Copper Sulfate: Uses, Benefits, and Warnings

Copper sulfate is an inorganic compound that combines copper and sulfate. In its liquid or powdered form, it’s most commonly called basic copper sulfate, BSC copper fungicide, CP basic sulfate, or tri-basic copper sulfate. In its solid, crystal-shaped stone form (known as a pentahydrate), copper sulfate is known as blue stone or blue vitriol for its blue color. In this form, it’s a popular raw material for producing other types of copper salts.

Copper sulfate uses include stopping the growth of fungus and bacteria. Overexposure can lead to possible toxicity in humans, though.

This article discusses the benefits of copper sulfate and the side effects that can come from copper sulfate exposure. It also covers what to look for when choosing a copper sulfate product along with how to handle copper sulfate safely.

Benefits of Copper Sulfate

The largest health benefit of copper sulfate is that it is used to control bacteria and fungus growth on fruits, vegetables, and other crops, as it’s been registered for pesticide use in the United States since 1956. This includes mildew, which can cause leaf spots and plant spoilage, as copper sulfate binds to the proteins in fungus, damaging the cells and causing them to die.

In tropical climates, it’s used as a molluscicide, which is a snail bait that controls pests like snails and slugs from damaging plants and crops.

Copper sulfate is also used in order to help with public health and safety. It destroys algae and bacteria in swimming pools. In addition, it's used to prevent athlete’s foot, a fungal infection that grows in between the toes, in warm environments such as an indoor swimming pool. This is done by mixing it into the flooring mixtures of showers, locker rooms, and swimming pools to prevent the bacteria from being able to live on the flooring indefinitely.

Health Risks

While copper is a trace element that occurs naturally in plants and animals, copper sulfate is not. It can act as an irritant when someone is exposed to it.

Crops and agriculture are cleaned after being treated with copper sulfate. There’s minimal risk of ingesting it from a treated crop as it primarily binds itself to soil sediments.

It is possible to be exposed to copper sulfate if you use it for farming or gardening purposes. If absorbed through the skin or eyes, copper sulfate may cause a burning, stinging sensation. This could result in itching, eczema, conjunctivitis, inflammation, fluid buildup, or cornea irritation if exposed to the eyes.

Should copper sulfate be ingested, it’s only mildly toxic as it’s most often vomited up relatively quickly due to the extreme irritation it causes to the gastrointestinal tract. If someone consumes copper sulfate and does not vomit, they could be at risk of copper sulfate poisoning.

Signs of copper sulfate poisoning include:

• Burning sensations in the chest or abdomen
• A metallic taste in the mouth
• Nausea
• Headaches
• Diarrhea (which may have a blue or green color to it from the compound’s hue)
• Excessive sweating

Regardless of whether vomiting has occurred or not, anyone who consumes copper sulfate should go to the ER to rule poisoning out as well as make sure there’s been no damage to the brain, liver, kidneys, or intestinal lining of the stomach. Though extremely rare, if left untreated, high-dose exposure to copper sulfate in some situations can cause death.

Long-Term Side Effects

The EPA hasn’t issued a cancer rating for copper sulfate because there isn’t enough evidence that links copper sulfate to cancer development in humans who can regulate copper in their bodies. This is a normal function as copper enters the bloodstream and is mainly collected in the liver before being excreted through feces. More research is needed to determine if long-term exposure to copper sulfate can cause cancer in humans and animals.

If you have constant exposure to copper sulfate from agricultural use, you may have an increased risk of liver disease. However, that's most likely if you have a preexisting condition called Wilson’s disease, a condition associated with excessive copper accumulation in the body.

Side Effects in Children

While more research is needed, it’s possible that children may be more sensitive to copper sulfate exposure than adults. Children are most likely to be exposed if they crawl on the ground near copper sulfate or put into their mouths objects that have been exposed to copper sulfate. Keep this in mind when using copper sulfate, and make sure children are nowhere near the area just to be safe.

Animal Exposure

The EPA considers copper sulfate to only be moderately toxic for birds, but it is extremely toxic to fish, as using copper sulfate in lakes and ponds reduces their oxygen and causes excess debris.

How to Use Copper Sulfate

In some areas, copper sulfate may be used to line drain or sewage pipes to prevent roots from growing in them and causing clogs. The United States Environmental Protection Agency (EPA) has set a copper sulfate limit of 1 ppm in any drinking water, which is not a toxic amount to any individual.

When using copper sulfate for large areas of land or water, it’s important to follow the directions for the type of copper sulfate you are using. Different forms, like liquid and powder, will have different measurements depending on the area it’s being used for.

When handling copper sulfate, boots, gloves, and goggles should be worn at all times to minimize the risk of exposure or ingestion.

What to Look For

Copper sulfate pentahydrate crystals, powder, or liquid are the most convenient ways to handle copper sulfate when cleaning gardens, pools, or drains. Copper sulfate dissolves well in liquid, which is what makes it such an effective cleaner for pools and reservoirs.

Summary

An inorganic compound that combines sulfur with copper, copper sulfate can kill fungi, bacteria, and algae. It is an approved pesticide and protects plants as they grow.

Overexposure to copper sulfate can cause mild side effects, and long-term exposure to high amounts can lead to serious problems.