Evaluation of toxicity and sex-related variation of PCB levels in Mediterranean striped dolphins affected by an epizootic

Individual PCB congener concentrations, including non-ortho chloro substituted, were determined in 30 striped dolphins (Stenella coeruleoalba) affected by the 1990–1992 Mediterranean epizootic to investigate their toxic potential. PCB congener concentrations in these dolphins were among the highest ever found in comparable studies on marine mammals. Concentrations in males and females were significantly different because of pollutant transfer to offspring by females. Thus, PCB concentrations and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalents (TEO) in males were approximately double those in females. Non-ortho, mono-ortho and di-ortho coplanar congeners accounted for approximately one third of the overall toxicity assessed through toxic equivalent factors (TEFs), as defined by Ahlborg et al. (1994). Di-ortho congener 170 and non- ortho congener 126 were the major contributors to TEQ (33% and 30% respectively).