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There are several areas in Canada that could receive acidic fallout. Only in the area that produces Canada's largest single source of sulfur oxides has there been appreciable research. In the Sudbury region of Ontario, Canada, fallout of sulfur oxides has been shown to be responsible for damage to vegetation, lakes and fishes. The acidic fallout has been shown to effect a rate of acidification in many lakes that over several decades has resulted in the extinction of many species of fishes. Fishes exhibit profound differences in acid tolerance but show some similarities in their physiologica...

Current and historic geographic distributions of acidity in Adirondack lakes were examined in relation to regional edaphic, climatic, and physiographic features. Acid conditions are currently predominant in high elevation drainage lakes having small watershed/surface area ratios. Comparable levels of acidity were found only in small seepage lakes and bog ponds during the 1930's. Increased acidity in the high elevation lakes can be quantitatively related to the occurrence of excess acid forming anions of atmospheric origin. Knowledge of this stoichimetric relationship and the morpho-edaphic...

Rain experiments were run with various temperature differences between the warm rain and the cool receiving water. The rain intensities were uniform and the raindrop sizes were usually uniform (2.2 mm, 3.6 mm, and 5.5 mm diameter drops). Two drop size distributions were also used.

Recurrent biological investigations have been made in six lakes in two areas in western Sweden. It has been found that the supply of acid substances induces long-term biological perturbations at all trophic levels in the lake ecosystem. Among these changes, the sphagnum expansion is believed to strongly affect the dynamics in the lake. A quantification of the Sphagnum expansion in different depth zones of a lake was made. The rate of this invasion was found to be highest in shaded and sheltered areas of the littoral. The abundance of Sphagnum mats is furthermore negatively correlated to...

The pH and amount of rainfall from over 60 selected stations throughout northern and lower Michigan was determined from September 1972 to December 1974. Precipitation pH was determined for each station by calibrated electrode meters. The seasonal weighted average and median pH from all stations in the study was 5.0 and 6.3, respectively. Daily readings from stations throughout Michigan indicate that pH is dependent on the amount of rainfall and that variations in it are often locally controlled. Collectively the pH values suggest carbonic acid control for most of the state. Annual median...

The dense network of 12 rainguages, covering an area of 6 km in diameter, was reinstalled near PEPCO's 710 MW Chalk Point power plant in southern Maryland. The rainwater samples were collected from July to December 1974. This second season's collection of rainwater samples were analyzed and results showed a general shifting of pH toward higher values since the operation of a cooling tower. The pH values changed from a range of 3.4 to 4.6 to a range of 4.0 to 4.8. Graphs of mean pH distribution over our dense network show the influence of the cooling tower. Several selected cases of...

The rainwater pH was measured in a total of 22 storms which occurred in 1972 and 1974 in the METROMEX (METROpolitan Meteorological EXperiment) rainwater sampling network. The network consists of 81 collectors in an area of 1800 km² over and east of St. Louis, Missouri. The data set is composed of dry fallout samples as well as precipitation samples which have been analyzed independently. An analysis of the frequency distribution of these data show the rainfall samples form a bimodal distribution of pH with relative frequency maxima at pH 7.0 and 4.0 while the dry samples are unimodal with...

An integrated analytical system consisting of combined scanning electron microscopy and x-ray analysis, atomic absorption, colorimetry and coulometry was used to study rain water chemistry. The coulometry facilitated the determination in molarities of strong and non-volatile and volatile weak acids. The pH of individual rains in St. Paul - Minneapolis, Minnesota ranged from 4.0 to 5.65 during the summer of 1974. Samples of a given rain from different sites had different qualitative and quantitative bases for the measured pH. Increase in strong acid concentrations with a decrease in pH was...

The history and present distribution of precipitation acidity in eastern North America is reviewed. Precipitation chemistry from the 1920's indicates heavy ionic deposition, but low acidity (calculated) in Tennessee (pH 7.4) and New York (pH 6.15). However, high acidity was apparently widespread over northeast North America by 1955-56 and measured pH's below 4.5 were observed earlier. The geographic distribution of acid precipitation has spread through the present. Yearly average pH values for 1972-73 are not significantly different in New York and New Hampshire, indicating a regional...

The principal aim of this project is to produce a mass balance for the SO2 that is emitted into the atmosphere from sour gas plants in various localities in Alberta. Partial sulphur budgets for two plants at dissimilar locations are shown to exhibit major differences. The rise and dispersion of sour gas plant plumes have been investigated in detail. In order to investigate the chemical transformation of SO2 within these plumes, the use of a conserved tracer that can be detected by neutron activation is discussed.