Credit: Jenni Spinner

Triclocarban has been found to persist in municipal sludge after treatment. Because the sludge is used to fertilize crops, it could pose a public health threat.

According to a recent study, an ingredient in antibacterial hand soap remains in municipal sludge after waste-water treatment and accumulates in crop fertilizer.

Researchers at the Johns Hopkins Bloomberg School of Public Health found that as much as 75% of the soap ingredient triclocarban washed down the drain by consumers persists after treatment. The material builds up in municipal sludge, which is later used as a fertilizer in crops. Researchers now are working to determine if triclocarban—which is toxic when ingested—can migrate from sludge into foods, creating a human health risk.

“Triclocarban is leading a peculiar double life,” said senior study author Rolf U. Halden, PhD, assistant professor and cofounder of the Johns Hopkins Center for Water and Health. “Following its intended use as a topical antiseptic, we are effectively and inadvertently using it as an agricultural pesticide that is neither regulated nor monitored. The study just shows how important it is to consider the full life cycle of the chemicals we manufacture for use in our daily life.”

Halden also pointed out that triclocarban has been determined by the Food and Drug Administration determined as having no scientifically proven benefit. For more information, visit