Mercury and Other Trace Elements in Sediment Cores from Central Texas Lakes

Abstract

Metals released during fossil fuel use are important atmospheric pollutants. Mercury and other trace metals can be transferred to an aquatic environment through atmospheric deposition. In the work reported here, a number of sediment cores were retrieved from central Texas lakes in the proximity of a coal-fired power plant in search of local anthropogenic effects. Cores were collected along a transient parallel to the prevailing wind direction (S-SE) in the area. Trace element concentrations in the lignite and in effluents from the power plant showed that some elements remained constant (Al, Cu) throughout the different lignite combustion and power production processes. Some (like Cd and Se) showed an affinity for the smaller particles, whereas others (Hg) showed very low concentrations in all the solid wastes, indicating that they probably escaped with the flue gases. Sediment cores from a lake next to the power plant showed higher trace metal concentration in the upper part of the cores (more recent sediment). For example, there was as much as a tenfold increase in Hg concentration between the core bottom (10 ng/g), where the sediment was approximately 100 years old and the surface (100 ng/g). Cd and Se at surface sediments were also found to be as high as 1.6 and 3.45 microg/g, respectively. The excess metal inventory was higher for the lakes located next to the power plant than for two lakes about 30 km away.

Local Impacts of Mercury Emissions From the Monticello Coal Fired Power Plant.

“…Therefore, at this time, the most reliable way to understand the impacts of coal-fired power plants on Hg deposition is based on empirical data. In terms of excesses over background, local soil concentration Hg increments are around 30%-60%; sediment increments are 18-30% (Anderson et al 1977, Menounou et. al.…”

Mercury concentrations in wetlands associated with coal-fired power plants

“…Mercury from lakes throughout the US ranged from 30 to 330 ng/g (Menounou and Presley 2003;Huggett et al 2001;Cooper and Gillespie 2001;Sorensen et al 1990;He et al 2007) and varied greatly across regions. No previously published studies of mercury content in wetlands or ponds in Illinois were found.…”

Studies on Sediment Physico-Chemical Properties of the Ulhas River Flowing along Dombivli City near Mumbai

“…The suspended and precipitated substances eventually settle down at the bottom and serve as a reservoir for trace substances of low solubility, low degree of degradability and many pollutants [14][15][16]. Information related to natural and anthropogenic influence on the water bodies, which is environmentally significant, can be obtained from the chemical analysis for characterization of sediments [17][18][19][20][21][22]. Thus, to evaluate the quality of total ecosystem of a water body, in addition to the water sample analysis, the analysis of sediment is of equal importance [23-31].…”