You can take a sample to the pool store and have them test for metals, but I don't know how accurate they are. Several threads on here recommended various sequesterants, can't recall of the top of my no longer green head...LOL
Try a search for "Sequesterant" and read some of the threads, I'm sure you'll come across a recommended brand.
copper turns hair green, period! IF you need to remove the green color start a thread and I will answer. I am a liscensed cosmetologist and used to be a colorist and have a lot of experience removing the green with citric acid and sodium thiosulfate (which happen to be the active ingredients in the Nexus Aloe Rid treatment and shampool!)
Yes, I should add that Waterbear is the person who gave me the solution to the green hair thread that I posted 15 months ago, and saved my kids and my dog from looking like we were going to a St. Patricks day parade....