RICHMOND, Va. (CN) – The Fourth Circuit held Wednesday that an arsenic leak from a Virginia coal ash pond is not a violation of the Clean Water Act, The ruling is a blow to environmentalists who are currently arguing otherwise around the country.

In a 24-page opinion, U.S. Circuit Judge Paul Niemeyer, a Reagan appointee, was unmoved by the plaintiff Sierra Club’s argument that ponds containing toxic discharge from coal-fired power plants were seeping dangerous chemicals into groundwater in violation of the Clean Water Act.

The Sierra Club, represented by the Southern Environmental Law Center, claimed Dominion Virginia Power had allowed rainwater to seep into and ultimately through coal ash ponds linked to a Chesapeake Bay-area power plant, and that arsenic was carried into the groundwater around the facility, and , eventually, into oceans, rivers in streams.

The Clean Water Act only allows the government to punish entities who dump without a permit into “navigable” waters. For years environmental groups have tried to link coal ash ponds to navigable water sources, however Niemeyer, in line with judges before him, adopted a literal interpretation of the federal law and found otherwise.

Neimeyer said the law requires violating water sources to be a “discrete conveyance” which includes “any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation, or vessel or other floating craft.”

“Here, the arsenic was found to have leached from static accumulations of coal ash on the initiative of rainwater or groundwater, thereby polluting the groundwater and ultimately navigable waters,” Neimeyer wrote. “In this context, the landfill and ponds were not created to convey anything and did not function in that manner; they certainly were not discrete conveyances.”

In a statement, lawyers for the Southern Environmental Law center said they were disappointed with the court’s decision and warned of the continued threat posed by the existing ash ponds.

“Of the 3.4 million tons of coal ash at the site, 2.1 million tons of coal ash is sitting in unlined lagoons, with the ash in some areas extending six feet below sea level,” the group said. “Any closure proposal for this facility should ensure that arsenic is no longer dumped in the river, and take into account the vulnerability of the site to storm surges, hurricanes, and daily tidal erosion in order to protect the citizens of Chesapeake.”

The group, and its clients at the Sierra Club, however, found a silver lining in the decision in the court’s linking the presence of arsenic in the ground water with the ponds.

“Arsenic is in the water and Dominion put it there,” said Nachy Kanfer, acting eastern regional director of the Sierra Club’s Beyond Coal campaign. “But the court found we could not bring an enforcement action under the Clean Water Act to address that pollution.”

Kanfer pointed to similar suits aiming to consider coal ash ponds point sources that were heard in Kentucky and Tennessee and have worked their way into higher courts in those regions. He said he attended 6th Circuit hearings in those cases and the judges seemed interested in understanding the matter.

“This decision is not the last word on the matter,” he said.