A federal judge has rejected city of Evanston’s claims that pollutants in a public park and near a water main pose an imminent threat.U.S. Judge John Z. Lee has denied an injunction sought by Evanston that would have forced Commonwealth Edison and Northern Illinois Gas Co. to investigate and clean up waste alleged to have come from a long-abandoned oil pipeline.In a 45-page decision, the court ruled the city couldn’t prove the materials, methane gas and compounds known as polycyclic aromatic hydrocarbons, or …