(AP) -- Jewelry branded by Miley Cyrus and sold exclusively at Walmarts nationwide contain high levels of the toxic metal cadmium, an Associated Press investigation shows.

The world's largest retailer learned in February that the items are tainted, but has continued selling them.

The AP also found that a separate line of jewelry charms being sold at Wal-Mart also had high levels.

Long-term exposure to cadmium can lead to bone softening and .

Representatives for both Wal-Mart and Miley Cyrus have not responded to repeated requests for comment.

Last month, Wal-Mart revealed its suppliers now have to prove that children's and other kids' products have little cadmium. But that policy didn't apply to items already on store shelves.