Because of its concern for the environmental impact of roadside herbicide spraying, the Maine Department of Transportation initiated a preliminary study of small-scale monitoring methods of herbicide residues in soil and water. Samples were collected at certain time intervals after the application of herbicides to target plants. The herbicides were extracted in the department's Materials and Research Division chemistry lab, and the amount of the extracted herbicides was determined by high-performance liquid chromatograph (HPLC) in the Department of Food Science and Technology at the University of Maine, Orono. The phytotoxicity of Banvel 720 on brush was evident. One week after application, the plants started to show the effect of the herbicide, and by one month, all the foliage showed no signs of life. Herbicide residue was not detected in the water samples taken from the nearby streams. The results of soil analysis on the herbicide content were predictably erratic. The reasons for this could be attributed to many factors. For example, varying amounts of off-target spraying occurred; the sampling process was not totally systematic; and there was a long period of delay in analyzing all the samples stored in a freezer throughout the period. Viewing the individual test site separately, it is obvious that the level of herbicide suddenly diminished between l day and l week after application. In spite of the oversights and drawbacks of this project, it is encouraging that the methods of extraction and HPLC determination of the herbicide are adequate for future use. It is feasible to develop a low-budget monitoring program from local resources, the cost of which could be included in ongoing roadside spray operations.

Roadside vegetation management has long been an integral part of highway maintenance operations. Unwanted brush growth diminishes the driver's viewing range and increases pavement shading, which lowers surface temperatures thus causing ice to form in winter. Therefore public safety is a direct concern, in addition to the obvious aesthetic criteria for highway roadsides.