Discovery and widespread occurrence of polyhalogenated 1,1'-dimethyl-2,2'-bipyrroles (PDBPs) in marine biota

Polyhalogenated 1,1′-dimethyl-2,2′-bipyrroles (PDBPs) are halogenated natural products (HNPs) previously shown to bioaccumulate in marine mammals and birds. Since their discovery in 1999, six hexahalogenated and a few lesser halogenated congeners have been identified in diverse marine mammal samples. Here we report the identification of 17 additional hexahalogenated PDBPs in the blubber extract of a humpback dolphin (Sousa chinensis) from Queensland, Australia. Thirteen of these new PDBPs were also detected in an Australian sea cucumber (Holothuria sp.). Additional samples were also tested positive on several new PDBPs, including an Australian venus tuskfish (Choerodon venustus) as well as a white whale (Delphinapterus leucas) and a sperm whale (Physeter macrocephalus) from the Northern Hemisphere. GC/ECNI-MS-SIM quantification of the molecular ions was carried out with the help of synthesized standards. The sum concentration of PDBPs was 1.1 mg/kg lipid in the humpback dolphin and 0.48 mg/kg lipid in the sea cucumber. •Polyhalogenated 1,1′-dimethyl-2,2′-bipyrroles (PDBPs) are natural products.•17 New hexahalogenated PDBPs were identified in marine biota from Australia.•A humpback dolphin (Sousa chinensis) contained 1.1 mg/kg lipid PDBPs.•New PDBPs were also detected in marine mammals from the Northern Hemisphere. Detection of new polyhalogenated 1,1′-dimethyl-2,2′-bipyrroles indicates a higher toxic risk of these halogenated natural products in the marine environment than previously known.