PCB sources and degradation in sediments of Ashtabula River, Ohio, USA, determined from receptor models.

The PCB pollution in Ashtabula River sediments was evaluated using a factor analysis (FA) model with non-negative constraints, and a chemical mass balance (CMB) model. The FA model identified Aroclor 1248 as the major PCB source, and also a congener pattern significantly different from that of any Aroclor. The CMB model that uses linear combinations of Aroclors, failed to reproduce the sample congener profiles with good statistical fit. The findings from both models indicate that the PCBs in Ashtabula River sediments have undergone significant alterations changing their profiles from those of the original sources. These alterations may be explained by the anaerobic dechlorination of highly chlorinated congeners, according to dechlorination activities H/H'.