Perfluoroalkyl and polyfluoroalkyl substances in entire clutches of Audouin's gulls from the ebro delta

Abstract The aim of the present study was to determine the distribution of per- and polyfluoroalkyl substances (PFASs) in three-egg clutches of Audouin’s gull ( Larus audouinii ) breeding in Ebro Delta’s colony according to the laying order (a, b and c eggs). Five PFASs were analyzed in 30 eggs (yolk and albumen separately), corresponding to 10 three-egg clutches. Carbon and nitrogen stable isotopes were measured as dietary tracers. PFASs were not detected in albumen. In egg yolks, perfluorooctane sulfonate (PFOS) was the main compound detected followed by perfluorononanoic acid (PFNA), perfluorohexane sulfonate (PFHS) and perfluorooctanoic acid (PFOA). Perfluorooctane sulfonate (PFBS) was not detected. Mean ΣPFASs for a-eggs was of 236 ± 57 ng g −1 yolk wet weight (ww), for b-eggs was of 140 ± 56 ng g −1 yolk ww and for c-eggs, 133 ± 54 ng g −1 yolk ww. PFOS concentration decreased according to the laying order of the eggs, showing significant differences between consecutive eggs. In addition, significant correlation ( r s 2  = 0.7–0.9) was observed for PFOS concentration within the eggs from the same clutch. No relationship was found between PFOS levels and stable isotopes signatures. Capsule: In Audouin gull’s eggs, PFOS was the main PFASs detected and its concentration decreased according to the laying sequence.