At least two of the contaminants Owensboro Municipal Utilities discovered last year in the groundwater around its coal-fired Elmer Smith Station have also been detected at potentially unsafe levels in local drinking water supplies.

 

In 2014, molybdenum, a naturally occurring trace mineral that is also found in coal ash, was detected in OMU's drinking water at a level almost four times higher than the U.S. Environmental Protection Agency's lifetime health advisory. Hexavalent chromium, a toxic chemical compound partially derived from the burning of coal, was also discovered at a level more than 766% higher than the California Office of Environmental Health Hazard Assessment's public health goal and nearly double the state and national average.

 

These contaminants are unregulated, however, and local drinking water is in compliance with all relevant state and federal regulations. The EPA doesn't consider unregulated contaminants when determining whether water is legally safe to drink, but according to a statement the EPA drafted Wednesday, the agency may recommend additional actions.

 

"When exceedances of health advisory levels of unregulated contaminants are identified in drinking water, EPA recommends that states consider additional actions, such as taking additional sampling, notifying the public and, if necessary, conducting mitigation," the statement read. "EPA will continue to support state and local actions as they work to address drinking water concerns in their communities."

 

Officials at OMU say it is not yet possible to determine the source of the contaminants.

 

In small amounts, molybdenum is part of a healthy diet, but in excess, it has been linked with a change in blood chemistry that spikes the body's production of uric acid and causes gout-like symptoms, according to the U.S. National Library of Medicine.

 

Federal code regulations list hexavalent chromium, or chromium-6, as cancer-causing. High exposure reportedly increases a person's risk of developing oral or intestinal cancers.

 

Last month, the Messenger-Inquirer reported that both molybdenum and chromium-6, among other contaminants, had been detected by a groundwater monitoring system in 2018 around ponds where OMU temporarily stores the power plant's spent coal ash. The amount of molybdenum, in fact, exceeded the EPA's groundwater protection standards, triggering the installation of an additional monitoring well and requiring that OMU assess potential corrective measures.

 

Those ash ponds are very near 11 of Owensboro's more than 60 municipal drinking water production wells, and drawing on comparisons between the utility's own data may lead to one of the nation's clearest examples of coal ash drinking water contamination, said Washington D.C.-based Earthjustice Senior Counsel Lisa Evans.

 

"It seems to me that there's a red flag here — that the contamination that was documented by the Environmental Working Group in 2014 is the same contamination that we're seeing in the coal ash ponds that are very close to the (drinking) water intakes," she said. "I understand that OMU (may not) believe that's the source, but good protective practices require that OMU test the water for the contaminants that are in that groundwater. It's common sense and good practice to make sure that drinking water doesn't contain unsafe levels of contamination."

 

OMU was only required to test for molybdenum and chromium-6 in 2014 during the third iteration of the EPA's Unregulated Contaminant Monitoring Rule, which applies a new list of scientifically derived contaminants every five years to annual tests water utilities are already required to do.

 

According to Sonya Dixon, a spokeswoman with the utility, OMU issued a UCMR report in 2014 because public notification is only required when contaminants reach detectable levels. During the 2004 and 2009 iterations of the rule, there were none.

 

Although the EPA sets minimum safe drinking water contaminant level advisories for molybdenum in its 2018 Drinking Water Standards and Health Advisories report, the transition metal is, for now, an unregulated contaminant, and it is not among those OMU will be required to test for during the fourth iteration of the UCMR later this year.

 

The EPA lists specific one-day and 10-day healthy limits of molybdenum for a 22-pound child, and OMU drinking water surpassed both of those in some cases, but, because it remains unregulated, surpassing those limits is not illegal nor does it require any further testing.

 

The agency will use data it collected from the third UCMR round of testing in deciding whether there is a substantial likelihood that the contaminant will occur in public water systems with a frequency and at levels of public health concern, but that determination may not be made until 2021.

 

"If I lived in Owensboro, I would be on red alert," said Wendy Bredhold, a senior campaign representative for the Sierra Club's Beyond Coal Campaign in Indiana and Kentucky. "I would want to know how my water source is being protected because coal ash is not on people's radar. When people look at coal-fired power plants, they're always worried about air quality, but in order to clean up the air, we've created a drinking water problem. It's every coal power plant's dirty little secret that these problems exist."

