Testicular atrophy increased in birds as they were fed larger amounts of copper sulfate. These data suggest that copper sulfate is unlikely to be teratogenic in humans at expected exposure levels. Copper sulfate may cause mutagenic effects at high doses. However, the relevance of these results to mammals, including humans, is not known. Absorption of copper sulfate into the blood occurs primarily under the acidic conditions of the stomach.
Copper sulfate is practically nontoxic to birds.
It poses less of a threat to birds than to other animals. Its toxicity to fish generally decreases as water hardness increases. Copper is bound, or adsorbed, to organic materials, and to clay and mineral surfaces. Because copper sulfate is highly water soluble, it is considered one of the more mobile metals in soils. When applied with irrigation water, copper sulfate does not accumulate in the surrounding soils.