Organochlorine concentrations in franciscana dolphins, Pontoporia blainvillei, from Brazilian waters

► Regarding DDTs, p,p′-DDE predominated in all samples. ► There was predominance of PCB-153, followed by PCB-138. ► The ΣDDT/ΣPCB ratio varied between 0.27 and 0.42 in Northern and Central SP coast. ► The ΣDDT/ΣPCB ratio varied between 1.6 and 1.9 in Southern SP and Paraná coast. ► Results suggest different sources of organochlorine compounds to franciscana dolphins.