you might think copper is better for the environment, but you would be wrong in a number of instances.
copper pollution is a huge issue. mostly due to "organic" farms spraying copper sulfate, but also due to copper leaching from mines and shit like that, though the EPA has closed alot of the bad copper mines.
a strip of copper sitting on the surface of some soil probably wont leach anything appreciable into the soil, especially since copper is strongly sequestered by organic soils etc.
but if you have sandy soils without clay or without much organic material, spraying copper, or spreading copper salt hydrates onto the soil can cause runoff issues.