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.
Swimmers are also at risk.
Copper is a popular algaecide in commercial and residential pools. The metal can leach into your skin with enough exposure. Too much salt can slow hair growth. If you aren't intimate friends with your salt shaker, the answer could be too much stress. Stress naturally increases sodium retention.