Drinking water is one source. In many cases, copper water pipes are the culprit. They are common in older homes. If you see a bluish green discoloration on your porcelain plumbing fixtures, I'll bet the ranch you have copper pipes. Copper also enters the food chain through foods you buy at the grocery store.
Feed lots add copper to the animals' diet.
The mineral remains in the flesh that you eat. Farmers also use copper to spray vegetables and grains to prevent fungus and algae growth. Women are more likely to have too much copper because they probably use some form of birth control. Birth control pills and the IUD both use copper. Then you may have been born with too much copper to start with.