In the northeastern Barrens lies a pool of water sickened by pollution.  The locals call it the Sludge Fen; the Venture Company has turned the once crystal-blue waters into a mire of industrial byproducts and waste.  In the heart of this fen lies what you seek, $N.$B$BBe warned - the Venture Company does not tolerate trespassers, and they consider anyone who does not work for them as such.  You'll especially be a target as a protector of nature, something they vehemently oppose.