Thyroid cancer cluster: scientists zeroing-in on soil, air

In response to Mooresville’s higher-than-average numbers of thyroid cancer, Duke Energy has contended that science doesn’t link coal ash to cancer.

Not so fast, says a team of Duke University chemists.

The researchers are zeroing-in on Mooresville’s soil after discovering elevated levels of radiation in the area, which is also home to some of the highest amounts of coal ash in the state. Coal ash – the byproduct of burning coal – is radioactive. Radiation is a known risk factor for thyroid cancer.

“Coal ash contains relatively high levels of radium nuclides – about five times higher than regular soil,” Duke University’s Heather Stapleton told a crowded room of local doctors on Thursday. They met at Mooresville’s Town Hall to discuss with state elected and public-health officials the higher-than-average number of thyroid cancer cases in the town’s two ZIP codes, 28117 and 28115.

“Exposure to radiation has been associated with thyroid cancer, and so we’re very interested in exposures that could potentially be sources of radiation,” added Stapleton’s research assistant, Duke University’s Kate Hoffman.

Maps from Duke University chemists show thyroid-cancer cases relative to the state’s coal-ash sites and nuclear power plants.

Stapleton leads the team of chemists that is digging for answers to why Mooresville has so many reported cases of thyroid cancer. They have identified radiation in local soil samples, including one collected near Lake Norman High School, where 40,000 tons of coal ash was recently disrupted because of construction and heavy rain. “We’re not saying it is coal ash, but we’re saying it’s suggestive and it needs further follow-up,” Stapleton said.

The team of researchers is scheduled to visit Duke Energy on March 27 to collect samples of coal ash directly from Marshall Steam Station.

Stapleton said local drinking-water samples did not show any impact from coal ash. “There are some suggestions in the soil samples, yes, which is why we want to do more follow-up on the soil and the air, in particular, for radionuclides,” she said, responding to a question from a healthcare provider.

Duke University’s Avner Vengosh “is continuing to look at the radium levels in the soil to determine if they are associated with coal ash or not,” Stapleton added.

Monitoring of air over the course of several weeks in three homes – two in 28117 and one in 28115 – also showed elevated radon levels. “There are definitely higher radon levels in this area,” Stapleton said. “I’m not saying this is associated with thyroid cancer, but it is a source of ionizing radiation and something that we need to follow-up on.”

Thursday was the first official update from the Duke University researchers on their ongoing environmental study. They were privately commissioned last year by Mooresville resident Susan Wind after her teenage daughter, Taylor – a student at LNHS at the time – was diagnosed with thyroid cancer.

“As you know as doctors, it is not normal for these young kids to get thyroid cancer,” Wind told the room of healthcare providers on Thursday.

A former crime analyst and mapping specialist, Wind said she used GIS software – and help from people contacting her on social media – to map the cancer cases being reported to her. “I was finding out other people had different rare cancers on some of these blocks,” she said.

Addressing some of the flak she’s caught about her study from some neighbors, including local doctors, Wind said: “I did not do this to cause trouble for the community or to hurt your property values. For those of you who live here in Iredell County, I want to make sure it’s safe for your children, and I needed to know if it was safe for my other children.

“We need to come together and fix this.”

Dr. Michael Borja, a Statesville pediatrician, said the issue is personal for him. His son, with no risk factors, developed testicular cancer. One of his son’s friends has thyroid cancer. Both attended LNHS. Borja asked if the state has looked into any possible connection between the coal ash near the high school and the incidences of cancer there.

State Senator Vickie Sawyer said it’s personal for her, too. “I live behind Lake Norman High School, and my well is about 2,000 feet away from that coal ash deposit. I’m very concerned. I’m working very hard to make sure that coal ash is not leeched. (The N.C. Department of Environmental Quality) is making the developers of that site rework it so they can cap that and make sure there is no leeching.”

Sawyer said she has introduced legislation that aims to stop coal ash, in any amount, being used for structural fill.

She said she is proud of the leadership demonstrated by N.C. Rep. John Fraley, who she said has worked diligently to bring together state elected and public-health officials on the issues of thyroid cancer and coal ash. “I think this is probably one of the best, well-organized, well-run and well-researched issues in North Carolina from what I’m seeing from a state level,” Sawyer said.

State public health officials brought little new to the table on Thursday.

The N.C. Central Cancer Registry and the epidemiology section of the N.C. Department of Health and Human Services conducted a “literature review” on possible links between coal ash and thyroid cancer. The resulting report, released in January, concluded that “although coal ash can contain radionuclides, there are no published studies to support an association between coal ash exposure and thyroid cancer.”

