LE3 .A278 2010

2010

O'Driscoll, Nelson

Acadia University

Bachelor of Science

Honours

Environmental Science

Earth & Environmental Sciences

Mercury is a toxic element that is atmospherically transported around the Earth and deposited in remote ecosystems where it can accumulate and harm organisms. Estimates of global mercury emissions from natural sources vary widely due to a lack of quantitative data on mercury volatilization from natural surfaces. In situ volatilization measurements are time consuming, expensive, and subject to many environmental variables. Improved methods for the quantification of mercury release from soils are required in order to improve modeled emission estimates and to refine global models for the transport of mercury. A preliminary controlled analysis system for the quantification of mercury photo- volatilization potential from soils was developed and tested. The system consisted of a Tekran 2537B gaseous mercury analyzer combined with a quartz reaction cell and Rayonete photoreactor. The cumulative amount of mercury released over a 24- hour period for UV- B radiation ( 196.39 pg) was found to be almost 5 ½ times larger than for UV- A radiation ( 36.36 pg) in a 1.400 g soil sample, suggesting that UV- B radiation is much more efficient for mercury reduction. Preliminary testing involved determining the volatilization potential of mercury from an internal geological standard reference material ( QUA- 1) and Kejimkujik soil. Volatile mercury release rate constants ( k) were calculated for a series of 8 soil samples from the PH horizon with varying total mercury concentrations ( 12- 372 ng g- 1) and organic carbon content ( 1.6- 41.3%). The effects of organic carbon and total mercury content on mercury volatilization from soil were compared under UV- B radiation and mercury content was found to be the predominant variable as tested by correlation and linear regression ( Pearson’s correlation co- efficient of - 0.77; p = 0.012; linear regression R2 = 0.60; p < 0.05).

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https://scholar.acadiau.ca/islandora/object/theses:677