Copper sulfate pentahydrate is a blue compound that forms striking blue crystals and dissolves readily in water. It's often used in agriculture, especially as a pesticide, soil additive and feed additive. It's also used in the manufacture of other copper compounds and in electroplating baths. You're most likely to encounter copper sulfate around the home in its capacity as a fungicide. If you do use copper sulfate, the following steps will help you dispose of it properly.
Do not dump copper sulfate into local streams, ponds or waterways. Copper sulfate can be toxic to fish and other aquatic organisms. Never allow copper sulfate to be washed away in runoff; and do not permit copper sulfate to drain away into the soil.
Sweep up solid crystals or dust from copper sulfate; these can be safely disposed of in the trash.
Flush small quantities of dissolved copper sulfate down the drain, and use plenty of water. If you have large quantities of copper sulfate, rules for how to handle may vary depending on your location; consult your county environmental department for guidelines on how to handle the situation.