Legacy industrial pollutants in the South American black bumblebee Bombus pauloensis inhabiting peri-urban and rural fields from the Argentinean pampas

Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants (POPs), banned worldwide due to their effects on biota. In South America, studies on POPs in wild bees, like Bombus pauloensis, a continentally widespread bumblebee, are lacking, and information on its health is limited. This study assessed, by GC-ECD, PCBs and PBDEs levels in B. pauloensis, flowers and soils from fields located at different distances from urban activities: PU and LF, two peri-urban fields near the local industrial park, with LF also next to an overloaded solid waste landfill, and RU, a rural field. For all matrices, the peri-urban fields registered significant higher pollutant levels compared to RU, especially in workers, where LF showed the highest ∑PCBs and ∑PBDEs levels (21.09 ± 2.57 and 10.29 ± 0.37 ng/g, respectively). In males, PU and LF showed the highest nominal ∑PCBs (PU; 24.97 ± 1.03 ng/g) and ∑PBDE (LF; 10.39 ± 0.77 ng/g) concentrations, which confirms the influence of the landfill. Across matrices, lighter PCB congeners dominated, possibly explained by the past use of PCB mixtures and atmospheric transport, and a biomagnification pattern was observed. PCB concentrations were similar to those proven to cause sublethal effects in bees, and males showed significantly higher POP levels than workers. Thus, drivers and population effects were discussed. This may be one of the first studies of industrial POPs in wild bees in South America, emphasizing the need to look beyond insecticides and unique castes in environmental exposure studies.