Validation and application of an analytical method for determination of Persistent Organic Pollutants in Rainbow trout (Onchorhynchus mykiss) collected from Tehran retail markets

Persistent organic pollutants are a wide group of toxic and dangerous compounds. These organic compounds are chemically and physically stable even beams. In this study an analysis method for simultaneous determination of 18 persistent organic pollutants including eleven Organochlorine pesticides (OCPs): HCB, Dieldrin, Methoxychlor, α-, ϒ-Chlordane, α-, β-Endosulfan and o,p’-DDE, p,p’-DDE, o,p’-DDT, p,p’-DDT and seven indicator Polychlonitated biphenyls (PCBs); IUPAC nos.: 28,52,101,118,138,153,180 congeners were determined in Rainbow trout by GC-MS/MS in MRM monitoring mode and LLE extraction. The validation results showed the calibration curves over the concentration range of 0.1-30 ng/mL for PCBs and 0.5-150 ng/mL for OCPs were linear and coefficient of determination (r2) ranged between 0.990-0.999. The LODs and LOQs for POPs studied were between 0.6-8.3 and 2-25 ng/g, respectively. The average recoveries obtained for analytes in five different spiked levels (1-10 ng/g for PCBs and 5 times for OCPs) were in the range of 73%-112%. The relative standard deviations of POPs in fish were in the range of 1.4-17.9% for all of the concentration levels. The ranges of uncertainty were reported between 2.77%-30.88%. The results indicated the presence of organochlorine pesticides in trout samples and the highest level of contamination was related to p,p’-DDT with average values of 113 ng/g ww (wet weight). Dieldrin and p,p’-DDE were among the next level of contamination with mean values of 13.3 and 10 ng/g ww, respectively. Study of other OCPs in the trout samples indicated the presence of α-, ϒ-Chlordane, o,p’-DDE, o,p’-DDT and HCB in which the amount were lower than the limit of quantitation (LOQ) of the method. OCPs residues were lower than maximum residue levels set by European Council Directives, SANTE (2017) No.11813. Also, the study of PCBs in trout samples indicated the presence of only PCB 28 and its amount was lower than maximum residue levels set by European Commission Regulation (EU) (2017) No.644.