Chemical characterization of rainwater at Akkalkuwa, India

The chemical composition of rainwater changes from place to place and region to region under the influence of several major factors, viz., topography, its distance from sea and overall rainfall pattern. The present study investigated the chemical composition of precipitation at Akkalkuwa, district Nandurbar, in the State Maharashtra during southwest monsoon. The rainwater samples were collected on event basis during June-September 2008 and were analyzed for pH, major anions (F, Cl, NO3, SO4) and cations (Ca, Mg, Na, K, NH4). The pH varied from 6.0 and 6.8 with an average of 6.29 ± 0.23 indicating alkaline nature and dominance of Ca in precipitation. The relative magnitude of major ions in precipitation follows the pattern as Ca>Cl>Na>SO4>NO3>HCO3>NH4>Mg>K>F>H. The Neutralization factor (NF) was found to be NFCa = 0.95, NFNH4 = 0.31, NFMg = 0.27 and NFK = 0.08 indicating below cloud process in which crustal components are responsible for neutralization of anions. Significant correlation of NH4 with SO4 and NO3 was observed with correlation coefficient of r = 0.79 and 0.75, respectively.

Source Apportionment of Atmospheric Deposition Species in an Agricultural Brazilian Region Using Positive Matrix Factorization

We investigated the influence of natural and anthropogenic sources on bulk atmospheric deposition chemistry, from November 2017 until October 2019, in a Brazilian agricultural area. The pH mean value was 5.99 (5.52–8.46) and most deposition samples (~98%) were alkaline (pH > 5.60). We identified Ca2+ as the predominant species, accounting for 33% of the total ionic species distribution and the main precursor of atmospheric acidity neutralization (Neutralization Factor = 6.63). PMF analysis resulted in four factors, which demonstrated the influence of anthropogenic and natural sources, such as fertilizer application and production, marine intrusion/biomass burning, and biogenic emissions, and revealed the importance of atmospheric neutralization processes.

Ion Scattering Spectrometry

The scattering of ions from the surface and near surface region is a common method of analyzing solid surfaces. The basic principles of ion scattering spectrometry are reviewed with emphasis on those factors which affect the interpretation of the scattering measurements. In particular we emphasize the role of the interatomic potential and the neutralization factor involved in ion-surface scattering. Several aspects of ion scattering spectrometry are then outlined, including its application to studies of the composition and crystallographic structure of surfaces. Some factors of ion scattering spectrometry peculiar to surfaces are mentioned, e.g. the sequential 'double' collision event. The use of photon emission studies as a means of inferring something of the neutralization processes involved is briefly outlined, emphasizing the study of polarized emission from scattered ions at glancing incidence to the target surface.