Acid deposition aquatic effects

Receptors. The receptor can be a person, animal, plant, material, or ecosystem. The criteria and hazardous air pollutants were so designated because, at sufficient concentrations, they can cause adverse health effects to human receptors. Some of the criteria pollutants also cause damage to plant receptors. An Air QuaUty Criteria Document (12) exists for each criteria pollutant and these documents summarize the most current Hterature concerning the effects of criteria pollutants on human health, animals, vegetation, and materials. The receptors which have generated much concern regarding acid deposition are certain aquatic and forest ecosystems, and there is also some concern that acid deposition adversely affects some materials. 

One of the major effects of acidic deposition is felt by aquatic ecosystems in mountainous terrain, where considerable precipitation occurs due to orographic lifting. The maximum effect is felt where there is little buffering of the acid by soil or rock structures and where steep lakeshore slopes allow little time for precipitation to remain on the ground surface before entering the lake. Maximum fish kills occur in the early spring due to the "acid shock" of the first meltwater, which releases the pollution accumulated in the winter snowpack. This first melt may be 5-10 times more acidic than rainfall. 

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. 

Legislation enacted by both Canada and the United States (see the US-Canada Air Quality Accord, 1991) will, when implemented, reduce the North American emissions of sulphur dioxide by about 50% based upon the 1980 baseline. These projected emission fields have been appplied in the atmospheric source-receptor models that were described above, to provide a projected deposition field for acidic sulphate that would be expected (14). The predicted sulphate deposition fields have then subsequently been appUed in aquatic effects models that provide estimates of regional surface water acidification distributions (50). The regional acidification profiles have then been used in a model of fish species richness (51) that results in an estimate of the expected presence of fish species as compared to that expected in an unacidified case. 

Acids and alkalis. Most freshwater lakes, streams, and ponds have a natural pH in the range of 6 to 8. Acid deposition has many harmful ecological effects when the pH of most aquatic systems falls below 6 and especially below 5. 

Effects of acid deposition on life aquatic systems... 

Sensitivity of European ecosystems to acid deposition The calculation and mapping of CDs of acidity, sulfur and nitrogen form a basis for assessing the effects of changes in emission and deposition of S and N compounds. So far, these assessments have focused on the relationships between emission reductions of sulfur and nitrogen and the effects of the resulting deposition levels on terrestrial and aquatic ecosystems. 

What types of effects can you differentiate regarding the influence of acid deposition on terrestrial and aquatic ecosystems ... 

RMCC. (1990). The 1990 Canadian long-range transport of air pollutant assessment and acid deposition report Part 4—aquatic effects. Federal/provincial Research and Monitoring Coordinating Committee, Ottawa, Ontario, Canada. 

Air pollution sources in the United States and Canada currently emit more than 25 million tons of sulfur dioxide each year. SO2 and wet acidic deposition are believed to cause damage to aquatic life, crops, forests, and materials. The effects on materials include damages to common construction materials including galvanized steel (zinc), paint, copper, building stones and mortar, as well as damages to cultural or historic objects and buildings. 

It is clear from the above summary that CDOM plays a central role in the interaction of UVR and aquatic ecosystem function, and that the effects and implications of CDOM photochemistry are not always straightforward. Moreover, the effects become exacerbated by climate change and anthropogenic modification of aquatic ecosystems (e.g., acid deposition see Chapter 17). 

The Hubbard Brook Experimental Forest is a long-term ecological research site established by the U.S. Department of Agriculture Forest Service in the White Mountains of New Hampshire to investigate the structure and function of forest and aquatic ecosystems, and their response to disturbance (Likens and Bormann 1995 Groffman et al. 2004). Hubbard Brook was the site where acidic deposition was first reported in North America (Likens et al. 1972). Hubbard Brook receives elevated inputs of acidic deposition and the forest ecosystem is very sensitive to these inputs. There have been long-term measurements and studies of acidic deposition and its effects on forests and streams at Hubbard Brook (Likens et al. 1996 Driscoll et al. 2001). 

