Persistent organic pollutants in killer whale (Orcinus orca) from Argentina

GERPE, MARCELA; LOUREIRO, JUAN PABLO; DE LEÓN, MARTA CAROLINA; MIGLIORANZA, KARINA

Valdivia

Congreso; Reunión Latinoamericana de SETAC (Society of Environmental Toxicology and Chemistry) - 14th Biennial Meeting; 2021

The killer whale (Orcinus orca) is a cosmopolitan marine top predator species, even preying on other marine mammals. This characteristic and the magnification of POPs in their trophic food web, it is responsible for the high accumulation in the species. The levels of POPs, mainly polychlorinated biphenyls (PCBs), have been evaluated by several authors, because they represent a threat to different populations, even the data have been modeled to estimate the risk. Three killer whales stranded in northern Argentina, two females (estimated age < 10 years, and < 15 years) and one male (estimated age < 15 years) were analyzed. Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were analyzed by GC-ECD in blubber, skin, liver, kidney, muscle, intestine (wall and content). Total OCPs showed higher concentrations than PCBs. Blubber showed the highest levels of both POPs groups, followed by liver/kidney, muscle/intestine wall and skin. The concentrations pattern of OCP was DDTs > drins heptachlors> endosulfans > chlordans > HCHs. DDE had a detection frequency of 100% in all tissues and specimens, with maximum levels in blubbler (688.9 ± 162.3 ng·g -1 , ww), while DDT only in one blubber sample; usually in marine mammals DDE is the main compound of DDT group, evidencing its capacity to biotransformation. Among HCH group, only α- and β-isomers were found, with a predominance of β-HCH in tissues and levels. Among 40 PCBs congeners, three dioxin-like (mono-ortho- substituted #118, #156 and #167) were found, and #118presented the highest levels. Similar to OCPs, PCBs showed the maximum concentrations in blubber (total PCB concentration 788.8 ± 203.0 ng·g -1 , ww), and they were present in 100% of samples. A predominance of 5-CB and 6-CB was observed in all analyzed tissues. These results indicate that despite the forbidden use of POPs, a bioaccumulation of PCBs and legacy OCPs were found in killer whales from Argentina, as it was reported for specimens fromother geographical regions of the world.