Acid precipitation measurement

A variety of techniques to identify and quantify acid and base components in rainwater are applied to data for southern California. Charge balance calculations using major cation and anion concentration data indicate southern California probably had alkaline rain in the 1950 s and the 1960 s with the exception of the Los Angeles area which probably had acidic precipitation. Measurements of the chemical composition of precipitation collected in Pasadena, California, from February 1976 to September 1977 are compared with the charge balance and conductivity balance constraints. A chemical balance is used to determine the relative importances of different sources. The pH is found to be controlled by the interaction of bases and strong acids with nitric acid being 32% more important on an equivalent basis than sulfuric acid. The uncertainties in the various calculations are discussed. 

The sodium hydroxide is titrated with HCl. In a thermometric titration (92), the sibcate solution is treated first with hydrochloric acid to measure Na20 and then with hydrofluoric acid to determine precipitated Si02. Lower sibca concentrations are measured with the sibcomolybdate colorimetric method or instmmental techniques. X-ray fluorescence, atomic absorption and plasma emission spectroscopies, ion-selective electrodes, and ion chromatography are utilized to detect principal components as weU as trace cationic and anionic impurities. Eourier transform infrared, ft-nmr, laser Raman, and x-ray... 

The primary constituents to be measured are the pH of precipitation, sulfates, nitrates, ammonia, chloride ions, metal ions, phosphates, and specific conductivity. The pH measurements help to establish reliable longterm trends in patterns of acidic precipitation. The sulfate and nitrate information is related to anthropogenic sources where possible. The measurements of chloride ions, metal ions, and phosphates are related to sea spray and wind-blown dust sources. Specific conductivity is related to the level of dissolved salts in precipitation. 

AE catalyses the cleavage of acetyl groups from different substrates. The enzyme activity was determined by measuring the release of acetic acid. The amount of acetic acid was measured spectrophotometrically using an acetic acid analysis kit (Boehringer, Mannheim). The activity of AE was measured in 0.6% sugar beet pectin solubilised in 25 mM Na-succinate pH 6.2 and incubated with enzyme fraction in total 500 nl assay. The samples were incubated at 40°C and aliquots were examined after 0, 1, 2 and 3 hours of incubation. The enzyme reaction was stopped by incubating the samples at lOO C for 5 min. Precipitated... 

The solubility of Hp in different acids has been given by Jayle and Moretti (J12). The relatively high solubility in 0.6 M perchloric acid explains why some of the haptoglobins are included in Winzler s mucoproteins (V2). Judging from our experience, on measurement of the mucoprotein by perchloric acid precipitation according to Winzler, the supernatant contains a relatively larger amount of Hp 1-1 than of Hp 2-2. 

Recent publications lead to the conclusion that ammonia contributes to the effects of acid precipitation. The main source of ammonia is animal production and regions with a high animal density are expected to have a high emission of ammonia. Because it is a volatile compound research workers in the field of odour measurement and odour control have the best knowledge and the best tools to study ammonia emissions. A proposal is made for the main goals of a research program. 

APPL is determined by acid precipitation (12M HC1) using either turbidity measurements (nephelometry abs. at 600 nm) or gravimetry according to Crawford et al. (4). All experiments reported in this paper were carried out with uninoculated controls whose values were always substracted. 

The term acid precipitation refers to any form of precipitation, such as rain, snow, sleet, or hail, with a pH less than that typical of rainwater. You may recall that pH is a measure of the concentration of hydrogen ions in a solution, an indication as to how acidic the solution is. Plain water has a pH of 7.0, while acidic solutions have a pH less than 7 and basic solutions, a pH of greater than 7. 

The denatured protein isolate (DPI) was prepared as follows. Acid precipitated curd is washed, resuspended at pH 7.0, heated at temperatures above 90 C, and spray dried. DSC measurements indicate this isolate to be totally denatured. 

Tartaric Acid. Quantitative measures of total tartrate are useful in determining the amount of acid reduction required for high acid musts and in predicting the tartrate stability of finished wines. Three procedures may be used. Precipitation as calcium racemate is accurate (85), but the cost and unavailability of L-tartaric acid are prohibitive. Precipitation of tartaric acid as potassium bitartrate is the oldest procedure but is somewhat empirical because of the appreciable solubility of potassium bi-tartrate. Nevertheless, it is still an official AO AC method (3). The colorimetric metavanadate procedure is widely used (4, 6, 86, 87). Tanner and Sandoz (88) reported good correlation between their bitartrate procedure and Rebeleins rapid colorimetric method (87). Potentiometric titration in Me2CO after ion exchange was specific for tartaric acid (89). 

