title: External heart deformities in passerine birds exposed to environmental mixtures of polychlorinated biphenyls during development.
abstract: Necropsy-observable cardiac deformities were evaluated from 283 nestling passerines collected from one reference site and five polychlorinated biphenyl (PCB)-contaminated sites around Bloomington and Bedford, Indiana, USA. Hearts were weighed and assessed on relative scales in three dimensions (height, length, and width) and for externally visible deformities. Heart weights normalized to body weight (heart somatic index) were decreased significantly at the more contaminated sites in both house wren (Troglodytes aedon) and tree swallow (Tachycineta bicolor). Heart somatic indices significantly correlated with log PCB concentrations in Carolina chickadee (Parus carolinesis) and tree swallow and with log 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalent values in tree swallow alone. Ventricular length was increased significantly in eastern bluebirds (Sialia sialis) and decreased significantly in Carolina chickadee and tree swallow from contaminated sites versus the reference site. Heart length regressed significantly against the log PCB concentrations (Carolina chickadee and tree swallow) or the square of the PCB concentrations (red-winged blackbird [Agelaius phoeniceus]) in a sibling bird. The deformities that were observed most at the contaminated sites included abnormal tips (pointed, rounded, or flattened), center rolls, macro- and microsurface roughness, ventricular indentations on the ventral or dorsal surface, lateral ventricular notches, visibly thin ventricular walls, and changes in overall heart shape. A pooled heart deformity index regressed significantly against the logged contaminant concentrations for all species except red-winged blackbird. These results indicate that developmental changes in heart morphometrics and shape abnormalities are quantifiable and may be sensitive and useful indicators of PCB-related developmental impacts across many avian species.
authors.affiliation: Curriculum in Toxicology, University of North Carolina at Chapel Hill, Campus Box 7270, 256 Rosenau Hall, Chapel Hill, North Carolina 27599, USA.
authors.forename: Jamie C
authors.initials: JC
authors.lastname: DeWitt
authors.forename: Deborah S
authors.initials: DS
authors.lastname: Millsap
authors.forename: Ronnie L
authors.initials: RL
authors.lastname: Yeager
authors.forename: Steve S
authors.initials: SS
authors.lastname: Heise
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Sparks
authors.forename: Diane S
authors.initials: DS
authors.lastname: Henshel
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001835:Body Weight; D004781:Environmental Exposure; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000009:adverse effects*; D006256:Hazardous Waste; D006321:Heart / Q000254:growth & development; D006330:Heart Defects, Congenital / Q000139:chemically induced* / Q000662:veterinary*; D046109:Passeriformes / Q000002:abnormalities* / Q000254:growth & development; D011078:Polychlorinated Biphenyls / Q000009:adverse effects*
chemical_list: D004785:Environmental Pollutants; D006256:Hazardous Waste; D011078:Polychlorinated Biphenyls