Research Article Spectrophotometric Method for the Determination of Atmospheric Cr Pollution as a Factor to Accelerated Corrosion Dereje Homa, Ermias Haile, and Alemayehu P. Washe Department of Chemistry, Hawassa University, P.O. Box 05, Hawassa, Ethiopia Correspondence should be addressed to Alemayehu P. Washe; alemayehup@yahoo.com Received 24 December 2016; Accepted 16 March 2017; Published 2 April 2017 Academic Editor: Jaroon Jakmunee Copyright © 2017 Dereje Homa et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te efect of Cr(VI) pollution on the corrosion rate of corrugated iron roof samples collected from tanning industry areas was investigated through simulated laboratory exposure and spectrophotometric detection of Cr(III) deposit as a product of the reaction. Te total level of Cr detected in the samples ranged from 113.892 ± 0.17 ppm to 53.05 ± 0.243 ppm and showed increasing trend as sampling sites get closer to the tannery and in the direction of tannery efuent stream. Te laboratory exposure of a newly manufactured material to a simulated condition showed a relatively faster corrosion rate in the presence of Cr(VI) with concomitant deposition of Cr(III) under pH control. A signifcant ( = 0.05) increase in the corrosion rate was also recorded when exposing scratched or stress cracked samples. A coupled redox process where Cr(VI) is reduced to a stable, immobile, and insoluble Cr(III) accompanying corrosion of the iron is proposed as a possible mechanism leading to the elevated deposition of the latter on the materials. In conclusion, the increased deposits of Cr detected in the corrugated iron roof samples collected from tanning industry zones suggested possible atmospheric Cr pollution as a factor to the accelerated corrosion of the materials. 1. Introduction Accelerated corrosion of corrugated iron roof (galvanized- steel) is a subject of global concern because of its importance to the service life of the material and its aesthetic appearance [1, 2]. Atmospheric corrosion is the result of a redox reaction between the metal component of the material and its atmo- spheric environment that occurs in the presence of a con- ducting thin aqueous adlayer [3]. Te common incorporation of pollutant species into this adlayer usually enhances the degradation process. Although steel structures are employed in atmospheric environments with some means of surface protection, considerable researches have demonstrated the efects of both steel alloy composition and atmospheric environments on its corrosion behavior [1]. For instance, the ability of zinc to galvanically protect iron is relatively efective in neutral environment but very sensitive to any change of atmospheric acidity [2]. Air pollutants such as sulfur dioxide, hydrogen sulphide, oxides of nitrogen, and chlorides and weathering factors such as temperature, moisture, rainfall, solar radiation, and wind velocity have been recognized as conventional atmospheric parameters that may contribute to the corrosion [1–3]. Industrial sites particularly those in most tropical locations are the most corrosive sites due to the polluting chemicals (such as H 2 S and SO 2 -precursors of acid rain), solid particles in the atmosphere including soot, the time of wetness (humidity), and the high temper- ature experienced [1, 2]. Te synergistic interaction of the atmospheric pollution variables and coupled processes can also play considerable role in the corrosion phenomena. For instance, the presence of metallic pollutants such as Cr that can galvanically couple with the iron of the roofng material through the adlayer can accelerate the degradation process [4–7]. Te major sources of Cr in the atmosphere are indus- tries including leather tanning industries, textile (printing, dyeing), chromium plating, steel production, and refractories [8, 9]. Among these, the leather tanning industry is the major source of chromium in the environment due to the disposal of chromium-contaminated sludge [9–11]. Studies have already indicated the above regulation limit contamination of soil, water, and vegetables in villages adjacent to tanneries by Cr [12–14]. Although Cr(III) is the most expected form in Hindawi Journal of Analytical Methods in Chemistry Volume 2017, Article ID 7154206, 9 pages https://doi.org/10.1155/2017/7154206