The use of lichen fumigation studies to evaluate the effects of new emission sources on class i areas

Abstract

Allowable increments of SO2from new emission sources near Class I areas are severely limited by the PSD provisions of the Clean Air Act, unless the applicant can prove that the expected emissions will not adversely affect the air quality related values of the Class I area. Lichens are considered to be the resource that is most sensitive to SO2- If projected concentrations will not injure lichens, other resources should not be affected. Four lichen species native to two Class I areas, Cape Romain National Wildlife Refuge and Everglades National Park, were fumigated in the laboratory with SO2doses that simulated the frequencies, durations, and concentrations expected from potential new sources. Lichens from Cape Romain were fumigated with 240 μg/m3400/μg/m3and ambient air 3 hours/week for 6 weeks. No differences in biomass gain, percent electrolyte leakage in solution (an indicator of membrane damage) or14CO2assimilation were observed among treatments. Lichens from Everglades National Park were fumigated with 100 μg/m3200 pg/m3400 ng/m3and am-. bient air 6 hours/week for 10 weeks. Percent electrolyte leakage of Parmotrema tinctorum was greater at the two higher concentrations, but there was no significant effect on biomass gain or14C02assimilation. Percent electrolyte leakage increased and biomass gain and14CO2assimilation decreased in Ramalina denticulata at 400 μg/m3S02in comparison with lower concentrations. Studies of fumigation effects on lichens are a useful technique for the evaluation of impacts of emission sources on air quality related values in Class I areas. © 1988 Taylor & Francis Group, LLC.