RAINS Model of Acidification Science and Strategies in Europe. Kluwer Publishers, Dordrecht (in press). 

Land, vegetation, and bodies of water are the surfaces on which acidic deposition accumulates. Bodies of fresh water represent the smallest proportion of the earth s surface area available for acidic deposition. Yet, the best-known effect is acidification of freshwater aquatic systems. 

Hrabik TR, Watras CJ. 2002. Recent declines in mercury concentration in a freshwater fishery isolating the effects of de-acidification and decreased atmospheric mercury deposition in Little Rock Lake. Sci Total Environ 297 229-237. 

Taylor, E.J., E.M. Rees, and D. Pascoe. 1994. Mortality and drift-related response of the freshwater amphipod Gammarus pulex (L.) exposed to natural sediments, acidification and copper. Aquat. Toxicol. 29 83-101. 

An important consequence of acidification is mobilization of metals from terrestrial watersheds [14]. Particularly important is the release of aluminium because of its toxic effects on freshwater biota especially on fish [15]. Not all A1 forms are toxic. Only cationic species contained within the operational forms termed labile A1 (LAI) or inorganic monomeric A1 (Ali) are gUl-reactive and hence affect fish health [16]. It has been shown that concentrations of soluble aluminium increase with decreasing pH from a pH of ca. 6.3 [17]. 

Similar results were reported in the literature for most European (Scandinavia, UK, Germany, Poland and Czech Republic) and North American (Ontario, Vermont, Quebec, Adirondack Mountains, Appalachian Mountains, Blue Ridge Mountains) freshwater sites, where monitoring of the effects of long-range transboundary air pollution on acidification occurs [23]. 

Estimates of denitrification rates range from 54 to 345 xmol/m2 per hour in streams with high rates of organic matter deposition, 12 to 56 xmol/m2 per hour in nutrient-poor oligotrophic lakes, and 42 to 171 xmol/m2 per hour in eutrophic lakes (62). Rudd et al. (64) reported an increase in the rate of denitrification from less than 0.1 to over 20 xmol/m2 per hour in an oligotrophic lake when nitric acid was added in a whole-lake experimental acidification. This result suggests that freshwater denitrification may be limited by N03" availability. In deep muds of slow-flowing streams, the process can effectively reduce N03" concentrations in... 

Methe and Zehr (1999) Freshwater Natural DOC Water chemistry and acidification 16S rRNA cloning and sequencing No N/A N/A p-Proteobacteria and y-Proteobacteria correlated with DOC... 

Malcolm Cresser and Anthony Edwards Acidification of Freshwaters... 

Nelson WO, Campbell PGC. 1991. The effects of acidification on the geochemistry of Al, Cd, Pb, and Hg in freshwater environments a literature review. Environ Pollut 71 91-130. 

Deposition of sulfur in regions where the soils are deficient in sulfur may be considered a beneficial effect all of the other effects of sulfur air pollution are considered adverse. They include effects on human health, materials degradation, vegetation, and atmospheric visibility, and acidification of soils, watersheds and freshwaters. Limitations on the scope of this paper will greatly restrict our discussions of the details of these effects see the References 1-11 for more detailed information. 

M.S. Cresser and A.C. Edwards, Acidification of Freshwaters , Cambridge University Press, Cambridge, 1987. 

Ford J, Young TC (1994) In Steinberg CEW, Wright RF (eds) Acidification of Freshwater Ecosystems Implications for the Future, Wiley... 

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