A methodology to study the behacior of mercury chloride in aqueous solution using radioactive tracer

Abstract

ABSTRACT A METHODOLOGY TO STUDY THE BEHA VJOR OF MERCURY CHLORIDE IN AQUEOUS SOLUTION USING RADIOACTIVE TRACER Karaca, Ferhat M.S., Department of Environmental Engineering Supervisor: Prof. Dr. Namık K. Aras Co-Supervisor: Prof. Dr. İlhan Ölmez Auuust 2000 Mercury contamination in remote regions can occur through long-range atmospheric transport. Because of its volatility, mercury is unique among the trace metals in its cycling in the environment, and we now understand its ability to be emitted (or re-emitted) from surfaces once deposited. Wet and dry processes to deposit atmospheric mercury environmental surfaces, however, the air/surface exchange processes in the cycling of llg in aquatic ecosystems are not well known. This process can significantly influence its persistence in both terrestrial and aquatic systems, and llg emissions from surface waters could influence the formation of methylmercury. Sediments in estuarinc and coastal marine areas are one of the most important sinks for environmental contaminants. It is clear from a wide range of studies that a fraction of mercury ends up in bottom sediment.Ill In this study a simple experimental methodology was used to be used to model and measure Hg air/ water and water/sediment surface exchanges. We developed a simple box-chamber to see if we could explain the behavior of dissolved mercury. Radioactive mercury tracer was used, in order to measure direct evaded and deposited mercury amounts. Nuclear spectroscopic techniques were used for measurements. Understanding in natural processes of actual air/water and water/sediment exchange mechanisms are out of the scope of this thesis. Further model studies are recommended for this purpose. The relationships between evasion and temperature, solar effects, microorganisms, etc were investigated during 140 hours period. As a result of this experiment it was observed that the 28% of mercury chloride remained in the water phase, 25% of it emitted via the evasion process and 47% of it deposited in sediment. The results are not conclusive. Keywords: Dissolved Mercury (II), Evasion, Deposition, Sediment, and Radioactive tracer, nuclear spectroscopic techniques.

ABSTRACT A METHODOLOGY TO STUDY THE BEHA VJOR OF MERCURY CHLORIDE IN AQUEOUS SOLUTION USING RADIOACTIVE TRACER Karaca, Ferhat M.S., Department of Environmental Engineering Supervisor: Prof. Dr. Namık K. Aras Co-Supervisor: Prof. Dr. İlhan Ölmez Auuust 2000 Mercury contamination in remote regions can occur through long-range atmospheric transport. Because of its volatility, mercury is unique among the trace metals in its cycling in the environment, and we now understand its ability to be emitted (or re-emitted) from surfaces once deposited. Wet and dry processes to deposit atmospheric mercury environmental surfaces, however, the air/surface exchange processes in the cycling of llg in aquatic ecosystems are not well known. This process can significantly influence its persistence in both terrestrial and aquatic systems, and llg emissions from surface waters could influence the formation of methylmercury. Sediments in estuarinc and coastal marine areas are one of the most important sinks for environmental contaminants. It is clear from a wide range of studies that a fraction of mercury ends up in bottom sediment.Ill In this study a simple experimental methodology was used to be used to model and measure Hg air/ water and water/sediment surface exchanges. We developed a simple box-chamber to see if we could explain the behavior of dissolved mercury. Radioactive mercury tracer was used, in order to measure direct evaded and deposited mercury amounts. Nuclear spectroscopic techniques were used for measurements. Understanding in natural processes of actual air/water and water/sediment exchange mechanisms are out of the scope of this thesis. Further model studies are recommended for this purpose. The relationships between evasion and temperature, solar effects, microorganisms, etc were investigated during 140 hours period. As a result of this experiment it was observed that the 28% of mercury chloride remained in the water phase, 25% of it emitted via the evasion process and 47% of it deposited in sediment. The results are not conclusive. Keywords: Dissolved Mercury (II), Evasion, Deposition, Sediment, and Radioactive tracer, nuclear spectroscopic techniques.