Barcelona (Freddie Mercury and Montserrat Caballé song) sessions. The song was co-written by Mercury with Mike Moran, who also appeared in its video and played piano and all keyboards for the studio recording. The song starts with an orchestral introduction, which fades and is followed by Mercury and Caballé singing alternately their solo lines, sometimes merging into a duet. When singing the chorus "Barcelona" and a few other parts for the studio version, Mercury dubs over his voice in his usual multi-tracking style. Mercury leads the song whereas Caballé provides a powerful "background" soprano. Since Caballé covers the soprano part, Mercury sings in his natural baritone voice
Mercury in fish plant emissions. Chlorine chemical plants use mercury to extract chlorine from salt, which in many parts of the world is discharged as mercury compounds in waste water, though this process has been largely replaced by the more economically viable membrane cell process, which does not use mercury. Coal contains mercury as a natural contaminant. When it is fired for electricity generation, the mercury is released as smoke into the atmosphere. Most of this mercury pollution can be eliminated if pollution-control devices are installed. Mercury in the United States frequently comes from power plants, which release about 50% of the nation's