title: Contaminant exposure of barn swallows nesting on Bayou d'Inde, Calcasieu Estuary, Louisiana, USA.
abstract: Current and historical point source discharges, storm water runoff, and accidental spills have contaminated the water, sediment, and biota within the Calcasieu Estuary in southwestern Louisiana. In 2003, barn swallow (Hirundo rustica) eggs and nestlings were collected beneath two bridges that cross Bayou d'Inde, the most contaminated waterway within the Calcasieu Estuary. Samples were also collected from a bridge over Bayou Teche, a reference site in south central Louisiana. Polychlorinated biphenyl (PCB) concentrations in barn swallow eggs and nestlings were significantly higher at the downstream site on Bayou d'Inde (2.8 micro g/g PCBs in eggs and 1.5 micro g/g PCBs in nestlings) than at the other two sites (< 0.2 micro g/g PCBs in eggs and nestlings at both sites). Ethoxyresorufin-O-dealkylase activity in nestling livers was significantly higher at the downstream site on Bayou d'Inde (50 pmol/min/mg) compared to the other two locations (24 pmol/min/mg, each), probably because of exposure to PCBs. Polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran concentrations in eggs and polycyclic aromatic hydrocarbons in nestlings were at background concentrations at all sites. Trace element concentrations in barn swallow eggs and nestling livers were at background levels and did not differ among the three sites. A biomarker of DNA damage did not differ among sites.
authors.affiliation: U.S. Geological Survey, Upper Midwest Environmental Sciences Center, 2630 Fanta Reed Road, La Crosse, WI 54603, USA. tcuster@usgs.gov
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Custer
authors.forename: Christine M
authors.initials: CM
authors.lastname: Custer
authors.forename: Buddy L
authors.initials: BL
authors.lastname: Goatcher
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Melancon
authors.forename: Cole W
authors.initials: CW
authors.lastname: Matson
authors.forename: John W
authors.initials: JW
authors.lastname: Bickham
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D019363:Cytochrome P-450 CYP1A1 / Q000032:analysis; D004249:DNA Damage; D004781:Environmental Exposure; D004784:Environmental Monitoring; D006843:Hydrocarbons, Chlorinated / Q000032:analysis* / Q000592:standards / Q000633:toxicity; D008099:Liver / Q000201:enzymology; D008145:Louisiana; D009425:Nesting Behavior; D010063:Ovum / Q000737:chemistry* / Q000187:drug effects; D046388:Swallows / Q000502:physiology*; D014131:Trace Elements / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000592:standards / Q000633:toxicity
chemical_list: D015415:Biomarkers; D006843:Hydrocarbons, Chlorinated; D014131:Trace Elements; D014874:Water Pollutants, Chemical; D019363:Cytochrome P-450 CYP1A1