CHARLESTON, W.Va. — Less than a week before leaving office, the Bush administration appears ready to issue an emergency health advisory for drinking water polluted with the toxic chemical C8.

The surprise move comes as federal scientists quietly investigate concerns that C8 contaminated the food chain through beef, after tainted sewage sludges were dumped on agricultural land in Alabama.

U.S Environmental Protection Agency officials are expected to announce the advisory as early as today, though an agency spokesman said Tuesday night he wasn’t aware of the action.

C8 is another name for ammonium perfluorooctanoate, or PFOA. DuPont Co. has used the chemical since the 1950s at its Washington Works plant south of Parkersburg. C8 is a processing agent used to make Teflon and other nonstick products, oil-resistant paper packaging and stain-resistant textiles.

Around the world, researchers are finding that people have C8 and other perfluorochemicals, or PFCs, in their blood at low levels. Evidence is mounting about the chemical’s dangerous effects, but regulators have yet to set a binding federal limit for emissions or human exposure.

Now, EPA plans to recommend reducing consumption of water that contains more than 0.4 parts per billion of C8, according to a draft of the agency advisory obtained by The Charleston Gazette.

The advisory level is tighter than a guideline currently in effect for residents near the DuPont Parkersburg plant.

But the Parkersburg-area standard and the new EPA advisory are both 10 times weaker than a similar C8 water guideline set by New Jersey Environmental Commissioner Lisa Jackson. This morning, Jackson is appearing at a Senate confirmation hearing for her nomination as President-elect Barack Obama’s EPA administrator.

One possible difference is that New Jersey set its standard to protect residents from the long-term effects of drinking small amounts of C8 in their household water. EPA set the Parkersburg limit as an emergency standard to protect the public from “an imminent and substantial endangerment” from short-term exposure to C8.

It’s not clear whether the new EPA advisory is intended to protect against short- or long-term exposure. Several EPA staffers have urged top agency officials to give the public “specification of the time frame for which the Provisional Health Advisory was derived,” according to a summary of peer-review agency comments.

DuPont, which also owns a huge plant in Deepwater, N.J., has been lobbying hard for that state to modify its current C8 rules.

The chemical company agreed to the Parkersburg limit — 0.5 parts per billion — as part of a deal with EPA. DuPont was required to provide treatment equipment or alternative water where the limit was exceeded.

It was not immediately clear what — if any — water supplies around the country might be affected by the EPA action.

The EPA document describes the “provisional health advisory … Developed to provide information in response to an urgent or rapidly developing situation.”

Such advisories “reflect reasonable, health-based hazard concentrations above which action should be taken to reduce exposure to unregulated contaminants in drinking water.”

The document says the “number will be updated as additional information becomes available and can be evaluated.”

But the EPA action puts the agency on record supporting a C8 standard that, while acceptable to DuPont, is far weaker than environmentalists and lawyers for some residents with C8-polluted water believe is needed.

Experts hired by residents’ lawyers have proposed C8 limits as low as 0.02 parts per billion. And in a class-action settlement in 2004, DuPont agreed to provide residents around Parkersburg — but not in the city — with water treatment or alternative supplies if their water contained more than 0.05 parts per billion of C8.

EPA has never finalized a broad study of C8’s health effects, issued in draft form in January 2005. Agency officials have said that no binding limits on the chemical would be put in place until that study was completed.

EPA did launch a DuPont-backed program for industry to voluntarily reduce C8 emissions and cut the amount of C8-like chemicals that ended up on consumer products. And in December 2005, DuPont agreed to a $16.5 million settlement with EPA to resolve the agency’s lawsuit over allegations that DuPont covered up information about the health risks of C8.

Last year, EPA scientists disavowed a study that they had published which found — apparently for the first time — C8 in chicken eggs in the United States.

The new health advisory was apparently driven in large part by an EPA investigation of high levels of C8 found in agricultural soils in Decatur, Ala.

That investigation, first reported publicly by the Environmental Science and Technology, is focused on sewage sludge that was applied to about 5,000 acres of agricultural land.

“Chief among the likely sources [for the contamination] are process wastewater from nearby manufacturing plants and chemicals on consumer products that could break down” to C8 and similar chemicals, according to that journal article. “These compounds can enter the sewage system from private homes after washing off goods such as stain-repellant fabrics and coated paper products.”

EPA and the U.S. Department of Agriculture, along with the Food and Drug Administration, were especially concerned after learning that the grasslands where the sludge was applied were used for grazing beef cattle for 12 years, according to the article.

If the chemicals are found to have contaminated meat, the results could mark the first time that PFCs would have been traced from sludge to commercially produced food.

The EPA health advisory does not mention food contamination. It does say that the agency has tested community water systems in two Alabama counties, and found chemical concentrations far below the advisory level.

“Based on its current understanding, EPA believes these levels are not of concern and residents may rely upon public water systems,” the EPA document says. EPA will soon begin testing to see if the chemicals have migrated into any private water systems, groundwater or ponds, the advisory said.