2,4,6,8-Tetrachlorodibenzothiophene in the Newark Bay Estuary: The likely source and reaction pathways

Historic industrial activity along the Newark Bay Estuary has resulted in pollution from a number of contaminants; one of which is 2,4,6,8-tetrachlorodibenzothiophene (2,4,6,8-TCDT), a unique chemical contaminant whose origins have not been adequately explained. This research demonstrates that the probable source of 2,4,6,8-TCDT was the chlorination of phenol produced via the sulfonation method. Thiophenol, the major impurity in this type of phenol, was likely converted to 2,4,6,8-TCDT through one or more pathways during the production of 2,4-dichlorophenol, 2,4-dichlorophenoxyacetic acid (2,4-D), or 2,4,6-trichlorophenol. From a mass balance standpoint, production of these chemicals at an industrial plant along the Passaic River could account for the 2,4,6,8-TCDT in the Newark Bay Estuary.