Materials Degradation Effects. Virtually all of the effects of S02 on materials are associated with its dissolution in surface moisture as the primary mechanism of deposition (19). Thus an appropriate environmental index for materials damage should include not only the average ambient S02 concentration but also a measure of the portion of time that the material surfaces are wet and thus receptive to S02 deposition. Sulfur in the atmosphere has an additional adverse affect on some materials through acidification of precipitation however, for both "dry" deposition of S02 and impact by acid precipitation, the primary damage mode is attack by dilute acids. 

Interfacial mass transfer is an important consideration in many dynamic processes involving the transport of a gaseous species across a gas-liquid interface. In particular the rate of trace gas incorporation into aqueous drops in the atmosphere has recently received much attention because of its relevance to acid precipitation (1,2). In the present paper, mass accommodation coefficient measurements are reported for O3 and SO2 on water surfaces, using an UV absorption-stop flow technique. The results are incorporated into a simple model considering the coupled interfacial mass transfer and aqueous chemistry in aqueous drops. Some implications of the measured accommodation coefficients on the oxidation of SO2 by O3 in cloud water are discussed. 

Table V. Equilibrium and Potential Gas-Phase Concentrations of Organic Acids Calculated From Wisconsin and Virginia Precipitation Measurements...

Topol, L.E. "Plan for Controlling the Quality of Measurements and Data Base in the Utility Acid Precipitation Study Program (UAPSP)" Environmental Monitoring Services, Inc., January 1982. 

We shall present our findings on the chemical nature of so-called labile sulfur in adrenodoxin. (1) The determination of dehydroalanine formation gives a negative result in measuring pyruvate after mild acid hydrolysis of trichloroacetic acid precipitates of adrenodoxin (Table 12). 

To monitor the progress of the reaction, aliquots of the reaction mixture are removed at intervals of 20 min and acid-insoluble radioactivity is measured as described previously. When the level of acid-precipitable radioactivity reaches a plateau, the master reaction is terminated by addition of EDTA to 20 mM on ice. The radioactive DNA can be isolated by gel filtradon as described previously, with or without prior removal of the enzymes by phenol extracdon. 

They could remove the coat of waxes on the leaf surface, and so then the sea salt could penetrate into the cells and could kill the cells. I just wanted to know if this has been cleared in your country, or is it still in discussion The other point you mentioned quite rightly that NH 4 is no really neutralizing agent. In the soil it will be transformed into NO i, and nitric acid will contribute to acidity. The measurement of total acidity by just titrating the amount of acidity is a questionable thing. You have to determine the species of N0 3 and NH" 4 in the precipitation and add it to the acidity, so you have to do more than titrating... Well, I have a question what happens on the surface of leaves or other material in dry deposition of acids Maybe if you have a coat of SO2 which is then transformed into sulphuric acid, will this sulphuric acid be a permanent coat on the leaves and can nitric acid then be added to this ... 

Some authors have documented that present-day base cation fluxes measured in North America and Northern Europe watersheds are signihcantly faster than long-term past weathering rates due to the impacts of acidic precipitation... 

In carrying out this analysis a measured quantity of the liquid in which chlorine is to be estimated is taken. It should contain no sulphuric acid. A slight excess of sodium thiosulphate is added and the whole warmed for a short time in a vessel closed with a tightly fitting stopper. The odour of chlorine completely disappears. A slight excess of hydrochloric acid is then added and the whole heated to boiling to decompose the excess thiosulphate. The liquid is then filtered and the sulphuric acid precipitated in the filtrate with barium chloride in the usual way. 

The fact that dissolved mucin produces turbidity with acetic or trichloroacetic acid (G2, S40) has been the basis of other techniques. However, the opacity produced by various mucosubstances at the same concentration differs markedly under similar conditions, and may be caused not only by mucosubstances, but by proteins contained in gastric juice as well, lessening the value of these techniques. This applies to other methods (B35) which measure opacity development upon addition of alcohol to the total filtrate of gastric juice after sulfosalicylic acid precipitation. Here, the acid precipitation partly removes some of the products of mucus digestion, and the method is standardized on submaxillary mucin with physicochemical features different from those of gastric mucin. 

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