ABSTRACT
Mercury contamination in the environment is problematic due to the unusual physical properties and well-recognized toxicity of this common metal. The bioavailability of mercury depends strongly on its chemical speciation. Anthropogenic mercury and its compounds appear in soil as "hot spots" located close to industrial facilities that used or produced mercury. The nature of the chemical production process, transportation and disposal practices often determined the chemical composition and distribution of mercury in the surrounding soils. Current ex situ soil remediation methods are expensive, produce undesirable side effects to the environment and usually involve transportation of contaminated soil. In this project, sponsored by the U.S. Department of Energy, a low-cost, simple approach to removing mercury from soil was evaluated. The process uses low-temperature thermal desorption of volatile metallic mercury and its compounds, and subsequent vapor capture. The project consisted of laboratory and plot-scale experiments. The laboratory efforts evaluated theoretical calculations of mercury removal as a function of time and temperature. The plot-scale experiment was a practical application of the laboratory results. For both experiments, mercury-polluted soil was obtained from a chemical production facility located in southern Poland. In laboratory experiments, at temperature 373 K total mercury concentration decreased in soil by nearly 32%. In plot-scale experiments, at temperature 440 K, about 60-70% of total mercury was removed from the soil. At the end of the experiment, a test of soil biological activity was performed to check if the high temperature applied to the soil did not impair the soil growth properties. There was no negative effect of temperature found.
Subject(s)
Mercury/isolation & purification , Sanitation/methods , Soil Pollutants/isolation & purification , Temperature , PolandABSTRACT
The incidence of keratinolytic fungi in an acidic petroleum waste lagoon (before bioremediation) at a petroleum refinery situated within a highly populated area was examined. High concentrations of petroleum hydrocarbons (aliphatics and PAHs) made the growth of keratinolytic fungi in clay and litter collected from the lagoon impossible. The natural self-purification process considerably decreased the hydrocarbon contamination, increased the pH and caused the abundant growth of Trichophyton ajelloi in organic soil that contained the root-adjacent material from the grass growing in green oases at the lagoon. Ecological and epidemiological aspects of the data were discussed.
