title: Temporal and spatial trends of PCB congeners in UK gannet eggs.
abstract: Gannet (Sula bassana) eggs collected from Ailsa Craig, Western Scotland between 1977-1998 have been analyzed retrospectively for several PCB congeners. Concentrations of a range of congeners were determined in 8-10 eggs analyzed separately for several individual years. All congeners declined in concentrations throughout the time period, but the rates of decline differed for different congeners. Declines were first order and half-lives varied between 5.4 years for PCB-101 to 10.1 years for PCB-180. Egg concentrations reflect the maternal body burden, which itself is controlled by the birds rate of intake (principally via the diet) and losses (via metabolism and other clearance mechanisms). The declining concentrations in eggs, therefore, broadly reflect reductions in prey concentrations (principally herring and mackerel) and--in turn--water column concentrations. Rates of change in PCB concentrations from this study were similar to those noted in fish-eating birds from the Baltic Sea and North American Great Lakes, and ambient air in the UK. This provides indirect evidence that gannet eggs are broadly reflecting regional/global scale clearance/removal mechanisms which are controlling ambient PCB concentrations.
authors.affiliation: Department of Environmental Science, Institute of Environmental and Natural Sciences, Lancaster University, Lancaster, LA1 4Yq, UK. r.alcock@lancaster.ac.uk
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Alcock
authors.forename: Ruth
authors.initials: R
authors.lastname: Boumphrey
authors.forename: Heath M
authors.initials: HM
authors.lastname: Malcolm
authors.forename: Daniel
authors.initials: D
authors.lastname: Osborn
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Jones
mesh_terms: D000818:Animals; D001717:Birds; D004032:Diet; D004531:Eggs; D004781:Environmental Exposure; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis*; D005399:Fishes; D020387:Food Chain; D006207:Half-Life; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D014018:Tissue Distribution; D006113:United Kingdom
chemical_list: D004785:Environmental Pollutants; D011078:Polychlorinated Biphenyls