Reuters Health, August 15, 2006


[Rachel's introduction: Septic systems do not effectively remove hormone-disrupting chemicals, which can leach into groundwater.]

By Megan Rauscher

NEW YORK (Reuters Health) -- Septic systems may not remove natural hormone-disrupting chemicals -- like estrogen excreted in women's urine -- from wastewater before it gets into groundwater, which feeds many drinking water supplies, according to tests conducted in Cape Cod, Massachusetts.

In Cape Cod, more than 85 percent of residential and commercial properties use septic systems.

In a telephone interview, Dr. Chris Swartz said: "We did find both natural estrogen and alkyl phenols from detergents entering groundwater at concentrations very similar to concentrations that have been documented in the literature to show adverse reproductive effects in fish swimming in rivers downstream of wastewater treatment discharges."

Other chemicals detected in groundwater near the tested septic system include caffeine and detergent brightening compounds.

Swartz, senior scientist at the Silent Spring Institute in Newton, Massachusetts, said there is still "hot debate" in the Environmental Protection Agency and among scientists in general as to whether the concentrations of these and other chemicals that are being found in the environment have human health implications.

"The biggest concern is for prenatal exposures, because fetuses are exquisitely sensitive to any type of hormonal imbalances during their development," he explained.

Swartz hopes publication of his team's findings in the August 15 issue of Environmental Science and Technology will fuel dialogue among land use planners and policy makers about what septic systems are and are not removing.

"It's important to understand this if we are going to rely on septic systems," said Swartz.

Currently about 25 percent of US households and probably a larger amount globally, Swartz noted, use on-site septic systems for household waste treatment as opposed to public sewage treatment plants.

"And there is a US and global trend toward decentralized wastewater treatment," Swartz said.

Prior research on septic systems have dealt only with nutrients such as nitrogen and phosphorus that may leach from septic tanks, get into groundwater, and eventually make it to surface body waters that the groundwater feeds.

The current tests, Swartz said, clearly show that other chemicals, like natural estrogens, known to interfere with human hormonal regulation, are also getting away from septic system treatment. Future studies, he concludes, are needed to determine the extent and potential effects of drinking water contamination with hormone- disrupting chemicals and other potentially harmful chemicals.

SOURCE: Environmental and Science Technology August 15, 2006.

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