UrbanWild said: It's made from sewage. The problem is. A LOT of compound make it through even the most aggressive of sewage treatments. And industrial wastes are not the only concern. Think about all the toxic products one can but from the store. Most of those get washed down drains and are processed by sewage plants. To add to this mess, think of sewers as mad collectors. Compounds can also be made as water streams hit each other and react. Be careful about "studies" facilitated by product proponents. What are they showing? Of the teens of thousands of compound, what did they actually test for? Testing is expensive and time consuming. Testing is usually done on a limited number of compounds that may be performed fairly inexpensively.
I guess by now you might have figured out that I'm not a fan of any of the processed sewage materials. That's the side affect of minoring in chemistry and having previously worked in an industrial waste department.