Acidic deposition alters soils, stresses forest vegetation, acidifies lakes and streams, and harms fish and other aquatic life. These effects can alter important ecosystem services such as forest productivity and water quality. Decades of acidic deposition have also made many ecosystems more sensitive to continuing pollution. Moreover, the same pollutants that cause acidic deposition contribute to a wide array of other important environmental issues at local, regional, and global scales (see Table 3.1). 

In sum, acidic deposition is a pervasive problem that has had a greater impact on soils, terrestrial vegetation, surface waters, and aquatic biota than previously projected. Although abatement strategies in Europe and North America have had positive effects, emissions remain high compared to... 

Driscoll, C.T., Driscoll, K.M., Mitchell, M.J. and Raynal, D.J. (2003). Effects of acidic deposition on forest and aquatic ecosystems in New York State. Environmental Pollution, 123, 327-336. 

Jeffries, D.S. (1991). Southeastern Canada An overview of the effect of acidic deposition on aquatic resources. In Acidic Deposition and Aquatic Ecosystems Regional Case Studies, Charles, D.F. (Ed.), Springer-Verlag New York, pp. 273-289. 

The detrimental effects of acid deposition on both the aquatic and terrestrial environments in Europe and North America were documented extensively in the 1980s. As a result, sulfur (S) emission control programs were put into effect in both continents. In Canada, sulfur dioxide (SO2) emissions declined from 3.81 million tons in 1980 to 2.52 million in 1990, 1.74 million in 1996 and 1.25 million in 2000, a drop of 68% over 20 years. Over the same time period, emissions of SOj in the United States dropped from 17.3 million tons in 1980, the baseline year for the Clean Air Act amendments of 1990, to 15.7 million in 1990, and 10.6 million in 2001, a total drop over 21 years of 39% (Stoddard et al. 2003). An additional drop of 3.3 million tons by 2010 will bring the total decrease to 10 million tons or almost 60%. 

Sullivan, T.J., Cosby, B.J., Munson, R.K., Webb, J.R., Snyder, K.U., Herlihy, A.T., Bulger, A.J., Gilbert, E.H. and Moore, D. D. (2002). Assessment of the Effects of Acidic Deposition on Aquatic Resources in the Southern Appalachian Mountains, Final report to the Southern Appalachian Mountains Initiative, Asheville, NC. 

The primary purpose of the acid rain NOx emission reduction program is to reduce the adverse effects of acidic deposition on natural resources, ecosystems, visibility, materials, and public health by substantially reducing annual emissions of NOx- NOx emissions are a principal acidic deposition precursor. Although sulfate deposition is considered to be the major contributor to long-term aquatic acidification, nitric acidic deposition plays a dominant role in the "acid pulses" associated with the fish kills observed during the springtime meltdown of the snowpack in sensitive watersheds. 

Scientists have documented many exampies of the effect of acid deposition on aquatic organisms. One exampie invoives the work of Dr. Ken Simmons, who investigated how acid rain affected rainbow trout in the waters of Whetstone Brook in north-centrai Massachusetts. He piaced the trout in cages in the brook so that their behavior and survivai couid be monitored. Three days iater, the trout were dead. Acid rain had iowered the pH ievei of the water to a point at which the trout simpiy couid not survive. 

Sublethal effects in birds are similar to those in other species and include growth retardation, anemia, renal effects, and testicular damage (Hammons et al. 1978 Di Giulio et al. 1984 Blus et al. 1993). However, harmful damage effects were observed at higher concentrations when compared to aquatic biota. For example, Japanese quail (Coturnix japonica) fed 75 mg Cd/kg diet developed bone marrow hypoplasia, anemia, and hypertrophy of both heart ventricles at 6 weeks (Richardson et al. 1974). In zinc-deficient diets, effects were especially pronounced and included all of the signs mentioned plus testicular hypoplasia. A similar pattern was evident in cadmium-stressed quail on an iron-deficient diet. In all tests, 1% ascorbic acid in the diet prevented cadmium-induced effects in Japanese quail (Richardson et al. 1974). In studies with Japanese quail at environmentally relevant concentrations of 10 pg Cd/kg B W daily (for 4 days, administered per os), absorbed cadmium was transported in blood in a form that enhanced deposition in the kidney less than 0.7% of the total administered dose was recovered from liver plus kidneys plus duodenum (Scheuhammer 1988). 

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