Scientists Found Sediments in North Carolina Lakes That Shows Decades of Coal Ash Contamination

An examination of sediments from five North Carolina lakes near coal-burning power stations revealed that coal ash contamination of surface waterways was more persistent and pervasive than previously thought.

The study's authors warned that this is likely to be an issue for any surface water body near a coal plant and that it will only become worse as climate change causes more intense weather events and flooding.

Lake sediments show decades of coal ash contamination

(Photo : Volodymyr Hryshchenko/Unsplash)

Scientists from Duke University and Appalachian State University discovered that huge amounts of coal ash had been moved and deposited in lake sediments since the start of coal activities in North Carolina, as per ScienceDaily.

According to Avner Vengosh, a Duke University Distinguished Professor of Environmental Quality at the Nicholas School of the Environment, the bottom sediments of a lake provide a comprehensive history of what has fallen into the lake water and settled to the bottom.

They were able to recreate the history of the lakes using age-dating methods that allowed them to travel back in time, in some cases even before the coal plant was established.

Coal ash is a byproduct of coal combustion that contains toxic elements, such as lead, chromium, cadmium, mercury, arsenic, selenium, and molybdenum, all of which have been linked to human malignancies and other health problems.

According to Vengosh, the toxins are not bound into the lake sediments.

Metals leached out of the buried coal ash and might enter the aquatic food chain, according to a chemical examination of the pore water inside the lake sediments.

The research was published on October 3 in the journal Environmental Science & Technology.

"These are recreational lakes," said Zhen Wang, the study's principal author and a Ph.D. student at Duke's Nicholas School of the Environment.

Some of them, such as Hyco Lake, was initially developed for the coal plant, but have since become highly coveted real estate on which individuals may build their dream houses.

It appears pure and gorgeous, yet digging deeper reveals poisonous coal ash mounds.

The five lakes in the study were built for nearby coal plants: Hyco Lake and Mayo Lake in Person County; Belews Lake in Rockingham, Forsyth, and Stokes Counties northwest of Greensboro; Mountain Island Lake in Mecklenburg County northwest of Charlotte; and Lake Sutton in Brunswick County northwest of Wilmington.

For comparison, the researchers also took water samples from Lake Waccamaw in Columbus County, west of Wilmington, a natural lake that was dammed in 1926 to keep it from drying out during droughts.

"We were able to distinguish the different forms of coal ash that were accumulated over time in the lakes by using a microscope," said Ellen Cowan, professor of Geology at Appalachian State University and co-author of the study.

According to Cowan, it seems that coal ash was first thrown into a neighboring lake at several of the locations.

When the Clean Air Act was implemented and scrubbers were installed in coal plant smokestacks to capture fine particulates, the researchers saw changes in coal ash with increasing proportions of tiny particles.

Despite this, the microscopic particles of coal ash have the highest quantities of hazardous substances, aggravating lake pollution, according to Vengosh.

Because the microscopic particles contain larger amounts of trace elements, the toxicity of coal ash increases.

Also Read: Ancient Fossilized DNA Found in Subglacial Lake Sediment

Coal Ash Is Not "Hazardous Waste"

Coal ash, a catch-all phrase for several types of debris left over from coal-burning power plants, often includes a variety of toxic elements to human health, including arsenic, chromium, lead, and mercury, as per NRDC.

Short-term exposure can cause nose and throat irritation, dizziness, nausea, vomiting, and shortness of breath, while long-term exposure can cause liver and kidney damage, as well as cardiac arrhythmia and a variety of malignancies.

Every year, around 110 million tons of the substance are produced by hundreds of coal plants in the United States.

The majority of it is combined with water and kept in sludgy basins known as coal ash ponds, which have a bad habit of leaking, flooding, or spilling, sometimes in catastrophic numbers.

More than a billion gallons of coal ash slurry streamed out of a Kingston, Tennessee, power plant a few days before Christmas in 2008, flowing into neighboring rivers and flooding 15 houses when the six-story earthen barrier that had been contained failed.

The catastrophe is still considered the greatest industrial leak in American history.

Over 900 personnel were swiftly dispatched to clean up the damage, which took five years.

When those same employees began to become ill and even die under conditions that suggested coal ash poisoning, 200 of them filed a lawsuit against the contractor who had hired them, claiming that they had been significantly deceived about the hazards of their exposure.

The distinction is significant. Coal ash, as solid waste, is subject to separate and significantly less rigorous federal laws regulating how it is treated than something formally labeled "hazardous."

Surprisingly, the United States did not have any control over the disposal of coal ash until 2015, when President Obama's EPA enacted the first-ever federal regulation governing its disposal in direct reaction to the Tennessee leak.

Coal firms fought for the solid-waste classification during the rule-making process, knowing that it would eventually give states and utilities the lion's share of enforcement duty.

And they received it in exchange for the federal government's (very restricted) acceptance of coal ash for the first time.

Related article: Duke Energy Foots the Cleanup Bill for Dan River Spill