Rain samples

Samples of rainfall in Iowa have been analyzed for levels of pesticides (Nations and Hallberg 1992). Samples collected in April, May, and June of the three years in the study period of 1987-1990 had the highest levels of methyl parathion, corresponding to the application to crops. Methyl parathion was found in 4 of the 318 rain samples analyzed at a maximum concentration of 2.77 pg/L. In a study of... 

Rain samples collected from around the Great Lakes contained both a- and P-endosulfan (Strachan and Huneault 1979). Mean concentrations of a-endosulfan in rain samples from the Great Lakes ranged from 0.1 ng/L (n=13) to 3.8 ng/L (n=16). Mean concentrations of P-endosulfan in rain samples ranged from 1 (n=14) to 12 ng/L (n=16). The endosulfans were not found to any significant extent in snow-core samples (Strachan and Huneault 1979). Detection limits were not reported. 

Mirex has been detected in wet precipitation over rural areas at concentrations of less than 1 ng/L (ppt) (EPA 1981b). Rainfall samples collected at several sites in 1985-1986 as part of the Great Lakes Organics Rain Sampling Network contained from >0.2 to <0.5 ng/L (ppt) of mirex. Mirex was not detected consistently at many stations throughout the sampling period therefore, quantitative results for mirex were not presented (Strachan 1990). Air samples taken over southern Ontario in 1988 showed mirex in 5 of 143 samples, at an annual mean concentration of 0.35 pg/sol m (range, 0.1-22 pg/m ) with all of the positive samples detected in polluted environments (Hoff et al. 1992). 

Di-ft-octylphthalate was detected in five of seven ambient air and six of seven rainwater samples collected during rain events that occurred in February through April 1984 in Portland, Oregon. Di-/ -octylphthalate concentrations ranged from 2.6 to 20 ng/L in rain samples and from 0.06 to 0.94 ng/m3 in air samples (Ligocki et al 1985). 

Several investigators reported the presence of nickel concentrations in rain. The annual mean nickel concentration in precipitation at Lewes, Delaware, was 0.79 pg/L (Barrie et al. 1987). The mean concentration ( standard deviation) of nickel collected from rain showers in southern Ontario, Canada, in 1982 was 0.56 0.07 pg/L (Chan et al. 1986). The mean concentrations in northern and central Ontario were both 0.61 pg/L, indicating a lack of spatial variability. Sudbury, the site of a large nickel smelter, is located in central Ontario. Nickel concentrations from rain samples collected at four sites in Sweden had a mean range of 0.017-0.51 pg/L (Hansson et al 1988). 

Sempere, R., and K. Kawaniura, Low Molecular Weight Dicarboxylic Acids and Related Polar Compounds in the Remote Marine Rain Samples Collected from Western Pacific, Atmos. Environ., 30, 1609-1619 (1996). 

Besides gas and particulate phases, samples of precipitation collected in the 1980s in a number of cities in China were analyzed for organochlorine pesticides. For example, Zhao et al (1985) and Yang and Zhang (1987) detected HCH and DDT in rain samples collected in Shijiazhuang and... 

Kawamura and Kaplan [482] have described a sensitive method for measuring volatile acids (Ci-C7) in rain and fog samples using /j-bromophcnacyl esters and a high resolution capillary gas chromatograph employing fused silica columns. Experiments showed that the measured concentrations of volatile acids in spiked rain samples increased linearly in proportion to the concentrations of volatile acids added. Relative standard deviations were less than or equal to 18% for Q, C2 and C3 acids. The distributions of volatile acids in Los Angeles rain and fog samples are discussed. 

The unused portions of the rain samples were transported to Dearborn, still refrigerated. Some 7 months later they were reanalyzed to selected samples H2O2 was added before analysis (final [H2O2] - 1.5%) to make certain that all S(IV) had been oxidized to sulfate. At this time NH +, Na and K were determined by ion chromatography. 

The relations between the rate of oxidation of S(IV) and the metallic ions were also investigated using actual rain samples. The effect of pH on the oxidation of S(IV) to S(VI) was also examined. 

Storms sampled by this network were pre-selected based on synoptic meteorological information in an attempt to sample cyclonic frontal rain that was fairly uniform over the 80 km. extent of our network. The sampling protocol required that a period of good atmospheric ventilation preceed rain sampling. Dry deposition was not evaluated but is expected to be small compared to wet deposition due to low ambient pollutant concentrations during rainy weather. 

Measurement of the experimental uncertainties in our rain sampling procedures and the application of these uncertainties in a screening procedure to eliminate questionable samples from the data set increases the confidence in the interpretation of spatial variations in rainwater composition and of the principal component analysis. Results presented here for a storm collected during smelter operation suggest that it was the major source of the downwind excess SO. elevation above background and the pH depress ion oelow the background value of 5. 

The study of pollutant deposition in an urban environment is often reported from bulk rain samples (1) without due consideration being given to the individual contributions of wet and dry deposition. 

The collected rain samples were analysed by INAA at the McMaster Nuclear Reactor. Ten elements (AL, Br, Ca, Cl, Cu, I, Mg, Mn. Na and V) were determined. 

Total organic chlorine in the rainwater was 0.3 p.p.b., with atrazine and the 2,4-D ester amounting to about 0.1 p.p.b. each. Since the soil one mile away contained 6 p.p.m. of atrazine, it can be calculated that no more than 16-17 mg. of soil per liter of rainfall would be sufficient to yield the 0.1 p.p.b. of atrazine actually found in the rain, and 16 to 17 mg. of suspended solids in a rain sample is not unusual. 

They conclude that, "in view of the world-wide use of organo-chlorine insecticides and the extensive distribution of their residues in soil, together with the foregoing evidence, it is possible that they might now contaminate the atmosphere continuously. This conclusion is entirely consistent with their data and with the evidence of organo-chlorine compounds in the rainfall samples reported by Weibel (11) and Cohen (4). Similar results were obtained from rain samples collected in the metropolitan area of London by Abbott et al. (1). These authors were also able to demonstrate the presence of pesticides in the atmosphere (2). 

Neutralizing 5.00 L of an acid rain sample required 11.3 mL of 0.0102 M KOH. Calculate the hydronium ion concentration in the rain sample. 

A separation of the ions in acid rain is shown in Fig. 8.7 using conductivity detection. The peaks of the anions (sulfate, chloride and nitrate), which are highly ionized, are positive. The cation peaks are of lower conductivity than the tartaric acid eluent and hence are in the negative direction. The detection limits are low enough to handle most acid rain samples without any preconcentration (Table 8.4). 

Synthetic acid rain samples have been allowed to percolate through pieces of coquina, the material of construction at Castillo de San Marcos National Monument, St. Augustine, Florida. Chemical analyses of the solutions are used to determine the extent of dissolution of the coqiuna, a limestone material, by acid rain. Because of the location of the Castillo on the Atlantic coast, the effect of salt spray on weathering of coquina appears to be as significant as the influence of acid rainfall. 

TABLE 1 Composition of Synthetic Acid Rain Samples... 

A fraction of the rain samples was preserved immediately with chloroform (CHCI3) and refrigerated at 4 °C for later chemical composition analysis. The pH was measured with a pH meter OP-401/2, Radelkis, using a glass electrode, standardised with pH = 6 buffer solution. The hydrogen ion concentration was calculated from the measured pH. Presently the samples have not yet been completely analysed from the chemical composition point of view. 

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