High iodine in 24 hour urine test.

Does anyone know about high Iodine results in a 24 hour urine test? The range was 35-500 and mine came back over 70,000. The doctor's nurse doesn't know what this means because they usually see low numbers. I called my endorinologist, but she blew me off saying she doesn't know anything about it, but thinks it's not endocrine related. I'm wondering if it might be related to the thyroid or well water? Thyroid tests came back "normal" 6 months ago. Thanks for any insight.