A yearlong study of groundwater in some southern coalfield communities showed no evidence of widespread pollution related to mining, the West Virginia Department of Environmental Protection said Tuesday.

After its own investigation failed to establish a link, the DEP hired Triad Engineering of Scott Depot to study water supplies in and around the Boone County towns of Seth and Prenter. The goal was to determine whether mining activities, including the underground injection of coal slurry, were to blame for longstanding complaints of discolored, foul-smelling well water and residents' health problems.

Slurry is the wastewater created when coal is washed to help it burn more cleanly, and mining companies have long disposed of it in Appalachia by pumping it into worked-out underground mines.

The DEP says Triad sampled 33 wells and found evidence of possible links to mining activities in only two of them, neither of which is used as a drinking water supply. Those wells, which the DEP said deserve more attention, showed elevated levels of sulfate, iron, manganese and aluminum. Triad says further investigation would be required to confirm or rule out a link to mining.

"This was a thorough, comprehensive study,'' said DEP Secretary Randy Huffman. "I hope the results help put the people in the Prenter community at ease.''

Not quite, said attorney Roger Decanio, who represents hundreds of people who sued eight coal companies over the alleged pollution. Last year, he publicly challenged Triad's approach and methodology, arguing that there were too few samples to be representative.

"The DEP really lacks the credibility to say anything about the regulation of coal mining in West Virginia, and it has been lacking credibility for many years,'' he said. "They are nothing but a shill of the industry.''

DEP spokesman Kathy Cosco defended the study and denied the DEP is taking industry's side in the Prenter dispute.

"This study was objective and conclusive,'' she said, "and the result of a commitment we made to the Legislature to investigate the potential impacts of the underground injection of coal slurry on groundwater in the Prenter area.''

Decanio says the question will soon be settled in court.

His lawsuits initially targeted the former Massey Energy Co. and four subsidiaries -- all now owned by Virginia-based Alpha Natural Resources -- as well as Federal Coal Co., Patriot Coal Corp., AK Steel, and Peabody Energy and its former subsidiary, Pine Ridge Coal Co.

After its own investigation failed to establish a link, the DEP hired Triad Engineering of Scott Depot to study water supplies in and around the Boone County towns of Seth and Prenter. The goal was to determine whether mining activities, including the underground injection of coal slurry, were to blame for longstanding complaints of discolored, foul-smelling well water and residents' health problems.

Slurry is the wastewater created when coal is washed to help it burn more cleanly, and mining companies have long disposed of it in Appalachia by pumping it into worked-out underground mines.

The DEP says Triad sampled 33 wells and found evidence of possible links to mining activities in only two of them, neither of which is used as a drinking water supply. Those wells, which the DEP said deserve more attention, showed elevated levels of sulfate, iron, manganese and aluminum. Triad says further investigation would be required to confirm or rule out a link to mining.

"This was a thorough, comprehensive study,'' said DEP Secretary Randy Huffman. "I hope the results help put the people in the Prenter community at ease.''

Not quite, said attorney Roger Decanio, who represents hundreds of people who sued eight coal companies over the alleged pollution. Last year, he publicly challenged Triad's approach and methodology, arguing that there were too few samples to be representative.

"The DEP really lacks the credibility to say anything about the regulation of coal mining in West Virginia, and it has been lacking credibility for many years,'' he said. "They are nothing but a shill of the industry.''

DEP spokesman Kathy Cosco defended the study and denied the DEP is taking industry's side in the Prenter dispute.

"This study was objective and conclusive,'' she said, "and the result of a commitment we made to the Legislature to investigate the potential impacts of the underground injection of coal slurry on groundwater in the Prenter area.''

Decanio says the question will soon be settled in court.

His lawsuits initially targeted the former Massey Energy Co. and four subsidiaries -- all now owned by Virginia-based Alpha Natural Resources -- as well as Federal Coal Co., Patriot Coal Corp., AK Steel, and Peabody Energy and its former subsidiary, Pine Ridge Coal Co.

Decanio said all but the Alpha companies have agreed to confidential settlements.

"The court system is the great equalizer of America,'' he said. In the courtroom, "We are going to be on the same footing as Massey, as Alpha and as the DEP, and we will put them in their place.''

The first of the cases is set to be tried April 25 in Boone County Circuit Court, where Decanio said his expert witnesses are prepared to testify they have established a link between mining activities and bad water.

Decanio says they include a hydrologist from Penn State University and an environmental engineer from Marshall University who have studied the problem longer and gathered more data.

The DEP said nearly half the residents interviewed for the Triad study reported odors and discoloration, "but there was a very poor correlation'' between those complaints and lab results.

None of the wells sampled exceeded primary drinking water standards for metals, it said. But one exceeded secondary standards for aluminum and 12 exceed the secondary standard for manganese and iron.

Primary standards are enforceable limits that are based on potential health risks, while secondary standards are merely guidelines for contaminants that cause changes in taste, color or odor, or create cosmetic effects such as skin or tooth discoloration.

Of the 13 residents with the strongest complaints, Triad says only four had samples that showed high sulfate levels. Triad determined the complaints were most likely related to iron and sulfate metabolizing bacteria rather than human activity.

It also said groundwater flow in the study area is localized, and wells penetrate different rock formations, producing different water quality despite their proximity to each other.

"What we saw was typical water for southern West Virginia,'' Triad's senior geologist, John Meeks, said in a DEP press release. "Water quality was actually better than that reported by the U.S. Geological Survey for this part of the state.''

The study began in December 2010 and cost about $130,000.