ABSTRACT
The maintenance of rights-of-way of large utility transmission systems, some of which are in excess of 20,000 km in length, presents a formidable problem. One of the most economical approaches for herbicide application is the use of rotary-wing aircraft or helicopters. Some operators feel that helicopters are more satisfactory than fixed-wing aircraft because a lower flying speed is possible and greater maneuverability of the helicopter contributes to more accurate placement of the spray pattern. From the high rates of herbicides that were applied during the years of testing spray equipment, it was obvious that the Test Area offered a unique opportunity to study herbicide persistence and soil leaching. A total of 73 species of vertebrate animals were observed on Test Area C-52A and in the surrounding area. Detection of the highly potent impurity tetrachlorodibenzo-p-dioxin in the herbicide 2,4,5-T necessitated an environmental assessment of the impact of this contaminate.