Duke Energy recently sent the month-old report to media outlets, resulting in a flurry of reports suggestive that the state determined coal ash doesn’t cause thyroid cancer.

But the state’s report was based only on a review of available subject-matter literature. “There’s nothing new in our report in terms of findings about causes of thyroid cancer – it’s just a summary of all the available literature,” State Epidemiologist Zack Moore told WBT’s Mark Garrison in a recent radio interview. “Our report summarizes the existing data. Our report doesn’t add any new information in terms of causes of thyroid cancer.”

In fact, stated in the report itself: “Most importantly, this is not a research study. No conclusions can be drawn from this report about the association between any environmental contaminant and thyroid cancer. It is important to note that only a comprehensive research study can determine if any environmental exposures are associated with thyroid cancer diagnosis rates in Iredell County.”

Susan Wind said it would be negligent and irresponsible not to rule-out coal ash as a possible contributing factor in the high numbers of cancer being reported around Lake Norman.

“The reason the state cannot detect any links between coal ash and thyroid cancer is because it has never been studied until now,” she said.

But a study was recently conducted on the general impact of coal ash on human health. A September 2018 article in the N.C. Medical Journal reads: “Over the past 30 years, scientists reported that the people living in close proximity to coal-fired plants had higher rates of all-cause and premature mortality, increased risk of respiratory disease and lung cancer, cardiovascular disease, poorer child health, and higher infant mortality.”

The article points to the lack of studies and available information on coal ash and human health. “At present, information about the health impact of coal-fired plants on human health, including the health of the residents of communities located in close proximity to coal power plants, remains sparse,” the article reads.

The article’s authors urge further studies into the health impacts of coal ash: “Further studies are required to profile the severity of the cumulative impacts of multiple air, water, and soil contaminants related to coal power plants and coal ash impoundments on human health and the environment.”

On April 18, state and local officials plan to meet at Mooresville High School’s Performing Arts Center to hear results from Virginia Tech’s community water testing in Iredell County. Another meeting on May 9 – location TBD – will aim to update the public on thyroid cancer and structural coal-ash fill. 


4 thoughts on “Thyroid cancer cluster: scientists zeroing-in on soil, air

  1. I live in Mooresville NC. I’ve been healthy all my life until 2014. I started to have major health problems. I started having memory issues, hormone, skin, liver, eye, digestive, hearing, then in 2017 Diagnosed with a rare RGNT Brain tumor. I had brain surgery in 2018 at Duke University.

    Currently I’m still having health problems.

  2. Are coal dusts/exhausts/residues from burning coal to make energy, different from those from burning it to heat buildings? Is it due to multiple exposure routes (water, air), instead of one route? Is it due to the type of coal used (soft or hard)? Is it due to length of exposure? Have waste toxins been found in water tables in areas that heat all their buildings using coal boilers and fireplaces? How many years does exposure take to cause the cancer? What other types of cancers might be related to coal effluent?
    Because, if coal-fired electric plants can trigger that thyroid cancer, mightn’t we expect to also see cancer clusters in city areas that use coal to heat all buildings, especially areas that routinely use the spent clinkers & ash on their roads?
    If so, then, UT cities, where coal has chronically been used to fire every building’s boiler and fireplace, and routinely spread the clinkers and ash on roads, should also have higher cancer rates, because that went on for over 100 years, I think.
    Were there cancer clusters in London, along with breathing problems, when London, UK, used coal to the point of choking everyone? Shouldn’t there be lots of documentation on disease-rates, at least (though, it’d be very incomplete due to there being far less diagnostics then)?
    I’m no proponent of coal burning, at all. Ever.
    Maybe there might be data to help the case better, sooner, if the researchers look to corroborate in other areas with similar exposures, over longer time.
    Knowing this is a current political hot-button issue….why isn’t it bad enough that people get permanent breathing ills from coal effluent, bad enough to shut coal down? Do we need to add cancer to the list, because people can still live a fairly long life with pretty severe breathing ills…but cancer kills faster and the public opinion is worse for cancers? In today’s political milieu, yes.
    In fact, searchers should expand the list to all regions with chronic coal-burning, to look at data on multiple illnesses triggered by coal effluent….mining it, burning it….and, compare especially areas that did, but quit…how long before there was a drop in certain illness rates?

Leave a Reply

Your email address will not be published. Required fields are marked *

About Author

Hi! I’m Jaime

I was a newspaper reporter in Mooresville, NC for a decade and covered local government issues from 2003 to 2006.


Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors