Hydrogen sulfide, trace element and sulfur hexafluoride tracer treatment from the Geysers-Calistoga Geothermal Resource Area based on aircraft and surface sampling

This four-day study has provided initial data regarding the short-range transport of pollutants from The Geysers geothermal operations. The initial analysis of the data has shown that a measureable plume of gaseous sulfur (H{sub 2}S) is emitted from the Geysers and transported by surface and upper-level winds to distances beyond 20 km. Only one day had concentrations above 30 ppB and on this day H{sub 2}S was detected as a distinct odor at 1500 m (m.s.1.) at 4 km or more from the Geysers. The initial data analysis of the H{sub 2}S and SF{sub 6} plume data have revealed the important role that vertical wind shear plays in changing plume trajectories with height and enhancing diffusion of pollutants. Surface and aircraft sampling of aerosols indicate that small quantities of trace elements such as As, Cd, Hg, Pb, Cr and Br may be transported from the area.