The Minnesota Department of Health (MDH) announced that it is taking further steps to protect the health of residents in South Washington County from long-term exposure to perfluorochemicals (PFCs) in groundwater.

Based on the latest scientific information, MDH has lowered its Health Based Values (HBVs) for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), two members of PFC group of chemicals that have been found at low levels in groundwater in southern Washington County. The new HBVs are 0.5 parts per billion (ppb) for PFOA and 0.3 ppb for PFOS. The guidelines previously used were 1 ppb and 0.6 ppb respectively.

"We have been reviewing the available data over the last few months and concluded that there is sufficient scientific basis at this time to justify revising the health based values for PFOA and PFOS," said Minnesota Health Commissioner Dianne Mandernach.

While research to date has shown no direct evidence that PFCs cause health problems in humans, studies in laboratory animals indicate that at higher doses, PFCs may interfere with liver and thyroid function and may cause developmental effects.

"The new values are protective, scientifically sound and well-researched," said John Linc Stine, director of the Environmental Health Division for MDH. The new value for PFOA, 0.5 ppb, is the same as a number implemented by the Environmental Protection Agency (EPA) in an enforcement action in West Virginia that became effective Nov. 17, 2006.

A Health Based Value is the concentration of a groundwater contaminant, or a mixture of contaminants, that poses little or no risk to health, even if consumed daily over a lifetime. The updated HBVs for PFOA and PFOS take into consideration the potential for health impacts during fetal and other developmental life stages. A clearer understanding of how long these chemicals stay in the human body is also reflecteded in the revised HBVs.

MDH is working with Oakdale and Lake Elmo to address public and private wells that may be affected by the lowering of the HBVs for PFOA and PFOS. Most residents in the Lake Elmo and Oakdale area will not be affected by the change because they are connected to municipal water systems that don’t contain PFCs or treat the groundwater before distribution.

The lowering of the Health Based Values for PFOA and PFOS does not affect those portions of southern Washington County and northern Dakota County where only perfluorobutanoic acid (PFBA), another PFC compound, has been found in groundwater.

Those areas fall under the department ,, s drinking water advice on PFBA, which the department reiterated.

"We recommend that anyone who has concerns about the potential health impacts from PFBA in their water should limit or reduce their intake of water that has a concentration of more than 1 ppb," Stine said.

Intake of contaminated drinking water can be reduced by drinking bottled water or by filtering tap water used for drinking or cooking through a point-of-use (POU) activated carbon filter, which removes or greatly reduces PFBA. Water used for bathing, showering or other non-ingestive household uses does not pose a health risk, based on current data.

"We’ve had an initial round of community meetings where more than 800 people heard our advice and heard us talk about things they can do to limit their exposure if they choose," Stine said. "But we know that there are far more than 800 people in the communities and areas affected by the contamination, so we want to take every opportunity we can to re-emphasize our advice. We also want to share as broadly as possible what we know about point-of-use filters, small, inexpensive filters that can be used to filter tap water."

Point-of-use (POU) filters can be an effective way to reduce exposure, MDH staff found. They recently tested a number of POU filters commonly available in stores. The testing found that a simple pitcher filter that contains activated carbon was partially effective at removing PFBA from the water, but allows more PFBA to pass through as additional water is filtered. A faucet-mounted filter containing activated carbon worked better, showing full removal of PFBA through about half of its manufacturer’s predicted filter lifetime, and good removal at up to 70-80 percent of its lifetime. Faucet-mounted filtering devices commonly range in price from $15 to $25 and replacement filters cost approximately $15 to $20. Additional information on POU filters with activated carbon is available from the MDH Web site or by calling 651-201-4897.

Stine said MDH staff have determined that sufficient toxicity data does not exist to calculate a chemical-specific HBV for PFBA. However, the advice is based on a comparison of the existing PFBA data to what is known about other PFCs.

"The data that are available for PFBA indicate that this chemical is less toxic than PFOA, a similar chemical," Stine said. "We believe that 1 ppb is a protective number for PFBA, based on the most recent science, and is protective even of those who may have higher relative water consumption rates, such as pregnant women, nursing mothers and small children."

Mandernach added, "As more data become available, we will examine it, with the intent of developing a Health Based Value for PFBA. We will continue to work with the EPA, private sector and academia, to accelerate that research and continue to consult with experts on this group of chemicals."