Second article in a two-part series.

Recent EPA samples of surface and well water in Lawrence County showed high levels of PFOA and other perfluorinated chemicals.

The U.S. Environmental Protection Agency released final test results Tuesday and, for the first time, identified the general locations of the contaminated water.

Jim Giattina, director of EPA’s water protection division, said EPA took water samples from farms that had used sludge from the Decatur Utilities wastewater treatment plant as fertilizer. Test results obtained in November 2008 revealed extremely high PFOA levels in soil treated with the sludge.

The highest water concentrations came from two farms just east of Moulton. Citing privacy concerns, EPA officials refused to specify the exact locations of the farms, but a rough map the agency prepared indicated one — identified as Location 8 on EPA data — was near the intersection of Lawrence County 212 and Lawrence County 87, north of Alabama 157.

The other — Location 7 — is near the intersection of Lawrence County 180 and Lawrence County 215, south of Alabama 157.

Nearby residents said a cattle farm at Location 8 had received large amounts of DU sludge from Synagro, a company that DU hired to distribute it to farms. Wednesday, several cattle waded in a farm pond and in a water-filled ditch on the property.

Drinking wells at both farms tested over a PFOA provisional health advisory of 0.4 parts per billion for drinking water, set by EPA in January.

Complicating EPA’s analysis is a lack of regulatory guidance.

Giattina explained that even the 0.4 ppb limit on PFOA is of little help in evaluating test results.

The limit means that EPA would not expect adverse health effects for people who, in the short term, drink water with less than 0.4 ppb PFOA.

Long-term ingestion of drinking water — more likely for many longtime residents of Lawrence County — is not addressed.

No regulatory guidance exists on other methods by which people are exposed to PFOA. At a public meeting Tuesday, residents asked dozens of questions regarding the harmful effects of other methods of PFOA exposure. Is their health at risk if they swim in contaminated ponds? If they eat contaminated fish or vegetables irrigated with contaminated water? If they eat contaminated beef or drink milk from contaminated cattle?

Officials repeatedly answered that they did not know, although they said all of those forms of exposure likely increase PFOA levels within humans. The unanswered question is whether they raise them to levels that could cause harm.

Also not addressed by the EPA advisory limit is the impact of perfluorinated chemicals other than PFOA and PFOS, the two that have received the most scientific attention.

In its samples, EPA analyzed for 10 different perfluorinated chemicals. Almost all showed up in the wells and surface water at Locations 7 and 8. A farm in Limestone County had a drinking well that tested positive for a perfluorinated chemical with four carbon atoms. A farm in Trinity had a pond that tested positive not just for PFOA and PFOS, but also for C6, C4 and PFBS.

C9 and C10 — which many scientists suspect are more toxic than PFOA — were found at unusually high levels at two farms midway between Moulton and Decatur.

Understanding the history behind studies of perfluorinated chemicals helps in understanding the current scientific debate about their toxicity in humans.

Created by accident

In 1938, Roy Plunkett accidentally created PTFE while trying to develop a refrigerant. DuPont soon realized the value of its unique nonstick property and by 1950 was producing 450 tons a year of Teflon. PTFE has the second lowest coefficient of any solid known to man. It is the only known substance to which a gecko cannot stick.

For all its remarkable properties, Teflon has some problems. Bird owners discovered one of the first. At temperatures over 500 degrees, Teflon begins to degrade. It gives off gases, and people who overheated Teflon pans discovered those gases killed their pet birds. In humans, the gases can cause “Teflon flu.”

Another problem — especially relevant to Decatur — involves the chemicals used to make Teflon. One is PFOA. The chemical is not on the Teflon pans, but manufacturers of Teflon use it during manufacturing.

PFOA also is called C8, which refers to the number of carbon atoms in the molecule. It is closely related to PFOS, which was an ingredient in 3M’s Scotchgard until the company reformulated it in 2003.

Most scientists believe PFOS is more toxic than PFOA, but they consider the extensive studies on PFOS to be relevant to PFOA. EPA’s January health advisory warned against drinking water with PFOS above 0.2 ppb, half the concentration of its PFOA advisory.

Numerous studies on PFOS demonstrate its toxicity to animals. Fewer studies exist on PFOA, although they generally show the same symptoms.

In animal studies the chemicals cause cancer, neonatal mortality, developmental delays and endocrine disruption. Exposure also reduces the birth size of animals.

Studies on humans have been less conclusive. One theory is that the little-understood mechanism that harms animals does not exist in humans.

“We don’t know if it’s toxic to humans,” Neal Sass, a biochemist and toxicologist with the Alabama Department of Public Health, said before the public meeting. “There’s nothing conclusive out there.”

The more common assumption among scientists is that the different results in animal and human studies reflect the limitations on tests when humans are the subject. As EPA toxicologist Joyce Donohue said, “We can’t very well start injecting humans with PFOA. We can with mice.”

In a press conference before Tuesday’s public meeting, Sass said he did not believe PFOA is toxic to humans. When asked why local, state and federal agencies are spending so much money to reduce its prevalence in the area, he shrugged.

Donohue and Giattina stressed, after Sass left the room, that state toxicologists have a limited role in EPA’s investigation. Donohue holds the more common view among toxicologists.

There is, she said, no conclusive evidence that the chemicals are toxic in humans. Usually, though, toxicity to animals is a good indication that a chemical also is toxic in humans.

When doctors diagnose cancer or developmental defects, they do not typically ask their patient about exposure to perfluorinated chemicals. Even if they ask, the patient is unlikely to know.

If scientists had a better understanding of the physical process that makes the chemicals so toxic to animals, they might be able to come to a more definitive understanding of its toxicity in humans.

Two characteristics of PFOA and other perfluorinated chemicals convince Donohue and other EPA officials that they must treat their investigation of the high local levels with extreme care.

One, the chemical does not degrade in the environment. Dump a pound of PFOA on a Lawrence County field in 2008, and it will still be there — or somewhere — in 2108. It does not exist naturally, and it does not decay.

Two, it bioaccumulates. In humans, PFOA has a half life of about four years. That means that four years after you drink a glass of PFOA-contaminated water, one-half of the PFOA is still in your body. Contaminated water is therefore a particular concern, because people ingest the PFOA much faster than they excrete it. Levels in the blood and organs therefore grow much higher than the levels of the chemical in the drinking water.

The first issue — persistence — also explains the concern environmentalists have about the chemicals. Low levels of PFOA can be detected not just in all humans, but also in polar bears and seals that live far from Decatur or any other manufacturers that use PFOA. That comes as no surprise to scientists. The fish near industrial discharge points in the Tennessee River have high PFOA levels. Birds eat fish, and birds migrate. PFOA also can migrate to some extent in the air and in water.

Speaking not for attribution because he did not want to create friction with state officials, one EPA official expressed frustration with Sass’ view that PFOA is not toxic to humans.

“We know it’s toxic to animals, and we know it does not go away,” he said. “Our guess is in 10 years or so, we’ll understand it well enough to realize it is toxic in humans. The thought of having another decade of this stuff accumulating in the environment before we figure out the mechanism is, well, terrifying.”