Effect of 60-Hz High Intensity Electric Fields on Living Plants

To secure information on the biological and ecological effects of 60-Hz electric fields on living plants, studiesliave tiincarried out over the past two years to determine their existence and magnitude. This work has been funded by the Electric Power Research Institute as a portion of their comprehensive program to determine the environmental impact of electric fields produced by EHV and UHV transmission lines. Studies on 74 species of green plants indicated that 60-Hz electric fields of sufficient intensity can result in injury to limited portions of the aerial parts of some species. Fleshy, rounded or blunt plant parts were not damaged at 50 kV/m. However, plant parts with a pointed shape evidenced very limited damage at 25 kV/m with the amount of tissue damaged increasing, but still remaining limited, as the field intensity was increased to 50 kV/m. The apparent threshold for damage. in such plants was 20 to 22 kV/m. A coronal discharge was observed at the same field strengths and for the anieplant geometries that resulted in tissue injury and death. Calculated 60-Hz electric fields within the right-of-way of power transmission lines nominally rated at 345, 500, 735, and 1,500 kV do not exceed approximately 8, 12, 12, and 16 kV/m, respectively, at a height up to 2 m above the soil surface.1 This is below the threshold for damage observed in these studies.