2002 Research Fair Archive - Chemistry Abstracts
Soil-Lead Contamination in Salt Lake Valley Play Areas
The United States Geological Survey has estimated that lead, a bluish-gray metal, occurs naturally in soil at a national geometric mean concentration of 16 ppm. Soil-lead concentrations may be elevated due to anthropogenic sources, primarily lead-based paint, leaded gasoline emissions, and point source emitters. In many regions, the elevated soil-lead levels are due to a combination of sources. Lead contamination of soil is cumulative; additional sources simply increase the extent of the contamination.
In light of the established threat of lead poisoning to children's health, this study explores whether lead soil contamination is present in child play areas in the Salt Lake Valley. Despite the renovation of many play areas, in which metal equipment was replaced with plastic counterparts, lead contamination may persist in the soil due to previous leaded gas emissions and/or dust from lead paint used on the removed equipment or surrounding buildings.
In this study, soil samples were analyzed from play areas located throughout the Valley. Specifically, high traffic areas of the play zone were targeted for sampling, such as the base of slippery slides or the home base of baseball diamonds, where children are particularly at risk for inhaling disturbed surface soil. Standards adopted by the Environmental Protection Agency were used to determine that soil from the play areas under study is contaminated with relatively low levels of lead, and thus do not pose a significant threat to children for health effects associated with lead poisoning.
Selenium and the Great Salt Lake
Selenium is a trace element essential for life, but it is also toxic at relatively low concentrations. If present in water, selenium is known to bioaccumulate in aquatic flora and fauna resulting in the decimation of fish and bird populations. The seleniferous soils of the Western deserts combined with anthropogenic activities, e.g., copper mining, in the vicinity of the Great Salt Lake make it a likely repository for selenium. The presence of bird sanctuaries makes it necessary to monitor the concentration of selenium in this unique environment so that potential disasters may be avoided. In this study, we have analyzed selenium levels in water and brine shrimp collected from the Great Salt Lake, Utah, using fluorescence spectroscopy. In addition, we have investigated the role of high concentrations of NaCl on the extraction and proper quantification of Se using this analytical technique.