The Regional Influence of an Oil-Fired Power Plant on the Concentration of Elements in Native Materials in and Near South Florida National Parks

Gough, Larry; Jackson, Larry; Bennett, J; Severson, R; Engleman, E; Briggs, Paul; Wilcox, J

In July 1983 the U.S. Geological Survey and the U.S. National Park Service signed an interagency agreement which facilitates joint investigations of suspected biogeochemical problems originating from airborne contaminants in and near selected national park units. Study designs and specific objectives differ from one park region to another and include: (1) the use of lichens (or other epiphytes) or vascular plant species as biomonitors of possible phytotoxic conditions; (2) the use of native materials to determine the region of measurable influence of a suspected point source of sulfur and/or metal contamination; and (3) the establishment of baseline biogeochemical and geochemical levels so that the magnitude of chemical changes with time can be monitored. This report presents results of FY-84 and FY-85 studies in and near Everglades and Biscayne National Parks, Florida. The following list is a summary of the major conclusions from the study: 1. This study was designed to measure the relative importance of the effect of emissions into the air from the Turkey Point electrical power generation facility on the sulfur and trace-metal levels of nearby vegetation. The region of measurable influence of the power plant could not be precisely defined by utilizing total sulfur, stable suflur isotope ratios, and trace-metal information from samples of plant and soil materials. This area has an extremely complex set of ecosystems and even though the operation of the power plant has had some effect on the chemistry of materials sampled close in (within about 1 km) a major regional influence could not be demonstrated. 2. Plant and soil materials were collected using a study design of three parallel east-west traverses all of which originated on the coast; one also originated at the power plant on the coast. Element regression trends along the power plant traverse were usually dissimilar to trends along the other two traverses. This dissimilarity is interpreted to be the result of a complex set of influences that include (1) dry and wet deposition of substances of marine origin, (2) dry and wet deposition of substances originating from the operation of the power plant (general construction and maintenance activities as well as stack emissions); (3) dry and wet deposition of substances from other complex anthropogenic sources; and (4) uptake and translocation by plants of substances from supporting soils. 3. It is unclear whether or not the activities of the power plant elevate the concentration of certain metals in vegetation samples above some reference level. Levels of aluminum, cobalt, chromium, copper, lead, nickel, vanadium, and zinc in Australian pine and Brazilian pepper leaf samples do not markedly decrease with increasing distance from the power plant (traverse 1). This is due in part because the concentrations in samples from the closest site (0.97 km) are generally low in trace metals. These low values may be due to a "shadow" effect; measurable deposition not found close to the facility. There is a general increase in metal concentrations between 4 and 8 km along traverse