ENVIRONMENTAL-IMPACT OF TRACE-ELEMENT EMISSIONS FROM GEOTHERMAL POWER-PLANTS

Concentrations of several trace elements were determined in mosses, hi gher plants and organs of small mammals from a geothermal area in Tusc any (central Italy). Increased deposition of Hg, As, B, and Sb was det ected in biological samples collected within a few hundred meters of g eothermal power plants. Among the species considered, the moss Hypnum cupressiforme was the most efficient accumulator of trace elements. Co ntamination levels in a fodder-plant (Hedysarum coronarium) and vegeta bles grown in the geothermal field did not seem to pose health risks f or consumers. However, a statistically significant increase in Hg, B, and As concentrations was found in the kidney and muscle of small mamm als living close to geothermal installations. Biological effects of B pollution were detected in two sensitive plant species. In view of pla ns to increase the exploitation of geothermal resources in the area, a dequate measures to monitor the environment should be taken. Mosses ar e the most suitable accumulative biomonitors for a surveillance networ k, and studies on small mammal populations should be intensified. Avai lable technologies should be used to diminish atmospheric emissions fr om geothermal power plants.