Arsenic high at Indian River power plant

Rehoboth Beach resident and retired scientist John Austin wants shellfish beds in Indian River Bay closed because of potential arsenic contamination from landfills at the Indian River power plant. Arsenic leaches out of coal ash piles at the plant and into groundwater that flows into Island Creek, and Austin says it threatens human health. State environmental officials agree there is arsenic in groundwater wells, but they say it poses no threat to human health.

Austin strongly disagrees. He said arsenic and selenium from groundwater under the landfill enter Island Creek and Indian River, then move into the Inland Bays. As arsenic increases, the cancer risk associated with shellfish consumption increases, he said. “Thus, releases from these adjacent sites do pose a danger to human health and the environment,” said Austin in an email to the Department of Natural Resources and Environmental Control (DNREC). He asked that shellfish beds in Indian River Bay be closed until further tests are done.

Austin regularly requests DNREC send him results from groundwater wells in and around the coal-ash landfills at the power plant.

Last weekend, Austin was poring over documents he obtained through the Freedom of Information Act. They were the test results for two specific wells with a history of higher-than-normal arsenic.

Austin said he was shocked to see levels of arsenic – a carcinogen – spiked to more than 10 times acceptable levels in February and April 2009. State officials say the levels are high, but only at one place, and that power plant owner NRG Energy is working to correct the problem.

Groundwater contamination

The two wells – one adjacent to the landfill and the other near the banks of Island Creek – have shown contamination before, Austin said. In 2009, arsenic in one well reached 140 parts per billion, he said, and the other 110 parts per billion. Those numbers come from two readings, one in February and one in April, Austin said. The second reading was presumably to see if the first was correct, he said.

Selenium levels at both wells were also high. “It’s not just one chemical that is above the level needed for corrective action,” said Austin. The levels are surprising, but so is the speed with which they became so high. “You don’t normally see arsenic spike like this; usually you see a slow progression if there is leaching,” he said. Austin said he can’t explain why selenium and arsenic levels jumped. A period of heavy rain began late in 2009, he said. During those weeks, groundwater would have risen and more rainwater could have percolated through the coal ash pile than normally.

DNREC hydrologist Frank Gavis said the well might have been partially installed in ash, over time allowing ash to infiltrate the water. That would have made arsenic levels artificially high, he said. The department has asked NRG Energy to install another well nearby, so it can compare arsenic levels from the two to prove or disprove that the first well was compromised, said Gavis. Brian Ashby, program manager of DNREC’s solid and hazardous waste section, said levels of arsenic are well above safe drinking water standards, but not above safe surface water levels, he said.

In all other wells at the landfill, arsenic levels are nearly nondetectable. “It really is an anomaly. It doesn’t fit historically and it doesn’t fit with other readings in the area,” said Ashby.

“The numbers are concerning, but they do not pose a significant threat to human health,” Ashby said. It’s not a threat because groundwater under the landfill moves into Island Creek – it is not drinking water, he said.

Marjorie Croft, acting director of DNREC’s division of air and waste management, said in additional tests, conducted after the high numbers were found in 2009, concentrations of selenium and arsenic decreased in deeper groundwater and in samples taken farther from the landfill. She said some samples exceeded maximum contaminant levels (MCL), but those are drinking water standards, and groundwater beneath the landfill is not drinking water.

“Taking into account the levels on constituents detected, the direction of groundwater flow and the potential for impact, we believe that there is no current risk to human health or the environment at this time,” she said.

Landfill to be closed

“We do test Island Creek, and it does have elevated levels of arsenic,” said Ashby. He said the old coal-ash landfill on Burton Island contributes more arsenic to groundwater than the unlined landfill that NRG Energy is closing. The power company is putting a waterproof cap on the landfill to prevent any further rainwater infiltration, Ashby said. The plant will now begin using a lined landfill. “Now that they will be using the lined cell, there shouldn’t be any future contributions except from Burton Island,” Ashby said.

Austin said, in an email to DNREC, “While capping the Phase I mound was already planned, this effort can do nothing to stop the flow of groundwater contaminated from 31 years of operations without a cover,” he said. The only way to stop further releases is to block groundwater flow with a slurry wall around the site and treat the water inside, said Austin.

“Many people would like to see this coal ash hauled out and safely disposed of somewhere else,” said Austin. Coal ash on Burtons Island has been built up to 20 feet above sea level, Austin said, and converted from marsh to upland forest over 50 years. DNREC and NRG Energy have secured the shoreline to prevent erosion, but that does not stop arsenic and other chemicals from leaching into groundwater, said Austin. “Nothing stops the rainwater from percolating through the ash pile, or tidal water from percolating in and percolating back out,” he said.