Distribution and partitioning of organic pollutants and effects in coastal birds
- Autores: Joana Vicente de Bobes
- Directores de la Tesis: Agustín Sánchez-Arcilla Conejo (dir. tes.), Silvia Lacorte Bruguera (dir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2013
- Idioma: inglés
- Tribunal Calificador de la Tesis: Anna Rigol Parera (presid.), Carles Barata Martí (secret.), Rafael Mateo Soria (voc.)
- Materias:
- Enlaces
- Tesis en acceso abierto en: TDX
- Resumen
Coastal areas are very susceptible to contamination due to the interaction of marine and anthropogenic processes. Persistent Organic Pollutants (POPs) are organic compounds very resistent to photolysis and chemical and biological degradation. According to its physicochemical characteristics, POPs are worldwide distributed. These contaminants tend to bioaccumulate through the food webs, so that predators are more sensitive to this contamination. Seabirds are highly exposed to organic pollutants due to their feeding habits and its relatively long life. In this thesis, it has been studied the accumulation of various families of organic pollutants in two species of gulls breeding in the Iberian Peninsula, the yellow-legged gull (Larus michahellis) and Audouin's gull (L. audouinii). Yellow-legged gull is a large gull very common in the Iberian Peninsula. It is an omnivorous and opportunistic species. Audouin's gull is endemic of the Mediterranean region. Few years ago it was endangered but the great population growth made to be considered now as "nearly threatened" species. It is a piscivorous species but it is increasingly exploiting more fishery discards and continental preys. In the first study there are determined 6 families of organic pollutants considered by the Stockholm Convention (PCDD/Fs, PBDEs, PCBs, OCs, PFASs and SCCP) in eggs of the two gull species from the Ebro Delta Natural Park. In the following studies, the analyses are based on the study of PFASs in eggs and blood of both gull species and from different colonies of the Iberian Peninsula (Ebro Delta, Medes Islands, Columbretes Islands, Dragonera Island, Grosa Island, Chafarinas Islands, Atlantic Islands of Galicia and Berlengas Islands). From PFASs levels found in the different matrices the effect of these pollutants on physical (biometric parameters of egg, shell thickness and desiccation index) and hormonal level (through the analysis of the steroid hormones: testosterone and 17ß-estradiol) is studied. It is also assessed the accumulation of these pollutants from the diet of both species (analyzing their own food and through the study of the stable isotopes d13C and d15N, as dietary tracers) and it is estimated the PFASs depuration in blood and its transfer from females to eggs. The results indicate that organic pollutants are present in the populations of yellow-legged and Audouin's gull breeding in the Iberian Peninsula colonies, being OCs and PCBs the families of compounds with higher concentrations. Among PFASs, the main compound detected in all samples was PFOS. The transfer of organic contaminants from mother to offspring is demonstrated with the levels found in eggs of both species. Analysis of PFASs in blood of males and females shows that females discharge a fraction of the compounds accumulated to the eggs, thus females had lower blood PFASs levels than males. However, the study of hormonal level allows the comparison between the levels in both gull species and with other studies and to discuss the influence of the different diet. The analysis of PFASs in albumen and egg suggests that these compounds have more affinity for egg-yolk lipids because they are not detected in albumen. The decreasing concentration of PFOS along the egg sequence shows that females PFOS transfer is higher in the first egg but there is also a good correlation between the levels of PFOS among the 3 eggs from the same clutch. The higher concentrations of some PFASs in 3rd eggs (c), comparing with 1st (a) and 2nd (b), and the differences in d13C values between the a-b and b-c eggs are attributed to the "mother effect". This thesis permits increase the knowledge about the accumulation of POPs in yellow-legged and Audouin's gull from the Iberian Peninsula, to evaluate the differences between the two species and determine the geographical distribution of POPs using eggs as a biomarker of environmental contamination and to study the processes of accumulation and transfer of PFAS
