title: Influence of diet in the accumulation of organochlorine compounds in herons breeding in remote riverine environments.
abstract: The composition of organochlorine compounds (OCs), pentachlorobenzene (PeCB), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), DDTs and polychlorobiphenyls (PCBs), has been analyzed in eggs from cattle egret (Bubulcus ibis) and little egret (Egretta garzetta), two species of herons (family Ardeidae), nesting at the same remote riverine environment (Aiguabarreig, Ebro River). These two species were selected to evaluate the importance of diet in the accumulation of OCs. Cattle egret essentially feeds on dry grassy habitats and follow cattle or other large animals whereas little egret feeds on fish, amphibians and crustaceans captured in shallow waters. The δ(15)N and δ(13)C isotopic composition of the sampled eggs was studied and the results were consistent with these species feeding habits. In both species, the compounds accumulated the most were the less volatile and more lipophilic, e.g. PCB congeners of higher chlorination, DDT and metabolites. The distinct foraging species preferences were reflected in significant higher concentrations in little egret than cattle egret of all pollutant groups analysed. These differences were statistically significant for DDTs and PCBs (p < 0.015 and p < 0.047, respectively), e.g. the p,p'-DDE and PCB concentrations were 6 and 4.5 times higher, respectively, in the former than the latter. This strong contrast indicates that in remote environments aquatic riverine ecosystems are more efficient OC reservoirs than the terrestrial ecosystem.
authors.affiliation: Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18-26, 08034 Barcelona, Catalonia, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Huertas
authors.affiliation: Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18-26, 08034 Barcelona, Catalonia, Spain. Electronic address: joan.grimalt@idaea.csic.es.
authors.forename: Joan O
authors.initials: JO
authors.lastname: Grimalt
authors.affiliation: Department of Public Health, Faculty of Medicine, University of Barcelona, Casanova 143, 08036 Barcelona, Catalonia, Spain.
authors.forename: Lluis
authors.initials: L
authors.lastname: Jover
authors.affiliation: Department of Animal Biology, Faculty of Biology, University of Barcelona, Av. Diagonal 645, 08028 Barcelona, Catalonia, Spain.
authors.forename: Carola
authors.initials: C
authors.lastname: Sanpera
mesh_terms: D000818:Animals; D001717:Birds / Q000378:metabolism*; D002247:Carbon Isotopes / Q000032:analysis; D004032:Diet; D004784:Environmental Monitoring; D006843:Hydrocarbons, Chlorinated / Q000378:metabolism*; D009587:Nitrogen Isotopes / Q000032:analysis; D010063:Ovum / Q000737:chemistry; D045483:Rivers; D013030:Spain; D013045:Species Specificity; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D002247:Carbon Isotopes; D006843:Hydrocarbons, Chlorinated; D009587:Nitrogen Isotopes; D014874:Water Pollutants, Chemical
keywords: Diet; Egrets; Herons; Organochlorine compounds; Riverine systems; Stable isotope composition