Farmers have used copper sulfate for dairy cow hoof baths for many years. Many risks go along with the long-term use of copper sulfate on animals, such as copper toxicity due to skin absorption. As an alternative, zinc sulfate can be used and works just as well. It is slightly more expensive than copper sulfate and there is still some degree of toxicity risk, but not nearly as high as using copper sulfate.
Pond and private lake owners often use copper sulfate as a means of controlling excessive overgrowth of algae. However, the concentrated percentage of copper sulfate needed to exterminate algae poses great danger to fish and other pond life. Algaecide is undoubtedly more costly than copper sulfate, but is more effective in controlling algae and less harmful to plants, fish and the pond's natural life balance.
Because copper sulfate has been readily available and relatively cheap for many years, it's been widely used for destroying plant life such as unwanted weeds and tree roots. Unfortunately, copper sulfate is so potent and toxic that it often destroys all life around it, poisoning the soil, plants and any animals that come into contact with it. As a safer alternative, dichlobenil is a strong herbicide that still carries dangers, but not to the same extent of as copper sulfate.