In addition to the authority of the State Air Pollution Control Board, the State Water Control Board, the Virginia Waste Management Board and the Director to bring actions in the courts of the Commonwealth to enforce any law, regulation, case decision or condition of a permit or certification, the Attorney General is hereby authorized on behalf of such boards or the Director to seek to intervene pursuant to Rule 24 of the Federal Rules of Civil Procedure in any action then pending in a federal court in order to resolve a dispute already being litigated in that court by the United States through the Environmental Protection Agency.