In recent years, there has been much concern and scrutiny regarding the microconstituents found in biosolids and whether or not they present a human health risk. Several research projects have focused on one type of microconstituent – antimicrobial compounds. In particular, many studies have looked at the antimicrobial Triclosan (TCS), a common ingredient in many household and personal care products. TCS is routinely detected in treated biosolids and wastewater effluents. But what exactly does this mean to human health? Is it harmful in the amounts found? Does it get into the food grown on biosolids-amended farm fields? If so, is that a problem? Researchers have looked at these issues and concluded that there is a negligible risk to human health in any of these circumstances.
Let’s clear one thing up first: antimicrobials are not the same as antibiotics. While “all antibiotics are antimicrobials…not all antimicrobials are antibiotics.”[i] Antibiotics are molecular substances produced by a microorganism. Antimicrobials, on the other hand, may be natural or synthetic. They also tend to have a narrow window of effectiveness for specific microorganisms and are thus less likely to cause bacterial resistance with repeated use.
Now, back to the antimicrobial, Triclosan, whose primary use is in antibacterial soaps and washes. Research focused on TCS has been reported on by the Food and Drug Administration (FDA) and Water Environment Research Foundation (WERF) as well as in several industry journals.[ii] All reports conclude that there is a minimal risk to humans from TCS in land-applied biosolids or in its presence in crops grown in fields amended with biosolids. The FDA had first reviewed TCS in 2010 and again in 2013, concentrating only on antibacterial soaps and body washes that are used with water, not hand sanitizers, wipes, or antibacterial soaps used in health care settings. In both studies, they concluded that the presence of TCS in biosolids was not hazardous to humans, but did warrant further study because it was so prevalent in household products.
A fascinating result of the FDA’s research was the finding that the benefits of using antibacterial soap products are unproven and that “…no evidence that OTC (over the counter) antibacterial soap products are any more effective at preventing illness than washing with plain soap and water.”[iii] This raises the question of the need for antibacterial soaps and washes for the general public and whether TCS and other antimicrobials are necessary in consumer products at all. Might it not be more efficacious to launch a public education campaign to discourage the use of antibacterial products while promoting more thorough hand-washing? A novel thought, indeed! In this way, less TCS and other microconstituents would find their way into biosolids while the health and well-being of the human race would not be compromised by avoiding antibacterial products. Sounds like a win-win!
That being said, because of this particular antimicrobial’s ubiquitous nature in products worldwide and its inefficient removal during wastewater treatment, some researchers have recommended that TCS be placed on the priority list of emerging microconstituent contaminants and its use in products regulated.[iv]
In other words…keep an eye on it.
________________________________________________________________________________________________ [i] “Antimicrobials: An Introduction” Antimicrobial Resistance Learning Site for Veterinary Students. Michigan State University, East Lansing, MI. 2011.
[ii] Versylcke, T; Mayfield, D. B; Tabony, J. A; Capdevielle, M; Slezak, B. “Human health risk assessment of triclosan in land-applied biosolids.” Environmental Toxicology and Chemistry. 14 January 2016.
[iii] Versylcke, T; Mayfield, D. B; Tabony, J. A; Capdevielle, M; Slezak, B. “Human health risk assessment of triclosan in land-applied biosolids.” Environmental Toxicology and Chemistry. 14 January 2016.
[iv] Versylcke, T; Mayfield, D. B; Tabony, J. A; Capdevielle, M; Slezak, B. “Human health risk assessment of triclosan in land-applied biosolids.” Environmental Toxicology and Chemistry. 14 January 2016.