A pulsed carbon dioxide laser-induced breakdown analysis for chemical profile of tsunami-affected soil

Abstract

BACKGROUND AND OBJECTIVES: The catastrophic 2004 Indian Ocean tsunami left a profound mark, triggering significant contamination of organic and inorganic chemical components in the water and soil of affected regions. The effects of the tragedy, which occurred almost twenty years ago, are still evident in the soil as salt and metal pollutants continue to linger. It is crucial to conduct a chemical analysis of the soil samples obtained from the regions affected by the Indian Ocean tsunami in 2004. This not only aids in identifying areas hit by the catastrophe but also facilitates periodic monitoring of chemical contamination levels. This study aims to promptly detect and measure chemical indicators in soil samples collected from areas in Aceh Province that were impacted by the 2004 Indian Ocean tsunami. METHODS: Three regions in Aceh Province, specifically Banda Aceh, Aceh Besar, and Aceh Barat, were selected for the collection of soil samples following severe impact from a tsunami. Soil samples were obtained from regions unaffected by the tsunami, including Tungkob, Blang Bintang, and Pango Deah. Plasma was produced by concentrating a pulsed carbon dioxide laser beam on the surface samples. An optical multichannel analyzer captures plasma emissions with a spectrograph and photodiode array. Data is stored for processing with SpectraView software and compared with the National Institute of Standards and Technology database for identification. FINDINGS: The utilization of a pulsed carbon dioxide laser for analysis revealed its superior ability to identify a wider array of elements with high intensity-to-background ratios, particularly excelling in the detection of zinc, chromium, copper, cobalt, and nickel compared to the neodymium-doped yttrium aluminum garnet laser. Chemical quantification through calibration-free laserinduced breakdown spectroscopy closely correlated with x-ray fluorescence but surpassed x-ray fluorescence in rapid detection and identification of lighter elements. The concentrations of salt components and particular heavy metals in soil that was impacted by a tsunami exhibited a more than tenfold increase in comparison to soil that was not affected and was collected in 2006. Sodium surged from 0.02 percent to 4.18 - 4.95 percent, while calcium increased from 0.46 percent to 11.26 - 13.53 percent. Potassium concentration rose from 0.11 percent to 5.50 - 6.96 percent, alongside magnesium, which increased from 0.36 percent to 7.62 - 8.67 percent. CONCLUSION: The utilization of a pulsed carbon dioxide laser-induced breakdown spectroscopy has demonstrated remarkable proficiency in the identification of a diverse range of elements. This technique has surpassed conventional methods like neodymium-doped yttrium aluminum garnet laser-induced breakdown spectroscopy, energy dispersive spectroscopy, and x-ray fluorescence in terms of its detection capabilities. This study underscores the potential of a pulsed carbon dioxide laser as a versatile and reliable method for qualitative and quantitative analysis of soils from 2004 Indian Ocean tsunami-affected regions in Aceh Province, emphasizing its significance for environmental monitoring in disaster-affected areas.