It is clear. There are a lot of toxins that we are exposed to in this day in age. There are numerous thing you can do to reduce free radicals and toxins in your system.
I recommend reading the book 8 Weeks to Optimum Health by Dr. Weil or a book on natural medicine if you are concerned.
You can do a blood test
for foreign substances in your blood at your local clinic.
I wish you well!