Groundwater testing at Georgia Power's Plant McIntosh in Rincon revealed a high level of arsenic in one test well, company spokesman Jacob Hawkins said.

"At McIntosh, the concentration of arsenic was .034 parts per million (ppm) and the reporting limit for Georgia EPD is .010 ppm," Hawkins said. "Again, this was in the single well - all other wells and all other substances were under state reporting limits."

The testing is being done as part of the coal ash pond closure process for 29 ash ponds at six of the company's 11 coal-fired generating plants - Plants Bowen, Hammond, McIntosh, Scherer, Wansley and Yates. The company is conducting several rounds of groundwater testing for 19 different substances regulated by the state Environmental Protection Division or the U.S. Environmental Protection Agency.

Coal ash is a byproduct of burning coal at power plants. It contains contaminants such as mercury, cadmium and arsenic associated with cancer and other serious health effects.

The U.S. EPA has determined that, without proper protections, coal ash contaminants can leach into groundwater and can potentially migrate to drinking water sources, posing significant public health concerns.

Coal ash found its way into headlines after enormous spills from ponds in Tennessee in 2008 and North Carolina in 2014 polluted nearby waterways. Closer to Savannah, Wayne County residents are scrutinizing plans by Republic Services to haul up to 10,000 tons a day of coal ash into the Broadhurst Landfill where the state Environmental Protection Division discovered toxic metals from coal ash have already leached into the soil and groundwater. (Georgia Power will not be using the controversial Broadhurst Landfill, Hawkins said.)

In the testing so far, four out of the 136 wells - one at Plant Hammond, one at Plant McIntosh and two at Plant Yates - indicated the presence of one substance above the state's standard. The test wells range in depth from 10 to 150 feet. Eleven of them were drilled at McIntosh.

Test results indicated the contamination found so far is contained on Georgia Power property. At McIntosh, the origin of the arsenic is in question.

"This result may have come from previous, historic use of herbicide on the property - we're working to determine if that's the case," Hawkins said.

Savannah Riverkeeper Tonya Bonitatibus said she wasn't surprised that arsenic contamination was discovered at McIntosh.

"The groundwater table is at the surface at the coast," she said. "To think it's safe in an unlined pond on the coast is likely not correct."

All of the company's 29 ash ponds in Georgia are slated to stop receiving coal ash within the next three years. At 16 of those ponds adjacent to lakes or rivers - including McIntosh's 22-acre, 20-foot deep pond - the company will remove the ash and either dispose of it in a lined landfill or recycle it in uses such as concrete or cinder blocks.

"We're going to completely dig it up and (the pond) will no longer be on site," Hawkins said of the McIntosh ash pond. The plant's 317,000 tons of ash will be stored in a lined landfill at McIntosh.

The company's remaining 13 ash ponds will be closed in place using permanent concrete barriers around them.

Environmentalists have supported the closure of coal ash ponds and are pushing the state EPD to tighten its regulations surrounding coal ash disposal, as the state updates its current guidelines.

"Coal ash in Georgia pollutes and threatens our drinking water supplies, rivers, lakes and groundwater," Chris Manganiello of the Georgia Water Coalition told the DNR board. "Coal ash should be removed from unlined, primitive leaking pits along our rivers to safe, dry, lined storage away from our rivers and lakes, and out of our groundwater and drinking water supplies. Properly-designed, permitted and maintained municipal solid waste landfills may store coal ash, but must apply for a major permit modification if the ash comprises more than 5 percent of their daily tonnage intake. Georgia should not become the low-cost, poorly protected dumping ground for other states' coal ash."

Plant Kraft, in Savannah, also has one ash pond that is slated for removal. Monitoring wells have not yet been installed at Kraft but are expected to be in place by the end of the year, Hawkins said.

More than 500 groundwater monitoring wells will be constructed and continue to operate even after the ash ponds are closed.

On the web

For more information, go to georgiapower.com/environment/ccr.cshtml and click on "CCR Rule Data and Information By Plant" or "Groundwater Monitoring Information."