Evaluating Relationships between Mercury Concentrations in Air and in Spanish Moss (\u3cem\u3eTillandsia Usneoides\u3c/em\u3e L.)

Mercury is a potent neurotoxin that is transported globally in vapor form. A major source of mercury contamination to soil, water, and biota is atmospheric deposition. Therefore, comprehensive monitoring of atmospheric concentrations is important. Limitations of conventional atmospheric measurement techniques include high cost and lack of temporal or spatial integration. Bioindicators, however, may serve as an integrative tool to add to conventional mercury measurement techniques. Spanish moss (Tillandsia usneoides L.) is a potential bioindicator of atmospheric mercury concentration in the southeastern United States because it is an abundant epiphyte that absorbs and accumulates atmospheric pollutants. A study was conducted in southeastern Georgia and northern Florida to test the hypotheses that 1) Spanish moss absorbs and retains atmospheric mercury in tissue, and 2) atmospheric mercury concentrations differ geographically due to nonpoint emission sources, and the concentration of mercury in Spanish moss tissue reflects these differences. To determine if Spanish moss exhibits uptake and retention of mercury, an experiment was conducted in which I transplanted Spanish moss saturated with mercury vapor in the laboratory to a field site unimpacted by mercury emissions and measured tissue mercury concentration over time. In addition, to determine if mercury concentrations in Spanish moss are reflective of atmospheric concentrations, I conducted two field studies in which the mercury concentrations of both resident and transplanted Spanish moss were compared to atmospheric concentrations at sites with different anthropogenic land use. In all studies, tissue was analyzed for mercury concentration using Inductively-Coupled Plasma Mass Spectrometry. Results suggest Spanish moss absorbs and retains atmospheric mercury, and mercury concentrations in Spanish moss tissue are associated with atmospheric concentrations over both small and large geographic scales. Thus, Spanish moss may serve as a useful measurement tool to add to existing monitoring protocols