DURHAM, N.C. – Duke University researchers have found high levels of toxic heavy metals in coal ash from the Dominican Republic’s largest coal-fired power plant.

“Our analysis of coal ash from the Punta Catalina Thermoelectric Power Plant revealed high concentrations of arsenic, selenium and other potentially harmful heavy metals – well beyond what we typically see in common soils,” said Avner Vengosh, professor of geochemistry and water quality at Duke’s Nicholas School of the Environment.

“Toxicity tests show that in some cases the level of contaminants that leach out of the ash when it is released into the environment could exceed World Health Organization and U.S. Environmental Protection Agency standards for drinking water and ecological health,” Vengosh said.

These findings suggest that “the unregulated disposal or release of coal ash from Punta Catalina into the environment could contaminate local soils and water resources and pose high environmental and human health risks in surrounding communities,” he said.

The 752-megawatt Punta Catalina power plant is located about 33 miles southeast of Santo Domingo on the Dominican Republic’s southern coast. The twin-unit plant was initially scheduled to be fully up and running in 2018 but has been plagued by construction delays, financing scandals and concerns about its environmental impact. When fully operational, it will account for about 30% of the nation’s total operating capacity.

Earlier this year, Enrique de Leon, a member of the National Committee for the Fight Against Climate Change and the Institute of Lawyers for the Protection of the Environment, sent a coal ash sample from the plant to Duke University to have it analyzed.

Vengosh and doctoral student Zhen Wang analyzed the heavy metal contents in the coal ash using a suite of toxicity tests that identify and measure the contaminants that leach out of the coal ash when it is released into the environment under different acidity conditions. This method is commonly used by the U.S. EPA to evaluate coal ash toxicity and has been successfully used in dozens of studies to detect the presence of heavy metals and other potentially harmful contaminants in coal ash and assess their potential effect on the environment.

The tests revealed that levels of molybdenum, selenium, lithium, thallium, barium, lead and other metals in leachates that are extracted from the coal ash exceeded World Health Organization and EPA standards for safe drinking water and ecological health.

Vengosh has posted a report about the Punta Catalina coal ash on his laboratory’s webpage to make his team’s findings easily accessible to policymakers and the public.

“One of the objectives of this project was to provide environmental groups, regulatory agencies and community leaders in the Dominican Republic with unbiased scientific information to support efforts to protect the environment and human health there,” he said.

While coal combustion has declined in the United States over the last decade, the export of U.S. coal to other countries, including the Dominican Republic, has increased, he noted. This can heighten environmental and human health risks, especially in countries without adequate coal ash-storage capacity or stringent regulations governing the transport and disposal of the ash.

“The same thorny issues relating to coal ash disposal and storage that we’ve been grappling with in the U.S. for years are being exported along with our coal,” he said. “Scientists, environmental groups, governments and other concerned stakeholders have to work together to limit the potential harm. We’re exporting Duke’s expertise to help in the effort.”