Potentially harmful chemicals spreading in groundwater from the former Wurtsmith Air Force Base in Oscoda exists in a far larger area around the shuttered facility than regulators initially believed — so much so that investigators don't yet know where the contamination stops.
At issue are perfluorinated chemicals, or PFCs, a legacy of firefighting foam used extensively at the base in training and fire suppression beginning in the 1970s. The chemicals are so pervasive in the groundwater that, in an area of the base where firefighting training took place for years, "if you pull the water out of the ground in that training area, it still foams, there’s so much in there," said Michigan Department of Environmental Quality specialist Robert Delaney.
Most of the area on the former base property and surrounding it is now on uncontaminated municipal water piped from nearby Lake Huron. But the number of homes or cottages in the area on well water, urged to switch to the municipal system or find alternate drinking water, rose in September from 60 households to more than 300, and is still growing.
"Everything we learn about this emerging contaminant is showing us we should be concerned, especially with pregnant women and elderly individuals," said Denise Bryan, health officer at the local district health department.
The state earlier this year appropriated $1 million to funding the water switches and short-term alternate water for affected homes. But switching all those with contaminated wells could take months.
Established as an air base in 1923, Wurtsmith closed in 1993, but had identified contamination from a variety of different toxic chemicals as far back as the 1970s. The site has seen cleanups spanning decades and costing tens of millions of dollars. But no pollutant discovered there has ever acted like PFCs, Delaney said.
Regulators thought lakes and rivers in the area, and the geologic formations below them, served as a natural barrier preventing groundwater chemical plumes from emanating too far off the base: 1,400-acre Van Etten Lake between Wurtsmith and Lake Huron; north-to-south-running Van Etten Creek to the base's southeast; and the Au Sable River running west to east to the base's south.
"Every other contaminant we have found on the base, the plumes ended at the surface water, or before," Delaney said. "We never looked on the other side of any of these lakes or rivers. Our whole concept was, everything just stops at the lake."
But in precautionary testing of residential wells on the other side of Van Etten Lake from the base this summer and fall, DEQ officials found elevated levels of PFCs in more than 40 residential wells, along with the telltale signatures of firefighting foam. Hits also were discovered in wells on the east side of Van Etten Creek, toward Lake Huron, Delaney said.
That prompted state officials, in September, to expand their map of homes urged to find alternative water sources; and eligible for state help, such as a reverse-osmosis filtration system or storage coolers for shipped-in water, until a switch to municipal water can occur. But Delaney said the recently changed map already needs to expand again, as testing of residential wells on its northeastern border and farther south of the base continues to show PFC contamination.
"These chemicals are not acting like the other chemicals; they’re much more extensive," he said. "They don’t break down. We don’t have a good feeling on where this stuff might be right now and how far it’s gone."
How big of a health concern the PFCs cause is not well understood. According to the federal Agency for Toxic Substances and Disease Registry, laboratory animals exposed to high doses of certain commonly occurring PFCs have shown changes in the liver, thyroid and pancreatic function, as well as some changes in hormone levels. Some, but not all, studies in humans have shown that certain PFCs may:
- Affect the developing fetus and child, including possible changes in growth, learning and behavior.
- Decrease fertility and interfere with the body’s natural hormones.
- Increase cholesterol.
- Affect the immune system.
- Increase cancer risk.
"We do have evidence that it bio-accumulates (in the body) and just doesn't go away," Bryan said.
The U.S. Environmental Protection Agency this year reduced its Health Advisory Levels for two of the most frequently occurring types of PFCs, to 70 parts per trillion in drinking water. But there are 3,000 to 4,000 related chemicals that exist, Delaney said. The DEQ is able to look for just 19 PFCs in its groundwater testing near Wurtsmith.
"Just those 19 we're looking at, we're finding 11 of them most of the time," he said. "But there are a whole host of other PFCs in this firefighting foam that we are not testing for."
The federal government regulates only 82 chemicals for drinking water, Delaney noted. And little is known about the health effects of combined exposures to multiple types of PFCs, or from long-term exposures at levels below the EPA standard.
"The science hasn't caught up on a lot of these other chemicals," Delaney said. "There's a difficulty between what the science tells us and where we are in regulating the chemicals."
An advisory has existed since 2012 against eating fish caught from Clark's Marsh and the lower Au Sable River, south of the former Wurtsmith Air Force Base, due to the PFC contamination. And a study on swallows nesting near the former base showed elevated levels of PFCs in the birds' plasma, eggs and crop contents, "suggesting the likelihood that other wildlife in the area would have PFCs in their bodies," Michigan Department of Health and Human Services toxicologist Christina Bush stated in a September 2015 letter to Delaney.
One home near Van Etten Lake was discovered with PFCs above the EPA Health Advisory Levels in its well last summer. The Air Force paid for switching the home to the Oscoda municipal water system, which gets its water from Lake Huron and does not test for elevated PFCs.
"The Air Force will not pay for any remediation, any residents going to municipal water, until their testing levels show higher than the Health Advisory Level," Bryan said.
"It is somewhat of a frustration to the residents, to find out there are detected PFCs, there are advisories about long-term human exposure," but that the Air Force won't pay for a fix.
Air Force officials attended an Oct. 25 meeting in Oscoda that featured nearly 200 residents, as well as DEQ and state and local health department officials.
"Our focus now is to understand how plumes are behaving so we can continue to protect human health," said David Strainge, base environmental coordinator for the Air Force Civil Engineer Center.
Oscoda Township Supervisor James Baier said residents are concerned, especially those not on the municipal water system.
"If they don't know much about the material, how can they be sure some number like 70 (parts per trillion) or 30 is accurate or sufficient?" he said.
The township will soon begin work switching homes with affected wells to the water system, utilizing a $500,000 U.S. Department of Agriculture grant obtained earlier this year, Baier said.
"I don't know if we can complete it before winter shuts us down," he said.
The Michigan Department of Health and Human Services is not waiting for well-users in the contamination zone to get their test results back, but is providing them with under-sink reverse osmosis filtration systems or a water cooler, Bush said.
"We're not sure how long people may have been exposed," she said. "And we're hoping to have an understanding what exposure levels may have been in the past, both on-base and off."
Technologies to effectively remove the most prevalent forms of PFCs are still developing, and Strainge said Wurtsmith "will be at the cutting edge." The Air Force has funded two remediation technology evaluations at Wurtsmith.
It's possible to clean up the PFCs contamination, but it will require millions of gallons of water to dilute the concentrated sources down to thresholds measured in the parts per trillion, Delaney said.
"It's going to be expensive to do, and it's not going to be fast," he said.