Determination of Toxic Heavy Metals in Wet Deposition and Ambient Air in Columbus, GA
Atmospheric pollution is one of the most significant and potentially catastrophic environmental issues threatening the United States and the world today. One such source of this pollution is heavy metals. The impact of heavy metal pollution on living organisms can be disastrous, having the potential to cause the deterioration of ecosystems and posing danger to the health and survival of the human race. Chronic and acute human exposure to this type of pollution can damage the proper functioning of vital body organs by inhibiting important neurological pathways. In plants, it essentially acts as a counter-agent to proper growth. In areas across the United States and the World, anthropogenic sources have been a large contributing factor to the exacerbation of heavy metal concentrations in the atmosphere. Certain particulate matter and even some common aerosols harbor toxic heavy metals like arsenic, lead, chromium and cadmium and are thus categorized as 'hazardous air pollutants' by the U.S. EPA. The heavy metal pollutants that exist suspended in the air are subject to wet and dry atmospheric deposition. From the air they may be released by precipitation events or direct dry deposition unto various environmental compartments near or far from their sources. These have caused increased concern since they are known to persist in the environment. In this study, wet deposition and ambient air samples were collected over a 15 month period at a single site on Columbus State University's main campus in Columbus, Georgia, United States. The concentrations of lead, cadmium, chromium and arsenic in ambient air and wet deposition samples were determined using Atomic Absorption Spectroscopy. A comparison between concentrations of heavy metals in ambient air and concentrations in wet deposition are presented. The monthly and seasonal variations of lead, cadmium, chromium and arsenic are examined. A comparison between concentrations for individual heavy metals, in dry and wet deposition was also conducted. The concentrations of Cd, Cr, Pb and As in wet deposition samples ranged from ND to 0.656 |ug/l, ND to 20 (iig/1, ND to 0.8 (j.g/1 and 0.103 jLxg/1 to 10.5 |ig/l, respectively. Concentrations of Cd, Cr, As and Pb in ambient air samples ranged from 0.679 ng/m 3 to 17.36 ng/m 3 , ND to 1 16 ng/m 3 , ND to 32.80 ng/m 3 and 1.78 ng/m 3 to 33.30 ng/m 3 , respectively. Cd and Pb showed high monthly and seasonal variability in ambient air samples. In addition, a strong correlation was observed between Cd and Pb in ambient air indicating that they may have originated from the same source. Overall, results imply that traffic emissions and construction are the most likely sources for heavy metals in this study.
Atmospheric Pollution, Columbus Georgia, Toxic Heavy Metals, Aerosols, Heavy Metal Pollutants, Earth Sciences, Environmental Monitoring, Environmental Sciences
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