Correlation of Atmospheric Dust and Rainfall as Basalt Chemical Weathering Precursors
- PDF / 186,561 Bytes
- 10 Pages / 432 x 648 pts Page_size
- 52 Downloads / 182 Views
Correlation of Atmospheric Dust and Rainfall as Basalt Chemical Weathering Precursors M. Teutli León1, L.A. Térrez Tufiño1, G. Jiménez Suárez1, E. León Hernández2, L.M. Tenorio Téllez2 1 Facultad de Ingeniería, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico. e-mail: [email protected] 2 Facultad de Arquitectura, Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, Puebla, Puebla, CP 72570, Mexico. ABSTRACT Basalt chemical weathering can be related to chemical composition of both atmospheric dust and rainfall, in published works authors have shown that weathered basalt exhibits a raise in anions like sulfate, nitrate, phosphate, chloride and carbonate, and doing a follow up of rainfall chemistry during 2009 at downtown Puebla, it was shown that rainfall has not an acid pH because there is a strong contribution from atmospheric dust. In this paper it is reported obtained results for dust samples collected during the dry season, collection was done in 3 places exposed to different environment, analysis of solid samples clearly reflect anthropogenic activities since the highest oil and grease content corresponds to a site with high population, also mineral carbonate amounts 30% in weight. An analytical sample was prepared and the filtrate used to measure pH which ranges from 6.3 to 7.84, and conductivity from 11.91-13.87 mS-cm-1. Main soluble ions range are as follow: sulfate 3.4-5.9 mg g-1, nitrate 0.19-0.54 mg g-1, chloride 0.7-8.91 mg g-1, sulfide 47 mg g-1, carbonate 304-364 mg g-1, this last correspond to 10% of the mineral content. Also, metals were determined as total (applying an acid digestion) and water soluble, obtained results allow to affirm that there are highly soluble metals like Ca, Pb (up to 97%), moderately soluble ones such as Cu and Mn (60% and 20% respectively) and non soluble ones like Al, Fe and Zn. It was confirmed that atmospheric dust has all properties, which could produce an alkalinization of rainwater. Also, its water soluble ionic content can be a source for those ions causing basalt weathering. INTRODUCTION Basalt chemical weathering at historical buildings is consequence of environmental quality at each place where buildings are located. Stone structural modifications can be related to chemical composition of both atmospheric dust and rainfall, in published works authors have shown that weathered basalt exhibits a raise in anions like sulfate, nitrate, phosphate, chloride and carbonate [1], and doing a follow up of rainfall chemistry during 2009 at downtown Puebla, it was shown that rainfall has not an acid pH because there is a strong contribution from atmospheric dust, authors arrived to this conclusion based on rainfall statistical correlations ions present in rainwater can have a common origin if they correlate positively as example in this published work marine components like sodium and chloride correlate with a 0.6 factor, otherwise sodium and carbonate correlate with -0.02 factor; from the same report calcium, magnesium, carbonate and sulfate should have
Data Loading...
