Many people look to Merck as an authoritative source. I feel I must provide some clarity. Here is the source, and the text. (my clarifications are in parenthesis like this, and bold):
By Larry E. Johnson , MD, PhD, University of Arkansas for Medical Sciences
Last full review/revision Dec 2021
Copper excess can be caused by a genetic abnormality that stops the body from getting rid of copper (Wilson disease) or, rarely, from consuming too much copper.(They do not say “how much” copper! It’s usually 20,000 mg!)
Most of the copper in the body is located in the liver, (usually, only 10% of body copper stores are in the liver, 7 mg out of 72 mg), bones, and muscle, but traces of copper occur in all tissues of the body. The liver excretes excess copper into the bile for elimination from the body. (copper is also lost in the sweat and urine) Copper is a component of many enzymes, including ones that are necessary for the following:
Formation of red blood cells, bone, or connective tissue (which binds other tissues and organs together)
Antioxidant action (to help protect cells against damage by free radicals, which are reactive by-products of normal cell activity)
(See also Overview of Minerals.)
Copper excess (toxicity) may be acquired or inherited (as Wilson disease).
Consumption of excess copper is rare. People may consume small amounts of excess copper in acidic food or beverages that have been in copper vessels, tubing, or valves a long time.
Consuming even relatively small amounts of copper (such as 3-4 mg) may cause nausea, vomiting, and diarrhea. Large amounts, usually consumed by people intending to commit suicide, (such as 20,000 mg) can damage the kidneys, inhibit urine production, and cause anemia due to the rupture of red blood cells (hemolytic anemia) and even death.
Rarely, liver damage or cirrhosis occurs in children. It probably results from drinking milk that has been boiled or stored in corroded copper or brass vessels.
In rare cases, liver damage has been reported in children IN INDIA, where mothers boiled milk in copper pots, giving the children an exposure of a mild 3 mg of copper. While this is used by the government as an example of copper toxicity, it is not likely enough copper to cause toxicity, and there are many other co variables not taken into account, such as poverty, exposure to other toxins due to this being in India, and the fact that the mothers are boiling the milk, perhaps attempting to kill bacteria in spoiled milk, and dead bacteria could be the source of toxins.
Diagnosis of Copper Excess
Blood or urine tests (blood tests are not reliable, because elevated copper in the blood occurs in copper deficiency as the body is attempting to mobilize copper into deficient tissues. Copper is elevated 100% in pregnancy, with birth control, with copper deficient inflammation, with copper deficient heart disease, and many other copper deficient conditions. This leads some practitioners to wrongly diagnose copper toxicity, during conditions of copper deficiency.)
A liver biopsy
Doctors measure copper and ceruloplasmin levels in blood or urine. However, a liver biopsy to measure the amount of copper and look for damage in the liver is usually required for diagnosis unless large amounts of copper were consumed.
Treatment of Copper Excess
Pumping the stomach
Dimercaprol injected into a muscle
If large amounts of copper were consumed, the stomach is pumped.
(Administration of Vitamin C and Zinc also works. Often practitioners wrongly diagnose “copper toxicity” during situations of “zinc deficiency”.)
If copper toxicity has caused problems such as anemia (to my knowledge, this has only happened one time in the literature in a man who took 2000 mg of copper daily for 4 months) or has damaged the kidneys or liver, dimercaprol is injected into a muscle, or a drug that binds with copper, such as penicillamine (given by mouth), is given to remove excess copper. Children with liver damage are treated with penicillamine (which chelates and removes copper, which is needed to heal the liver.)
If used early, hemodialysis (a procedure that filters the blood) may be effective.
Occasionally, death occurs despite treatment. (But death happens about 15% of the time in people who are trying to kill themselves with up to 20,000 mg of copper sulfate.)