Update: Triclosan & Other Trace Chemicals in Biosolids
Biosolids contain traces of chemicals used in our daily lives. But research continues to indicate negiligible human health risks from such traces in biosolids. Triclosan is an example of a chemical that should probably be phased out, in part because it taints public perception of biosolids.
USGS researchers found trace chemicals from biosolids in deeper soil, suggesting that some may migrate more than assumed. The research, conducted 5 years ago, gained media attention when it was published this May (EHN, Sci. American). The publicity generated provided little context about the potential risks to human health (likely miniscule); exposure through product uses and daily living are much greater than ever possible through any biosolids exposure route. For example, triclosan was noted as being at a relatively high concentration in soil: 156 parts per billion. Context: 1 part per billion = 1 second in 31.7 years. Triclosan is 0.1% - 0.45% of many hand soaps; people are handling it daily at 1 to 45 parts per thousand. Context: 1 part per thousand = 1 second in 16.7 minutes. NEBRA members may obtain a copy of the paper by contacting the NEBRA office.
But because it potentially raises environmental concerns and seems to have little efficacy, triclosan (TCS) - the active antimicrobial ingredient in soaps and other products - is under attack. Minnesota just became the first U. S. state to ban it. Last winter, U. S. FDA asked manufacturers to demonstrate its efficacy and safety. And, as reported in Science News May 17th, because of direct use of TCS-containing soaps, it shows up in urine, serum, and breast milk - as well as in snot. A paper in mBio notes that "having triclosan-containing snot could double a person's likelihood of carrying staph" (Staphylococcus aureus).
The concern with TCS is not new: all the way back in July 2006, the Chicago water reclamation utility urged EPA to review triclosan (and its cousin TCC), given its limited value in consumer soaps and its potential impact on biosolids programs, "undermining public confidence." (EPA's response.) For more, see this literature review regarding TCS efficacy and potential negative impacts. Biosolids are not a significant human exposure route for TCS and many other trace chemicals - but public perceptions of biosolids are still tainted by them.