SPRINGFIELD — Coal ash dump sites across Illinois, including at Dynegy's E.D. Edwards power plant, have severely contaminated surrounding groundwater sources, according to a report released Wednesday by a consortium of environmental groups.

The results are based on data sets made public for the first time earlier this year as part of new federal regulations of coal ash, a toxic byproduct of coal-fired power generation that is commonly stored in unlined ponds or landfills near power plants. The report by the Environmental Integrity Project, Earthjustice, Prairie Rivers Network and the Sierra Club found toxic pollutants emanating from 22 of 24 coal ash dump sites for which the data became available in March.

At the Edwards power plant on the Illinois River south of Peoria, lead levels in groundwater were 18 times the U.S. Environmental Protection Agency's drinking water standard, the report stated.

Dynegy's Hennepin coal plant in the Illinois River floodplain south of Starved Rock State Park had groundwater levels of arsenic and boron more than three times higher than what is considered safe, and lithium levels up to 12 times higher than safe levels, the report stated. The safety standard used for the comparison was not immediately clear.

"Illinois needs to act now to strengthen rules that protect the public from coal ash," said Andrew Rehn, a water resources engineer from Prairie Rivers Network. "We're reaching a turning point as Energy companies are proposing to leave coal ash in floodplains of rivers and exposed to groundwater. We need stronger rules that provide permanent protection with a financial guarantee, and give the public a voice in these decisions."

Jenny Cassel, an Earthjustice attorney, argued the ash ponds should be as "far as possible" from water and contained in modern, lined landfills.

“These pollutants we are talking about — these heavy metals — they don’t disappear, they don’t dissolve into the environment,” he said. “They stay there for years and years, and so as long they remain in contact in water, they will continue to leach out literally for hundreds of years.”

City Water, Light and Power's (CWLP) Dallman Power Station in Springfield dumps coal ash into ponds near a dam on Lake Springfield, where four monitoring wells capture groundwater content. The report found unsafe levels of boron in three of the four wells; concentrations of sulfate exceeded the health threshold in two wells; and arsenic concentrations 20 times higher than the safe level in one well. CWLP officials, however, maintain the ash ponds don't pose a risk to Springfield's water supply.

The new report comes about 14 months after the Sangamon Valley Group of the Sierra Club, the NAACP and the Prairie Rivers Network asked the Illinois Pollution Control Board to order CWLP to clean up contaminated groundwater at its coal ash storage site.

The complaint from September 2017 states that there have been 623 instances of self-reported groundwater violations at the coal ash site since 2010. These include violations for elevated levels of arsenic, lead, boron, chromium, manganese iron and other pollutants.

The groups that authored the report called on lawmakers to institute more stringent regulations on power producers, noting that Illinois abandoned plans to regulate coal ash after starting the process in 2013.

Matt Buedel can be reached at 686-3154 or mbuedel@pjstar.com. Follow him on Twitter @JournoBuedel. The Springfield Journal-Register contributed to this report.