Antibacterial Soap Additive Accumulates in Fish: Study

THURSDAY March 31, 2011 -- An antibacterial agent that's an ingredient in some bar soaps has a "strong" tendency to accumulate in the bodies of fish, finds a new study.

The agent, triclocarban (TCC), is a source of environmental health concerns due to its potential hormone-disrupting effects.

Bioaccumulation occurs when fish or other organisms ingest certain chemicals and are unable to metabolize and excrete the chemical quickly enough, allowing it to build up in their bodies.

There is no evidence that TCC bioaccumulates in humans, the researchers pointed out. Instead, people are able to quickly break down TCC and excrete it in urine and feces.

But the situation appears to be different for fish, the study authors suggest. The findings were presented March 30 at the American Chemical Society meeting in Anaheim, Calif.

"Due to its widespread usage, TCC is present in small amounts in 60 percent of all rivers and streams in the United States," study leader Ida Flores of the University of California, Davis, said in an American Chemical Society news release. "Fish are commonly exposed to TCC, even though much of it is eliminated by wastewater treatment plants."

In the study, Flores and colleagues exposed fish larvae to the amount of TCC commonly found in U.S. waterways.

"The fish quickly accumulated TCC," Flores said. "The levels of the TCC in the fish soon after exposure were about 1,000 times higher than the concentration in the water. To the best of our knowledge, this is the first report of uptake and metabolism of TCC in fish species. We found evidence of strong accumulation and also got details on exactly how TCC is metabolized in these animals."

Prior research suggests that TCC and another similar antibacterial agent, triclosan, don't prevent the spread of disease any better than ordinary soap, yet both may cause disruption of reproductive hormones, according to the news release.

The research will help improve understanding about the environmental and health effects of TCC, Flores added.

Because this study was presented at a meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.

More information

The U.S. Geological Survey has more about water quality.

Posted: March 2011


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