Brominated flame retardants and polychlorinated biphenyls evaluation on Portuguese shrimp samples

Introduction: Brominated Flame Retardants (BFRs) and Polychlorinated Biphenyls (PCBs) are persistent organic pollutants. BFRs are mixtures of man-made chemicals applied to reduce the flammability of polymers and PCBs have been widely used as dielectric fluids in capacitors and transformers and paints. The harmful health effects of these chemicals can be related to their persistency, bioaccumulation and biomagnification potential1,2. They have the capacity to accumulate in animal fats including aquatic species3. BFRs and PCBs can act as endocrine disruptors and the continuous human exposure to them are associated with several disorders. Shrimp are one of the most popular consumed seafood in the world and can be a healthy addition to our diet, They are rich in proteins and omega-3 fatty acids4. However, they can also accumulate pollutants such as BFRs and PCBs. Experimental: Palaemon serratus and Palaemon varians shrimp species were collected in Portugal. P. serratus was collected along the Portuguese coast (namely in Vila do Conde, Matosinhos, Aveiro, Ria de Aveiro and Figueira da Foz) by local fishermen and P. varians (wild and aquiculture origin) was collected in Sado estuary. BFR and PCB residues were extracted by Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) methodology. The extent of the contamination was reached through the quantification of twelve BFRs, seven PBDE congeners: BDE 28, BDE 47, BDE 99, BDE 100, BDE 153, BDE 154, BDE 183 and five novel BFRs: TBECH, PBT, PBEB, TBB, and BTBPE. And thirteen PCBs: PCB 28, PCB 52, PCB 101, PCB 77, PCB 118, PCB 114, PCB 153, PCB 138, PCB 126, PCB 156, PCB 157, PCB 180, PCB 169 and 5′- fluoro-2,3′,4,4′,5-pentabromodiphenyl ether as internal standard (IS), using gas chromatography (GC) coupled with electron-capture detector and confirmation was performed using GC coupled with mass spectrometric detector. Briefly, shrimp’s edible portions were mechanically homogenized, 5 g were weighted, and the IS solution was added to a final concentration of 50 μg/L. Next, 8 mL of ACN were added to the shrimp, followed vortex homogenization for 3 min. QuEChERS AOAC was added and the mixture was again vortexed for 3 min and then centrifuged at 4000 rpm during 5 min. Afterwards, 1 mL of supernatant was transferred to a 2 mL tube containing the clean-up sorbents (150 mg anhydrous magnesium sulphate, 50 mg PSA, 50 mg C18 and 2 mg graphitized carbon black). The tubes were vortexed for 2 min followed by centrifugation at 4000 rpm for 5 min. An aliquot of the supernatant 600 μL was transferred to a vial and concentrated just to dryness using a gentle stream of nitrogen. The sample residue was reconstituted in 150 μL of n-hexane and injected in the GC for analysis. Conclusions: The QuEChERS method applied in this study proved to be a good choice for the analysis of BFRs and PCBs in shrimps; Good recoveries were achieved for BFRs and PCBs (between 65% and 91%), with exception of 136% for BDE 47; Method detection limits for BFRs and PCBs were between 1.1 and 3.7 ng/g ww; Method quantification limits for BFRs and PCBs were between 3.6.0 and 12.3 ng/g ww; BFRs and PCBs were not detected in any shrimp sample from Portuguese coast analyzed.