 

OMU supplies the city and three surrounding county water districts or associations with water from a deep aquifer that borders the Ohio River from downtown Owensboro northeast to Elmer Smith Station. There, OMU's wellhead protection plan indicates that, instead of flowing north toward the river, groundwater that feeds the aquifer flows directly toward drinking water wells, partly because of the suction vacuum they cause underground.

 

Barbara Bennett, who is associated with the Sierra Club in western Kentucky and is an OMU customer herself, said she is particularly concerned about what these reports may indicate about the levels of molybdenum in the city's drinking water aquifer.

 

"I have been very proud to be from a community that has municipal utilities," Bennett said. "I think that's a very responsible thing for a community to provide, and, for the most part, it's very cost-effective for the citizens of a community who have municipal-provided utilities — not private enterprise. Most of us, myself included, take for granted that it will be safeguarded. I take clean water for granted."

 

Although most Daviess County water districts reported similar levels of molybdenum and chromium-6 during the 2014 UCMR, not all did. The East Daviess County Water Association, for example, detected no molybdenum in drinking water, pointing to the extreme range of reportable data samples returned. True also is that only the highest reportable ranges of molybdenum and chromium-6 were unsafe, according to the EPA, Environmental Working Group and California Office of Environmental Health Hazard Assessment health guidelines.

 

In a phone interview last week, OMU General Manager Kevin Frizzell said he fully trusts that local water is safe to drink. Safety, he said, is a daily priority that the utility takes seriously.

 

OMU's newest groundwater monitoring well, in fact, has returned preliminary data with lower concentrations of molybdenum than the initial 2018 tests had shown, he said.

 

"You take multiple samples so you make sure you've got a good database of analysis," Frizzell said. "(From) the initial sample that we've done there, though, we are not seeing that molybdenum at (the plant) boundary. But that's just initially; we have more sampling to do under the rule. The purpose of adding this well is really to see how far away from the presumed source — which, in our case, would be the ash pond — that the constituent may have traveled. It's really independent of where other wells may be. Like I said, it's very preliminary data. I wouldn't make a judgment on what that means either way, whether we saw molybdenum or we didn't. I do think it's encouraging that we didn't, but we have to go through the process of the sampling rounds and the analysis to make sure that we understand and that we properly analyze the data. It's not uncommon, in these situations ... for all these facilities to have some level of some constituents at the ash pond boundary."

 

Molybdenum ore does exist naturally in bedrock across North America. In 2017, researchers at Duke University and The Ohio State University determined that numerous coal ash disposal sites in southeastern Wisconsin were not the source of high levels of molybdenum contamination there, despite what many environmental groups had claimed.

 

Using forensic isotopic fingerprinting and age-dating techniques, the researchers were able to distinguish between what would be relatively young molybdenum recharged by the burning of coal and much older molybdenum ore with unique ratios of boron and strontium isotopes that exists naturally.

 

Data the new well gives OMU may lead it to do further testing, Frizzell added. He said he has not ruled out choosing to test for molybdenum or chromium-6 regularly, even though that isn't required by the EPA at this time.

 

Asked whether he personally believed that the EPA should crack down on unregulated contaminants that are linked to coal ash, Frizzell had a mixed response.

 

"There is a lot of science and analysis that is done to set these levels, and I'm not qualified to (determine that)," he said. "I don't have access to all that data and all the information that they use to set these levels. The reality is, they have not yet, so it's not of a high level of concern to the EPA, and, if you look at that lifetime level, that's based on a certain amount of liters of drinking water with those amounts of, in this case, molybdenum in them consistently. We haven't seen that. ... We have a range, and that range likely changes over time. The other thing with molybdenum is, it is naturally occurring. There may be some level that's already there. Certainly, it also is a component that we see in the fly ash, so I'm not saying that is all of it. I don't want to give that impression. I think we have to look at, from our perspective, what is EPA telling us? What are they regulating? What are they focusing on? And that's what we focus on to make sure we are in compliance with those regulations and providing quality drinking water to our customers."