First Evidence of Environmental Formation of Sulfonated PCBs

Abstract

Several types of metabolites can be produced from the environmental degradation of PCBs such as OH-PCBs, sulfated PCBs, methoxylated PCBs, and others. However, while sulfonated and OH-sulfonated PCBs were recently found in soil, little information is available on their formation and their environmental path. In this study, the environmental formation of OH-sulfonated and sulfonated PCBs was shown for the first time in treatments using eight PCB congeners as a carbon source in a flask experiment. Here, 10 environmental inocula from different sources were tested to evaluate, in a semiquantitative way, the formation of OH-sulfonated and sulfonated PCBs. OH-PCBs were also monitored, as they represent one of the first degradation steps of PCBs. All inocula could generate these metabolites, although the number of congeners varied greatly. In general, OH-PCBs and OH-sulfonated PCBs were produced at the highest concentrations. For sulfonated PCBs, the highest number of congeners was produced from an inoculum derived from plant leaves and from a PCB-contaminated site. The results show that OH-sulfonated and sulfonated PCBs can be environmentally formed by microbial inocula, even by the generalist ones, not specifically selected in PCB rich environments.